Speaker
Description
Synthetic muscles that replicate the distinct contraction and force-generating properties of native skeletal muscle are highly sought after. They are used in a variety of applications, including actuators and regenerative therapies such as muscle replacement. Two-photon stereolithography is a promising tool to fabricate bio-scaffolds with micrometer resolution, ideally replicating soft native microtissues in vitro.
(A) We utilize this technique to 3D print synthetic muscle fibers from bovine serum albumin to form a contractile hydrogel structure with tailored mechanical properties. Using a custom microscale tensile strength device, we quantify force-length relations and elastic properties in these 3D printed protein muscle fiber models at a constant temperature of 20 ± 0.1°C.
(B) The observed pH-dependent contraction of the synthetic muscle (non-activated at pH 7, activated at pH 4) resulted in active forces comparable to those in native skeletal muscles. Manipulating the length of the synthetic fiber affects force production, following a parabolic force-length relationship similar to native muscle fibers, characterized by an ascending limb, an optimum, and a descending limb as the length increases. Furthermore, we conducted work loops on the synthetic muscle, which revealed a viscoelastic behavior and a significant impact of velocities on the muscle’s mechanical work and power output.
(C) Next, we seek to recapitulate physiological muscle fibers where myocytes align and regenerate to exert contractile forces. Therefore, we studied tissue alignment of C2C12 precursor myocytes in spatially confined 3D printed structures. The results revealed several significant relationships between tissue morphology and the substrates topology.
Ultimately, our two-photon crosslinked synthetic fiber can replicate the contractile dynamics of skeletal muscle tissue. This opens new avenues to further explore contractile synthetic materials, as well as their future refinement by integrating myocytes for a more realistic synthetic muscle fiber.
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