Foremost, I would like to express my deepest gratitude to my supervisor, Associate Professor Lin Zhiping and co-supervisor, Professor Liu Ai Qun for their constant support, professional guidance and continuous encouragement through my four years of Ph.D. study and research. Without their insightful comments and constructive suggestions, I would not have completed my Ph.D. research and this thesis. Their insightful, passionate and strict attitude towards research works will continuously benefit me throughout my lifetime. I would also show my gratitude to Professor Kar-Ann Toh, Associate Professor Sun Lei and Dr. Zhang Jing Bo for providing great help and support to my research works. I sincerely thank the technicians from the Center for Bio Devices and Signal Analysis for their technical support during my Ph.D. study. I would like to thank Nanyang Technological University for the four years financial support of my Ph.D. scholarship. During the years of my Ph.D. study, I have been in the company of numerous wonderful friends. I have enjoyed spending my time with Mr. Liang Yunfeng, Mr. Peng Siyuan, and Mr. Zhuang Huiping. I benefit a lot from their help in my daily life. Finally, and most importantly, I would like to thank my beloved family for the endless love and unconditional support throughout the journey of my study.