* Corresponding authors

^a School of Chemical Engineering, Shaanxi Key Laboratory of Degradable Medical Material, Northwest University, Xi'an 710069, Shaanxi, China
E-mail: lvxq@nwu.edu.cn
Fax: +86-29-88302312
Tel: +86-29-88302312

^b School of Chemistry, Eastern Illinois University, Charleston, IL 61920, USA
E-mail: hhe@eiu.edu

^c Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, P. R. China
E-mail: wai-yeung.wong@polyu.edu.hk

^d Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen 518057, China
E-mail: wai-yeung.wong@polyu.edu.hk