A feasible approach to all-electronic digital labeling and readout for cell identification

We present two critical innovations that enable a unique, purely electronic approach to microfluidic whole-cell analysis, focusing on the problem of cell identification and sorting. We used fully-scalable lithographic techniques to microfabricate digital barcodes, providing a means for low-cost, large volume production. We have demonstrated molecular functionalization of the barcodes, using biotin–streptavidin, as well as human CD4 antibody, and we have successfully linked the barcodes to polystyrene beads using the biotin–streptavidin complex. This functionalization allows unique barcodes to be attached to specific cell types, based on phenotype. We have also implemented an electronic barcode readout scheme, using a radio frequency microsensor integrated in an elastomeric microfluidic channel, that can read individual barcodes at rates in excess of 1000 labels s⁻¹. The barcodes are biologically compatible, and coupled with the electronic sensing technology, provide a route to compact, inexpensive, disposable cell identification, sorting and purification.