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MINI-REVIEW
Efficient surface modification of biomaterial to prevent
biofilm formation and the attachment of microorganisms
Kateryna Bazaka &Mohan V. Jacob &
Russell J. Crawford &Elena P. Ivanova
Received: 9 January 2012 / Revised: 27 April 2012 / Accepted: 28 April 2012 / Published online: 18 May 2012
#Springer-Verlag 2012
Abstract Biomaterials play a fundamental role in disease
management and the improvement of health care. In re-
cent years, there has been a significant growth in the
diversity, function, and number of biomaterials used
worldwide. Yet, attachment of pathogenic microorganisms
onto biomaterial surfaces remains a significant challenge
that substantially undermines their clinical applicability,
limiting the advancement of these systems. The emergence
and escalating pervasiveness of antibiotic-resistant bacteri-
al strains makes the management of biomaterial-associated
nosocomial infections increasingly difficult. The conventional
post-operative treatment of implant-caused infections using
systemic antibiotics is often marginally effective, further
accelerating the extent of antimicrobial resistance. Meth-
ods by which the initial stages of bacterial attachment
and biofilm formation can be restricted or prevented are
therefore sought. The surface modification of biomaterials has
the potential to alleviate pathogenic biofouling, therefore
preventing the need for conventional antibiotics to be
applied.
Keywords Biomaterials .Surface treatment .Biofilm .
Bacterial attachment
Introduction
Whether they are intended to sustain functions and physio-
logical processes critical to life, to restore or preserve a level
of activity, for diagnosis of disease, treatment delivery,
tissue engineering, or to be used as a part of an elective
aesthetic procedure to improve contour and visual appear-
ance, biomaterials play an important role in disease man-
agement and in the advancement of health care (Tan et al.
2011; Van Vlierberghe et al. 2011; Ansari and Husain 2012).
Their applications range from being coatings on tablets and
capsules in pharmaceutical preparations, to being essential
components of extracorporeal devices such as contact lenses
or kidney dialyzers, and indwelling devices and implants
(Dorozhkin 2011; Wagoner and Herschler 2011). Their
chemical composition and physical and biological proper-
ties are equally diverse, with incessant advancements in
technology being driven by the increasing need to care for
an ageing population, with its associated need for extended
medical care (Hoppe et al. 2011; Khan and Sefton 2011;
Lewis 2011; Saito et al. 2011; Shadanbaz and Dias 2012).
An increasing human life expectancy places a strong em-
phasis on the need for the long-term, stable performance of
permanent devices and biomaterials used to replace host
tissues and organs (Cardoso et al. 2011; Gioe et al. 2011;
Kitao et al. 2011;Zhaoetal.2011). Concurrently, bio-
resorbable materials are gaining importance for the facilita-
tion of host tissue restoration. This is done as an alternative
to failed tissue replacement, hence overcoming any limita-
tions that might be imposed by the use of foreign structures
(Bendrea et al. 2011; Naderi et al. 2011). These limitations
include poor biocompatibility, causing inflammation, inad-
equate tissue integration, and non-haemocompatibility, and
time-dependent deterioration of properties (Donald 2011;
Sun et al. 2011).
K. Bazaka
Electronic Materials Research Lab, School of Engineering,
James Cook University,
Townsville, Queensland 4811, Australia
M. V. Jacob :R. J. Crawford (*):E. P. Ivanova (*)
Faculty of Life and Social Sciences,
Swinburne University of Technology,
PO Box 218, Hawthorn, Victoria 3122, Australia
e-mail: RCrawford@swin.edu.au
e-mail: EIvanova@swin.edu.au
Appl Microbiol Biotechnol (2012) 95:299–311
DOI 10.1007/s00253-012-4144-7
The development of infections in or around the indwelling
biomaterial devices, such as orthopaedic prostheses, urinary
tract and cardiovascular catheters, intraocular lenses and den-
tures, continues to be a key issue that hinders the utilisation of
these devices (Hanssen 2002; Montanaro et al. 2007). While
evidently detrimental to the healing process and overall well-
being of the patient, the attachment of bacterial cells, together
with the ensuing formation of a biofilm, may also impede the
performance of the device onto which they colonise (Liu et al.
2004;Stobieetal.2008). Schematization of the four-stage
universal growth cycle of a biofilm with common character-
istics, including initiation, maturation, maintenance, and dis-
solution is presented in Fig. 1. The functions that the biofilm
performs are vast, ranging from acting as a physical defence
barrier against phagocytic predation and preventing cell
detachment under normal flow conditions, to working as a
selective permeability barrier (Costerton et al. 1999;
Subbiahdoss et al. 2009). Physical and chemical permeability
ensures the effective transport of organic molecules and ions
to cells at distance from the surface of the biofilm, binding and
concentrating nutrients close to cells to ensure the survival of
the cell population (Decho 2000). The very same mechanism
limits the diffusion of agents that are damaging to the bacteria,
including the systemic antibiotics routinely used to treat post-
operative infections, and antibacterial agents leaching out
from the biomaterial matrix. In some instances, the inability
for conventional antibiotic therapies to make ready con-
tact with the bacteria leads to only partial suppression
of the infection, resulting in the development of chronic infec-
tions (Pavithra and Mukesh 2008). Elderly and immune-
compromised patients are particularly susceptible to the
development of sepsis, in some cases resulting in lethal
Fig. 1 The temporal evolution of a biofilm. Schematic representation
of the characteristic steps associated with the formation of a biofilm,
including initiation (I), maturation (II and III), maintenance (IV), and
dissolution (V). Pseudomonas aeruginosa cells present during these
steps are represented in the second row of images, the first three images
obtained using DAPI, followed by chromosomal GFP, then a LIVE/
DEAD BacLight kit, as observed with confocal microscopy. The S.
aureus attachment is presented in the third row, each obtained using
scanning electron microscopy. (From Bordi and de Bentzmann 2011,
used with permission)
300 Appl Microbiol Biotechnol (2012) 95:299–311
consequences. Furthermore, continuous exposure of bacteria
to high doses of conventional antimicrobials exerts a selective
pressure on these microorganisms, positively affecting their
ability to resist those broad-spectrum antibiotics (Andersson
and Hughes 2011; Freire-Moran et al. 2011). It is not surpris-
ing then, that treating biomaterial-associated infections can be
complicated, often demanding the physical (surgical) removal
of the infected device.
Clearly, follow-up surgeries resulting in the requirement
for extended hospital care are of no benefit to either the
patient or the already overburdened healthcare system.
Therefore, rather than addressing the consequence of bacte-
rial colonisation, scientists are searching for methods by
which the initial stages of bacterial attachment can be pre-
vented. This can be achieved via a synthesis of novel mate-
rials and composites with advantageous characteristics
integrated directly into the material matrix. A more econom-
ically attractive approach, however, is to enhance materials
that are already being used by the medical industry (Raynor
et al. 2009). Presently, numerous surface modification tech-
niques are under intense investigation for their ability to
effectively impart biocompatibility and biofunctionality on-
to a variety of biomaterials, while preserving their valuable
bulk properties and physical dimensionality (Fu et al. 2011;
Morent et al. 2011; Solouk et al. 2011; Vasilev et al. 2011;
Wu et al. 2011a). In this review, we will concentrate on the
methods currently being used to manipulate the nanoscale
surface architecture with a view to imparting bactericidal
activity onto the surface, and the effect of these modifica-
tions on bacterial attachment and biofilm formation. We will
first give a brief overview of the current opinion regarding
the factors that contribute to controlling cell–surface inter-
actions, with particular regard to the influence of the surface
micro- and nanotopographies on this process. We will then
review several instances where the deterministic modifica-
tion of a biomaterial surface has been successfully employed
in order to mitigate the extent of bacterial attachment and
biofilm formation. Finally, interesting developments in the
area of bactericidal biomaterial coatings will be discussed.
Cell-surface dynamics
Although concentrated research efforts have been made in
order to understand cell-surface dynamics, many of the
facets of these mechanisms remain unclear. There is a par-
ticular scarcity of theoretical and experimental evidence on
this topic on the nanometer and atomic length scales. Re-
cently, the advancement of manufacturing and characterisa-
tion techniques has equipped researchers with the necessary
tools for the effective investigation of the physico-chemical,
mechanical, and biological cues that affect cell–surface in-
terface dynamics (Desmet et al. 2009; Parreira et al. 2011).
The fundamental behaviour of living cells, including their
adherence to biomaterials, has been found to be intimately
linked to the surface properties of such a material and the
characteristics of the medium that separates the cells and the
substrate surface. The latter can either promote or impede
cell attachment, in part by influencing the characteristics of
the biomaterial surface, and by applying selective pressure
on the bacterial cells (Fig. 2) (Döring et al. 2011; Lee et al.
2011). Phenotypic plasticity in response to environmental
stimuli include turning regulatory genes on and off, thus
regulating the size, shape, metabolic rate, and the substances
that the cells excrete. In addition, these stimuli can cause the
production of diverse progeny with distinct phenotypes via
hypermutation and localized increased mutation rates
(Dobrzyński et al. 2011; Lele et al. 2011). Chemical com-
position, temperature, nutrient availability, presence of other
colonisers, the concentration of harmful substances (antimi-
crobials, metabolic by-products, and ions), and predation by
host immune cells are some of the environmental factors that
will directly impact the interface dynamics (Ardehali et al.
