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Images from scanning electron microscopy of laser-treated polystyrene foils doped with 5 wt. % of acetylsalicylic acid and laser fluence of 6-20 mJ·cm −2 . The scanning area represents 5 × 5 µm 2 and 100 × 100 µm 2 (bottom right).
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Homogeneous polystyrene foils doped with different concentrations of acetylsalicylic acid were prepared by the solvent casting method. The surface morphology and surface chemistry of as-prepared foils were characterized in detail. Excimer laser (krypton fluoride, a wavelength of 248 nm) was used for surface nanopatterning of doped polystyrene foils...
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Context 1
... confirm the acquired results, we also applied a surface morphology study with scanning electron microscope. The surface morphology images are shown in Figure 4 for laser exposure of PS foils with 5 wt. % of ASA. ...
Context 2
... confirm the acquired results, we also applied a surface morphology study with scanning electron microscope. The surface morphology images are shown in Figure 4 for laser exposure of PS foils with 5 wt. % of ASA. ...
Context 3
... particular stages of LIPSS formation are apparent at the initial stage of the pattern formation. For higher applied laser fluences, we have chosen a larger square on a sample (Figure 4, bottom line), on which the formation of structures similar to the honeycomb-like ones is well visible. ...
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Citations
... During the treatment of polylactide films with the CO2 laser, depressions in the form of grooves and ridges protruding above the surface, repeating at a distance of 40 to 60 μm, are formed on the surface [56]. The authors of [57] have observed folds and depressions during processing with an excimer laser. Thus, laser processing allows one to modify the surface of polymer products and cause significant changes in its morphology, affecting adhesive and other properties. ...
The results of surface modification of solvent casting films made from polyhydroxyalkanoates (PHAs) of various compositions are presented: homopolymer poly-3-hydroxybutyrate P(3HB) and copolymers comprising various combinations of 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV), 4-hydroxybutyrate(4HB), and 3-hydroxyhexanoate (3HHx) monomers treated with a CO2 laser in continuous and quasi-pulsed radiation modes. The effects of PHAs film surface modification, depending on the composition and ratio of monomers according to the results of the study of SEM and AFM, contact angles of wetting with water, adhesion and growth of fibroblasts have been revealed for the laser radiation regime used. Under continuous irradiation with vector lines, melted regions in the form of grooves are formed on the surface of the films, in which most of the samples have increased values of the contact angle and a decrease in roughness. The quasi-pulse mode by the raster method causes the formation of holes without pronounced melted zones, the total area of which is lower by 20% compared to the area of melted grooves. The number of viable fibroblasts NIH 3T3 on the films after the quasi-pulse mode is 1.5–2.0 times higher compared to the continuous mode, and depends to a greater extent on the laser treatment mode than on the PHAs’ composition. The use of various modes of laser modification on the surface of PHAs with different compositions makes it possible to influence the morphology and properties of polymer films in a targeted manner. The results that have been obtained contribute to solving the critical issue of functional biodegradable polymeric materials.
... The creation of an LIPSS pattern on an aromatic polystyrene polymer following laser irradiation is a well-known phenomenon [28]. An LIPSS pattern created on composite aromatic polymers containing acetylsalicylic acid has also been reported in the literature [29] for polystyrene, or for different polymers [30,31]. ...
In this article, we present a unique combination of techniques focusing on the immobilization of noble metal nanoparticles into a honeycomb polystyrene pattern prepared with the improved phase-separation technique. The procedure consists of two main steps: the preparation of the honeycomb pattern (HCP) on a perfluoroethylenepropylene substrate (FEP), followed by an immobilization procedure realized by the honeycomb pattern’s exposure to an excimer laser in a noble metal nanoparticle solution. The surface physico-chemical properties, mainly the surface morphology and chemistry, are characterized in detail in the study. The two-step procedure represents the unique architecture of the surface immobilization process, which reveals a wide range of potential applications, mainly in tissue engineering, but also as substrates for analytical use.
