Copyright ©2009 Baishideng.
World J Stem Cells. Dec 31, 2009; 1(1): 55-66
Published online Dec 31, 2009. doi: 10.4252/wjsc.v1.i1.55
Table 1 Different types of stem cells, their properties, and functions
Stem cell typePropertiesFunctions
MSCsMultipotent and pluripotent. Bone marrow is the major source of MSCMSCs are capable of differentiating into bone, cartilage, fat, muscle, marrow stroma, and other tissue types
ESCsDerived from an early stage embryo and can differentiate into derivatives of all three primary germ layers. ESCs are multipotent and pluripotentCan differentiate into brain and nervous system cells, insulin producing cells of the pancreas, bone cells, hematopoietic cells, endothelial cells, cardiomyocytes
ASCsMultipotent, oligopotent, or unipotent progenitor cells. Derived from a more mature tissue, such as the umbilical cord, bone marrow, or skinTo treat leukemia and related bone/blood cancers through bone marrow transplants
HSCsFound in the bone marrow. MultipotentAll types of blood cells
iPSDerived from epithelial cells. PluripotentThe iPS cell lines could be differentiated into heart muscle and neuronal cells, in addition to basic cell types (ectoderm, mesoderm, and endoderm)
Mammary stem cellsIsolated from human and mouse tissueGrowth of mammary glands
Endothelial stem cellsMultipotent cells found in the bone marrowCan differentiate into endothelial cells, the cells that make up the lining of blood vessels
Table 2 Various fabrication techniques to achieve nanotopography
Fabrication techniqueAdvantagesDrawbacks
Laser depositionUniform distribution of pore size, simple and fastReduced resolution and poor surface finish
Self assemblyCan generate fibrous networks capable of supporting cells in three dimensions. Cell-seeding problems associated with using prefabricated nanofibrous scaffolds eliminated owing to spontaneous assemblyLack mechanical strength, Limited amphiphilic materials, random and very short nanofibers
LithographyRelatively good resolutionTime consuming and expensive.
ElectrospinningThe properties of electrospun nanofibers, such as fiber diameter, can be controlled readily via manipulation of spinning parameters. Capable of mimicking the stem cell nicheElectrospinning yields a flat mat that has limited three dimensionality and suffers from cell infiltration problems because of the small pore size of the mats
Phase separationA nanofibrous (fibers with diameters of 50-500 nm) three-dimensional scaffold can be constructed. Has controllable high porosity, surface-to- volume ratios, and well as defined mechanical propertiesNanofiber distribution and uniformity is subject to the controllability of the processing
Table 3 Various cell types and the nanotopographies on which they are cultured
Cell typeNanotopographyAdvantagesRef.
Chondrocytes(a) PCL nanofibrous scaffold (200-800 nm) in the presence of TGF-β1; (b) Collagen nanofibers of diameter 110 nm-1.8 μmThe differentiation of the stem cells into chondrocytes in the nanofibrous scaffold was comparable to an established cell pellet culture. Nanotopography supports chondrocyte growth and infiltration[82,90]
Osteoblasts(a) Ceramics like HA, alumina and titania having nanostructures of grain sizes less than 100 nm and nanophase zinc oxide (23 nm); (b) PLGA, PLLA and PCL nanofibers (diameter 200-800 nm); (c) Nanotubes of diameter less than 100 nmEnhanced proliferation and differentiation of MSC to osteoblasts[67,77-79,105-113]
Smooth muscle cells (SMC)(a) PLGA and PCL, PLLA-CL nanofibers (diameter 200-800 nm); (b) Nanogratings of 350 nm in width, spacing, and depth imprinted on PMMA or PDMSSMC adhesion was enhanced on the nanostructured substrates compared to the conventional submicron substrates[114-118]
Fibroblasts(a) PLGA (85:15 ratio) nanofibers of diameter 500-800 nm; (b) NanocolumnsIncreased endocytic activity. Nanotopography can be used to improve hemocompatibility of blood-contacting biomaterials[82]
Nerve cells(a) Silicon wafer in the range of 20-70 nm; (b) PLLA or PCL scaffolds via electrospinning and phase separationThe cell adhesion and viability significantly improved on the nanofeatured surface[70,91]