Creating photoresponsive hydrogels from plant-based polymers for tissue engineering

Jackson Chory

Abstract

Biocompatible hydrogels were created using different polysaccharides and manipulated under light irradiation to change the mechanical properties of the gels. Alginate G (Alg G) and Alginate M (Alg M) were used with Agarose to form the hydrogel, and iron (FeCl₃) was added to the hydrogels to make the gels photoreactive. The gels were irradiated using a 405 nm light, and a change in shear modulus was observed after the irradiation. The results show we can prepare the gels from 65% Alginate G or Alginate M and 35% Agarose. There was a change in modulus after 30 minutes of irradiation, and Alg G had a larger increase in change compared to Alg M. Alg G produced stiffer hydrogels, while Alg M produced softer hydrogels. However, 30 minutes of irradiation showed that there was alginate left inside both Alg G and Alg M hydrogels because calcium was able to cross-link the alginate and keep the gel strong and biocompatible. While, irradiation past 90 minutes showed that most of the alginate has dissolved in the solution and calcium was not able to cross-link the alginate. Scanning Electron Microscope (SEM) pictures showed a change in structure of the gel after the hydrogel was irradiated because the gel was broken down due to the photoreaction creating a porous enviroment. The dark gel was not as porous as the irradiated gel, showing the change in mechanical properties after the irradiation.