Content uploaded by Min Zhang
Author content
All content in this area was uploaded by Min Zhang on May 29, 2018
Content may be subject to copyright.
A preview of the PDF is not available
The Preparation of Cellulose/Collagen Composite Films using 1-Ethyl-3-Methylimidazolium Acetate as a Solvent
Abstract and Figures
Cellulose/collagen composite films with weight ratios of 30/1 (Blend-1) and 10/1 (Blend-2) were prepared using 1-ethyl-3-methylimidazolium acetate as a common solvent. The morphology of the films observed with a field-emission scanning electron microscope displayed a dependence on the ratio of cellulose/collagen. Collagen was successfully composited with cellulose without degradation and showed a denaturation temperature (Td) higher than that of native collagen. Fourier transform infrared spectroscopy suggested that there were hydrogen-bond interactions between collagen and cellulose in the regenerated composite films. Thermogravimetric analysis revealed that the maximum decomposition temperature (Tmax) of cellulose decreased after regeneration, while the Tmax of Blend-1 increased; however, it was reduced again for Blend-2. Elastic moduli from dynamic mechanical analysis exhibited a trend similar to that of Tmax. As indicated by X-ray diffraction, the distance between cellulose molecular chains was shortened for Blend-1 and elongated for Blend-2. Furthermore, the crystallization indices were calculated to be 75.3%, 68.3%, 66.2%, and 55.4% for native cellulose, regenerated films of cellulose, Blend-1, and Blend-2, respectively. These results confirm the dependence of the structural properties of composite films on cellulose/collagen ratios through the interactions between cellulose and collagen.
Figures - uploaded by Min Zhang
Author content
All figure content in this area was uploaded by Min Zhang
Content may be subject to copyright.
... [Ac] a common solvent and they have been also used in regenerating triple helical structure, which is indicative of potential applications in tissue engineering [23]. Similarly, the solubility and dispersion degree of calf skin collagen in [EMIM] [Ac] and [EMIM] [BF 4 ] has also been investigated and they found out that the aggregation of collagen decreases with increase in ionic liquids polarity [24]. ...
... Also, it is important to know the effect on protein structure and how it affects protein stability. Frameworks and methodologies are critical for end-to-end understanding and that applies for a range of [21][22][23][24][25][26][27][28][29] Decrease in the stability of protein with the increase in concentration of ammonium-based ionic liquid [59] Destabilized the collagen to a larger extent [60] Competitive bonding between collagen & ionic liquids leading to destabilization of collagen [70] Can be utilized as biocompatible cross-linkers for the preparation of collagenbased biomaterials owing to stabilization effect [27,[76][77][78] ...
Owing to highly tunable nature, ionic liquids are nesting stance in the scientific community for a wide variety of applications ranging from electrochemistry to product purification, from chemical and biomedical applications to biotechnological interventions and proteomics. Proteins are unstable in its native form and several attempts have been made to stabilize them by addition of various additives. This review focusses on the studies conducted to improve protein stability with ionic liquids along with an emphasis on the mechanism of interaction. This review also specifies and discusses about the brief introduction to ionic liquids, evolution of first-, second-, and third generation of liquids over the years and their selection criterion and applications. Though, there are several elegant reviews available on proteins-ionic liquids interaction, this review systematically highlights the effect of ionic liquids viz., imidazolium, ammonium, phosphonium and choline-based ionic liquids (amino acid-based anions & classical anions) on fibrous proteins viz., collagen and keratin and globular proteins viz., bovine serum albumin and cytochrome c. Thus, this review elaborates the thorough investigations conducted to explore the stabilizing properties of ionic liquids over fibrous and globular proteins.
... [Ac] a common solvent and they have been also used in regenerating triple helical structure, which is indicative of potential applications in tissue engineering [23]. Similarly, the solubility and dispersion degree of calf skin collagen in [EMIM] [Ac] and [EMIM] [BF 4 ] has also been investigated and they found out that the aggregation of collagen decreases with increase in ionic liquids polarity [24]. ...
