Pectin Methacrylate (PEMA) and Gelatin-Based Hydrogels for Cell-Delivery: Converting Waste-Materials into Biomaterials.

The emergence of non-toxic, ecofriendly and biocompatible polymers derived from natural sources have added a new and exciting dimension to the development of low-cost and scalable biomaterials for tissue engineering applications. Here, we have developed a mechanically strong and durable hydrogel comprised of an ecofriendly biopolymer that exists within the cell walls of fruits and plants. Its trade name is pectin and it bears many similarities with natural polysaccharides in the native extracellular matrix (ECM). Specifically, we have employed a new pathway to transform pectin into a UV-crosslinkable pectin methacrylate (PEMA) polymer. To endow this hydrogel matrix with cell differentiation and cell spreading properties, we have also incorporated thiolated gelatin into the system. Notably, we were able to fine-tune the compressive modulus of this hydrogel in the range ~0.5 to ~24 kPa: advantageously, our results demonstrated that the hydrogels can support growth and viability for a wide range of three-dimensionally (3D) encapsulated cells that include muscle progenitor (C2C12), neural progenitor (PC12) and human mesenchymal stem cells (hMSCs). Our results also indicate that PEMA-Gelatin encapsulated hMSCs can facilitate the formation of bone-like apatite after five weeks in culture. Finally, we have demonstrated that PEMA-Gelatin can yield micropatterned cell-laden 3D constructs through UV-light assisted lithography. The simplicity, scalability, processability, tunability, bioactivity and low cost features of this new hydrogel system highlight its potential as a stem cell carrier that is capable of bridging the gap between that exists between the clinic and the laboratory.