Surface chemistry from wettability and charge for the control of mesenchymal stem cell fate through self-assembled monolayers

Self-assembled monolayers (SAMs) of alkanethiols on gold are highly controllable model substrates and have been employed to mimic the extracellular matrix for cell-related studies. This study aims to systematically explore how surface chemistry influences the adhesion, morphology, proliferation and osteogenic differentiation of mouse mesenchymal stem cells (mMSCs) using various functional groups (-OEG, -CH3, -PO3H2, -OH, -NH2 and -COOH). Surface analysis demonstrated that these functional groups produced a wide range of wettability and charge:-OEG (hydrophilic and moderate iso-electric point (IEP)), -CH3 (strongly hydrophobic and low IEP), -PO3H2 (moderate wettability and low IEP), -OH (hydrophilic and moderate IEP), -NH2 (moderate wettability and high IEP) and -COOH (hydrophilic and low IEP). In terms of cell responses, the effect of wettability may be more influential than charge for these groups. Moreover, compared to -OEG and -CH3 groups, -PO3H2, -OH, -NH2 and -COOH functionalities tended to promote not only cell adhesion, proliferation and osteogenic differentiation but also the expression of alpha(v) and beta 1 integrins. This finding indicates that the surface chemistry may guide mMSC activities through alpha(v) and beta 1 integrin signaling pathways. Model surfaces with controllable chemistry may provide insight into biological responses to substrate surfaces that would be useful for the design of biomaterial surfaces. (C) 2016 Elsevier B.V. All rights reserved.