“Self-fitting” Shape Memory Polymer Scaffolds to Treat Craniomaxillofacial (CMF) Bone Defects
Cranio-maxillofacial (CMF) defects (as well as other types bone defects) can result from traumatic injury, infection, tumor removal, surgical burr holes, or congenital bone disease. The current gold standard to treat CMF bone defects is with autografts, but these suffer from limited availability, complex harvesting procedures as well as donor site morbidity. A particular difficulty is shaping and fixing the rigid autograft tightly into the defect so as to prevent premature resorption. Regenerative engineering represents a promising alternative to heal CMF bone defects.
We are developing “self-fitting” scaffolds based on shape memory polymers (SMPs) that conformally fit into defects following the mere exposure to warm saline.
Synthetic Cartilage
A host of different cartilage tissue types exist and play critical roles in human function, but are often lost due to disease, injury, age, or congenital defect. Because of their hydrated nature, synthetic hydrogels have been considered potential replacements for cartilage. However, the complex bulk mechanical, and lubrication properties of cartilaginous tissues remain elusive to recapitulation.
We are developing ultra-strong and ultra-stiff multi-network hydrogels to resurface joints and and to replace of other types of cartilage (e.g., tracheal cartilage).
Silicon-containing Hydrogels to Heal Osteochondral Defects
Osteochondral defects (OCDs) – joint damage extending from cartilage into the underlying bone – are characterized by pain, loss of function and osteoarthritis. Autograft-based surgeries remain the “gold standard” to treat OCDs of the knee and other joints but are limited by defect size, donor site morbidity, and graft integration. As OCDs progress, total joint replacement is often required. Tissue engineering represents a promising alternative to heal OCDs of knees and other joints.
We are developing a regenerative engineering strategy that leverages a potently instructive hydrogel scaffold with a spatially-distributed, inorganic polymer component to direct associated cells to heal OCDs.
“Self-cleaning” Membranes for Glucose Biosensors
Glucose biosensors or “continuous glucose monitors (CGMs)” that would continuously monitor blood sugar levels (from the interstitial fluid) have advanced diabetes management beyond that afforded by conventional finger prick tests. However, on-the-market CGMs have a high user burden associated with their limited lifetime and the need for a transcutaneous design to enable frequent exchanges. The lifetime of current and emergent CGMs are limited by “biofouling” – surface adsorption of proteins and cells (part of the foreign body response) – which quickly blocks glucose diffusion.
We are developing a “self-cleaning membrane” using thermoresponsive hydrogels that undergo cyclical and subtle deswelling/reswelling to “clean off” proteins and cells in order to maintain glucose diffusion and extend biosensor lifetime.
Anti-fouling Coatings for Blood-contacting Medical Devices
A variety of medical devices are made from silicones and polyurethanes, but these rapidly adsorb proteins, and cells, often leading to clotting and infection.
Our research is directed at developing coating technologies to prevent protein adsorption and subsequent negative events on medical devices, including reducing clotting and infection, as well as enabling pumpless flow of blood in microfluidic point-of-care devices. Towards this goal, we have developed “PEO-silane amphiphiles” as surface modifying additives (SMAs) for silicones and polyurethane devices.
Environmentally-friendly, Anti-fouling Marine and Dairy Coatings
There exists a critical environmental and economic need for non-toxic marine coatings which effectively control biofouling on vessels and other submerged structures. A feasible approach must be broadly effective but also must not be economically prohibitive or overly complex in its implementation. Dairy fouling during pasteurization is another biofouling problem associated with significant costs and environmental impact stemming from cleaning protocols.
We are developing surface modifying additives (SMAs) that can be readily blended into silicones and polyurethanes, and upon contact with the aqueous environment, rapidly undergo surface restructuring to afford high antifouling efficacy. Towards this goal, we have developed non-toxic, “PEO-silane amphiphile” SMAs that can boost coating resistance to marine biofoulers and to dairy mixtures.