... Halogenated azo-aspirin derivatives exhibited better antibacterial activities against both Gram-negative and Gram-positive bacteria than the ampicillin and ASA alone [42]. Fajstavr et al. (2020) demonstrated the use of a nanostructured honeycomb-like pattern doped with ASA [43]. Selected nanostructured surfaces were confirmed to have excellent antibacterial properties when tested against a model bacterial strain of S. aureus [43]. ...
... Halogenated azo-aspirin derivatives exhibited better antibacterial activities against both Gram-negative and Gram-positive bacteria than the ampicillin and ASA alone [42]. Fajstavr et al. (2020) demonstrated the use of a nanostructured honeycomb-like pattern doped with ASA [43]. Selected nanostructured surfaces were confirmed to have excellent antibacterial properties when tested against a model bacterial strain of S. aureus [43]. ...
... Fajstavr et al. (2020) demonstrated the use of a nanostructured honeycomb-like pattern doped with ASA [43]. Selected nanostructured surfaces were confirmed to have excellent antibacterial properties when tested against a model bacterial strain of S. aureus [43]. ...
Acetylsalicylic acid (ASA) is one of the most commonly used drugs in the world. It derives from the extract of white willow bark, whose therapeutic potential was known in Egypt since 1534 BC. ASA’s pharmacological effects are historically considered secondary to its anti-inflammatory, platelet-inhibiting properties; however, human studies demonstrating a pro-inflammatory effect of ASA exist. It is likely that we are aware of only part of ASA’s mechanisms of action; moreover, the clinical effect is largely dependent on dosages. During the past few decades, evidence of the anti-infective properties of ASA has emerged. We performed a review of such research in order to provide a comprehensive overview of ASA and viral, bacterial, fungal and parasitic infections, as well as ASA’s antibiofilm properties.
... This phenomenon is desirable for constructing a biocompatible material or for enhancing its properties [35]. Material biocompatibility is closely related to surface roughness, which reflects surface topography created by laser modification, and it is an important factor for the preparation of an antibacterial substrate [36,37]. Therefore, an increase in the antibacterial effect and biocompatibility of the polymeric composites achieved by laser modification offers new attractive material properties for applications in the healthcare industry and medicine [38,39]. ...
A polydimethylsiloxane (PDMS) composite with multi-walled carbon nanotubes was successfully prepared. Composite foils were treated with both plasma and excimer laser, and changes in their physicochemical properties were determined in detail. Mainly changes in surface chemistry, wettability, and morphology were determined. The plasma treatment of PDMS complemented with subsequent heating led to the formation of a unique wrinkle-like pattern. The impact of different laser treatment conditions on the composite surface was determined. The morphology was determined by AFM and LCM techniques, while chemical changes and chemical surface mapping were studied with the EDS/EDX method. Selected activated polymer composites were used for the evaluation of antibacterial activity using Gram-positive (Staphylococcus epidermidis) and Gram-negative (Escherichia coli) bacteria. The antibacterial effect was achieved against S. epidermidis on pristine PDMS treated with 500 mJ of laser energy and PDMS-C nanocomposite treated with a lower laser fluence of 250 mJ. Silver deposition of PDMS foil increases significantly its antibacterial properties against E. coli, which is further enhanced by the carbon predeposition or high-energy laser treatment.
... Another study [83] demonstrated surface modification of poly(L-lactide)/hydroxyapatite films using femtosecond laser and formation of 10-50-µm grooves, which enlarged surface area. Formation of a wrinkled structure and changes in the surface roughness of the polystyrene films doped with acetylsalicylic acid and irradiated using excimer laser (krypton fluoride, a wavelength of 248 nm) were reported in [84]. ...