... Also, it is important to know the effect on protein structure and how it affects protein stability. Frameworks and methodologies are critical for end-to-end understanding and that applies for a range of [21][22][23][24][25][26][27][28][29] Decrease in the stability of protein with the increase in concentration of ammonium-based ionic liquid [59] Destabilized the collagen to a larger extent [60] Competitive bonding between collagen & ionic liquids leading to destabilization of collagen [70] Can be utilized as biocompatible cross-linkers for the preparation of collagenbased biomaterials owing to stabilization effect [27,[76][77][78] ...
Owing to highly tunable nature, ionic liquids are nesting stance in the scientific community for a wide variety of applications ranging from electrochemistry to product purification, from chemical and biomedical applications to biotechnological interventions and proteomics. Proteins are unstable in its native form and several attempts have been made to stabilize them by addition of various additives. This review focusses on the studies conducted to improve protein stability with ionic liquids along with an emphasis on the mechanism of interaction. This review also specifies and discusses about the brief introduction to ionic liquids, evolution of first-, second-, and third generation of liquids over the years and their selection criterion and applications. Though, there are several elegant reviews available on proteins-ionic liquids interaction, this review systematically highlights the effect of ionic liquids viz., imidazolium, ammonium, phosphonium and choline-based ionic liquids (amino acid-based anions & classical anions) on fibrous proteins viz., collagen and keratin and globular proteins viz., bovine serum albumin and cytochrome c. Thus, this review elaborates the thorough investigations conducted to explore the stabilizing properties of ionic liquids over fibrous and globular proteins.
... In terms of DTG curve analysis, the Td max1 temperature (maximum degradation rate temperature) for the polymer blends exceeds that of the PCL polymer. This increase in the maximum degradation temperature values may be related to the compatibility of these two polymers and the presence of intermolecular interactions between them [41][42][43] . ...
... Accompanied by the increased hydrogen bond, the denser structure helped to reduce the mobility of chains and restrained the chain unzipping during the degradation process [42]. As a result, the system required higher energy to decompose completely, thus increasing the thermal decomposition temperature of the films [43][44][45]. When CNF was added to collagen films, there was further increase in degradation temperature. ...
This study examines the effect of three collagens and the addition of carboxymethylated cellulose (CNF) on the properties of collagen-based film. The three collagens include macroscale collagenous fiber bundle (Ma-COL), microscale collagen fiber (Mi-COL), and nanoscale collagen fibril (Na-COL). With the decrease of the collagens' size, the viscosity of the dispersions decreased dramatically, besides, the collagen-based film showed an increased elastic modulus (from 13.32 GPa to 24.47 GPa) and tensile strength (from 46.18 MPa to 72.73 MPa). The opacity first decreased and then increased when the collagen's size ranged from macro-to nanoscale. The decrease of collagen's size could increase the film density and possessed more hydrogen bonds of film captured by FTIR. The addition of CNF further intensified the above trends. Besides, the reinforcing mechanisms of CNF could be proved by the combination of pull-off and intercrystalline fracture from microstructure and the finite element models.
... Similar works were carried out by Meng et al. [101] who found partial loss of triple helical structure in [Bmim][Cl] induced collagen during dissolution and regeneration. Zhang et al. performed experimental and computer analyses on cellulose/collagen films through using [Emim] [Ac] and utilized to regenerate triple helical structure, suggestive of potential uses in tissue engineering [102,103]. ...
Biopolymeric materials have been studied extensively over the past few decades because of their intrinsic biological characteristics and remarkable biocompatibility. The noticeable solubility of most of the biopolymers and lignocellulose matrices in ionic liquids (ILs) have paved new avenues in biopolymer dissolution, regeneration, and their subsequent employment as biomaterials. The literature suggests that diversifications in precursor raw material origin, extraction methods, polymer’s quality, and polymorphic forms play an indispensable role in ILs-mediated dissolution of biopolymers. ILs have not only furnished sturdy performance in the development of lignocellulose-based biorefinery but have also produced highly promising opportunities in exploiting biomolecules like chitin, chitosan, silk, and keratin in context of biorefinery. The goal of this chapter is to briefly summarize the recent progress in the use of ILs for dissolution, processing, and as reaction media for the functionalization of peculiar biopolymers for promising medical, biomaterial, and other applications.
