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.