3,3′,5,5′-Tetramethylbenzidine Oxidation on Paper Devices for Horseradish Peroxidase-based Assays

摘要

We report on the colorimetric oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) by hydrogen peroxide using horseradish peroxidase on photolithography-fabricated (P-PAD) and wax-printed (W-PAD) paper-based analytical devices. Fabricating PADs via photolithography exposes the hydrophilic areas to polymers (photoresists) and solvents, not only reducing the hydrophilicity, but also affecting the TMB–H2O2 assay system with an unavoidable incomplete elimination of photoresist during fabrication. Detection signals are then observed in the presence of photoresist residues on the P-PAD, even at a blank HRP concentration.