This paper describes the biosynthesis of a novel collagen-bacterial cellulose (COL/BC) composite by adding collagen to the culture medium of Acetobacter xylinum. The morphology of COL/BC composite was observed by SEM and TEM and compared with pristine BC. The composite was further characterized by FTIR and XRD. It is found that the structure of BC network changes when collagen is present in the nutrient medium. Further work is underway to gain insights into the mechanisms governing the experimental phenomena.

A combined procedure of sol-gel and microwave-assisted emulsion polymerization has been developed to prepare TiO2/polystyrene core-shell nanospheres with nano-scale TiO2 core and smooth and well-defined polystyrene shell. The core-shell structure and morphology were examined by TEM. The diameter and its distribution of the nanospheres were measured by dynamic light scattering. The nanospheres were characterized with Fourier transform infrared spectroscopy (FTIR). It is found that the diameter and its distribution of the TiO2/polystyrene core-shell nanospheres can be regulated by the concentration of styrene monomer in the emulsion solution.

Magnesium alloys are currently used in many structural applications. It is believed that magnesium and its alloys may also find applications in biomedical fields. In this study, a new biomedical magnesiumbased alloy, i.e., magnesium-calcium (Mg-Ca) has been designed from biological and metallurgical viewpoints. The microstructure, mechanical and corrosion behaviors of Mg-Ca alloys with varying calcium content were investigated. The results show that a magnesium alloy with 0.6 wt.% calcium content (denoted as Mg-0.6Ca) shows good corrosion and mechanical properties. Our preliminary results demonstrate a good potential of this Mg-0.6Ca alloy as a new biomedical material.

It is believed that magnesium and its alloys may find applications in biomedical fields as implants, bone fixation devices, and tissue engineering scaffolds. However, their corrosion rate must be controlled. In this study, biomedical magnesium-calcium (Mg-Ca) alloys were ion-implanted with zinc. The surface nanomechanical performance and corrosion behavior of the ion-implanted Mg-Ca alloys are determined. The results show that zinc ion implantation at a dose of 0.9×10 17 ions/cm2 significantly improves the surface hardness and modulus. However, the results on corrosion resistance reveal that zinc ion implantation degrades the corrosion behavior of Mg-Ca alloys. Thus, zinc is not a favorable element for the ion implantation treatment of biomedical Mg-Ca alloys.

The effect of copper ion implantation on the antibacterial activity, wear performance and corrosion resistance of medical metals including 317 L of stainless steels, pure titanium, and Ti-Al-Nb alloy was studied in this work. The specimens were implanted with copper ions using a MEVVA source ion implanter with ion doses ranging from 0.5×10 17 to 4×10 17 ions/cm2 at an energy of 80 keV. The antibacterial effect, wear rate, and inflexion potential were measured as a function of ion dose. The results obtained indicate that copper ion implantation improves the antibacterial effect and wear behaviour for all the three medical materials studied. However, corrosion resistance decreases after ion implantation of copper. Experimental results indicate that the antibacterial property and corrosion resistance should be balanced for medical titanium materials. The marked deteriorated corrosion resistance of 317 L suggests that copper implantation may not be an effective method of improving its antibacterial activity.