Fabrication of silver doped nano hydroxyapatite-carrageenan hydrogels for articular cartilage applications

It can be found from the results that nano hydroxyapatite- silver -3.0 wt% carageenan (nHA-Ag-CG3.0) improved the mechanical properties of the as-formed hydrogel scaffold after incorporation of higher CG concentration. The Youngs modulus of hydroxyapatite- silver - 1.5wt% carageenan (nHA-Ag-CG1.5) was found to be 0.36 {+/-} 0.07 MPa that increased in case of nHA-Ag-CG3.0 demonstrating better interfacial compatibility of their matrix with respect to the reinforcement. This increase in reinforcement concentration resulted in higher stiffness that dissipated energy. The higher swelling ratio is envisaged to induce better cell adhesion and proliferation. The biodegradability test was performed in phosphate buffered saline at body temperature for 3 weeks. The biodegradability rate of nHA-Ag-CG1.5 was found to be equivalent to nHA-Ag-CG3.0 hydrogels at day 7 while it increased faster in nHA-Ag-CG3.0 on days 14 and 21 that may be ascribed to the possible interaction of nHA and Ag with their CG matrix. The bacterial cell viability of Staphylococcus aureus (S. aureus) was performed after 10 h, 20 h and 30 h of culture. The nHA-Ag-CG1.5 exhibited restrained growth of S. aureus as compared to nHA-Ag-CG3.0 and these results were validated by CLSM analysis. Hence, nHA-Ag-CG3.0 may be considered to have more cytocompatibility than nHA-Ag-CG 1.5.