Biodegradable Hydrogels as Drug Delivery Systems for Tissue Engineering Applications pp. 459-474
Authors: Kacey G. Marra, Alicia J. DeFail, Division of Plastic and Reconstructive Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, USA, and others
Abstract: Tissue engineering is a potential therapeutic strategy which combines scaffolds, cells, and/or growth factors that provide a suitable environment to direct the growth of new, healthy tissue. Scaffolds that are biodegradable, biocompatible, mechanically support tissue growth, and can be shaped to fill an irregularly shaped defect are ideal. Polymeric poly(lactic-co-glycolic acid) (PLGA) biomaterials are among the most widely studied tissue-engineered scaffolds. However, polymeric hydrogels, such as poly(ethylene glycol) (PEG) are also being examined as drug delivery scaffolds. Delivery of drugs or growth factors from these scaffolds is desirable to enhance tissue regeneration. The delivery of drugs or growth factors can be controlled by various parameters such as drug loading, polymer composition, and processing techniques. Drugs can also be encapsulated in microspheres or nanospheres for controlled delivery. Other methods of delivery include adsorption of drugs or growth factors to the surface prior to implantation or incorporation during the scaffold fabrication process. The incorporation of microspheres within PLGA scaffolds, fibrin scaffolds, gelatin scaffolds, and poly(ethylene glycol)-based hydrogels is also an option. This chapter describes several of these approaches that results in a controlled, localized release of drugs from the biomaterials. Clinical applications that will be discussed include bone regeneration, breast cancer adjuvant therapies, and nerve regeneration.