The Application of Micro/nanotechniques and Approaches n Studying of Nerve Regeneration
Date Issued
2009
Date
2009
Author(s)
Wang, De-Yao
Abstract
This work demonstrates how micro/nanotechniques, laser micromachining, soft lithography, and electrospining define material properties and applications at the nanoscale or microscale for broad capabilities in the development of processes of nerve regeneration such as needs of induced cell, engineered scaffold, and patterned signal.o obtain alter neuron cell resources, induced cues of cocultured neuron and physical structure were used to transdifferentiate mesenchymal stem cells (MSCs) into euron-like cells. Green fluorescent protein expressing (GFP+) mMSCs and red fluorescent protein expressing (RFP+) neuron cells were microfluidic patterned separately on the same cover glass. When cocultured with neuron cells, more mMSCs expressed neural markers, Beta tubulin III and Glial fibrillary acidic protein (GFAP) in the microfluidic patterned coculture system than cells in a transwell system. Also, two reporters, GFP and RFP, provide us a way to assay that a very few case of fused cell happened. The microfluidic patterned coculture system facilitates to valuate the plasticity and behavior of cells and dynamic cross-talks between cells. Besides, aligned and random collected electrospun polycaprolactone (PCL) fibers ere fabricated to provide not only contact guidance but also nanometric cues to affect cell fate. Compared to mMSCs cultured on cover glass, cells expressed protein evel of Beta tubulin III and GFAP, and even higher mRNA level of Nestin, Beta tubulin III, TH, Synapsin, GFAP, and MBP. Nanometric topographies used to change cell functions are a way to evaluate cell plasticity and cell-biomaterial interactions.urthermore, to provide the induced cell with physical supporting and potential transdifferentiated cues, particle leaching and lyophilizing were introduced into lectrospinning to fabricate engineered scaffold with electrospun fibers and microstructured pores. We used the rotating multichannel electrospinning (RM-ELSP) o produce gelatin electrospun scaffolds with controllable porosity. Gelatin electrospun fibers and PCL microparticles were formed and blended simultaneously using the RM-ELSP. The composites were turned into the porous electrospun caffolds with the use of acetone to leach out PCL microparticles and leave space for cell ingrowth to improve its poor porosity. Besides, a chitosan solution as a collector of electrospun PCL fibers is used to support the fibers after changed it to be a porous sponge using lyophilizing. A chitosan/PCL composute, a porous chitosan sponge distributed electrospun PCL fibers within its microstructure, provided topographical cues on its surface to not only improve GFP+ mMSCs infiltration within the lectrospun scaffolds but also increase higher mRNA level of Nestin, TH, Synapsin, GFAP and MBP. It implied that nano-topographical cues in engineered scaffold have great potential to make mMSCs transdifferentiated into neuron-like cells.oreover, turning engineered scaffold to nerve conduits employed multiple channels and microstructure in their lumen surface and providing pattern signal to orient the ell growth were considered also. We fabricated porous chitosan conduits employed designed patterns of engraved channels using the direct-write CO2 laser icromachining. Laser micromachining allows us to shape various selected materials in the regions engraved with the designed patterns. Besides, we presented a new way o fabricate nerve conduits using soft lithography and molding process. Afterwards the conduit subunit microfabrication, the conduit subunits were stacked coaxially to form a nerve conduit. Due to the precise capability and cost-effective of soft lithography, it s a well-suited way for us to fabricate nerve conduits having complex designs. Finally, we demonstrated the efficacy of microcontact printed laminin to align and edirect Schwann cells growth; and therefore, microcontact printing is able to pattern cell-recognition molecules on scaffolds for guided cell growth in tissue regeneration. hese micro- and nanotechniques and approaches, laser micromachining, soft lithography, and electrospinning, are useful in advanced material and biological studies in tissue engineering such as change of functions and behaviors of cells to be a new resource of induced neuron cells; development of engineered scaffolds with properties of scaffold size, network interconnectivity, and geometrical designs; and establishment of artificial microenvironment composed of biochemical, physical, and topographical cues used for regenerated cell adherence, viability, proliferation, and differentiation to integrate the nerve regeneration processes.
Subjects
Laser micromachining
Soft lithography
Electrospinning
Mesenchymal stem cell
Microfluidic system
Transdifferentiation
Polycaprolactone
Microenvironment
Nerve conduit
Microcontact printing
Schwann cell
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-98-F93548019-1.pdf
Size
23.53 KB
Format
Adobe PDF
Checksum
(MD5):081cefce81452f610340937c16aadf7e