1. Institute of Biomedical Materials and EngineeringCollege of Materials Science and EngineeringQingdao University Qingdao 266071 P. R. China
2. Laboratory for New Fiber Materials and Modern TextileGrowing Base for State Key LaboratoryCollege of Chemistry and Chemical EngineeringQingdao University Qingdao 266071 P. R. China
3. Center for Bionanoengineering andKey Laboratory of Biomass Chemical Engineering of Ministry of EducationCollege of Chemical and Biological EngineeringZhejiang University Hangzhou 310027 P. R. China