Synthesis of new bio-based hydrogels derived from bile acids by free-radical photo-polymerization

In this article, the study on the swelling and thermal behaviors of a new series of bile acid-based polymeric hydrogels is reported. For this purpose, in the first step, the reduction of carboxyl acid groups of some common bile acids including cholic acid (CA), chenodeoxy cholic acid (CDCA), and lithocholic acid (LCA) to the corresponding alcohols by lithium aluminum hydride (LiAlH₄) in THF solution is performed. Then, hydroxyl functionalities of the obtained products are reacted with the acryloyl chloride in the presence of triethylamine (TEA). Finally, the cross-linking reactions between acryloyl functionalized bile acids and methoxy poly(ethylene glycol) monomethacrylate (MPEGMA) are conducted by free-radical photo-polymerization technique at λ = 350 nm in the presence of 2,2-Dimethoxy-2-phenylacetophenone (DMPA) as an initiator to achieve the desired bile acid-based polymeric hydrogels. The resulting hydrogels and their intermediates are characterized by Fourier transform infrared (FT-IR) and Proton nuclear magnetic resonance (¹H-NMR) spectroscopies. The swelling and thermal behavior of the obtained hydrogels indicates that the hydrogel starting from cholic acid is more swellable and has enhanced thermostability compared to others. Thus, the results of this study offer beneficial insights to researchers working in particularly bio-medical industry.