Fabrication of elastomer pillar arrays with height gradient for cell culture studies

- We fabricated dense PDMS pillar arrays with height gradient and uniform top surface.
- The stiffness gradientof the order of 0.7 kPa/µm was appropriate for migration studies of NIH 3T3 cells.
- NIH 3T3 cells migrated mostly to the stiffer areas after 24 h incubation.

We developed a method to fabricate dense elastomer pillar arrays with height gradient and uniform top surface by using photolithography and soft-lithography techniques. This method relies on formation of sloped tails aside pre-patterned stripes by spin-coating a low-viscosity resist and back side UV exposure through a Cr mask. PDMS pillar arrays were produced by casting to study migration of NIH 3T3 cells. With PDMS pillars of 2 μm diameter, 5.5 μm pitch size and variable heights in the range between 3.8 μm and 10.1 μm, we observed that NIH 3T3 cells migrated toward and then remained in the area of greater stiffness with smaller pillar heights. Thus, PDMS pillar arrays with height gradient and uniform top surface were shown to be useful in cell culture durotaxis studies.

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