Design and Synthesis of Hybrid Thermo-Responsive Hydrogels Based on Poly(2-oxazoline) and Gelatin Derivatives

Annelore Podevyn; Sandra Van Vlierberghe; Peter Dubruel; Richard Hoogenboom

doi:10.3390/gels8020064

Design and Synthesis of Hybrid Thermo-Responsive Hydrogels Based on Poly(2-oxazoline) and Gelatin Derivatives

Gels. 2022 Jan 18;8(2):64. doi: 10.3390/gels8020064.

Authors

Annelore Podevyn^{1

2}, Sandra Van Vlierberghe², Peter Dubruel², Richard Hoogenboom¹

Affiliations

¹ Supramolecular Chemistry Group, Centre of Macromolecular Chemistry (CMaC), Department of Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281, 9000 Ghent, Belgium.
² Polymer Chemistry and Biomaterials Group (PBM), Centre of Macromolecular Chemistry (CMaC), Department of Organic and Macromolecular Chemistry, Ghent University, Krijgslaan 281, 9000 Ghent, Belgium.

Abstract

The combination of natural and synthetic polymers to form hybrid hydrogels offers the potential of fabricating new materials that possess a combination of properties resulting from both types of polymer classes. Within this work, two alkene-functionalized poly(2-alkyl/aryl-2-oxazoline) (PAOx) copolymers and one gelatin derivative, thiolated gelatin (gel-SH), are synthesized as precursors for hybrid hydrogels through a photo-induced radical thiol-ene crosslinking process. In-situ photo-rheology revealed an increased mechanical stability for hydrogels that possess an excess amount of PAOx precursor. A final qualitative investigation of the thermo-responsive properties of a P(EtOx₂₇₀-norbornenOx₃₀):gel-SH (2:1) hydrogel film revealed a cloud point temperature (T_cp) in the same range as the T_cp of the P(EtOx₂₇₀-norbornenOx₃₀) polymer precursor, which is around 30 °C. This promising result demonstrates that thermo-responsive hybrid poly(2-oxazoline)-gelatin hydrogels could be prepared with predictable T_cps and that further investigation into this appealing feature might be of interest. Ultimately, this work shows a proof-of-concept of using PAOx as potential hybrid hydrogel precursor in combination with cell-interactive gelatin derivatives to potentially improve the mechanical stability of the final scaffolds and introduce additional features such as thermo-responsiveness for the purpose of drug delivery.

Keywords: amidation; gelatin; hybrid hydrogel; poly(2-oxazoline); thermo-responsive polymer.