Research Fellows Directory
Dr Xiang Zhang
The aim of this research is to understand the relationship between characteristics of nanostructure and biomaterials properties in relation to biological responses, in particular with regards to the effect of inorganic and organic hybrid composites on biocompatibility and/or bioactivity for biomedical applications. In this report, the progress made during last year 1 Apr 2015 – 31 March 2016 will be summarised as follows:
This year reports on progress of the project, in particular study the effect of particle size within a resorbable composite on the in vivo degradation rate and host response. Resorbable composites were developed which was a mixture of polyester with a bioceramic. The composite was formulated with grades of particle sizes: one micro meter and the other nanometre. The composites have shown suitable degradation, biological and mechanical properties for bone repair. Composites with nano-sized inorganic particles degrade more homogenously in vitro than equivalent composites with micro-sized particles. In this study, the polymer composites containing micro- or nano-sized particles were implanted into an ovine distal femoral condyle defect and harvested at 6, 12, 18 and 24 weeks. An intimate interface was observed between the new bone tissue and degrading implants. It was observed that bone growth into the implant site occurred at a similar rate for both composites and the polymer control. However, the in vivo degradation rate of the nanocomposite was slower than that of the microcomposite and consequently more closely matched the rate of bone growth. So far, the above work has shown good biological responses on the surfaces and improvement of biomechanical properties and conclude the size effect on the bone growth rate.