SYNTHETIC ENROUTES TO ENGINEER ELECTROSPUN SCAFFOLDS FOR STEM CELLS AND TISSUE REGENERATION - Micro and Nanotechnologies in Engineering Stem Cells and Tissues - page 132

chondrogenic, osteogenic, adipogenic, and myogenic cells with the application of
a biological or physical stimuli, is well understood and established. 77-80 The
hMSCs have enormous therapeutic potential for treatment of damaged or diseased
tissue; the complexity of events associated with such transformation of these
precursor cells leaves many unanswered questions about morphologic, structural,
proteomic, and functional changes in stem cells. Thus, there exist a need for better
understanding of hMSC behavior that would allow more effective approaches to
cell expansion in vitro and differentiation to a specific phenotype. Hence, there is a
need for favorable scaffolds and engineering for hMSCs to orient, adhere,
proliferate, and differentiate.
The multilineage differentiation potential of MSCs on 3D PCL nanofibrous
scaffolds was demonstrated by Li et al. 81 They tested the ability of the scaffold
to support and maintain multilineage differentiation of bone marrow-derived hMSCs
in vitro by culturing in different differentiation media such as adipogenic, chon-
drogenic, or osteogenic and found the PCL scaffold as the promising one. The
differentiation potential of MSCs into hepatocytes was observed by Kazemnejad
et al. 82 on PCL-collagen-polyethersulfone scaffolds. The ability of the differentiated
hepatocyte cells to produce albumin, urea, serum glutamic, pyruvic, transaminase,
and serum oxaloacetate aminotransferase on the scaffolds further confirms the
supporting role of the nanofibrous scaffolds. The osteoblastic differentiation poten-
tial of MSCs on poly( L -lactic acid) (PLLA)-collagen nanofibers was demonstrated
by Schofer et al., who identified the advantages together with disadvantages of more
stable PLLA-collagen fibers with respect to osteoblastic differentiation. 83 In vitro
differentiation of MSCs into cardiac cells is commonly carried being out by exposure
to 5-azacytidine, a DNA demethylating agent. 84 Expression of many cardiac specific
genes and peptides was observed. 85 Recently, Nerurkar et al. 86 observed improved
cellular ingress into electrospun scaffolds by adopting dynamic culture of MSCs on
aligned PCL nanofibrous scaffolds. This dynamic culture modification for MSC
culture has increased cellular infiltration and facilitated the use of aligned electro-
spun scaffolds for tissue engineering. In our laboratories, we studied the neuronal
differentiation potential of hMSCs on PLCL-collagen scaffolds. The results of our
study showed the neuronal phenotype of MSC differentiated cells together with the
expression of nerve proteins such as NF200 and nestin. 87 Thus, with a better
understanding of the behavior of MSCs on electrospun nanofiber scaffolds, a “stem
cell-scaffold construct” might find real application in regenerative medicine curing
various human diseases.
The transplantation of embryonic stem cells (ESCs) for the treatment of periph-
eral nerve injuries and possibly spinal cord injuries has also been demonstrated. 88,89
Functionalized electrospun nanofibrous scaffold with growth factors was found to
enhance the differentiation of ESCs into neurons and oligodendrocytes. 90 Xie et al. 91
demonstrated that the ESCs are differentiated into neural cell lineages guided by
electrospun nanofibrous scaffolds. They also found the ESCs to promote and direct
neurite outgrowth. The novel strategy of using a combination of electrospun
scaffolds together with ESC-derived neural progenitor cells might lead to better
nerve repair. Lam et al. 92 immobilized bFGF or epidermal growth factor (EGF) onto