The study reports results of using a CO2-laser in continuous wave (3 W; 2 m/s) and quasi-pulsed (13.5 W; 1 m/s) modes to treat films prepared by solvent casting technique from four types of polyhydroxyalkanoates (PHAs), namely poly-3-hydroxybutyrate and three copolymers of 3-hydroxybutyrate: with 4-hydroxybutyrate, 3-hydroxyvalerate, and 3-hydroxyhexanoate (each second monomer constituting about 30 mol.%). The PHAs differed in their thermal and molecular weight properties and degree of crystallinity. Pristine films differed in porosity, hydrophilicity, and roughness parameters. The two modes of laser treatment altered these parameters and biocompatibility in diverse ways. Films of P(3HB) had water contact angle and surface energy of 92° and 30.8 mN/m, respectively, and average roughness of 144 nm. The water contact angle of copolymer films decreased to 80–56° and surface energy and roughness increased to 41–57 mN/m and 172–290 nm, respectively. Treatment in either mode resulted in different modifications of the films, depending on their composition and irradiation mode. Laser-treated P(3HB) films exhibited a decrease in water contact angle, which was more considerable after the treatment in the quasi-pulsed mode. Roughness parameters were changed by the treatment in both modes. Continuous wave line-by-line irradiation caused formation of sintered grooves on the film surface, which exhibited some change in water contact angle (76–80°) and reduced roughness parameters (to 40–45 mN/m) for most films. Treatment in the quasi-pulsed raster mode resulted in the formation of pits with no pronounced sintered regions on the film surface, a more considerably decreased water contact angle (to 67–76°), and increased roughness of most specimens. Colorimetric assay for assessing cell metabolic activity (MTT) in NIH 3T3 mouse fibroblast culture showed that the number of fibroblasts on the films treated in the continuous wave mode was somewhat lower; treatment in quasi-pulsed radiation mode caused an increase in the number of viable cells by a factor of 1.26 to 1.76, depending on PHA composition. This is an important result, offering an opportunity of targeted surface modification of PHA products aimed at preventing or facilitating cell attachment.
... Biomimetic surfaces: Nature provides many highly optimized surface functionalities that may be transferred to technical applications via tailored laser-processing, including LIPSS. Examples are dirt-repellent surfaces through the well-known lotus effect, anti-icing [57,58], the directional transport of liquids inspired by moisture-harvesting lizards [59] and bark bugs [60], antiadhesive surfaces inspired by cribellating spiders [61], or antibacterial [62][63][64][65][66][67], cell-repellent [68], and cell-stimulating/-adapting surfaces [69][70][71] for medical applications [72]. A detailed review of the laser engineering of biomimetic surfaces is provided in [6]. ...
... • Combined processing strategies: Currently, several research groups are exploring the combination of LIPSS with additional surface treatment techniques-either "in situ" during the laser processing, or "ex situ" after the laser-processing. Examples are: (i) combined laser processing strategies (such as in situ double-pulse treatments [20,73,74] or ex situ LIPSS + DLIP, see Section 3.3), or a two-step laser processing of microstructures (e.g., lines, grids, or more complex microfluidic channels) patterned additionally with nanostructures (LIPSS) [59,75]; (ii) the combination of LIPSS processing with thermal heat during [76,77] or after [78,79] laser irradiation; (iii) electrochemical post-processing, such as anodization [67,80]; or (iv) ion beam post-processing for altering the electrical conductivity [81]. • Improved regularity of LIPSS through surface overlayers: On dielectrics, the generation of large surface areas covered homogeneously with LIPSS is often very difficult when the single photon energy is significantly smaller than the band gap energy, i.e., when nonlinear absorption is required to couple the laser beam energy with the solid. ...
Nanotechnology and lasers are among the most successful and active fields of research and technology that have boomed during the past two decades. Many improvements are based on the controlled manufacturing of nanostructures that enable tailored material functionalization for a wide range of industrial applications, electronics, medicine, etc., and have already found entry into our daily life. One appealing approach for manufacturing such nanostructures in a flexible, robust, rapid, and contactless one-step process is based on the generation of laser-induced periodic surface structures (LIPSS). This Perspectives article analyzes the footprint of the research area of LIPSS on the basis of a detailed literature search, provides a brief overview on its current trends, describes the European funding strategies within the Horizon 2020 programme, and outlines promising future directions.
