Title of Abstract
Hydrogels represent a class of biomaterials that have great promise for the repair of tissues, particularly due to our ability to engineer their biophysical and biochemical properties. Hydrogels can provide instructive signals through material properties alone (e.g., mechanics, degradation, structure) or through the delivery of therapeutics that can influence tissue morphogenesis and repair. Importantly, hydrogel design should reflect both the clinical context and the natural healing cascades of the damaged tissue. Here, I will give examples of the design of hydrogels based on hyaluronic acid (HA) for the repair of musculoskeletal tissues that have limited natural repair processes.
Towards application in cartilage repair, we have developed hydrogels that introduce numerous biochemical signals to mediate stem cell chondrogenesis. These include binding to receptors (e.g., CD44) through the use of HA backbones or the introduction of peptides (e.g., HAVDI) that mimic n-cadherin interactions found during development. We have utilized engineered screening platforms to probe the influence of these various chemical signals on stem cell fate, as well as developed 3D printing technology to translate the signals into scaffold environments. Towards meniscus repair, multi-polymer fibrous hydrogels that permit control over scaffold porosity and therapeutic release via the engineering of specific fiber populations have been developed. For example, multi-polymer fibers were designed with fibers that selectively release collagenase to provide an environment permissive to cell recruitment, chemotactic signals to actually recruit cells, and stable fibers for structural support. When investigated in tissue repair, each fiber population was important to the success of repair tissues.
The overall focus of the research in the Burdick Polymeric Biomaterials Laboratory is the fundamental understanding and development of polymeric materials for biomedical applications with a specific emphasis on tissue regeneration and drug delivery. Although significant advances in tissue engineering have been made in recent years, the continued lack of organs and tissue for transplantation calls for the development of innovative treatment alternatives. Advances in synthetic chemistry and materials processing may be the answer to meeting this organ and tissue shortage. The research in my laboratory involves: (i) developing novel synthetic polymeric materials and precursors that are both biocompatible and degradable; (ii) utilizing processing techniques to fabricate scaffolds with the desired micro- and macroscopic structures both spatially and temporally; (iii) investigating the interaction of cells with these materials while developing materials-based techniques to control cell differentiation; and (iv) using synthetic polymers to control the delivery of therapeutic molecules. The platform for ongoing projects in the laboratory is the use of either radical polymerizations (either photo or redox initiated) or self-assembly for material fabrication. Additionally, we are interested in stimuli-responsive materials, where external triggers can be used to modify material properties. To this end, the following topics are currently being investigated in my laboratory.