While lab-on-a-chip systems have become more and more widely used in many fields in diagnostics, analytical and life sciences, most of the systems still have to be considered as stationary, typically desktop-sized instruments. While the actual microfluidic cartridge often is comparatively compact, the associated instrument to operate this cartridge remains large, limiting the use of such systems in applications outside of a laboratory environment. Two main aspects contribute to this situation: Detection systems, especially sensitive optical (e.g. fluorescence) detection systems remain relatively large. The fluidic control elements, especially when reagents have to be delivered from a reservoir in the instrument to the cartridge, also contribute to the system size and weight. We have tried to circumvent these problems by integrating both the detection system as well as all required liquid reagents into the disposable microfluidic cartridge. The technology used for the realization of the detection system is the multilayer inkjet-printing of organic semiconductor materials (PEDOT:PSS) in order to create light sources and photodetector elements directly on the cartridge. This printing technology can be seamlessly integrated into the manufacturing workflow of the cartridge fabrication. All liquid reagents (currently 6) for an exemplary immunoassay on this platform are integrated using blisters which can be easily actuated either manually or by a simple linear actuator. Data readout as well as system control are planned to be executed using a smartphone, thereby further reducing the complexity and size of the instrument.
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