Abstract: A method of producing a microfluidic chip for use in flow cytometry, the method comprising the steps of providing an opaque substrate, a first surface of which is optically smooth for visible light providing a continuous transparent layer across said first surface by vapour deposition so as to provide conformal contact between the continuous transparent layer and the first surface of the substrate providing a flow channel bounded on a first side by the continuous transparent layer and etching an aperture in a second surface of the substrate extending to the first surface of the substrate so as to provide an optical path between said second surface and the flow channel wherein the continuous transparent layer is less reactive to the etching than the substrate.

Abstract: A method of producing a microfluidic chip for use in flow cytometry, the method comprising the steps of providing an opaque substrate, a first surface of which is optically smooth for visible light providing a continuous transparent layer across said first surface by vapour deposition so as to provide conformal contact between the continuous transparent layer and the first surface of the substrate providing a flow channel bounded on a first side by the continuous transparent layer and etching an aperture in a second surface of the substrate extending to the first surface of the substrate so as to provide an optical path between said second surface and the flow channel wherein the continuous transparent layer is less reactive to the etching than the substrate.