Nanopatterned Surfaces for Stem-Cell Engineering - Stem-Cell Nanoengineering - page 91

Chapter 7
Nanopatterned Surfaces for Stem-Cell
Engineering
Waleed Ahmed El-Said 1 , Tae-Hyung Kim 2,3 , Ki-Bum Lee 3 , and Jeong-Woo Choi 2
1 Department of Chemistry, Faculty of Science, Assiut University, Assiut, Egypt
2 Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, Republic of Korea
3 Department of Chemistry and Chemical Biology, Rutgers, The State University of New Jersey,
Piscataway, NJ, USA
Introduction
Applications of nanoengineering technologies and nanotopographical substrates to control
stem-cell differentiation become more important, owing to the ability of the nanomaterials to
interact with biological systems at the single molecular level with high specificity [1-3]. In
addition, any slightest change in geometry, width, depth, orientation, or pattern can affect
the differentiation of stem cells. Hence, investigation of the effects of structure and properties
of nanomaterials on the proliferation and differentiation of stem cells became a novel issue
in multi-interdisciplinary fields, such as regeneration medicine and material science [4, 5],
because the stem-cell differentiation is dependent largely on their interaction with a highly
specialized microenvironment or niche [6]. Therefore, various micro- or nanofabrication
technologies have been used to guide stem cells to develop into three-dimensional bio-
degradable scaffolds [7, 8]. Recently, different techniques, such as nanotemplating and
nanolithography, have been devised to control stem-cell behavior. For example, patterning of
surface topography on polymeric substrates by electron beam lithography has been used to
direct stem-cell fate [9, 10], and nanografted substrates have been used to spatially organize
myocardial cells and control protein expression [11]. The extracellular matrices (ECMs) or
their components were reported as one of the prime factors that play critical roles in the reg-
ulation of cell growth, adhesion, proliferation, and stem-cell behavior [12-15]. Thus, a variety
of ECM proteins or their components (e.g., fibronectin, collagen, laminine, PLL, etc.) were
applied to improve attachment of living cells to the cell-chip surface by chemical or physical
adsorption, which resulted in remarkable cell adhesion [16, 17]. However, the uncontrolled
thickness of ECM proteins was found to decrease the sensitivity of cell chips. Hence, other
techniques that can enhance cell adhesion without decreasing the electrical sensitivity of
electrodes were essential for the development of highly sensitive electrochemical cell-based
chips. Therefore, several soft micro- or nanolithographic tools, such as microcontact printing
[18], anodization, and dip-pen nanolithography (DPN) [19, 20] were potentially used to
generate ECM patterns on different surfaces at the micro- or nanoscale in order to study the
effects of ECM composition and morphology on stem-cell differentiation.