Pressure/colorimetric dual-readout immunochromatographic test strip for point-of-care testing of aflatoxin B1

Abstract Immunochromatographic test strip (ITS) for point-of-care testing (POCT) has attracted prominent attention due to the advantages including rapid response, low cost and good portability. Here, we developed a sensitive ITS for detecting aflatoxin B1 (AFB1) by using dendritic platinum nanoparticles (DPNs) as novel pressure/colorimetric dual-readout probes. DPNs-labeled antibody of AFB1 were used as the signal tracer of the immunochromatographic process. After 10-min competitive immunoreaction, black color appeared on the test line of ITS due to the accumulation of DPNs, which was observed visually as a colorimetric readout for qualitation purpose. Furthermore, DPNs with peroxidase-like activity caused decomposition of hydrogen peroxide aqueous solution to produce pressure change signal in vials, which was detected by a hand-held pressure meter for quantitation purpose. With the pressure readout mode, the detection range was 0.05 - 10 ng mL-1, and the detection limit was 0.03 ng mL-1 (S/N = 3) for AFB1. The proposed ITS was successfully utilized for detecting AFB1 in herbal medicine samples, and the acceptable recoveries of 93.77 – 114.09% indicated the reliability for real sample detection. It provides a new avenue for POCT with great application potential in various area including drug and food quality control, pollutants monitoring as well as medical diagnosis.