Vertically Aligned Carbon Nanotube (VACNT)/PDMS Composite with Changeable Lateral Stiffness

Abstract

Lateral stiffness and topography of culture substrate are critical parameters for controlling stem cell differentiation. However, controlling the lateral stiffness of the VACNT bundle tip, that is included in pillar category, is remained to be solved in a range of cell culture. In this study, we transferred the 18 μm VACNT length into PDMS matrix to control VACNT lateral stiffness with a partial immersion method. VACNT/PDMS composite was synthesized in which 5–10 μm of VACNT length at top surface was maintained free to move. The Lateral force measurement (LFM) demonstrated that VACNT/PDMS composite bundle tip with 6 μm PDMS was the stiffest, followed by raw VACNT and VACNT with 8.6 μm PDMS. The lateral stiffness values of the three VACNT condition were 1.037 N/m, 0.914 N/m, and 0.535 N/m, respectively. These values at certain thickness of PDMS could take a role as reinforcement or declination for VACNTs tips stiffness. We suggest that the VACNT have potential to control stem cell differentiation due to their sophisticate change of lateral stiffness.