Exploring adipogenic differentiation of a single stem cell on poly(acrylic acid) and polystyrene micropatterns

Surface chemistry is an important property of biomaterials and plays a pivotal role in the interaction between stem cells and biomaterials. Comparing the effect of the surface chemistry at the single-cell level should elucidate the mechanism of the interaction. In this study, a micropatterning method was used to investigate the electrostatic effect derived from different chemical groups on the functions of individual human mesenchymal stem cells (MSCs). Differently sized circular micropatterns of negatively charged poly(acrylic acid) (PAAc) and neutral polystyrene (PSt) were created using UV photolithography. The PAAc and PSt micropatterns showed different effects on actin cytoskeleton organization and adipogenic differentiation of MSCs. The assembly and distribution of actin filaments for individual MSCs correlated with the degree of cell spreading as well as the surface charge of the underlying substrates. The adipogenic differentiation at the single-cell level was enhanced on the PAAc micropatterns, and decreased as the diameter of the circular micropattern increased. The micropatterning method allows for the construction of diverse micropatterns on various organic substrates with different physicochemical compositions or topographical features, and it enables the analysis of entire cell populations at the single-cell level, significantly facilitating the identification of the optimal surface parameters to manipulate the functions of stem cells.