Microcavities on PDMS microchannel replicated from sandpaper templates trap cells to enhance cell adhesion and proliferation

Abstract

Polydimethylsiloxane (PDMS) gained its fame in the construction of microdevices for studying cell growth and cell–cell interaction and the assembly of organ-on-chip models because of its excellence in optical transparency, gas permeability, nontoxicity, elasticity, and well-developed soft lithography approaches. Yet, poor cell adhesion and growth on pristine PDMS drives the need to improve its cell compatibility. Herein, rough PDMS surfaces with microcavity structures were fabricated by one-step replication from a sandpaper template. The impact of physical topologies, such as microcavity size, density, and distribution, on cell anchoring and growth was systematically studied. Results show that sandpaper-templated, rougher PDMS can support significantly more cell growth than pristine, smooth PDMS. Most of the cells (80.27%) were observed at the microcavities replicated from sandpaper, suggesting the microstructure-trapped cells have increased chance of cell anchoring and growth. Moreover, the efficacy of the physical topology–enhanced cell compatibility was compared side-by-side with PDMS chemically functionalized with tannic acid (TA). The cell adhesion, growth, and apoptosis studies proved that sandpaper-templated PDMS has comparable efficacy to TA-functionalized smooth PDMS; both improved cell proliferation by ∼50% and reduced cell apoptosis. We also found that TA functionalization of the sandpaper-templated PDMS did not significantly improve the cell compatibility, suggesting that the simple one-step replication from sandpaper is a low-cost and effective way to prepare a PDMS surface for cell growth. Finally, the potential of sandpaper templating in building microdevices for cell culture is highlighted by assembling PDMS microchannels with rough surfaces for on-chip cell culture.