Chapter 12. Methods for Sterilization of Biopolymers for Biomedical Applications

Biopolymers have been found useful in biomedical applications because of their biocompatibility and degradability in the human body. Biopolymers can be formed naturally in living organisms and include polypeptides from proteins, polysaccharides from polymeric carbohydrates, and polynucleotides from nucleic acids – deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). Biopolymers can also be synthesized by using natural biological materials such as starch, sugars, fats, cellulose, and oils. Unsterilized biopolymers can cause severe infections in the human body when they are used for biomedical applications. Hence, biopolymers are required to undergo sterilization, which is a process to inactivate microorganisms including bacteria, spores, fungi, and viruses. The biopolymers that have been sterilized include both natural and synthetic biodegradable polymers such as chitosan, hyaluronic acid, polylactic acid, poly-l-lactic acid, and poly(lactide-co-glycolide), and are reviewed in this chapter. Sterilization methods that have been applied to biopolymers, including steam-autoclaving, dry heat sterilization, irradiation (gamma (γ)-rays, X-rays, ultraviolet, and electron beams), chemical treatment (ethylene oxide), gas plasma, and supercritical fluid sterilization, are reviewed.