Microfluidic antibody arrays for simultaneous cell separation and stimulus.

Abstract

A microfluidic chip containing stamped antibody arrays was developed for simultaneous cell separation and drug testing. Poly(dimethyl siloxane) (PDMS) stamping was used to deposit antibodies in a microfluidic channel, forming discrete cell-capture regions on the surface. Cell mixtures were then introduced, resulting in the separation of cells when specific antibodies were used. Anti-CD19 antibody regions resulted in 94% capture purity for CD19+ Ramos cells. An antibody that captures multiple cell types, for example anti-CD71, can also be used to capture several cell types simultaneously. Cells could also be loaded onto the arrays with spatial control using laminar streams. Both Ramos B cells and HuT 78T cells were isolated in the chip and exposed to staurosporine in the same channel. Both cell lines had similar responses to the drug, with 2-10% of cells remaining viable after 20h of drug treatment, depending on cell type. The chip can also be used to analyze the efficacy of antibody therapy against cancer cells. Anti-CD95 was deposited on the surface and used for simultaneous cell capture and apoptosis induction via the extrinsic pathway. Cells captured on anti-CD95 surfaces had significant viability loss (15% viability after 24h) when compared with a control anti-CD71 antibody (81% viability after 24h). This chip can be used for a variety of cell separation and/or drug testing studies, enabling researchers to isolate cells and test them against different anti-cancer compounds and to follow cell response using fluorescence or other readout methods.