Micropost array for force mapping of vascular smooth muscle cells

This paper describes the design, fabrication and characterization of micromachined arrays of 3 dimensional microposts with high aspect ratio and high density made of polydimethylsiloxane (PDMS) flexible material. The arrays are for use to measure quantitatively the cellular traction forces generated by vascular smooth muscle cells (VSMCs) and cells with weaker traction forces (pN-nN range). The fabrication steps were modified to ensure the construction of microposts with diameter and height of 3μm and 30μm, respectively, or aspect ratio up to 10, which has not been reported before. We also report detailed statistical measurements of Young's Modulus and spring constant of PDMS posts using Atomic Force Microscope (AFM) for calibration of each post-geometry used in the cell force measuring experiments. This ensured a higher degree of accuracy of the cell traction force measurements. To demonstrate the sensitivity of the high aspect ratio micropost, VSMCs were cultured on top of micropost array and the traction force maps were generated.