2002; Liu et al. 2011; Saldarriaga Fernández et al. 2011). For
instance, the flow conditions around a substrate surface have a
profound influence on the biofilm initiation, development, and
subsequent stability, by affecting the rate at which bacterial
cells are delivered to the surface, the time they reside in close
proximity to the surface, and the probability for the cell
detachment (Busscher et al. 2010). A significant decrease in
desorption probabilities have been demonstrated for bacteria
subjected to several minutes of direct cell−surface contact,
owing to the exponential increase in the adhesion forces,
namely, acid–base interactions, amongst cells and between
cells and the abiotic surface (Andrews 2009;Busscheretal.
2010). Similarly, the acidity and ionic strength of the physio-
logical solution have been shown to profoundly influence the
degree of hydrophobicity of the respective bacterial cell and
abiotic target surfaces, and as such on the strength of the
electrostatic interactions within biofilm architecture (Pavithra
and Mukesh 2008). Even though a precise understanding of
the role that the medium plays is essential for adequate cell–
surface interface characterisation and indeed, it can be effec-
tively controlled for in vitro three-dimensional tissue forma-
tion, it is not the case for in vivo biomaterial utilisation.
Over the past few years, a variety of advanced nanotechno-
logical tools have become available that allow for a high
degree of manufacturing control over the surface character-
istics of biomaterials. These have the potential to be used to
effectively modulate the cell response (Fu et al. 2011;Morent
et al. 2011;Solouketal.2011; Vasilev et al. 2011;Wuetal.
2011a). It is well established that both the stability of cell
attachmentand the dynamics of the colonisation process differ
with surface architecture, chemical composition, and surface
energy of the material, and how these compare to the
bacterium-specific factors. The bacterium-specific factors
Appl Microbiol Biotechnol (2012) 95:299–311 301
include the hydrophobicity, surface energy, and electrophoret-
ic mobility of the microorganism, and the existence of extra-
cellular appendages, such as pili and flagella (Donlan 2002;
Dorobantu et al. 2009). The nature of extracellular polymeric
substances (EPS), the level of secretion, and the manner in
which these undergo changes in spatial conformation and
structural arrangement in response to the nanoscopic features
of the abiotic surface also influence cell–surface interactions
(Cappella and Dietler 1999). Although obtaining a complete
description of an EPS biochemical profile would be a
challenge, most EPS is known to be comprised of a wide
range of polysaccharides, proteins, glycoproteins, and glyco-
lipids, and in some cases, substantial amounts of extracellular
DNA (Flemming et al. 2007; Flemming and Wingender
2010). Recently, the structural and functional diversity of
bacterial extracellular polysaccharides, together with their
effect on the colonisation, survival and pathogenicity of bac-
teria, have been reviewed (Bazaka et al. 2011b). The paper
highlighted the difficulties associated with obtaining a
detailed physico-chemical analysis of bacterial extracellular
carbohydrates, owing to the diversity of sugar monomers,
linkages, and unique structures present in the carbohydrate
fraction of the EPS, and the complexities associated
with the isolation of individual polysaccharides from
environmental biofilms. The biochemical composition of the
EPS is also dependent on the maturity of the microbial com-
munity, as well as the local physico-chemical environment
(Shenga et al. 2010). Jiao et al. (2010)showedthattheEPS
obtained from a mid-developmental stage and a mature
acidophilic microbial biofilm were both qualitatively and
Fig. 2 a Formation of a biofilm by Staphylococcus aureus on poly-
vinylchloride in response to various charged molecules and glycosa-
minoglycans. The asterisk shows the statistical difference (p< 0.01)
from a saline-only control. bEffect of heparin, which is frequently
used as an anticoagulant coating for catheters, on the adherence kinet-
ics of S. aureus. Sodium heparin (1,000 U/ml, 10 % vol/vol) stimulated
biofilm formation of S. aureus on polystyrene and polyvinylchloride.
Microscopic images of the S. aureus biofilms incubated with and
without heparin. Scanning electron micrographs of 12-h biofilm (c
and d, ×12,500 magnification, bar010 μm). Phase-contrast microsco-
py of 4-h biofilms on polystyrene (eand f, bar020 μm; the arrow
indicates a phase-bright microcolony), and epifluorescent microscopy
(gand h, Styo-9 fluorescent staining, 250-ms exposure, ×400 magni-
fication). Epifluorescent microscopy (iand j, ×100 magnification,
calcofluor staining) of 5-h biofilms. (From Shanks et al. 2005, used
with permission)
302 Appl Microbiol Biotechnol (2012) 95:299–311
quantitatively different, with more than twice as much
EPS being present in the mature biofilm. The presence
and relative concentrations of carbohydrates, metals, pro-
teins, and minor quantities of DNA and lipids, were also
different between the two biofilm stages.
Pseudomonas aeruginosa is a model biofilm-forming
bacteria, with many extrapolations commonly being made
from observations of P. aeruginosa biofilm behavior and
properties to biofilms in general (Flemming et al. 2007).
However, recent studies have shown that such an extrapo-
lation may be highly misleading. Even within a single
species of bacteria, there is a high degree of extracellular
polysaccharide diversity. For instance, a polyanion polysac-
charide, alginate, is the best-characterized component of P.
aeruginosa biofilms. The other two biofilm-related polysac-
charides produced by the microorganism are Psl and Pel.
Early studies of mucoid P. aeruginosa biofilms positively
correlated the surface-dependent induction of algC expres-
sion with attachment stability, with cells not exhibiting algC
up-expression shown to be less capable of remaining at a
surface under flow conditions (Davies and Geesey 1995).
Subsequent studies demonstrated that non-mucoid P. aeru-
ginosa strains, which are thought to be the first to colonize
cystic fibrosis patients, were not reliant on alginate for
biofilm development (Petrova and Sauer 2012). Similar
specificity has been demonstrated for Pel, which is crucial
for maintaining cell–cell interactions; it acts as a primary
structural scaffold for the PA14 biofilm community (Colvin
et al. 2011). Deletion of pelB in this strain resulted in a
severe biofilm deficiency due to an impaired extent of
monolayer formation, with little effect on the ability of
PA14 cells for biofilm initiation being observed. On the
other hand, in PAO1 strain, Psl was demonstrated to be the
primary structural polysaccharide for biofilm maturity, with
deletion of pel operon having no effect on PAO1 attachment
or biofilm development (Colvin et al. 2011). Disruption of
pslA and pslB, however, severely compromised the initiation
of biofilm formation by a P. aeruginosa PAO1 strain, sug-
gesting that expression of psl plays a notable role in cell–
surface and intercellular interactions (Ma et al. 2006). Other
polysaccharides produced by Pseudomonas spp., such as
levan and other yet-to-be-identified exopolysaccharides,
may have an equally significant role in biofilm formation
(Laue et al. 2006).Extracellular DNA has been shown to
contribute to biofilm formation by PAO1 P. aeruginosa
isolates (Whitchurch et al. 2002; Yang et al. 2007), as well
as by other bacterial species (Vilain et al. 2009); however,
the role of eDNA changed as biofilms evolved. It is not
surprising then, that genotypically distinct bacteria will have
notably different attachment preferences towards a surface.
By reconfiguring the spatial distribution of chemical
functionalities and nanoscale morphological features on
the surface of the biomaterials, it is possible to attenuate
the attachment, propagation, and biofilm formation. Poten-
tial uses for such surfaces extend beyond preventing bacte-
rial attachment to indwelling biomaterial devices and other
clinically relevant surfaces. The effect of surface hydropho-
bicity as a function of both surface chemistry and topogra-
phy on the attachment preferences of different bacterial
species has been discussed by Bazaka et al. (2011d). This
is due to focal adhesion sites of the microorganism being in
the range comparable to that of the nanoscale features of the
abiotic surface (Brunetti et al. 2010), and due to the fact that
surface attachment is a fundamental stage in biofilm devel-
opment and in the formation of chemical signalling path-
ways amongst bacterial cells (Hochbaum and Aizenberg
2010; Petrova and Sauer 2011). The environmental signals
and signaling pathways that regulate biofilm formation, the
components of the biofilm matrix, and the mechanisms and
regulation of biofilm dispersal, have been reviewedby Karatan
and Watnick (2009). A cell-to-cell communication system,
quorum sensing, is believed to regulate motility, adhesion,
cell-to-cell aggregation, and biofilm formation, as well as
virulence and metabolic activity in several bacterial species
(Bjellanda et al. 2012).
The surfaces of several animals and plants have been
studied for their behaviour, since they have evolved an
ability to prevent surface fouling even in environments that
are highly populated by biofilm-forming microorganisms.
The skin of whales, sharks, and dolphins remain clean of
bacteria, owing to a favourable fusion of surface chemistry
and micro- and nanoscopic topographies. Similarly, the hy-
drophobic chemistry of Nelumbo nucifera (lotus) leaf is
augmented by a two-layer morphology, resulting in a super-
hydrophobic surface with low adhesion (Rios et al. 2006,
2007; Dodiuk et al. 2007; Bhushan et al. 2008). Materials
that mimic these naturally occurring surfaces are proving
equally useful in effectively averting bacterial fouling with-
out the need to use bactericidal agents and by providing a
research platform for investigating the cell–surface dynam-
ics. The former is important since it provides the means of
responsible management of disease, particularly in the con-
text of rapidly evolving antibiotic resistant pathogenic
strains (Baum et al. 2002; Chung et al. 2007; Fadeeva et
al. 2011). The latter is essential for intelligent surface design,
as it provides researchers with an understanding of how the
individualsurface characteristics ofan abiotic material interact
with the chemical and topographical particulars of surfaces of
living cells (Malkin and Plomp 2011).
