Bisphenol a monitoring by commercial pregnancy test strips transformed by DNA walking machine.

Frequently occurred food contamination issues bring about a tremendous global demand for point-of-care testing (POCT) devices. Pregnancy test strip (PTS) retains the highest POCT market share and a low cost of $0.10 per test, but challenged by limited analytical sensitivity and non-autonomous signal transduction for drink contaminant monitoring. Herein, we developed a DNA walking machine-assisted commercial PTS method for on-site bisphenol A (BPA) analysis. DNAzyme was operated as the efficient autonomous catalytic walker chain to drive the DNA machine for the amplified signal output of BPA in drink samples. A detection limit of 16.8 pg/mL was obtained. The POCT strategy constructed in this work has the characteristics of low cost, convenient operation and high analytical sensitivity, represents an attractive option for biosensing and on-site drink safety monitoring.