With the advancement in material chemistry, a range of novel materials have been introduced to healthcare, among them, silica has received a great attention due to its high biological compatibility. Furthermore, it´s composites with other materials have opens up realm of novel applications. This book embodies the appreciation of silica based metals nanocomposites by presenting their synthesis and application for very important sensing and healthcare sector. The entire material is presented in two sections divided in 10 chapters. The synthesis of Au-poly (dimethylsiloxane) nanocomposites by in-situ synthesis and galvanic replacement approach, characterization and functionalization for biosensing application using human serum albumin as a model system are described in Section A. While Section B deals with the synthesis, characterization and antimicrobial activity of silica-silver nanocomposites against both Gram positive and Gram negative bacteria. The most exciting and unique aspect of the book is that the utilization of these nanocomposites not only enhances the biosensing capabilities, but also brings out newer approaches in healthcare.