It is important to note that alteration of individual prop-
erties, such as only the nanoscopic topography or chemical
functionality, is often difficult to achieve (Whitehead et al.
2010). First described by Wenzel (1949), there exists an
intimate link between the surface chemistry and topography
of a substrate, which becomes increasingly important as we
approach nanometer and sub-nanometer scale regimes. The
Appl Microbiol Biotechnol (2012) 95:299–311 303
relationship states that a chemically hydrophilic surface will
become increasingly more hydrophilic as the surface rough-
ness is increased. By the same reasoning, the wetting ability
of a hydrophobic surface decreases with increasing surface
roughness. Hence, the wetting behaviour and surface energy
of an abiotic surface are likely to change in response to
alterations in the chemistry and/or topography of a surface.
As a result, decoupling the contribution of a single variable,
such as surface roughness, from a bacterial response that is
invoked by a complex of material surface characteristics is
challenging. In part, this is due to the paucity of data exist-
ing for the fundamental behaviour of cells in a response to
physical environment at nanoscopic length scale (Anselme
et al. 2010;Bazakaetal.2011a). Finally, most surface
modifications are directed towards optimisation for a given
application, frequently modulating both surface chemistry
and topography.
Nanotopography and surface nanostructuring
As is the case with other external environmental stimuli,
there is little doubt that micro and nanoscale topographies
have an effect on the attachment behaviour and metabolic
activity of microorganisms (Bos et al. 1999). Yet, the extent
to which bacterial attachment and subsequent biofilm for-
mation is affected by the surface nanotopography remains a
subject of dispute (Anselme et al. 2010). Similarly, there are
vast differences in opinion regarding the length scale at
which the influence is most profound (An et al. 1995;
Boulangé-Petermann et al. 1997; Medilanski et al. 2002;
Whitehead et al. 2005,2006). In the literature, a number
of early studies determined surface topography to be a
comparatively insignificant factor in bacterial adhesion,
with microorganisms observed to have little predilection
for topographical cues (An et al. 1995; Bos et al. 1999;
Scheuerman et al. 1998). Subsequent investigations reported
afeature–cell size correspondence, where features of the size
comparable to the size of the bacterium allowed for max-
imisation of the bacteria–surface contact area, hence increas-
ing the microorganism’s binding potential (Katsikogianni and
Missirlis 2004). The same reckoning was applied to the inter-
pretation of reduced bacterial attachment to surfaces with
topographic attributes of smaller dimension than that of the
cell (Edwards and Rutenberg 2001). Regularity of the nano-
scopic features of the surface was also shown to alter bacterial
attachment preferences (Díaz et al. 2007; Rowan et al. 2002;
Rozhok et al. 2006; Whitehead et al. 2005). Surfaces with
regularly distributed pits of 1 and 2 μmweredemonstratedto
enhance the extent of attachment of P. aeruginosa and Staph-
ylococcus aureus, whereas topographies characterised by ir-
regularly scattered 0.2 and 0.5 μm did not instil the same
effect (Whitehead et al. 2005). The attachment patterns and
growth of pathogenic P. fluorescens and S. aureus were influ-
enced by the presence of defined trenches, within which cells
preferred to align and grow (Diaz et al. 2007;Harrisetal.
2004). On the other hand, a random cell distribution was
observed for smooth surfaces (Scheuerman et al. 1998;Diaz
et al. 2007). Similarly, an aligned attachment of Escherichia
coli cells was detected for surfaces with 1.3-μm-wide and
120-nm-deep microgrooves (Díaz et al. 2007) but not for
topographies containing grooves of 50 nm in height and
period of 1.6 μm(Plouxetal.2009).
Our own investigations into the role that surface proper-
ties play in bacterial cell adhesion, proliferation, and biofilm
development have shown that bacterial interactions with
materials are influenced by the level of surface roughness
and unique topographical peculiarities of that surface. A
variety of topographically distinct glass and polymer sub-
strates seeded with cells of taxonomically different bacteria
were investigated, with results showing enhanced attach-
ment and increased secretion of EPS for nanosmooth surfa-
ces irrespective of the microorganism species being used in
the study (Ivanova et al. 2008; Mitik-Dineva et al. 2008,
2009). In addition to being a major determinant of virulence
for numerous pathogenic bacteria, EPS impede antibody
opsonisation and phagocytosis, and induce inflammation
and aberrant complement activation that can be damaging
to host tissues (Bazaka et al. 2011b). Importantly, these
promote the colonisation of tissues and surfaces by enabling
cell adhesion and co-aggregation via dipole interactions,
covalent or ionic bonding, steric interactions, and hydropho-
bic association. Components of free EPS can be released
onto unfriendly surfaces, thus pre-conditioning the target for
subsequent colonisation. Indeed, Staleya guttiformis cells
were observed to excrete EPS to facilitate attachment to
poly(tert-butyl methacrylate) polymeric surfaces via the cre-
ation of biopolymer network (Ivanova et al. 2008). The size
and distribution of topographical peculiarities were also
demonstrated to be significant, with optical fibres etched
with regular features attracting lesser levels of bacterial
attachment compared to unmodified irregular topographies
(Mitik-Dineva et al. 2010).
Significant research efforts have been devoted to explor-
ing how metallic surface nanotopographies, such as those of
a titanium biomaterial, influence bacterial cell–surface dy-
namics. Excellent mechanical properties, biocompatibility,
and environmental stability make titanium and titanium
alloys a biomaterial of choice for a broad range of medical
applications, including orthopaedic and dental implants,
cardiac valves and in the microsurgical restoration of middle
ear function. Yet, similar to other implantable materials,
titanium surfaces are susceptible to bacterial colonisation
that is highly detrimental to the performance of the implant.
Furthermore, a reduction in the average grain size of titani-
um, imparted in order to improve mechanical strength,
304 Appl Microbiol Biotechnol (2012) 95:299–311
enhance the viability of mice fibroblast cells and accelerate
the proliferation of mice preosteoblastic cells (Estrin et al.
2009; Valiev et al. 2008), was also found to be susceptible to
a significant increase in levels of attachment of bacteria
(Truong et al. 2010a). Despite being chemically similar to
the pristine titanium, nanostructuring of the surface en-
hanced the hydrophilicity of the material. The complex
morphology of the nanostructured titanium surface was
designed to combine nanoscale smoothness with evenly
spaced 100- to 200-nm micro features. Despite some differ-
ences, S. aureus,P. aeruginosa,andE. coli cell attachment
was found to have increased appreciably on nanostructured
titanium compared to that of the nano-rougher untreated
sample, accompanied by contemporaneous increase in the
production of EPS and changes in cell morphology (Truong
et al. 2009). The result is contradictory to the finding of
other researchers that showed that preferential cell attach-
ment occurred on surfaces that were more hydrophobic
(Gottenbos et al. 2001). These results suggested that surface
nanotopography was indeed the major contributor to the
observed cell–surface dynamics (Truong et al. 2010b). Sub-
sequent experiments using magnetron sputter thin titanium
films with corresponding surface roughness parameters of
R
q
1.6, 1.2, and 0.7 nm confirmed an augmented attachment
response by S. aureus and P. aeruginosa, with 2- to 3-fold
increases in the number of retained cells and an elevated
level of EPS secretion being observed (Ivanova et al. 2010;
Truong et al. 2010c). Interestingly, the attachment of S.
epidermidis to titanium surfaces with an average roughness
between 0.43 and 1.25 nm was not influenced by the degree
of roughness (An et al. 1995).
Given the importance of titanium as a biomaterial,
there is a distinct need to design nanostructured metallic
surfaces that effectively limit bacterial attachment and
formation of complex biofilm communities, and hence
reduce the potential for implant-associated infections
and inflammations. Surface structuring, as a means to
achieve antifouling surfaces, has been identified as an
attractive solution for the long-term prevention of bac-
terial adhesion. The approach takes its inspiration from
a number of naturally occurring superhydrophobic sur-
faces that possess water-repellent, self-cleaning and anti-
icing properties due to a favourable combination of a
low intrinsic surface free-energy and a hierarchical
structural configuration (Webb et al. 2011). Such com-
plex hierarchical nanotopography can minimize the con-
tact area between an abiotic surface and the physiological fluid
containing bacterial cells, extending the maximum water con-
tact angles of 120° that can be achieved on a flat surface. A
number of fabrication techniques have been developed to
mimic these superhydrophobic surfaces, including vacuum-
ultraviolet lithography, e-beam lithography, soft lithogra-
phy, template lithography, templating from anodised alumina,
replica moulding, and microwave plasma-enhanced chemical
vapour deposition micropatterning (Fadeeva et al. 2009). Re-
cently, superhydrophobic (θ
W
0166°) titanium surfaces mim-
icking the surface of the lotus leaf were successfully
fabricated using a femtosecond laser-based micro- and
nanostructuring (Fadeeva et al. 2011). The resulting
surfaces were highly effective against P. aeruginosa,
greatly reducing the colonization propensity of the mi-
croorganism, whereas attachment of S. aureus cells was
enhanced by the presence of the superimposed nano-
and microtopography. The morphological dissimilarity,
with P. aeruginosa being a larger rod-shaped and S.
aureus being a smaller spherical cell, led to differences
in the surface contact area being achieved between the
respective cell and the surface, further influenced by the
ability of EPS to adequately anchor the cells to the
surface. The vastly distinct attachment preferences of
the two pathogens in response to the same surface
suggest that there exists the possibility to design top-
ographies that would selectively inhibit the attachment
and growth of one cell type while encouraging the
other. Structures that induce opposing response from
human versus pathogenic cells, such as osteoblasts and
Staphylococcus epidermidis (Colon et al. 2006)orE.
coli K12 (Ploux et al. 2009), respectively, are of particular
interest (Wu et al. 2011b). Since these have the capacity to
favour the competitive colonization by eukaryotic over bacte-
rial cells, such surfaces hold the potential to enhance biocom-
patibility and bacterial retardation of medical implants (Ploux
et al. 2010).
