1. Guangdong Provincial Key Laboratory of Advanced Biomaterials Department of Biomedical Engineering Southern University of Science and Technology Shenzhen 518055 P. R. China
2. Shenzhen Clinical Medical College Guangzhou University of Chinese Medicine Shenzhen 518000 P. R. China
3. Department of Neurosurgery Longgang Central Hospital of Shenzhen Shenzhen 518116 P. R. China
4. School of Materials and Environmental Engineering Shenzhen Polytechnic Shenzhen 518055 P. R. China