5.

Applications of VF-μPADs for noninfectious diseases. (A) VF-μPADs for POC measurement of iron from whole blood: (i) Sensor strip consists of four sandwiched membranes and hosts 50 μL of whole blood sample; (ii) GF membrane which acts as a primary filtration layer (top) while asymmetric polysulfone membrane which acts as a secondary filtration layer (bottom); and (iii) calibration curve for blood ion detection exhibited a slope of 0.0004 with a coefficient of determination (R²) of 0.95. Reproduced with permission from ref (). Copyright 2021 Royal Society of Chemistry. (B) VF-μPADs fabricated by origami method for programmable multifold analyte preconcentration: (i) Schematic representation and assembly of the 3D paper-based origami device for programmable analyte preconcentration and (ii) histograms showing a 407% and 406% signal increase for 5 and 10 ppb glucose, respectively, after preconcentration. Reproduced with permission from ref (). Copyright 2024 American Chemical Society.