Chapter 3 - Proteins and Poly(Amino Acids)

Abstract

Over the last two decades, significant advances have been made in the development of natural and synthetic biomaterials for biomedical applications. The overarching goal for most of these biomaterials is its ability to closely mimic native extracellular matrix of tissues. Most common sources of natural biomaterials have been of allogeneic origin, primarily due to its biocompatibility and ability to remodel in situ and eventually degrade to allow for tissue repair and regeneration. The most common of them being collagen, fibrin, elastin, and more recently silk. However, the cost associated with acellular allogeneic or xenogeneic tissues and its minimal availability has lead to development and characterization of other classes of protein-derived biomaterials. One such class, poly(amino acids) (PAA), composed of polymeric chains of single or multiple amino acids, has been receiving tremendous interest over the last decade. Such PAA-derived materials have been applied in several areas of biomedical engineering including coatings for therapeutic devices, scaffolds for tissue engineering, and as micro- and nanoparticles for controlled release. This review summarizes the synthesis, fabrication, characterization, and critical applications of some of these common poly(amino acids), such as poly(glutamic acid), poly-l-lysine, poly(aspartic acid), and cyanophycin, and the recent advances made in this area over the last 20 years.