ABSTRACT
There is an unmet demand for microfluidics in biomedicine. We describe contactless fabrication of microfluidic circuits on standard Petri dishes using just a dispensing needle, syringe pump, 3-way traverse, cell-culture media, and an immiscible fluorocarbon (FC40). A submerged micro-jet of FC40 is projected through FC40 and media on to the bottom of a dish, where it washes media away to leave liquid fluorocarbon walls pinned to the substrate by interfacial forces. Such fluid walls can be built into almost any imaginable 2D circuit in minutes, which we exploit to clone cells using limiting dilution in a way that beats the Poisson limit, sub-culture adherent cells, and feed arrays of cells continuously for a week. This general method should have wide application in biomedicine.
One sentence summary In the everyday world, we cannot build complex structures out of liquids as they collapse into puddles; in the microworld we can.
Competing Interest Statement
Oxford University Innovation, the technology transfer company of The University of Oxford, has filed provisional patent applications on behalf of C.S., P.R.C., and E.J.W. partly based on this study. P.R.C. and E.J.W. each hold equity in, and receive fees from, iotaSciences Ltd, a company exploiting this technology; iotaSciences Ltd also provided printers, FC40STAR, and scholarships for C.S. and C.D.