Radiation synthesis of functional hydrogels and their biomedical applications

Abstract

Hydrogels are three-dimensional networks of hydrophilic homopolymers or copolymers generally covalently or ionically crosslinked. They interact with aqueous media by swelling to some equilibrium value by retaining the aqueous media in their structures. This study concerns the synthesis of functional hydrogles using irradiation and their biomedical applications. In this study, $\gamma$-ray was irradiated by making use of $^{60}Co$ radioisotope in Korea Atomic Energy Research Institute (KAERI) as a radiation source. This dissertation consists of seven chapters. Chapter 1 described general overview of hydrogels for biomedical applications and radiation technology. In chapter 2, a simple crosslinking method was introduced to prepare the PVA/Glycerin (PVA/Gly) hydrogels with the use of $\gamma$-irradiation instead of chemical reagents. An absorption ratio and thermal properties of the PVA/Gly hydrogels can be controlled by varying the irradiation dose and weight ratio of the PVA/Gly. The PVA/Gly hydrogels showed excellent absorption properties ($\gt350%$). In chapter 3, the effects of humectants, i.e. glycerin on the swelling and gelation of the PVA hydrogels were evaluated as a function of glycerin content and freezing and thawing (FT) cycles. Interestingly, the gelation increases while swelling decreases with increasing glycerin content. In chapter 4, the PVA/propylene glycol (PVA/PG) hydrogel patches with Curcuma longa, Indian spice turmeric with potent anti-inflammatory effect were prepared by the FT and the $\gamma$-ray irradiation for treatment of atopic dermatitis. It showed eminent healing results as a consequence of long-term moisturizing effects on atopic wounds. In chapter 5, biocompatible and pH-responsive poly(ethylene glycol)/acrylic acid (PEG/AAc) hydrogels were prepared by using the $\gamma$-irradiation for controlled oral drug delivery. The gel fraction was over 80% and the equal amounts of PEG and AAc blended hydrogel had efficient insulin loadin...