This book deals with a subject of high interest and importance in all sectors, including biomedical, food, agriculture, energy, and environment. Biological systems are essential in nanotechnology, and many new applications are being developed by mimicking the natural systems. Approaching these topics from an engineering perspective, the book offers insight on the details of nanoscale fabrication processes as well as cell biology. The basics of biology and chemistry, with a focus on how to engineer the behavior of molecules at the nanoscale, are also explored and analyzed. The aim of the text is to provide the reader with broader knowledge of biological methods for signal transduction and molecular recognitions systems and how they can be replicated in bio-sensing applications. The reader will learn the basic structures and interactions of biomacromolecules for developing biocompatible and eco-friendly devices.