Optimisation of bullfrog skin collagen scaffolds for tissue engineering applications

Abstract

3D scaffolds have a wide range of applications both in vivo and in vitro. Collagen extracted from bullfrog (Rana catesbeiana) skin was selected as a possible cheap source of biomaterial in view of their biocompatibility and low risks of BSE and TSE transmissions. Natural polymers like collagen inherently have poor mechanical properties in comparison to their synthetic counterparts. 1, 4-Butanediol Diglycidyl Ether (BDE), which is known to be safe for in vivo applications, was employed as a cross-linker to improve the properties of the collagen-based scaffolds.

Scaffolds were made without BDE and with BDE of 0.125%, 0.25%, 0.5% and 1.0% concentrations. FTIR analysis confirmed the cross-linking action by BDE and the presence of collagen. Denaturation temperature had reduced with increasing BDE concentrations and was determined to be possibly caused by the water content in the scaffolds. SEM images showed that pore sizes are likely to be able to accommodate cell growth but were observed to have decreased inversely to BDE concentrations. Numerous thin sheet structures appeared at 0.5% and 1.0% BDE that could slow down nutrients transport through the scaffold. Mechanical testing found that the highest elastic modulus as well as swelling ratio peaked at 0.25% BDE with the rest trailing downwards as the BDE concentration deviate further from 0.25%.

These results collectively suggest that scaffolds fabricated with 0.25% BDE overall had the most suitable structure and mechanical properties for tissue-engineering applications. Additional studies and optimisation should be carried out for further improvement.