UCLA

The effective delivery of DNA locally could increase the applicability of gene therapy in tissue regeneration and therapeutic angiogenesis. One promising approach is through use of porous hydrogel scaffolds that incorporate and deliver DNA in the form of nanoparticles to the affected sites. Although the Segura group has previous reported the ability to load DNA nanoparticles within porous HA hydrogels at high concentrations, gene delivery and transfection levels remain too low for therapeutic application. In this study, we report two alternative approaches to polyplex presentation that attempt to increase transgene expression levels. The first approach attempts to reduce polyplex aggregation by utilizing polyethylene glycol modification to mitigate charge-charge interactions between polyplexes and the scaffold during gelation. The second approach utilizes surface coated polyplex presentation is increase cell-particle interaction that in not present with encapsulated presentation. sPEG-PEI polymer formed a smaller, less toxic, and more stable polyplex that exhibited little to no aggregation within HA gels when compared to the traditionally used LPEI polymer. Furthermore, sPEG-PEI retained transfection abilities comparable to LPEI in 3D, with no significant difference at 14 days. Surface coated polyplex presentation resulted in transgene expression levels that were three orders of magnitude greater than levels produced by encapsulated presentation. These results demonstrate a significant improvement in the porous HA gel system utilized by the Segura group, and hold promise for successful future studies in tissue engineering therapies.