University of Southampton

Ioannis Katis

Robert Eason

Collin Sones

Peijun He

Techniques for making fluid flow devices are described. The technique is based on radiation-induced conversion of a radiation-sensitive substance from a first state to a second state. With adjustment of the radiation parameters such as power and scan speed we can control the depths of barriers that are formed within a substrate which can produce 3D flow paths. We have used this depth-variable patterning protocol for stacking and sealing of multilayer substrates, for assembly of backing layers for two-dimensional (2D) lateral flow devices and for fabrication of 3D devices. Since the 3D flow paths can be formed via a single laser-writing process by controlling the patterning parameters, this is a distinct improvement over other methods that require multiple complicated and repetitive assembly procedures.

Fluid flow device and method for making the same

A method of making a fluid flow device comprises: providing a substrate of porous material () impregnated with a light-sensitive substance () in a first state and which is configured to change from the first state to a second state when exposed to light (), the second state being a solid state that is resistant to a solvent and the first being removable with the solvent; the substrate having a fluid flow channel () defined therein, the channel having a depth; exposing a beam of light () onto an area of the substrate surface within the fluid flow channel to deliver energy to a volume of the substrate below the area to change the light-sensitive substance to the second state; during exposure, creating a partial barrier to flow of fluid along the channel by controlling the amount of energy delivered to the volume below at least part of the area to change the light-sensitive substance to the second state in a volume of the substrate within the fluid flow channel that has a depth less than the depth of the fluid flow channel; and developing the substrate in the solvent to leave the light-sensitive substance which is in the solid state and remove the light-sensitive substance which is in the other state. The device may be a medical diagnostic device, and the substrate may be a paper substrate or may be a nitrocellulose substrate.

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Southampton, United Kingdom

Ioannis Katis