Fig. 1
Design of the microfluidic paper analytical device (µPAD) aptasensor used in this study, with relevant dimensions annotated. The flow of fluid is from left-to-right in the above figure. The sample reservoir is an 8 mm-wide circle. Zones 1, 2 and 3(circles, 5 mm in diameter) are areas where aptamers can be immobilised. Zones are joined together by a 4 mm-wide channel