The ability to utilize physical cues such as nanotopographical features, substrate stiffness, geometry, and the dimension of extracellular matrix (ECM) protein patterns to control stem cell fate has great potential in stem cell-based regenerative medicine. In particular, hybrid nano-biomaterials, which can be used to fabricate scaffolds and implantable substrates for the treatment of neurological disorders such as Alzheimer’s disease, Parkinson’s disease, and spinal cord injuries, are now being intensively investigated in order to elicit specific behaviors from stem cells, including differentiation, migration and proliferation.
Regarding this challenge, scientists from Prof. KiBum Lee’s laboratory (Aniruddh Solanki, Dean Chueng, and Perry Yin) with collaboration from Prof. Manish Chhowalla (MSE) have developed arrays of graphene-nanoparticle hybrid nanostructures for the differentiation and growth of human neural stem cells (hNSCs). More importantly, these graphene-hybrid nanostructures bring the formation of highly aligned axons from the differentiating hNSCs to fruition. This research result (Advanced Materials, 2013, 25, 5477.) can provide an engineered microenvironment to the NSCs through novel nanomaterial construct. This new technology, highlighted by Frontispiece in Advanced Materials, can specifically control the axonal alignment and growth of NSC-derived neurons for the development of more effective treatments for spinal cord injuries.
Figure. Axonal Alignment of differentiated hNSCs on SiNP-GO on flexible and biocompatible substrates made from polydimethylsiloane (PDMS): a) SiNP-GO monolayer on PDMS. b) Flexible PDMS substrate with SiNP-GO in media for culturing hNSCs. c) SEM image of SiNP-GO on PDMS substrate showing highly aligned axons from hNSCs on Day 14. d) Scheme depicting the significance of alignment and growth of axons from differentiating hNSCs. The hNSCs which can be transplanted into the injured region (lesion) of a spinal cord differentiate into neurons and glial cells (image on right). The axons from the neurons (derived from hNSCs) if aligned can hasten the recovery process. Our SiNP-GO hybrid structures can provide the idea microenvironment to align axons which could potentially improve communication leading to rapid recovery of the injured spinal cord (image on left).
For instance in spinal cord and peripheral nerve injuries, if the nerve gap resulting from an injury is too large, the distal and proximal sides of the damaged nerves will not be able to communicate efficiently, thus impeding the natural regeneration process (see the illustration). As a result, a significant amount of effort has been invested in developing biomaterials that can result in axonal guidance and the growth of transplanted neurons within the injured spinal cord. The specific response of neuronal cells to nanotopographical cues is reported as one of the critical factors that must be attained, as it is the specific guidance of axons that would lead to enhanced therapeutic effects within the injured spinal cord.
More Information: http://onlinelibrary.wiley.com/doi/10.1002/adma.201302219/abstract
Prof. KiBum Lee
Year of Research Highlight: 2013