Integrated Printed Electronics And Paper-based Microfluidics For POCT

Paper-based microfluidics combined with printed electronics has the potential to yield exceptionally powerful point-of-care testing(POCT) devices at extremely low cost. To achieve such devices, a microfluidic paper-based analytical device(μPAD) fabricated by high resolution inkjet printing of PDMS is described. Formulation of a PDMS “ink” which meets the fluidic requirements for droplet ejection through the nozzles of an inkjet printer head allowed high resolution patterning of hydrophobic barriers onto a nitrocellulose paper membrane. A low volume μPAD was designed to demonstrate proof-of-concept and shows feasibility of multiplexed, low sample volume analytical assays for point-of-care testing. Inkjet printing was also used to deposit antibodies and a fluorescent bead based immunoassay was implemented to demonstrate detection of cardiac troponin I(cTnI). A qualitative detection limit at approximately 1ng/mL after 15 mins using 20μL of sample shows promise for a clinically useful POCT device manufactured at low cost by printing. Further assay and device optimization should allow quantitative detection and lower detection limits in future devices.Printing methods are also used to deposit silver nanoparticle ink electrodes on nitrocellulose with good conductivity, this example serve to highlight the potential application of advanced printing techniques to the production of low-cost, highly functional diagnostic devices.