(476f) Polymer Nanoparticle Hydrogels: Rheological Properties to Biomedical Applications

Hydrogels have become essential tools for biomedical applications in regenerative medicine, cancer therapy, and immunology. Both precise engineering of hydrogels to yield distinct rheological properties and controlled presentation of cellular signals in hydrogels can enable advances in cell delivery strategies and therapies. Polymer-Nanoparticle (PNP) hydrogels are a novel type of injectable gel composed of modified cellulose and degradable PEG-PLA nanoparticles. These components interact to form a completely physical hydrogel network. PNP hydrogels are highly biocompatible and degrade over time in the body making them favorable for biomedical applications. In this talk, I will discuss both the fundamental material and mechanical properties of PNP hydrogels and then highlight how PNP hydrogels can be used as a promising material for cell therapies. I will examine the rheological properties with shear and extensional rheology, exploring how modifications to these complex interactions may lead to unique dynamic responses, such an shear-thinning, self-healing, extreme extensibility and yield stress behavior. I will then present how PNP hydrogels can be applied to a range of diverse impactful applications including enhanced delivery of human mesenchymal stem cells and improved immunotherapies. I demonstrate many advantages to using PNP hydrogels over saline injections for delivering therapeutic cells, such as preventing cell sedimentation and aggregation in the syringe, minimizing cell membrane damage in syringe needle flow during injection, and prolonged cell retention at the injection site after delivery. Co-delivery of slow-diffusing molecules with cells in engineered PNP hydrogels can allow for localized interactions and high efficacy treatments. We present both in vitro and in vivo experiments to validate the utility of PNP hydrogels in enhancing cell delivery. Overall this presentation will demonstrate that dynamic biomaterials afford unprecented materials and mechanical properties and enable unique opportunities in biomedicine.