... The reported moduli (E′) of our hybrid poplar films are superior to that of microcrystalline cellulose films (5.5 kPa), also regenerated from [EMIM] [OAc], and comparable to crosslinked chitosan films (4−8 GPa). 52,53 As given in Table 3, the HWE films undergo an alpha transition (T α ) around 185−208°C , followed by a rubbery plateau, which is characteristic to that of cross-linked or entangled polymeric materials. However, considering the very high T g of the rigid lignin phase (>200°C) and the temperature range (275−300°C) at which these films reached a modulus plateau, it may be wise to assume that the lignin fraction might have undergone partial degradation in the rubbery region. ...
... The difficulties in the solubility of cellulose can be overcome by electrospinning cellulose ester derivatives followed by regeneration to the cellulose. 26,27 In this study, chitosan-collagen hydrogel composite scaffolds comprising 3D printed PLA strut and nanofibrous cellulose were produced for meniscus cartilage regeneration. Poly(lactic acid) strut was embedded in the nanofibrous structure to have improved mechanical properties and homogenously distributed micro channels as well as, micro-and nano-sized topographical features were combined to obtain better cellular performance. ...
The main goal of the study was to produce chitosan-collagen hydrogel composite scaffolds consisting of 3D printed poly(lactic acid) (PLA) strut and nanofibrous cellulose for meniscus cartilage tissue engineering. For this purpose, first PLA strut containing microchannels was incorporated into cellulose nanofibers and then they were embedded into chitosan-collagen matrix to obtain micro- and nano-sized topographical features for better cellular activities as well as mechanical properties. All the hydrogel composite scaffolds produced by using three different concentrations of genipin (0.1, 0.3, and 0.5%) had an interconnected microporous structure with a swelling ratio of about 400% and water content values between 77 and 83% which is similar to native cartilage extracellular matrix. The compressive strength of all the hydrogel composite scaffolds was found to be similar (∼32 kPa) and suitable for cartilage tissue engineering applications. Besides, the hydrogel composite scaffold comprising 0.3% (w/v) genipin had the highest tan δ value (0.044) at a frequency of 1 Hz which is around the walking frequency of a person. According to the in vitro analysis, this hydrogel composite scaffold did not show any cytotoxic effect on the rabbit mesenchymal stem cells and enabled cells to attach, proliferate and also migrate through the inner area of the scaffold. In conclusion, the produced hydrogel composite scaffold holds great promise for meniscus tissue engineering.
Shaping cellulose into functional materials entered a new era with the introduction of ionic liquids as novel, green solvents about 20 years ago. As non-volatile solvents with high thermal and chemical stability, ionic liquids can provide an environmentally more benign tunable platform for cellulose processing, compared to existing technologies. The past decades have seen fruitful efforts devoted to the development of materials based on ionic liquid/cellulose processing systems. In this review we discuss the experiences gained, and highlight the emerging applications. In particular, coatings and thin film applications for structural materials (e.g., for packaging), thin film filtration membranes, immobilisation of enzymes, and catalytically active nanoparticles, separator membranes and conductive composites for energy storage and other electronics applications, cellulose/biopolymer green biocomposites, cellulose-based ionogels, hydrogels and aerogels, and cellulose-based or composite fibres will be discussed in detail. We will also take a critical look at the perspectives of this field. The use of a certain grade of technical cellulose, and the purity of the prepared materials should be more carefully justified in the future, as they have an influence not only on the properties of the fabricated material, but also on the economics of the process. Furthermore, to make ionic liquids truly green solvents, and competitive alternatives to existing technologies, more studies are needed on recyclability after material fabrication, and on ways to minimise the energy consumption of such processes, among other issues.
