This book focuses on the application of micro and nano biosensors in microsystems, where an introduction to the fundamentals of various types of biosensors should be considered an integral element. After introducing the theoretical knowledge, authors discuss the application of biosensors in the detection of various biomolecules in combination with their own experience in the above research activities. In the process of introduction, authors keep abreast of the latest frontier research of biosensors to ensure that the book has sufficient novelty. From a practical point of view, this book bridges the gap between theoretical design and applied testing by frontline biomedical personnel in a more intuitive way. This book is aimed at graduate students majoring in micro/nano systems technology, instrument science and technology, and biomedical engineering, which is an interdisciplinary subject of electricity, optics, biology, mechanical engineering, modeling, and process technology.