1. Department of Chemical Engineering, Faculty of EngineeringChulalongkorn University, Phayathai Road Bangkok 10330 Thailand
2. Department of Materials Science and TechnologyNagaoka University of Technology, 1603‐1 Kamitomioka Nagaoka Niigata 940‐2188 Japan
3. Biomaterial Engineering for Medical and Health Research UnitChulalongkorn University, Phayathai Road Bangkok 10330 Thailand