Study of the reactions to micromechanical loading of many biological structures and biomaterial surfaces have been limited by the currently available instrumentation for in-vitro analysis of tissue micromechanics. Most currently used systems either do not accurately measure the load deflection behavior of tissues or they do not maintain viable cells within the tissue during testing. Response to mechanical stimulation is currently an important research topic in a wide variety of biological systems (bone, endothelial cells, etc.). A system which can apply well characterized, well controlled loads and deflections to tissues, cells, surfaces, etc., would be a significant advance in the ability to study biological response to mechanical stimulation. The goal of the current application is to design, build, and evaluate a new micromechanical testing instrument which can concurrently maintain cell-culture conditions for prolonged periods, while also performing a wide array of controlled and well characterized mechanical tests so that viable biological tissues and structures can be evaluated. This micromechanical test instrument will be able to mechanically test small (from cell to 4 mm bone buds or larger), viable biological samples with highly precise and accurate loads (uN) and deflections (10's of nm), while maintaining culture conditions. This combination of precise control of both the biological and mechanical environments will allow for systematic evaluation of the interaction of local cell populations with the mechanical environment. Post-test biological analysis of cell response (DNA synthesis, specific protein synthesis, etc.) will be possible to correlate specific biological reactions to known mechanical loadings. The cell culture system will maintain controlled temperature, gas, nutrient, and waste exchange so that prolonged testing of viable tissues in-vitro can be performed. This micromechanical test system will have three-axis motion capability so that precise control of test location can be effected. A wide variety of testing techniques will be developed for this system including: compression, tension and flexural testing, as well as micro-to-nano indentation tests and adhesion tests. Furthermore, viscoelastic imaging of surfaces and tissues will be possible.
| Kunnel, J G; Gilbert, J L; Stern, P H (2002) In vitro mechanical and cellular responses of neonatal mouse bones to loading using a novel micromechanical-testing device. Calcif Tissue Int 71:499-507 |
| Gilbert, Jeremy L; Cumber, Jeffrey; Butterfield, Aaron (2002) Surface micromechanics of ultrahigh molecular weight polyethylene: Microindentation testing, crosslinking, and material behavior. J Biomed Mater Res 61:270-81 |