Bactericidal coatings
Bioactive coatings are becoming an increasingly attractive
solution for the prevention of biomaterial-associated infec-
tions, for they not only have the ability to inhibit bacterial
adhesion, but also to eliminate the attached pathogenic cells
that managed to overcome the antifouling property of the
surface (Fu et al. 2005; Gabriel et al. 2007; Norowski and
Bumgardner 2009; Zilberman and Elsner 2008). The latter is
achieved by means of releasing antibacterial agents, such as
antibiotics vancomycin, amoxicillin, and gentamicin, in a
controlled time-resolved fashion, thus inhibiting bacterial
growth at the implant site (Price et al. 1996; Stigter et al.
2004). However, with the quickly dwindling efficacy of
many systemic antibiotics and antiseptics and the speedy
rise of multi-resistant nosocomial bacteria (Madkour and
Tew 2008), alternative antimicrobial agents are being inves-
tigated. These include silver ions (Kumar and Münstedt
2005; Zaporojtchenko et al. 2006), nitric oxide (Nablo et
al. 2001), bioactive antibodies (Rojas et al. 2000), antimi-
crobial peptides (Shukla et al. 2010), and some naturally
Appl Microbiol Biotechnol (2012) 95:299–311 305
occurring broad-spectrum biocidal compounds, such as
essential oils (Bazaka et al. 2011c,d; Low et al. 2011).
The strong bactericidal effect of silver ions against S.
aureus,S. epidermidis,P. aeruginosa,E. coli and Klebsiella
pneumonia among others is well documented (Birla et al.
2009; Rai et al. 2009). The antimicrobial activity of Ag-
based materials is typically associated with their Ag
+
con-
tent, where Ag
+
is believed to interact with the cytoplasmic
components and nucleic acids, to inhibit respiratory chain
enzymes (Holt and Bard 2005), and to interfere with mem-
brane permeability (Lok et al. 2007). In Vibrio cholera, low
concentrations of Ag
+
were shown to induce a massive
proton leakage through the membrane, leading to a collapse
of proton motive force (Dibrov et al. 2002). Tile inactivation
of microorganism enzymes takes place via silver complexes
with electron donors containing sulfur, phosphorous, oxy-
gen or nitrogen, such as thiols, carboxylates, phosphates,
hydroxyl, amines, imidazoles, indoles (Ahearn et al. 1995).
Encouraged by the minimal detrimental effects to eukaryotic
cells (Silver 2003; Agarwal et al. 2010), silver-containing
coatings, nanoparticles, silver-exchanged zeolites, and hy-
brid silver composites with dendrimers and polymers are
being intensely investigated (Marambio-Jones and Hoek
2010; Shao and Zhao 2010b; Li et al. 2011).
Electroless plating, sputtering, ion beam-assisted deposi-
tion, and chemical deposition are among the techniques
employed to introduce silver onto the surface of the biomate-
rial (Sardella et al. 2006). Sol–gel processing was used to
fabricated silver-doped organic–inorganic hybrid coatings of
tetraethoxysilane- and triethoxysilane-terminated poly(ethyl-
ene glycol)-block-polyethylene, which at a weight ratio of
80:20 and a 5 wt.% silver salt were found to have notable
activity against E. coli and S. aureus (Marini et al. 2007).
Similar antibacterial activity against S. epidermidis and S.
aureus was observed for co-sputtered silver-containing hy-
droxyapatite (Chen et al. 2006) and silver-coated polymers,
where deposition was achieved by combining magnetron
sputtering with a neutral atom beam plasma source (Dowling
et al. 2001). Physical vapour co-deposition of titanium/silver
hard combined coatings provided significant antimicrobial
potency against S. epidermis and K. pneumonia strains and-
cytocompatibility with osteoblast and epithelial cells (Ewald
et al. 2006). With mechanical performance similar to that of
pure titanium, the application of TiAg coatings can impart
antimicrobial activity on load-bearing endoprosthetic surfa-
ces. Sol−gels containing titanium dioxide in combinations
with silver were found to attenuate P. aeruginosa growth;
however, the effect on S. aureus colonization was limited
(Tarquinio et al. 2010).
The photocatalytic activity of titanium dioxide can be
utilised to impart antiviral, antibacterial, and fungicidal
properties, and effectively inhibit biofilm formation on the
surface of TiO
2
implants. Titanium dioxide is known to
activate upon exposure to ultraviolet light, where irradiation
of the surface promotes electrons from the valence band to
the conduction band leaving a positively charged hole. As
electrons and holes migrate, the potent oxidative species,
such as OH and O
2
·
−
, are produced (Ditta et al. 2008). In
solution, these can further react to produce H
2
O
2
. These
photocatalytic species are believed to attack the outer mem-
brane of bacteria. It is generally believed that the surface
bound hydroxyl radicals (·OH) play the main role in killing
microorganisms, however its exact mode of action, whether
they remains bound or diffuse into the bulk of the solution,
the significance of other reactive oxygen species, such as
H
2
O
2
and O
2
·
−
, and the specific microorganism involved
remains a subject of active debate (Cho et al. 2005). For
instance, MS-2 phage were shown to be inactivated mainly
by the free hydroxyl radical in the solution bulk, whereas E.
coli cells were damaged by both the free and the surface-
bound hydroxyl radicals, and other reactive species, namely
O
2
·
−
and H
2
O
2
(Ditta et al. 2008).As the bactericidal effect
of illuminated TiO
2
has been positively correlated to the rate
of cell adsorption onto the titanium surface, the properties of
the liquid medium will also affect the killing efficacy of the
surface (Gogniat et al. 2006). Addition of silver or copper
can further enhance the antibacterial effectiveness of the
photocatalytic coating, even under weak UV irradiation
and lower exposure time. Compromised by the oxidative
species, the cytoplasmic membrane is susceptible to the
effectual permeation by the Ag or Cu ions (Hashimoto et
al. 2005). Once within the bacterial cell, the Cu ions are
thought to bind to specific sites in the DNA, particularly
guanosine residues, causing single-strand breakage and base
modification (Yates et al. 2008). The redox couples of
Cu
0
/Cu
2+
and Ag
0
/Ag
+
can cause the transfer of electron
leading to the O
2
−
generation even under dark conditions,
enhancing the bactericidal activities via the synergy of the
oxidation role of the O
2
−
and the bacteriostatic action of
antibacterial ions (Hu et al. 2007).
Thin TiN/Ag composite films prepared using pulsed mag-
netron spattering demonstrated an increase in P. aeruginosa
and S. aureus inhibition, corresponding to an increase in silver
content (Kelly et al. 2009). Heterogeneously distributed
throughout the TiN matrix, the presence of the silver resulted
in changes in the surface nanotopographies —surface fea-
tures, grain sizes, and physicochemistry —with most pro-
found changes observed at a silver concentration of 16.7 at.%
(Whitehead et al. 2010). Recently, Ivanova et al. (2011)used
magnetron sputtered nanoscopically thin silver films to show
that while silver ion concentration may be the major determi-
nant of bacterial viability, the extent of bacterial attachment
and the patterns are largely affected by surface topography of
the films (Ivanova et al. 2011). A strong correlation was also
detected between total surface energy γ
TOT
of the silver coat-
ing and P. aeruginosa adhesion, with the number of adhered
306 Appl Microbiol Biotechnol (2012) 95:299–311
bacteria increasing linearly with γ
TOT
but decreasing linearly
with an increasing electron donor component γ−(Shao and
Zhao 2010a).
Plasma assisted micro- and nanofabrication methods are
widely used to deposit a wide range of coatings, to pattern,
and to selectively modify the properties of biomaterials
(Hynek 2011). For deposition of nanocomposite coatings,
plasma enhanced chemical vapour deposition is frequently
employed to fabricate the organic matrix, in which particles
are then introduced (Sardella et al. 2006). A combination of
radiofrequency (RF) glow discharge and simultaneous sput-
tering from the silver RF electrode was used to deposit nano-
composite Ag/C
x
H
y
O
z
thin films characterized by sounds
antibacterial properties (Favia et al. 2000). Similar plasma
set up was used for the in situ formation of Ag nanoparticles
within a functional hydrocarbon matrix, with the ability to
control the concentrating of incorporated silver component
(Körner et al. 2010,2011). Silver nanoparticles bound to a
plasma-deposited thin polymeric binding layer of allylamine
were effective in preventing attachment of S. epidermidis and
biofilm formation while supporting attachment and spreading
of osteoblastic cells (Vasilev et al. 2009,2010). Phosphine-
stabilised silver maleimide complex deposited using plasma
polymerization onto glass and non-woven polypropylene fab-
rics demonstrated cytocompatibility with Swiss mouse fibro-
blasts and human neonatal keratinocytes, while effectively
limiting colonization by P. aeruginosa (Poulter et al. 2009).