The use of nanomaterials in medicine offers multiple opportunities to address neurodegenerative disorders such as Alzheimer's and Parkinson's disease. These diseases are a significant burden for society and the health system, affecting millions of people worldwide without sensitive and selective diagnostic methodologies or effective treatments to stop their progression. In this sense, the use of gold nanoparticles is a promising tool due to their unique properties at the nanometric level. They can be functionalized with specific molecules to selectively target pathological proteins such as Tau and α-synuclein for Alzheimer’s and Parkinson’s disease, respectively. Additionally, these proteins are used as diagnostic biomarkers, wherein gold nanoparticles play a key role in enhancing their signal, even at the low concentrations present in biological samples such as blood or cerebrospinal fluid, thus enabling an early and accurate diagnosis. On the other hand, gold nanoparticles act as drug delivery platforms, bringing therapeutic agents directly into the brain, improving treatment efficiency and precision, and reducing side effects in healthy tissues. However, despite the exciting potential of gold nanoparticles, it is crucial to address the challenges and issues associated with their use in the medical field before they can be widely applied in clinical settings. It is critical to ensure the safety and biocompatibility of these nanomaterials in the context of the central nervous system. Therefore, rigorous preclinical and clinical studies are needed to assess the efficacy and feasibility of these strategies in patients. Since there is scarce and sometimes contradictory literature about their use in this context, the main aim of this review is to discuss and analyze the current state-of-the-art of gold nanoparticles in relation to delivery, diagnosis, and therapy for Alzheimer’s and Parkinson’s disease, as well as recent research about their use in preclinical, clinical, and emerging research areas.
Graphical Abstract
Bacterial biofilms pose serious problems in medical and industrial settings. One of the major societal challenges lies in the increasing resistance of bacteria against biocides used in antimicrobial treatments, e.g., via overabundant use in medicine, industry, and agriculture or cleaning and disinfection in private households. Hence, new efficient bacteria‐repellent strategies avoiding the use of biocides are strongly desired. One promising route to achieve bacteria‐repellent surfaces lies in the contactless and aseptic large‐area laser‐processing of technical surfaces. Tailored surface textures, enabled by different laser‐processing strategies that result in topographic scales ranging from nanometers to micrometers may provide a solution to this challenge. This article presents a current state‐of‐the‐art review of laser‐surface subtractive texturing approaches for controlling the biofilm formation for different bacterial strains and in different environments. Based on specific properties of bacteria and laser‐processed surfaces, the challenges of anti‐microbial surface designs are discussed, and future directions will be outlined.
Laser-based methods have demonstrated to be effective in the fabrication of surface micro- and nanostructures, which have a wide range of applications, such as cell culture, sensors or controlled wettability. One laser-based technique used for micro- and nanostructuring of surfaces is the formation of laser-induced periodic surface structures (LIPSS). LIPSS are formed upon repetitive irradiation at fluences well below the ablation threshold and in particular, linear structures are formed in the case of irradiation with linearly polarized laser beams. In this work, we report on the simple fabrication of a library of ordered nanostructures in a polymer surface by repeated irradiation using a nanosecond pulsed laser operating in the UV and visible region in order to obtain nanoscale-controlled functionality. By using a combination of pulses at different wavelengths and sequential irradiation with different polarization orientations, it is possible to obtain different geometries of nanostructures, in particular linear gratings, grids and arrays of nanodots. We use this experimental approach to nanostructure the semiconductor polymer poly(3-hexylthiophene) (P3HT) and the ferroelectric copolymer poly[(vinylidenefluoride-co-trifluoroethylene] (P(VDF-TrFE)) since nanogratings in semiconductor polymers, such as P3HT and nanodots, in ferroelectric systems are viewed as systems with potential applications in organic photovoltaics or non-volatile memories.
