UC San Diego

Previous research into the problem of postsurgical cardiac adhesions has produced a hydrogel barrier that can be applied to the surface of the heart, preventing the formation of adhesions in the weeks following trauma during surgery. When developing this type of gel for clinical translation, two issues that must be addressed are the biocompatibility of the material as well as a method of hydrogel delivery to the tissue surface. Previous research yielded a hydrogel made from poly(ethylene glycol) functionalized with aldehyde, aminooxy and dopamine groups. Cell viability is reduced in culture treated with this material due to the inclusion of dopamine. Examination of the hydrogel in culture through fluorescence microscopy and spectrophotometry indicate that this is primarily due to oxidative stress, demonstrated by increased levels of hydrogen peroxide and lipid peroxidation. However, metabolic and morphological assays performed in vitro demonstrate that the biological antioxidant glutathione, a mediator of dopamine effects, can maintain cell viability when added as a culture supplement. Within this study, the effective application of the gel is achieved through air-assisted liquid spray, which allows equal distribution of two separate polymer solutions onto the surface of the heart. This result is predicted computationally through simulation of separate intersecting sprays and verified by spectroscopy and rheological testing of the material produced by a novel device. By investigating these factors, better understanding of the material's biological properties and implementation can be obtained to guide future research.