Recently, RF plasma polymerization was used to fabri-
cate thin film coatings from non-synthetic terpinen-4-ol, a
major constituent of Melaleuca alternifolia essential oil
attributed with the oil’s broad spectrum antibacterial, anti-
viral, antifungal, and anti-inflammatory activity (Bazaka et
al. 2010). The antifouling and bactericidal properties of the
coatings were found to be strongly dependent on the fabri-
cation conditions. Coatings deposited at lower input power
that favoured condensation and only limited monomer frag-
mentation retained most of the activity of the monomer,
effectively preventing adhesion and biofilm formation of
S. aureus,P. aeruginosa, and S. epidermidis. On the other
hand, films fabricated at conditions that resulted in high
degree of monomer fragmentation, promoted adhesion of
the aforementioned pathogens. In addition to differences in
surface chemistry and hydrophobicity, surface nanoarchitec-
ture was found to be a contributing factor to bacterial at-
tachment and biofilm formation, with non-active films being
significantly smoother compared to the unmodified sub-
strate and bactericidal counterparts (Bazaka et al. 2011c).
Concluding remarks and future prospects
This review demonstrates that there are surface engineering
methods that hold great potential in the fabrication of substrates
that can control microbial attachment and biofilm formation,
particularly with regard to alleviating biomaterial associated
infections. The presented physico-chemical modification
methods have the advantages of high efficiency and minimal
influence on the bulk properties of the biomaterials. Com-
pared to the conventional antimicrobial-based methods for
preventing and treating microbial colonisation, the approaches
discussed in this review would be associated with low toxicity
and minimal development of bacterial resistance. The latter
would be afforded through modification of the bacterial cell–
surface interactions rather than by simply killing the pathogen,
hence lessening the selective pressure for antibiotic resistance.
For the same reasons, such tailored surface modifications are
an attractive means of mitigating the attachment and prolifer-
ation of bacterial strains that have already developed resis-
tance to one or more currently available antibiotics. This area
is of particular importance within the clinical setting, where
nosocomial infections severely impede patient recovery and
are recognised as the foremost cause of death in intensive care
units (Livermore 2005). Lastly, these surfaces will provide
scientists with a platform for in-depth investigation of the
cell–surface interactions necessary for the effective manage-
ment of microorganism colonisation in a variety of natural and
engineered environments. With the ongoing advancement of
manufacturing and characterisation technologies and signifi-
cant research efforts dedicated to the area, nano-engineered
surfaces with high degree of control at molecular and atomic
length scales would evolve as a feasible alternative for eco-
logical management of biofouling.
Acknowledgements This study was supported in part by Australian
Research Council (ARC) and Advanced Manufacturing CRC.K. B. is a
recipient of an Australian Postgraduate Award (APA) and an Australian
Institute of Nuclear Science and Engineering Postgraduate Research
Award (AINSE PGRA).
References
Agarwal A, Weis TL, Schurr MJ, Faith NG, Czuprynski CJ, McAnulty
JF, Murphy CJ, Abbott NL (2010) Surfaces modified with
nanometer-thick silver-impregnated polymeric films that kill bac-
teria but support growth of mammalian cells. Biomaterials
31:680–690
Ahearn DG, May LL, Gabriel MM (1995) Adherence of organisms to
silver-coated surfaces. J Ind Microbiol Biot 15:372–376
An YH, Friedman RJ, Draughn RA, Smith EA, Nicholson JH, John JF
(1995) Rapid quantification of staphylococci adhered to titanium
surfaces using image analyzed epifluorescence microscopy. J
Microbiol Methods 24:29–40
Andersson DI, Hughes D (2011) Persistence of antibiotic resistance in
bacterial populations. FEMS Microbiol Rev 35:901–911
Andrews SS (2009) Accurate particle-based simulation of adsorption,
desorption and partial transmission. Phys Biol 6:046015
Ansari SA, Husain Q (2012) Potential applications of enzymes immo-
bilized on/in nano materials: a review. Biotechnol Adv 30:512–
523
Appl Microbiol Biotechnol (2012) 95:299–311 307
Anselme K, Davidson P, Popa AM, Giazzon M, Liley M, Ploux L
(2010) The interaction of cells and bacteria with surfaces struc-
tured at the nanometre scale. Acta Biomater 6:3824–3846
Ardehali R, Shi L, Janatova J, Mohammad SF, Burns Gregory L (2002)
The effect of apo-transferrin on bacterial adhesion to biomaterials.
Artif Organs 26:512–520
Baum C, Meyer W, Stelzer R, Fleischer LG, Siebers D (2002) Average
nanorough skin surface of the pilot whale (Globicephala melas,
Delphinidae): considerations on the self-cleaning abilities based
on nanoroughness. Mar Biol 140:653–657
Bazaka K, Jacob MV, Truong VK, Wang F, Pushpamali WA, Wang J,
Ellis A, Berndt CC, Crawford RJ, Ivanova EP (2010) Effect of
plasma-enhanced chemical vapour deposition on the retention of
antibacterial activity of terpinen-4-ol. Biomacromolecules 11:2016–
2026
Bazaka K, Crawford RJ, Ivanova EP (2011a) Do bacteria differentiate
between degrees of nanoscale surface roughness? Biotechnol J
6:1103–1114
Bazaka K, Crawford RJ, Nazarenko EL, Ivanova EP (2011b) Bacterial
extracellular polysaccharides. In: Linke D, Goldman A (eds)
Bacterial adhesion, vol. 715. Advances in experimental medicine
and biology. Springer, Netherlands, pp 213–226
Bazaka K, Jacob M, Truong VK, Crawford RJ, Ivanova EP (2011c)
The effect of polyterpenol thin film surfaces on bacterial viability
and adhesion. Polymers 3:388–404
Bazaka K, Jacob MV, Crawford RJ, Ivanova EP (2011d) Plasma
assisted surface modification of organic biopolymers. Acta Bio-
mater 7:2015–2028
Bendrea A-D, Cianga L, Cianga I (2011) Review paper: progress in the
field of conducting polymers for tissue engineering applications. J
Biomater Appl 26:3–84
Bhushan B, Koch K, Jung YC (2008) Nanostructures for superhydro-
phobicity and low adhesion. Soft Matter 4:1799–1804
Birla SS, Tiwari VV, Gade AK, Ingle AP, Yadav AP, Rai MK (2009)
Fabrication of silver nanoparticles by Phoma glomerata and its
combined effect against Escherichia coli,Pseudomonas aerugi-
nosa and Staphylococcus aureus. Lett Appl Microbiol 48:173–
179
Bjellanda AM, Søruma H, Tegegneb DA, Winther-Larsena HC,
Willassenb NP, Hansen H (2012) LitR of Vibrio salmonicida
is a salinity-sensitive quorum-sensing regulator of phenotypes
involved in host interactions and virulence. Infect Immun 80:1681–
1689
Bordi C, de Bentzmann S (2011) Hacking into bacterial biofilms: a
new therapeutic challenge. Ann Intens Care 1:19
Bos R, Van Der Mei HC, Busscher HJ (1999) Physico-chemistry of
initial microbial adhesive interactions —its mechanisms and
methods for study. FEMS Microbiol Rev 23:179–229
Boulangé-Petermann L, Rault J, Bellon-Fontaine MN (1997) Adhesion
of Streptococcus thermophilus to stainless steel with different
surface topography and roughness. Biofouling 11:201–216
Brunetti V, Maiorano G, Rizzello L, Sorce B, Sabella S, Cingolani
R, Pompa PP (2010) Neurons sense nanoscale roughness with
nanometer sensitivity. Proc Natl Acad Sci U S A 107:6264–
6269
Busscher HJ, Norde W, Sharma PK, van der Mei HC (2010) Interfacial
re-arrangement in initial microbial adhesion to surfaces. Curr
Opin Colloid Interface Sci 15:510–517
Cappella B, Dietler G (1999) Force–distance curves by atomic force
microscopy. Surf Sci Rep 34:5–104
Cardoso MV, de Almeida NA, Mine A, Coutinho E, Van Landuyt K,
De Munck J, Van Meerbeek B (2011) Current aspects on bonding
effectiveness and stability in adhesive dentistry. Aust Dent J
56:31–44
Chen W, Liu Y, Courtney HS, Bettenga M, Agrawal CM, Bumgardner
JD, Ong JL (2006) In vitro anti-bacterial and biological properties
of magnetron co-sputtered silver-containing hydroxyapatite coat-
ing. Biomaterials 27:5512–5517
Cho M, Chung H, Choi W, Yoon J (2005) Different inactivation
behaviours of MS-2 phage and Escherichia coli in TiO
2
photo-
catalytic disinfection. Appl Environ Microbiol 71:270–275
Chung KK, Schumacher JF, Sampson EM, Burne RA, Antonelli PJ,
Brennan AB (2007) Impact of engineered surface microtopogra-
phy on biofilm formation of Staphylococcus aureus. Biointer-
phases 2:89–94
Colon G, Ward BC, Webster TJ (2006) Increased osteoblast and
decreased Staphylococcus epidermidis functions on nanophase
ZnO and TiO
2
. J Biomed Mater Res, Part A 78:595–604
Colvin KM, Gordon VD, Murakami K, Borlee BR, Wozniak DJ, Wong
GC, Parsek MR (2011) Thepel polysaccharide can serve a struc-
tural and protective role in the biofilm matrix of Pseudomonas
aeruginosa. PLoS Pathog 7:e1001264
Costerton JW, Stewart PS, Greenberg EP (1999) Bacterial biofilms:
a common cause of persistent infections. Science 284:1318–
1322
Davies DG, Geesey GG (1995) Regulation of the alginate biosynthesis
gene algC in Pseudomonas aeruginosa during biofilm develop-
ment in continuous culture. Appl Environ Microbiol 61:860–867
Decho AW (2000) Microbial biofilms in intertidal systems: an over-
view. Cont Shelf Res 20:1257–1273
Desmet T, Morent R, Geyter ND, Leys C, Schacht E, Dubruel P (2009)
Nonthermal plasma technology as a versatile strategy for poly-
meric biomaterials surface modification: a review. Biomacromo-
lecules 10:2351–2378
Diaz C, Cortizo MC, Schilardi PL, de Saravia SGG, de Mele MAFL
(2007) Influence of the nano-micro structure of the surface on
bacterial adhesion. Mater Res 10:11–14
Díaz C, Schilardi PL, Salvarezza RC, Lorenzo F, de Mele M (2007)
Nano/microscale order affects the early stages of biofilm forma-
tion on metal surfaces. Langmuir 23:11206–11210
Dibrov P, Dzioba J, Gosink KK, Häse CC (2002) Chemiosmotic
mechanism of antimicrobial activity of Ag(+) in Vibrio cholerae.
