Biocompatibility of materials and its relevance to drug delivery and tissue engineering

Abstract All materials intended for application in humans as biomaterials, medical devices, or prostheses undergo tissue responses when implanted into living tissue. Similarly, when blood contacts a biomaterial surface, a variety of blood components interfere with the surface leading to thrombosis or complement activation. This chapter first describes fundamental aspects of tissue/blood responses to materials, which are commonly described as the tissue/blood response continuum. These actions involve fundamental aspects of tissue responses including injury, inflammatory and wound healing responses, foreign body reactions, and fibrous encapsulation of the biomaterial, medical device, or prosthesis. The second part of this chapter describes the biocompatibility of materials being used in medical device and prostheses to suit their applications. The review includes an emphasis on the biocompatibility of biomaterials being used in drug delivery and micro- and nanospheres for cancer drug delivery and tissue engineering applications. This also summarizes the use of scaffolds in the dual role of structural support for cell growth and vehicle for controlled release of tissue inductive factors or DNA encoding for these factors. The confluence of molecular and cell biology, materials science, and engineering provides the tools to create controllable microenvironments that mimic natural developmental processes and direct tissue formation for experimental and therapeutic applications and for improving the biointegration of implants. This ends with the recent approaches toward combination therapy devices such as stent modifications with surface engineering and site-specific drug delivery.