Tissue engineering is an interdisciplinary field that applies the principles of engineering and life science toward the development of biological substitutes that restore, maintain, or improve tissue function or a whole organ. In the part of this field, we are especially interested in the technologies to improve the central/peripheral nerve regeneration and investigate the specific mechanism of them. While the clinical importance of this topic, currently there is no perfectly effective treatment strategy following traumatic injury to the nervous system. As a solution, we are interested in applying multimodal stimulation to neuron or using multi-material fibers as a scaffold. Specifically, motivated by the findings that electrical stimulation promotes the functional recovery of peripheral nerves, we explored optogenetics as a means to increase neurite growth. Moreover, we confirmed that the fiber drawing process can be applied to various biocompatible materials for fabricating nerve guidance channels. These can have the scalable topographical features and porous structures on the interior surface. We are further extending these approaches to various tissue with different material platforms, for example, using hydrogel or bio-polymers in stem cell engineering.
S. Park, P. Anikeeva et al., Scientific Reports (2015)
Neural Tissue Engineering with Optogenetics. (a) A schematic demonstrating the LED array design and the experimental setup for optical stimulation. The blue light LED (465 nm) array was powered and driven by an Arduino circuit. Optically stimulated ChR2 DRGs were compared to unstimulated ChR2-DRGs as well as stimulated WT DRGs. (b) Representative confocal images of DRGs stained for neurofilament (red): a stimulated ChR2-DRG, ChR2-DRG without stimulation, Stimulated WT DRG, WT DRG without stimulation. (c) The mean values of neurite coverage area for stimulated and unstimulated ChR2-DRGs, and stimulated and unstimulated WT DRGs. Optogenetically-stimulated DRGs grew more than other controls.
R. Koppes, S. Park, P. Anikeeva et al., Biomaterials (2016)
Fiber Scaffold with Various Biomaterials and Applications to Tissue Engineering. (a) Fiber drawing process to fabricate tissue scaffold with various materials, size, and shape. PEI (bio-compatible material) preform was initially fabricated and it was drawn to a fiber through thermal drawing process. (b) Schematic representation of a DRG seeded-fiber-coverslip assembly. Picture indicates the neurite ingrowth through a grooved, 5 mm fiber scaffold (red = neurofilament, cyan = fiber scaffold). (c) Application of fiber-based tissue scaffold in tissue engineering. Stem cell or direct reprogrammed cell were seeded into the fiber-scaffold for nerve or muscle regeneration.