Synthesis and Characterisation of Collagen based Hydrogel Hybrids for Biomedical Applications

Abstract

Hydrogels are polymeric materials with swelling ability are known for maintaining their three dimensional structure after swelling with properties suitable for biomedical applications. Various methods for hydrogel biosynthesis are available, including copolymerisation, crosslinking via reactive polymer precursors and crosslinking through polymer-polymer reaction. Inadequacies with traditional methods of hydrogel formation include poor mechanical properties and slow response times to external stimuli. Introduction of crosslinking agents can potentially improve the physico- chemical and mechanical properties of hydrogels. Among the methods currently available for chemical crosslinking of hydrogels, the combination of collagen with inorganic hybrids, fabricated by the Redox reaction, is one of the efficient methods for hydrogel formation. The reaction occurs within less than a minute, and depending on the concentration of collagen to poly(ethylene glycol) diacrylate or PEGDA, concentrations of collagen, chemical crosslinking agents and promoters used, the mechanical properties of the final product can be varied. Collagen extracted from marine sources is currently seen as an alternative to bovine and porcine collagen with extensive applications in biomedical and tissue engineering. In this study, collagen extracted from fish waste (skin and bones) was used to form a synthetic hydrogel hybrid through chemical crosslinking and photocrosslinking with a commercial ketone (Irgacure). The mechanical strength of these hydrogels was improved with the addition of the secondary crosslinking agent PEGDA. In summary, the hydrogel hybrid formed with PEGDA and collagen had favourable swelling properties and mechanical strengths, which were dependent on the varying concentrations of collagen, with the optimal concentration ranging between 500 -1500 mg of collagen to 200 mg of PEGDA. The collagen and PEGDA hydrogels were investigated for forming flexible structures rather than forming brittle hydrogels. The avenue of exploring and optimising the concentrations of PEGDA to collagen type I are promising and can further enhance the prospects of using synthetic hydrogels for tissue engineering.