There is a strong interest in the use of biopolymers in the electronic and biomedical industries, mainly towards lowcost applications. The possibility of developing entirely new kinds of products based on cellulose is of current interest, in order to enhance and to add new functionalities to conventional paperbased products. We present our results towards the development of paperbased microfluidics for molecular diagnostic testing. Paper properties were evaluated and compared to nitrocellulose, the most commonly used material in lateral flow and other rapid tests. Focusing on the use of paper as a substrate for microfluidic applications, through an ecofriendly waxprinting technology, we present three main and distinct colorimetric approaches: (i) enzymatic reactions (glucose detection); (ii) immunoassays (antibodies antiLeishmania detection); (iii) nucleic acid sequence identification (Mycobacterium tuberculosis complex detection). Colorimetric glucose quantification was achieved through enzymatic reactions performed within specific zones of the paperbased device. The colouration achieved increased with growing glucose concentration and was highly homogeneous, covering all the surface of the paper reaction zones in a 3D sensor format. These devices showed a major advantage when compared to the 2D lateral flow glucose sensors, where some carryover of the coloured products usually occurs. The detection of antiLeishmania antibodies in canine sera was conceptually achieved using a paperbased 96well enzymelinked immunosorbent assay format. However, optimization is still needed for this test, regarding the efficiency of the immobilization of antigens on the cellulose fibres. The detection of Mycobacterium tuberculosis nucleic acids integrated with a noncrosslinking gold nanoprobe detection scheme was also achieved in a waxprinted 384well paperbased microplate, by the hybridization with a speciesspecific probe. The obtained results with the abovementioned proofofconcept sensors are thus promising towards the future development of simple and costeffective paperbased diagnostic devices.
Original languageUnknown
Pages (from-to)Online
Issue number9-094006
Publication statusPublished - 1 Jan 2014

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