Antimicrob Agents Chemother 46:2668–2670
Ditta IB, Steele A, Liptrot C, Tobin J, Tyler H, Yates HM, Sheel DW,
Foster HA (2008) Photocatalytic antimicrobial activity of thin
surface films of TiO
2
, CuO and TiO
2
/CuO dual layers on Escher-
ichia coli and bacteriophage T4. Appl Microbiol Biotechnol
79:127–133
Dobrzyński M, Bernatowicz P, Kloc M, Kubiak J (2011) Evolution of
bet-hedging mechanisms in cell cycle and embryo development
stimulated by weak linkage of stochastic processes. In: Kubiak JZ
(ed) Cell cycle in development, vol 53. Results and problems in
cell differentiation. Springer, Berlin, pp 11–30
Dodiuk H, Rios PF, Dotan A, Kenig S (2007) Hydrophobic and self-
cleaning coatings. Polym Adv Technol 18:746–750
Donald LE (2011) Liquid–liquid two-phase systems for the production
of porous hydrogels and hydrogel microspheres for biomedical
applications: a tutorial review. Acta Biomater 7:31–56
Donlan RM (2002) Biofilms: microbial life on surfaces. Emerg Infect
Dis 8:881–890
Döring G, Parameswaran IG, Murphy TF (2011) Differential adapta-
tion of microbial pathogens to airways of patients with cystic
fibrosis and chronic obstructive pulmonary disease. FEMS Micro-
biol Rev 35:124–146
Dorobantu LS, Bhattacharjee S, Foght JM, Gray MR (2009) Analysis
of force interactions between AFM tips and hydrophobic bacteria
using DLVO theory. Langmuir 25:6968–6976
Dorozhkin SV (2011) Biocomposites and hybrid biomaterials based on
calcium orthophosphates. Biomatter 1:3–56
Dowling DP, Donnelly K, McConnell ML, Eloy R, Arnaud MN (2001)
Deposition of anti-bacterial silver coatings on polymeric sub-
strates. Thin Solid Films 398–399:602–606
308 Appl Microbiol Biotechnol (2012) 95:299–311
Edwards KJ, Rutenberg AD (2001) Microbial response to surface
microtopography: the role of metabolism in localized mineral
dissolution. Chem Geol 180:19–32
Estrin Y, Kasper C, Diederichs S, Lapovok R (2009) Accelerated
growth of preosteoblastic cells on ultrafine grained titanium. J
Biomed Mater Res, Part A 90A:1239–1242
Ewald A, Gluckermann S, Thull R, Gbureck U (2006) Antimicrobial
titanium/silver PVD coatings on titanium. Biomed Engineer
Online 5:22
Fadeeva E, Schlie S, Koch J, Ngezahayo A, Chichkov BN (2009) The
hydrophobic properties of femtosecond laser fabricated spike
structures and their effects on cell proliferation. Phys Status Solidi
A 206:1348–1351
Fadeeva E, Truong VK, Stiesch M, Chichkov BN, Crawford RJ, Wang
J, Ivanova EP (2011) Bacterial retention on superhydrophobic
titanium surfaces fabricated by femtosecond laser ablation. Langmuir
27:3012–3019
Favia P, Vulpio M, Marino R, d'Agostino R, Mota RP, Catalano M
(2000) Plasma-deposition of Ag-containing polyethyleneoxide-
like coatings. Plasmas Polym 5:1–14
Flemming HC, Wingender J (2010) The biofilm matrix. Nat Rev
Microbiol 8:623–633
Flemming HC, Neu TR, Wozniak DJ (2007) The EPS matrix: The
“House of biofilm cells”. J Bacteriol 189:7945–7947
Freire-Moran L, Aronsson B, Manz C, Gyssens IC, So AD, Monnet
DL, Cars O (2011) Critical shortage of new antibiotics in devel-
opment against multidrug-resistant bacteria—time to react is now.
Drug Resist Updates 14:118–124
Fu J, Ji J, Yuan W, Shen J (2005) Construction of anti-adhesive and
antibacterial multilayer films via layer-by-layer assembly of hep-
arin and chitosan. Biomaterials 26:6684–6692
Fu R-H, Wang Y-C, Liu S-P, Huang C-M, Kang Y-H, Tsai C-H, Shyu
W-C, Lin S-Z (2011) Differentiation of stem cells: strategies for
modifying surface biomaterials. Cell Transplant 20:37–47
Gabriel GJ, Som A, Madkour AE, Eren T, Tew GN (2007) Infectious
disease: connecting innate immunity to biocidal polymers. Mater
Sci Eng, R 57:28–64
Gioe T, Sharma A, Tatman P, Mehle S (2011) Do “premium”joint
implants add value?: Analysis of high cost joint implants in a
community registry. Clin Orthop Relat Res 469:48–54
Gogniat G, Thyssen M, Denis M, Pulgarin C, Dukan S (2006) The
bactericidal effect of TiO
2
photocatalysis involves adsorption onto
catalyst and the loss of membrane integrity. FEMS Microbiol Lett
258:18–24
Gottenbos B, Grijpma DW, van der Mei HC, Feijen J, Busscher HJ
(2001) Antimicrobial effects of positively charged surfaces on
adhering Gram-positive and Gram-negative bacteria. J Antimicrob
Chemother 48:7–13
Hanssen AD (2002) Managing the infected knee: as good as it gets. J
Arthroplasty 17:98–101
Harris LG, Tosatti S, Wieland M, Textor M, Richards RG (2004)
Staphylococcus aureus adhesion to titanium oxide surfaces coated
with non-functionalized and peptide-functionalized poly(-lysine)-
grafted-poly(ethylene glycol) copolymers. Biomaterials 25:4135–
4148
Hashimoto K, Irie H, FujishimaA (2005) TiO
2
photocatalysis: a historical
overview and future prospects. Jpn J Appl Phys 44:8269–8285
Hochbaum AI, Aizenberg J (2010) Bacteria pattern spontaneously on
periodic nanostructure arrays. Nano Lett 10:3717–3721
Holt KB, Bard AJ (2005) Interaction of silver(I) ions with the respira-
tory chain of Escherichia coli: an electrochemical and scanning
electrochemical microscopy study of the antimicrobial mecha-
nism of micromolar Ag
+
. Biochemistry 44:13214–13223
Hoppe A, Güldal NS, Boccaccini AR (2011) A review of the biological
response to ionic dissolution products from bioactive glasses and
glass-ceramics. Biomaterials 32:2757–2774
Hu C, Guo J, Qu J, Hu X (2007) Efficient destruction of bacteria with
Ti(IV) and antibacterial ions in co-substituted hydroxyapatite
films. Appl Catal B Environ 73:345–353
Hynek B (2011) Nanocomposites and nanostructures based on plasma
polymers. Surf Coat Technol 205(Supplement 2):S10–S14
Ivanova EP, Mitik-Dineva N, Wang J, Pham DK, Wright JP, Nicolau DV,
Mocanasu RC, Crawford RJ (2008) Staleya guttiformis attachment
on poly(tert-butylmethacrylate) polymeric surfaces. Micron
39:1197–1204
Ivanova EP, Truong VK, Wang JY, Berndt CC, Jones RT, Yusuf II,
Peake I, Schmidt HW, Fluke C, Barnes D, Crawford RJ (2010)
Impact of nanoscale roughness of titanium thin film surfaces on
bacterial retention. Langmuir 26:1973–1982
Ivanova E, Hasan J, Truong V, Wang J, Raveggi M, Fluke C, Crawford
R (2011) The influence of nanoscopically thin silver films on
bacterial viability and attachment. Appl Microbiol Biotechnol
91:1149–1157
Jiao Y, Cody GD, Harding AK, Wilmes P, Schrenk M, Wheeler KE,
Banfield JF, Thelen MP (2010) Characterization of extracellular
polymeric substances from acidophilic microbial biofilms. Appl
Environ Microbiol 76:2916–2922
Karatan E, Watnick P (2009) Signals, regulatory networks, and materi-
als that build and break bacterial biofilms. Microbiol Mol Biol
Rev 73:310–347
Katsikogianni M, Missirlis YF (2004) Concise review of mechanisms
of bacterial adhesion to biomaterials and of techniques used in
estimating bacteria–material interactions. Eur Cells Mater 8:37–57
Kelly PJ, Li H, Whitehead KA, Verran J, Arnell RD, Iordanova I
(2009) A study of the antimicrobial and tribological properties
of TiN/Ag nanocomposite coatings. Surf Coat Technol 204:1137–
1140
Khan OF, Sefton MV (2011) Endothelialized biomaterials for tissue
engineering applications in vivo. Trends Biotechnol 29:379–387
Kitao T, Ando Y, Yoshikawa M, Kobayashi M, Kimura T, Ohsawa
H, Machida S, Yokoyama N, Sakota D, Konno T, Ishihara K,
Takatani S (2011) In vivo evaluation of the “tinypump”as a
pediatric left ventricular assist device. Artif Organs 35:543–
553
Körner E, Aguirre MH, Fortunato G, Ritter A, Rühe J, Hegemann D
(2010) Formation and distribution of silver nanoparticles in a
functional plasma polymer matrix and related Ag
+
release prop-
erties. Plasma Process Polymer 7:619–625
Körner E, Rupper P, Lübben JF, Ritter A, Rühe J, Hegemann D (2011)
Surface topography, morphology and functionality of silver con-
taining plasma polymer nanocomposites. Surf Coat Technol
205:2978–2984
Kumar R, Münstedt H (2005) Silver ion release from antimicrobial
polyamide/silver composites. Biomaterials 26:2081–2088
Laue H, Schenk A, Li H, Lambertsen L, Neu TR, Molin S, Ullrich MS
(2006) Contribution of alginate and levan production to biofilm
formation by Pseudomonas syringae. Microbiology 152:2909–
2918
Lee B, Schjerling CK, Kirkby N, Hoffmann N, Borup R, Molin S,
HØIby N, Ciofu O (2011) Mucoid Pseudomonas aeruginosa
isolates maintain the biofilm formation capacity and the gene
expression profiles during the chronic lung infection of CF
patients. APMIS 119:263–274
Lele UN, Baig UI, Watve MG (2011) Phenotypic plasticity and effects
of selection on cell division symmetry in Escherichia coli. PLoS
One 6:e14516
Lewis G (2011) Viscoelastic properties of injectable bone cements for
orthopaedic applications: state-of-the-art review. J Biomed Mater
Res, Part B 98B:171–191
Li W-R, Xie X-B, Shi Q-S, Duan S-S, Ouyang Y-S, Chen Y-B (2011)
Antibacterial effect of silver nanoparticles on Staphylococcus
aureus. BioMetals 24:135–141
Appl Microbiol Biotechnol (2012) 95:299–311 309
Liu X, Chu PK, Ding C (2004) Surface modification of titanium,
titanium alloys, and related materials for biomedical applications.
