In Situ Instrumentation
We design and fabricate precise in situ instrumentation that interrogates microscopic contacts of cells under microscale forces (25 µN to over 1,000 µN). A wide variety of cell and tissue types, along with soft biocompatible materials are frequently used in combination to create model interfaces from which to study fundamental mechanisms associated with biological responses to contact and shear. These instruments combine sensitive analytical instrumentation (e.g., interferometry, fluorescence microscopy, and various spectroscopies) with multiaxial loading and motion.
Biological Materials and Interfaces
Our research focuses on the forces, motions, mechanics, and signaling associated with interfacial interactions on biological interfaces. The specific materials and interface pairings of primary interest are hydrogels, soft elastomers, cells, cell layers, and tissues (including cancer). We experimentally test the connection between mechanical contact and shear to cell stress and cytokine production. We combine in situ instrumentation with quantitative analytical molecular biology techniques to investigate hypotheses ranging from friction-induced inflammation to contact- and shear-induced apoptosis. Our research opens the door for the exploration of entirely new engineering approaches and designs of soft implants that control surface shear stresses and manage inflammation and cell death through new surface chemistries, material properties (e.g., elastic modulus), improved interfacial interactions, and delivery of pharmacologic compounds. Such designs may be safer and more comfortable by reducing pain, swelling, and potentially preventing implant-associated cancers, such as lymphomas.
Soft, synthetic materials like hydrogels are often used as simple model materials for biological tissues due to their high water content, controllability, and repeatability. They are cross-linked networks of flexible polymer chains swollen with water that can be cast or 3D-printed as bulk materials, or grown, spin-coated, or dip-coated as thin films or coatings. We polymerize hydrogels with varying water content, permeability, and elastic properties by changing mesh size (ξ), the correlation length between all pairs of molecules comprising the hydrogel network. Our research is focused on linking the structure to the lubrication mechanisms of self-mated hydrogel systems.