Interfacial nanoengineering of surface-bound hydrogels via blockcopolymer self-assembly

• Applicant: Professorin Dr. Marie Weinhart
• Subject Area: Preparatory and Physical Chemistry of Polymers ; Biomaterials
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 506711010

Thermoresponsive surface-bound hydrogels are ubiquitously employed in the biomedical field, e.g., as switchable coating on bioactive, drug-releasing implants or on cell culture substrates to allow for an enzyme-free cell harvest. While the research focus has long been set on controlling the hydrogel network structure down to the nanoscale and thus improving its functionality and responsiveness, little attention has been paid so far on the surface of such hydrogels.In this project, we aim at an understanding of a block copolymer self-assembly process on surface-bound hydrogels with subsequent photo-immobilization of the formed brushes to precisely engineer the interfacial gel properties. Thereby, the impact of the modulable hydration state of the polymer chains in the gel as well as the assembling block copolymers together with their respective anchor block chemistry will be investigated to optimize the grafting process and control the resulting brush grafting density on top of the surface-bound gel. Further, the thermoresponsiveness of the resulting hydrogel-brush bilayer coating will be assessed via quasi-static temperature-ramping QCM-D in combination with temperature-dependent layer thickness and contact angel measurements to unravel mutual interferences of both layers. Structural variations of the surface-bound gels and grafted brushes will yield a detailed structure-property relationship and will further be correlated with distinct drug loading and controlled release properties. Therefore, the gels’ crosslinking density, layer thickness, and volume phase transition temperature will be varied as well as the brush grafting density, chain length, composition and anchor block chem-istry. The resulting cell response in terms of adhesion, proliferation, differentiation of anchorage-dependent mammalian cells cultured on such surface coatings will be evaluated before and after loading the coatings with effector molecules. In a proof-of-concept approach the controlled release of effector molecules from bilayers with and without external stimuli and its effect on epithelial and endothelial monolayers cultured at the nanoengineered functional interface will be studied to evaluate its utility for bioactive scaffolds and coatings.

• DFG Programme: Research Grants