Mater Sci Eng, R 47:49–121
Liu Y, Wang J-C, Ren L, Tu Q, Liu W-M, Wang X-Q, Liu R, Zhang Y-
R, Wang J-Y (2011) Microfluidics-based assay on the effects of
microenvironmental geometry and aqueous flow on bacterial ad-
hesion behaviors. J Pharm Anal 1:175–183
Livermore DM (2005) Minimising antibiotic resistance. Lancet Infect
Dis 5:450–459
Lok CN, Ho CM, Chen R, He QY, Yu WY, Sun H, Tam PKH, Chiu JF,
Che CM (2007) Silver nanoparticles: partial oxidation and anti-
bacterial activities. J Biol Inorg Chem 12:527–534
Low WL, Martin C, Hill DJ, Kenward MA (2011) Antimicrobial
efficacy of silver ions in combination with tea tree oil against
Pseudomonas aeruginosa,Staphylococcus aureus and Candida
albicans. Int J Antimicrob Agents 37:162–165
Ma L, Jackson KD, Landry RM, Parsek MR, Wozniak DJ (2006)
Analysis of Pseudomonas aeruginosa conditional Psl variants
reveals roles for the Psl polysaccharide in adhesion and maintain-
ing biofilm structure postattachment. J Bacteriol 188:8213–8221
Madkour AE, Tew GN (2008) Towards self-sterilizing medical devi-
ces: controlling infection. Polym Int 57:6–10
Malkin AJ, Plomp M (2011) High-resolution architecture and structur-
al dynamics of microbial and cellular systems: insights from in
vitro Atomic Force Microscopy. In: Kalinin SV, Gruverman A
(eds) Scanning probe microscopy of functional materials. Springer,
New York, pp 39–68
Marambio-Jones C, Hoek E (2010) A review of the antibacterial effects
of silver nanomaterials and potential implications for human
health and the environment. J Nanopart Res 12:1531–1551
Marini M, De Niederhausern S, Iseppi R, Bondi M, Sabia C, Toselli M,
Pilati F (2007) Antibacterial activity of plastics coated with silver-
doped organic–inorganic hybrid coatings prepared by sol–gel
processes. Biomacromolecules 8:1246–1254
Medilanski E, Kaufmann K, Wick LY, Wanner O, Harms H (2002)
Influence of the surface topography of stainless steel on bacterial
adhesion. Biofouling 18:193–203
Mitik-Dineva N, Wang J, Mocanasu RC, Stoddart PR, Crawford RJ,
Ivanova EP (2008) Impact of nano-topography on bacterial at-
tachment. Biotechnol J 3:536–544
Mitik-Dineva N, Wang J, Truong VK, Stoddart P, Malherbe F, Crawford
RJ, Ivanova EP (2009) Escherichia coli,Pseudomonas aeruginosa
and Staphylococcus aureus attachment patterns on glass surfaces
with nanoscale roughness. Curr Microbiol 58:268–273
Mitik-Dineva N, Wang J, Truong VK, Stoddart PR, Alexander MR,
Albutt DJ, Fluke C, Crawford RJ, Ivanova EP (2010) Bacterial
attachment on optical fibre surfaces. Biofouling 26:461–470
Montanaro L, Campoccia D, Arciola CR (2007) Advancements in
molecular epidemiology of implant infections and future perspec-
tives. Biomaterials 28:5155–5168
Morent R, De Geyter N, Desmet T, Dubruel P, Leys C (2011) Plasma
surface modification of biodegradable polymers: a review. Plasma
Process Polymer 8:171–190
Nablo BJ, Chen T-Y, Schoenfisch MH (2001) Sol–gel derived nitric-
oxide releasing materials that reduce bacterial adhesion. J Am
Chem Soc 123:9712–9713
Naderi H, Matin MM, Bahrami AR (2011) Review paper: critical
issues in tissue engineering: biomaterials, cell sources, angiogen-
esis, and drug delivery systems. J Biomater Appl 26:383–417
Norowski PA, Bumgardner JD (2009) Biomaterial and antibiotic strat-
egies for peri-implantitis: a review. J Biomed Mater Res, Part B
88B:530–543
Parreira P, Magalhães A, Gonçalves IC, Gomes J, Vidal R, Reis CA,
Leckband DE, Martins MCL (2011) Effect of surface chemistry
on bacterial adhesion, viability, and morphology. J Biomed Mater
Res, Part A 99A:344–353
Pavithra D, Mukesh D (2008) Biofilm formation, bacterial adhesion
and host response on polymeric implants' issues and prevention.