Owing to their inherent biocompatibility and biodegradability, biopolymer-based materials are a good replacement for synthetic materials. We prepared cellulose-based films blended with various biopolymers by co-dissolution in 1-ethyl-3-methylimidazolium acetate followed by regeneration in ethanol. Cellulose was blended with bacterial cellulose, β-cyclodextrin, dextran, starch, agarose, agar, arabic gum, κ-carrageenan, chitosan, tragacanth gum, xanthan gum, xylan, lignin, gelatin, collagen, and silk. Physicochemical properties including surface morphology, thermal properties, optical properties, and hydrophilicity/hydrophobicity of the blended films were highly dependent on the biopolymer types. The altered properties of the blended films influenced the adsorption capacity for dyes and proteins and cytotoxicity. The adsorption capacity of a cellulose/chitosan film for methyl orange was 9.1-fold higher, that of a cellulose/silk film for crystal violet was 7.9-fold higher, and that of a cellulose/chitosan film for lysozyme was 7.9-fold higher than that of cellulose film. Gelatin as a blending biopolymer most efficiently enhanced cell viability.
Ionic liquids represent a unique class of solvents that offer unprecedented versatility and tunabil-ity. Nature has developed a wide variety of materials based upon both proteins and polysaccharides. Many of these materials have unique properties that are a function not only of the material identity but are also largely dictated by processing conditions. Recent work has shown the potential of ionic liq-uids as solvents for the dissolution and processing of biopolymers. In this research we have expanded upon the limited data available to date using several biopolymers including: silk, chitin, collagen and elastin.
The production of cellulose/chitosan blends in alkyl imidazolium ionic liquids (ILs) was studied in this work. Selected organic solvents, such as dimethyl sulfoxide, ethyl acetate, and diethyl ether, were used as cosolvents. The addition of cosolvents decreased the viscosity of cellulose/chitosan solutions in ILs and facilitated the dissolution of polysaccharides, thereby decreasing the and polymer aggregates sizes in the solutions. The cellulose/chitosan films were produced from the studied solutions. The presence of one of cosolvent and ILs in the blended films was confirmed by FTIR spectroscopy. The blended film is stronger than pure cellulose film, and the addition of cosolvents has an influence on its mechanical properties.
1. Abstract2. Introduction3. Methods3.1. Electrospinning3.2. Scaffold Characterization3.3. Cell Lines and Cell Culture3.4. Scaffolding Crosslinking, Disinfection, Seeding, and Culture3.5. Preliminary Fabrication of a Three Layered Vascular Construct3.6. Histology4. Results4.1. Electrospinning Collagen4.2. Electrospinning Elastin4.3. Electrospinning Collagen/Elastin Blend4.4. Preliminary Fabrication of a Three Layered Vascular Construct5. Discussion6. Acknowledgements7. References
The solubility of collagen from squid (Illex argentinus) skin in salt solutions and the efficiency of removal of skin chromatophores were determined. Homogenization of minced squid skin in 5-15% NaCl solution at 0 degrees C solubilized 35-24% of total amount of crude protein and caused 2-5% loss of collagen but was not effective in removing pigments from the skin. The treatment of whole squid skins in 5-15% NaCl solutions at room temperature led to separation of the chromatophores, but the loss of soluble collagen was 57-16%. Collagen, soluble in dilute acid solutions was isolated from squid skins by 24 h soaking in 10% NaCl solution at room temperature, washing with water and bleaching for 48 h in 1% H2O2 in 0.01 M NaOH. The yield of collagen was 53%. It could be increased to 90% by using NaOH solution at pH 11.5 instead of 10% NaCl but the isolate was less soluble in dilute acid and the viscosity of 0.5% dispersion of collagen was four times lower. The rancid off-odour could be prevented by adding 0.5% of a nonionic detergent to all solution used in the procedure.
