1. Key Laboratory of Synthetic and Natural Functional Molecule of the Ministry of Education, College of Chemistry & Materials Science, Northwest University, Xi’an, Shaanxi province 710127, P. R. China
2. Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education; Biomedicine Key Laboratory of Shaanxi Province; Lab of Tissue Engineering, the College of Life Sciences, Faculty of Life Science & Medicine, Northwest University, Xi’an, Shaanxi province 710069, P. R. China