Biomed Mater 3:034003
Petrova OE, Sauer K (2011) SagS contributes to the motile-sessile
switch and acts in concert with BfiSR to enable Pseudomonas
aeruginosa biofilm formation. J Bacteriol 193:6614–6628
Petrova OE, Sauer K (2012) Sticky situations: key components that
control bacterial surface attachment. J Bacteriol 194:2413–2425
Ploux L, Anselme K, Dirani A, Ponche A, Soppera O, Roucoules V
(2009) Opposite responses of cells and bacteria to micro/nano-
patterned surfaces prepared by pulsed plasma polymerization and
UV-irradiation. Langmuir 25:8161–8169
Ploux L, Ponche A, Anselme K (2010) Bacteria/material interfaces:
role of the material and cell wall properties. J Adhes Sci Technol
24:2165–2201
Poulter N, Munoz-Berbel X, Johnson AL, Dowling AJ, Waterfield N,
Jenkins ATA (2009) An organo-silver compound that shows
antimicrobial activity against Pseudomonas aeruginosa as a
monomer and plasma deposited film. Chem Commun 7312–7314
Price JS, Tencer AF, Arm DM, Bohach GA (1996) Controlled release
of antibiotics from coated orthopedic implants. J Biomed Mater
Res 30:281–286
Rai M, Yadav A, Gade A (2009) Silver nanoparticles as a new gener-
ation of antimicrobials. Biotechnol Adv 27:76–83
Raynor JE, Capadona JR, Collard DM, Petrie TA, Garcia AJ (2009)
Polymer brushes and self-assembled monolayers: versatile plat-
forms to control cell adhesion to biomaterials (Review). Biointer-
phases 4:FA3–FA16
Rios PF, Dodiuk H, Kenig S, McCarthy S, Dotan A (2006) The effects
of nanostructure and composition on the hydrophobic properties
of solid surfaces. J Adhes Sci Technol 20:563–587
Rios PF, Dodiuk H, Kenig S, McCarthy S, Dotan A (2007) Transparent
ultra-hydrophobic surfaces. J Adhes Sci Technol 21:399–408
Rojas IA, Slunt JB, Grainger DW (2000) Polyurethane coatings release
bioactive antibodies to reduce bacterial adhesion. J Contr Release
63:175–189
Rowan B, Wheeler MA, Crooks RM (2002) Patterning bacteria within
hyperbranched polymer film templates. Langmuir 18:9914–9917
Rozhok S, Fan Z, Nyamjav D, Liu C, Mirkin CA, Holz RC (2006)
Attachment of motile bacterial cells to prealigned holed micro-
arrays. Langmuir 22:11251–11254
Saito N, Aoki K, Usui Y, Shimizu M, Hara K, Narita N, Ogihara N,
Nakamura K, Ishigaki N, Kato H, Haniu H, Taruta S, Ahm Kim Y,
Endo M (2011) Application of carbon fibers to biomaterials: a
new era of nano-level control of carbon fibers after 30-years of
development. Chem Soc Rev 40:3824–3834
Saldarriaga Fernández IC, Busscher HJ, Metzger SW, Grainger DW,
van der Mei HC (2011) Competitive time- and density-dependent
adhesion of staphylococci and osteoblasts on crosslinked poly
(ethylene glycol)-based polymer coatings in co-culture flow
chambers. Biomaterials 32:979–984
Sardella E, Favia P, Gristina R, Nardulli M, d'Agostino R (2006)
Plasma-aided micro- and nanopatterning processes for biomedical
applications. Plasma Process Polymer 3:456–469
Scheuerman TR, Camper AK, Hamilton MA (1998) Effects of substratum
topography on bacterial adhesion. J Colloid Interface Sci 208:23–33
Shadanbaz S, Dias GJ (2012) Calcium phosphate coatings on magnesium
alloys for biomedical applications: a review. Acta Biomater 8:20–30
Shanks RMQ, Donegan NP, Graber ML, Buckingham SE, Zegans ME,
Cheung AL, O'Toole GA (2005) Heparin stimulates Staphylococ-
cus aureus biofilm formation. Infect Immun 73:4596–4606
Shao W, Zhao Q (2010a) Effect of corrosion rate and surface energy of
silver coatings on bacterial adhesion. Colloids Surf, B 76:98–103
Shao W, Zhao Q (2010b) Influence of reducers on nanostructure and
surface energy of silver coatings and bacterial adhesion. Surf Coat
Technol 204:1288–1294
310 Appl Microbiol Biotechnol (2012) 95:299–311
Shenga GP, Yua HQ, Lib XY (2010) Extracellular polymeric substan-
ces (EPS) of microbial aggregates in biological wastewater treat-
ment systems: a review. Biotechnol Adv 28:882–894
Shukla A, Fleming KE, Chuang HF, ChauTM, Loose CR, Stephanopoulos
GN, Hammond PT (2010) Controlling the release of peptide antimi-
crobial agents from surfaces. Biomaterials 31:2348–2357
Silver S (2003) Bacterial silver resistance: molecular biology and uses and
misuses of silver compounds. FEMS Microbiol Rev 27:341–353
Solouk A, Cousins BG, Mirzadeh H, Seifalian AM (2011) Application
of plasma surface modification techniques to improve hemocom-
patibility of vascular grafts: a review. Biotechnol Appl Biochem
58:311–327
Stigter M, Bezemer J, de Groot K, Layrolle P (2004) Incorporation of
different antibiotics into carbonated hydroxyapatite coatings on
titanium implants, release and antibiotic efficacy. J Controlled Rel
99:127–137
Stobie N, Duffy B, McCormack DE, Colreavy J, Hidalgo M, McHale
P, Hinder SJ (2008) Prevention of Staphylococcus epidermidis
biofilm formation using a low-temperature processed silver-doped
phenyltriethoxysilane sol–gel coating. Biomaterials 29:963–969
Subbiahdoss G, Kuijer R, Grijpma DW, van der Mei HC, Busscher HJ
(2009) Microbial biofilm growth vs. tissue integration: "The race for
the surface" experimentally studied. Acta Biomater 5:1399–1404
Sun H, Meng F, Dias AA, Hendriks M, Feijen J, Zhong Z (2011) α-
Amino acid containing degradable polymers as functional bioma-
terials: rational design, synthetic pathway, and biomedical appli-
cations. Biomacromolecules 12:1937–1955
Tan A, Yildirimer L, Rajadas J, De La Peña H, Pastorin G, Seifalian A
(2011) Quantum dots and carbon nanotubes in oncology: a review
on emerging theranostic applications in nanomedicine. Nanome-
dicine 6:1101–1114
Tarquinio KM, Kothurkar NK, Goswami DY, Sanders RC Jr, Zaritsky
AL (2010) Levine AM (2010) Bactericidal effects of silver plus
titanium dioxide-coated endotracheal tubes on Pseudomonas aer-
uginosa and Staphylococcus aureus. Int J Nanomed 5:177–183
Truong VK, Rundell S, Lapovok R, Estrin Y, Wang JY, Berndt CC,
Barnes DG, Fluke CJ, Crawford RJ, Ivanova EP (2009) Effect of
ultrafine-grained titanium surfaces on adhesion of bacteria. Appl
Microbiol Biotechnol 83:925–937
Truong VK, Lapovok R, Estrin YS, Rundell S, Wang JY, Fluke CJ,
Crawford RJ, Ivanova EP (2010a) The influence of nano-scale
surface roughness on bacterial adhesion to ultrafine-grained tita-
nium. Biomaterials 31:3674–3683
Truong VK, Wang J, Lapovok R, Estrin Y, Malherbe F, Berndt C,
Crawford R, Ivanova E (2010b) Bacterial attachment response on
titanium surfaces with nanometric topographic features. In: Bucak S
(ed) Trends in colloidand interface science XXIII, vol 137. Progress
in colloid and polymer science. Springer, Berlin, pp 41–45
Truong VK, Wang JY, Shurui W, Malherbe F, Berndt CC, Crawford
RJ, Ivanova EP (2010c) Bacterial attachment response to nano-
structured titanium surfaces. International Conference on Nano-
science and Nanotechnology, pp 253–256
Valiev RZ, Semenova IP, Latysh VV, Rack H, Lowe TC, Petruzelka J,
Dluhos L, Hrusak D, Sochova J (2008) Nanostructured titanium
for biomedical applications. Adv Eng Mater 10:B15–B17
Van Vlierberghe S, Dubruel P, Schacht E (2011) Biopolymer-based
hydrogels as scaffolds for tissue engineering applications: a re-
view. Biomacromolecules 12:1387–1408
Vasilev K, Sah V, Anselme K, Ndi C, Mateescu M, Br D, Martinek P,
Ys H, Ploux L, Griesser HJ (2009) Tunable antibacterial coatings
that support mammalian cell growth. Nano Lett 10:202–207
Vasilev K, Sah VR, Goreham RV, Ndi C, Short RD, Griesser HJ (2010)
Antibacterial surfaces by adsorptive binding of polyvinyl-sulphonate-
stabilized silver nanoparticles. Nanotechnology 21:215102
Vasilev K, Griesser SS, Griesser HJ (2011) Antibacterial surfaces and
coatings produced by plasma techniques. Plasma Process Polymer
8:1010–1023
Vilain S, Pretorius JM, Theron J, Brözel VS (2009) DNA as an
adhesin: Bacillus cereus requires extracellular DNA to form bio-
films. Appl Environ Microbiol 75:2861–2868
Wagoner Johnson AJ, Herschler BA (2011) A review of the mechan-
ical behavior of CaP and CaP/polymer composites for applica-
tions in bone replacement and repair. Acta Biomater 7:16–30
Webb HK, Hasan J, Truong VK, Crawford RJ, Ivanova EP (2011)
Nature inspired structured surfaces for biomedical applications.
Curr Med Chem 18:3367–3375
Wenzel RN (1949) Surface roughness and contact angle. J Phys Col-
loid Chem 53:1466–1467
Whitchurch CB, Tolker-Nielsen T, Ragas PC, Mattick JS (2002) Ex-
tracellular DNA required for bacterial biofilm formation. Science
295:1487
Whitehead KA, Colligon J, Verran J (2005) Retention of microbial
cells in substratum surface features of micrometer and sub-
micrometer dimensions. Colloids Surf B 41:129–138
Whitehead KA, Rogers D, Colligon J, Wright C, Verran J (2006) Use
of the atomic force microscope to determine the effect of substra-
tum surface topography on the ease of bacterial removal. Colloids
Surf B 51:44–53
Whitehead K, Kelly P, Li H, Verran J (2010) Surface topography and
physicochemistry of silver containing titanium nitride nanocom-
posite coatings. J Vac Sci Technol B Microelectron Nanometer
Struct Process Meas Phenom 28:180–187
Wu S, Liu X, Yeung A, Yeung KWK, Kao RYT, Wu G, Hu T,
Xu Z, Chu PK (2011a) Plasma-modified biomaterials for
self-antimicrobial applications. ACS Appl Mater Interfaces
3:2851–2860
Wu Y, Zitelli JP, TenHuisen KS, Yu X, Libera MR (2011b) Differential
response of Staphylococci and osteoblasts to varying titanium
surface roughness. Biomaterials 32:951–960
Yang L, Barken KB, Skindersoe ME, Christensen AB, Givskov M,
Tolker-Nielsen T (2007) Effects of iron on DNA release and
biofilm development by Pseudomonas aeruginosa. Microbiology
153:1318–1328
Yates HM, Brook LA, Ditta IB, Evans P, Foster HA, Sheel DW, Steele
A (2008) Photo-induced self-cleaning and biocidal behaviour of
titania and copper oxide multilayers. J Photochem Photobiol A
Chem 197:197–205
Zaporojtchenko V, Podschun R, Schürmann U, Kulkarni A, Faupel F
(2006) Physico-chemical and antimicrobial properties of co-
sputtered Ag–Au/PTFE nanocomposite coatings. Nanotechnolo-
gy 17:4904
Zhao H, Yang Y, Yu G, Zhou J (2011) A systematic review of outcome
and failure rate of uncemented Scandinavian total ankle replace-
ment. Int Orthop 35:1751–1758
Zilberman M, Elsner JJ (2008) Antibiotic-eluting medical devices for
various applications. J Contr Release 130:202–215
Appl Microbiol Biotechnol (2012) 95:299–311 311
