1. Department of Chemistry and Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 701, Taiwan, Department of Applied Chemistry, National Chi Nan University, Nantou, Puli, 545, Taiwan, and Institute of Oral Medicine and Department of Stomatology and Center for Micro/Nano Science and Technology, National Cheng Kung University, Tainan 701, Taiwan