Biomimetic fabrication of mineralized composite films of nanosilver loaded native fibrillar collagen and chitosan.

Silver nanoparticles loaded fibrillar collagen-chitosan matrix (CC) was prepared by biomimetic approach by blending silver nanoparticles (tAgNPs), collagen fibril and chitosan hydrogel followed by cross-linking and biomineralization. Electron micrograph showed that the surface of the composites exhibited native fibrillar morphology of collagen and their cross-section revealed layer-like arrangement of native fibrillar collagen. The mineralized composites exhibited surface mineralization of calcium phosphates incorporated with magnesium. FT-IR ATR analysis revealed the uniform blending of collagen and chitosan without any chemical interaction between them. XRD analysis showed incorporation of silver nanoparticles and lamellar structure of collagen and chitosan. The mechanical property of the dry composite film showed increase in tensile strength with the addition of chitosan and raised to 4.6 fold in M-CC4 composite. The incorporation of chitosan in M-CC3 led to 2.2 fold increase in mineralization as confirmed by the TGA analysis. Contact angle analysis revealed the hydrophilic nature of the composite. Hemolysis analysis of the composites verified the hemocompatible nature of composites with hemolysis < 5%. MTT assay for the composites was carried by seeding MG-63 cells and indicated cell viability > 80%. Antibacterial activity analysis showed the percent growth inhibition of about 27% and 37% for S. aureus and E. coli respectively. The prepared composite would possess silver nanoparticles loaded collagen fibril in the native state and the formed biomineral will be similar to the bone mineral. Hence the fabricated composite -could be used as a biomaterial for bone tissue engineering applications.

Silver ion impregnated composite biomaterial optimally prepared using zeta potential measurements.

Biodegradable, antimicrobial composite of various silver ion concentrations was synthesized using zeta potential and isoelectric point measurements, for a controlled release of silver ions, and in addition to assess the effect of protein adsorption with the increase of the silver ion concentration. The interaction between hydroxyapatite (HAp) and silver incorporated hydroxyapatite (AgHAp) with gelatin was increased by optimally adjusting the zeta potential and isoelectric point of the ceramic (HAp and AgHAp), and bio-polymer individually. The electrostatic interactions between the ceramic and biopolymer were confirmed, through shifts in N-H stretching, decrease in the swelling ratio, and increase in the degradation temperature observed by the derivative thermo-gravimetric analysis (DTG). These results substantiate that, the zeta potential is a novel tool to increase the ceramic-biopolymer interaction. Increasing electrostatic interaction between the biopolymer and ceramic, decreases the release of silver ions in the simulated body fluid, due to the controlled degradation of the biopolymer. The isoelectric point decreases with the increase of the silver ion concentration, which evidenced the change in the net surface charge. With the increase of the silver ion concentration, the protein adsorption decreases due to an increase in hydrophilic character of the composite. This study examines the minimum concentration of silver ion essential for maximum protein adsorption, antimicrobial and hemocompatibility. This study provides a novel route to control the release of silver ions by enhancing the ceramic-polymer interaction and estimate the silver ion concentration suitable for protein adsorption. The prepared composite is nontoxic, degradable, and antimicrobial, with the controlled release of silver ions in the simulated body fluid.