Green Hydrogels Based on Starch: Preparation Methods for Biomedical Applications
Kevin J. Edgar, Joyann A. Marks
Abstract
Starch is a composite of two polysaccharides (amylose and amylopectin) that occurs naturally in a variety of plant sources, and is a critical source of nutrition for humans and other species. In many developing countries, starchy foods including yams, potato, rice, and corn, as well as the seeds of many types of fruit that are widely grown, represent important sources of starch. Hydrogels are versatile, porous, absorbent, crosslinked polymer networks that have found applications in many spheres. Hydrogels based on starch utilize this inexpensive, abundant resource in applications ranging from agricultural formulations, food preparation, oral drug delivery, scaffolding, hemostatic applications, dye absorption, and water purification, to name just a few. With the high cost often associated with preparation of biomaterials, it is crucial to focus on efficacious but lower cost formulations. Here we explore facile and environmentally friendly approaches to the preparation of starch hydrogels for biomedical applications. These approaches include a range of physical and chemical crosslinking methods including cryogelation, irradiation, polyelectrolyte complexation, and the use of facile chemical reactions with or without crosslinking agents.