Collagen, a prominent biopolymer, which is famous for its excellent biological activity, has been used extensively for tissue engineering applications. In this study, a novel solvent system for collagen was developed with an ionic liquid, 1‐ethyl‐3‐methylimidazolium acetate ([EMIM][Ac]), solvent system. A series of sodium salts were introduced into this solvent system to enhance collagen's dissolution procedure. The results show that the solubility of collagen was significantly influenced by the temperature and sodium salts. The solubility reached up to approximately 11% in the [EMIM][Ac]/Na2HPO4 system at 45°C. However, the structure of the regenerated collagen (Col‐regenerated) may have been damaged. Hence, we focused on the structural integrity of the collagen regenerated from the [EMIM][Ac] solvent system by the methods of sodium dodecyl sulfate–polyacrylamide gel electrophoresis, Fourier transform infrared spectroscopy, ultrasensitive differential scanning calorimetry, atomic force microscopy, X‐ray diffraction, and circular dichroism because its signature biological and physicochemical properties were based on its structural integrity. Meanwhile, a possible dissolution mechanism was proposed. The results show that the triple‐helical structure of collagen regenerated from the [EMIM][Ac] solvent system below 35°C was retained to a large extent. The biocompatibility of Col‐regenerated was first characterized with a fibroblast adhesion and proliferation model. It showed that the Col‐regenerated had almost the same good biological activity as nature collagen, and this indicated the potential application of [EMIM][Ac] in tissue engineering. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2245–2256, 2013
Collagen and cellulose nanofiber based composites were prepared by solution casting followed by pH induced in situ partial fibrillation of collagen phase and crosslinking of collagen phase using gluteraldehyde. Microscopy studies on the materials confirmed the presence of fibrous collagen and cellulose nanofibers embedded in the collagen matrix. The cellulose nanofiber addition as well as collagen crosslinking showed significant positive impact on the nanocomposite’s mechanical behaviour. The synergistic performance of the nanocomposites indicated stabilization and reinforcement through strong physical entanglement between collagen and cellulose fibres as well as chemical interaction between collagen matrix and collagen fibrils. The mechanical performance and stability in moist conditions showed the potential of these materials as implantable scaffolds in biomedical applications. The collagen-cellulose ratio, crosslinking agent and crosslinking level of collagen may be further optimised to tailor the mechanical properties and cytocompatibility of these composites for specific applications such as artificial ligament or tendon.
The rising interest in the valorisation of industrial by-products is one of the main reasons why exploring different species and optimizing the extracting conditions of collagen and gelatin has attracted the attention of researchers in the last decade. The most abundant sources of gelatin are pig skin, bovine hide and, pork and cattle bones, however, the industrial use of collagen or gelatin obtained from non-mammalian species is growing in importance. The classical food, photographic, cosmetic and pharmaceutical application of gelatin is based mainly on its gel-forming properties. Recently, and especially in the food industry, an increasing number of new applications have been found for gelatin in products such as emulsifiers, foaming agents, colloid stabilizers, biodegradable film-forming materials and micro-encapsulating agents, in line with the growing trend to replace synthetic agents with more natural ones. In the last decade, a large number of studies have dealt with the enzymatic hydrolysis of collagen or gelatin for the production of bioactive peptides. Besides exploring diverse types of bioactivities, of an antimicrobial, antioxidant or antihypertensive nature, studies have also focused on the effect of oral intake in both animal and human models, revealing the excellent absorption and metabolism of Hyp-containing peptides. The present work is a compilation of recent information on collagen and gelatin extraction from new sources, as well as new processing conditions and potential novel or improved applications, many of which are largely based on induced cross-linking, blending with other biopolymers or enzymatic hydrolysis.
The solubility of collagen from squid (Illex argentinus) skin in salt solutions and the efficiency of removal of skin chromatophores were determined. Homogenization of minced squid skin in 5–15% NaCl solution at 0°C solubilized 35–24% of total amount of crude protein and caused 2–5% loss of collagen but was not effective in removing pigments from the skin. The treatment of whole squid skins in 5–15% NaCl solutions at room temperature led to separation of the chromatophores, but the loss of soluble collagen was 57–16%. Collagen, soluble in dilute acid solutions was isolated from squid skins by 24 h soaking in 10% NaCl solution at room temperature, washing with water and bleaching for 48 h in 1% H2O2 in 0.01 M NaOH. The yield of collagen was 53%. It could be increased to 90% by using NaOH solution at pH 11.5 instead of 10% NaCl but the isolate was less soluble in dilute acid and the viscosity of 0.5% dispersion of collagen was four times lower. The rancid off-odour could be prevented by adding 0.5% of a non-ionic detergent to all solution used in the procedure. ©