Tribological properties of biocompatible Ti-10W and Ti-7.5TiC-7.5W.

This study investigates and compares the microstructure, biocompatibility, and tribological properties of two different Ti-based composites, Ti-10W and Ti-7.5TiC-7.5W, with those of pure Ti for their potential use in biomedical applications. In particular, cold and hot isostatic-pressing and arc-melting methods were utilized and compared for the microstructure of the composites. Nano-scratch measurements and pin-on-disk wear tests were employed to understand their tribological behavior. As compared to pure Ti, Ti-10W and Ti-7.5TiC-7.5W showed significantly improved nano-scratch resistance (by 85 and 77%, respectively) and wear resistance (by 64 and 66%, respectively), in good agreement with hardness measurements. For biocompatibility examination, both microculture tetrazolium test (MTT) and water soluble tetrazolium (WST-1) test were used to quantify the cell viability of human osteoblasts and mouse fibroblasts on the materials. Both of the Ti-based composites showed acceptable biocompatibility in comparison with the pure Ti control.

Preparation of water-soluble chitosan/heparin complex and its application as wound healing accelerator.

To make effective wound healing accelerator, water-soluble chitosan (WSC)/heparin (CH) complex was prepared using WSC with wound healing ability and heparin with ability to attract or bind growth factor related to wound healing process. Water-soluble CH complex was prepared by the reaction between WSC and heparin, and then, by adding distilled water to it, ointment type with high viscosity was made. To evaluate the wound healing effect, full thickness skin excision was performed on the backs of the rat and then WSC and water-soluble CH complex ointments were applied in the wounds, respectively. After 15 days, gross and histologic examination was performed. Grossly, untreated control group revealed that the wound had well defined margin and was covered by crust. The second group treated with WSC ointment revealed small wound size with less amount of covering crust and ill-defined margin, which appeared to regenerate from margin. The third group treated with water-soluble CH complex ointment appeared to be nearly completely healed. Histology of each group was well correlated to gross findings. The third group shows nearly complete regeneration of appendage structure similar to normal in the dermis in contrast to control and second group with absence and less number of skin appendages, respectively.