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The key challenge in tissue engineering is to develop structures with sufficient characteristics that will replicate the natural extracellular matrix (ECM) to promote tissue regeneration. Copper and manganese minerals substituted hydroxyapatite (CuMn-HA)/chitosan (CTS)–polyvinyl pyrrolidone (PVD) were fabricated by sol–gel and solvent casting techniques, respectively. Fabricated biocomposites have been identified by the use of Fourier transform infrared (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) for the analysis of functional groups, crystalline phases and surface morphology. The XRD and FTIR spectra of the biocomposite revealed the existence of functional groups and crystalline phases in the biocomposites. The SEM images revealed biocomposite and inclusion of CuMn-HA in rough morphology. Physicochemical characteristics such as swelling and compressive strength have been examined in the preparation of biocomposite materials. Biocomposites (10, 20, 30 wt% of CuMn-HA biocomposite) exhibited great material characteristics where 30% displayed the minimum swelling and a compressive property of 71 MPa was tested. It displayed the highest inhibition zone towards bacteria population and was also found to be blood-compatible with a haemolytic value of only about 2.5% relative to other compounds. Finally, in-vitro cell cultures were performed in biocomposite scaffolds to determine the effects of CuMn-HA on the proliferation of osteoblast cells, resulting in biocomposites contrast to pristine PVD/CTS. [ABSTRACT FROM AUTHOR]

A novel nanofibrous chitosan-based composite containing affinin and silver nanoparticles is obtained by electrospinning. Silver nanoparticles are synthesized by sunlight photoreduction of the metal complex [Ag-(affinin)](NO) in polymeric solution, via a green one-pot methodology, wherein chitosan and affinin act as reducing, dispersing and stabilizing agent. [ABSTRACT FROM AUTHOR]

A novel clay mineral biocomposite, chitosan-modified sepiolite (CMSEP), was prepared and used as adsorbent to remove atrazine from water. The adsorption behaviors including thermodynamic and kinetic parameters, effect factors and mechanisms of atrazine adsorption on CMSEP were studied. The results show that the adsorption capacity of atrazine on CMSEP increases with increasing temperature. Protonation of chitosan in biocomposite can improve adsorption ability of the composite to a certain extent. The parameters Δ G, Δ H and Δ S are −1.48-2.69 kJ/mol, 7.54 kJ/mol and 30.28 J/mol, respectively. Langmuir isotherm is proved to describe the adsorption data better than other isotherms with a maximum adsorption capacity of 17.92 mg/g, suggesting that the adsorption process is homogeneous. Pseudo-second-order kinetic model can fit the adsorption kinetic processes well although intraparticle diffusion can not be discarded. Briefly, CMSEP has potential value in the removal of atrazine from water and wastewater. [ABSTRACT FROM AUTHOR]

This work is part of a project aimed at developing a new biocomposite material that can be used for thermal insulation purposes. This material is mainly composed of sunflower stem chips. A chitosan-based biomatrix is used as binder between them. We focus here only on the mechanical response of this biocomposite. The goal is to investigate experimentally the link between its macroscopic response and phenomena which occur at the scale of the constituents, namely the bark and pith chips. The grid method, which is one of the full-field measurement systems employed in experimental mechanics to measure displacement and strain fields, is employed because of the very heterogeneous nature of this material. This heterogeneity is not only due to the contrast in rigidity between bark and pith, but also to the presence of voids within the material. These voids, as well as the presence of pith, lead us to develop and employ a specific marking procedure for the specimen surface under investigation. Two values for the mass percent fraction of chitosan are investigated, to observe the influence of this parameter on the global stiffness of the material and on local phenomena that occur in its bulk. The full-field measurement technique employed here leads us to detect and quantify significant heterogeneities in the strain fields, which are closely related to the material heterogeneities themselves. [ABSTRACT FROM AUTHOR]

A resorbable composite which acts as a active barrier in guided bone regeneration was fabricated using chitosan, demineralized bone matrix and bone ash. Its potential to form bone like apatite in simulated body fluid was assessed in this study. The mechanical strength of these composites was correlated with bone ash ratios and composites with better tensile strength were studied for their acellular bioactivity by incubating in simulated body fluid for 21 days. Composites without bone ash did not show acellular bioactivity which was confirmed by thermogravimetric analysis. In case of biocomposites with bone ash, there was an increase in residual weight indicating the mineralization of the composite. The composite containing bone ash has shown the peaks related to phosphate vibrations in its Fourier-transform infrared spectrum. Scanning micrographs revealed formation of apatite like crystals on its surface. Ca/P ratio was found to be 1·7 which is nearer to that of natural bone. Thus, prepared composites can be used as resorbable biocomposite in maxillofacial and oral defects. [ABSTRACT FROM AUTHOR]