Micro-technological solutions for skeletal muscle tissue engineering using static and dynamic micropatterned wavy topography on silicone substrates.

This thesis focuses on using microtechnology to advance the field of tissue engineering by using wavy microfeatured substrates that are statically and dynamically patterned. The prevailing issue hindering tissue engineering from dominating the tissue replacement market is the fact that engineered tissues are not equivalent in form or function to their natural counterparts. One way to overcome this is to make tissues more physiologically similar. In the case of skeletal muscle, tissue organization is key to organ function. During musculoskeletal myogenesis, a crucial organizational step is the alignment of cells prior to muscle formation. Micropatterned topography is a viable tool for aligning cells in vitro. Here, we develop methods for aligning muscle cells using wavy micropatterned poly(dimethylsiloxane) (PDMS) substrates. Various sized static wavy microfeature substrates were generated and optimized using C2C12 cell line cells. Precursor cells (myoblasts) aligned best on features 6 mum in size and differentiated into a monolayer of aligned myotubes. Once the feasibility of these surfaces was confirmed, they were used to tissue engineer skeletal muscle constructs of aligned cells, to investigate if pre-aligning cells would increase functionality. Primary muscle cells were cultured on the wavy substrates to form a monolayer of aligned myotubes. The cell monolayer was then successfully transferred into a biodegradable matrix of fibrin gel, capable of allowing construct formation. Over time, cells degrade the gel completely, leaving a cell-only final construct. Compared to constructs made of randomly oriented cells, aligned cell constructs produced 2 times the force, affirming the importance of pre-alignment of cells when tissue engineering skeletal muscle. Lastly, we developed dynamically controlled micropatterned wavy substrates for on-demand reversible cell alignment. PDMS substrates were plasma treated and compressed to obtain reversible wavy microfeatures on the surface, and were capable of aligning cells into a highly ordered configuration from random orientation. Muscle cells cultured on these surfaces initially attached in a random order, aligned once the substrate was compressed, and unaligned when the substrate was released. This technique provides a simple and reliable method by which to investigate developmental processes not yet easily studied in vitro.PhDApplied SciencesBiomedical engineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/126206/2/3238007.pd