One-step fabrication of flexible nanotextured PDMS as a substrate for selective cell capture

Efficient cancer cell capture has been previously demonstrated on functionalized surfaces with defined nanotopography such as nanoscale texture. However, conventional additive and subtractive methods to achieve nanotexture require access to specialized nanofabrication equipment within a dedicated cleanroom environment. Here, we present a technique to create flexible polydimethylsiloxane (PDMS) surfaces with high roughness (R-q similar to 680 nm) using a molding approach that can be performed in a standard laboratory environment. We also demonstrate a one-step integration of nanotextured PDMS into a reversibly sealed easy access modular microfluidic platform to simplify cell capture workflows (e.g. cell introduction, capture, and isolation). In our proof of concept, we characterize nanotextured PDMS surfaces and investigate the effect of increased surface area on cancer cell adhesion strength and capture compared to non-textured (plain) PDMS. We found that cells attached more strongly to antibody-functionalized nanotextured surfaces (26% +/- 5% increase in threshold fluid shear stress, tau(50%)) and captured 71% +/- 19% more cancer cells than functionalized plain surfaces. Our reversibly sealed microfluidic platform enabled a user-friendly method to access cells for post-capture analysis, and we report an efficient nucleic acid isolation process. We anticipate the easy fabrication, one-step microfluidic integration, and streamlined experimental workflow will simplify the incorporation of nanotextured substrates in applications that investigate cell-surface interactions.