Smartphone-Based Dual-Channel Immunochromatographic
Test Strip with Polymer Quantum Dot Labels for Simultaneous Detection
of Cypermethrin and 3‑Phenoxybenzoic Acid
posted on 2021-09-30, 17:04authored byYuting Zhao, Xiaofan Ruan, Yang Song, Jordan N. Smith, Natalia Vasylieva, Bruce D. Hammock, Yuehe Lin, Dan Du
Currently,
gas chromatography–mass spectrometry (GC–MS)
and liquid chromatography–MS (LC–MS) are the primary
methods used to detect pesticides and their metabolites for biomonitoring
of exposure. Although GC–MS and LC–MS can provide accurate
and sensitive measurements, these techniques are not suitable for
point-of-care or in-field biomonitoring applications. The objective
of this work is to develop a smartphone-based dual-channel immunochromatographic
test strip (ICTS) for on-site biomonitoring of exposure to cypermethrin
by simultaneous detection of cypermethrin and its metabolite, 3-phenoxybenzoic
acid (3-PBA). Polymer carbon dots (PCDs) with ultrahigh fluorescent
brightness were synthesized and used as a signal amplifier in ICTS
assay. Cypermethrin (a representative pyrethroid pesticide) and its
major metabolite 3-PBA were simultaneously detected to provide more
comprehensive analysis of cypermethrin exposure. After competitive
immunoreactions between the target sample and the coating antigens
preloaded on the test line, the tracer antibody (PCD-conjugated antibody)
was quantitatively captured on the test lines. The captured PCDs were
inversely proportional to the amount of the target compound in the
sample. The red fluorescence on the test line was then recorded using
a smartphone-based device capable of conducting image analysis and
recording. Under optimal conditions, the sensor showed excellent linear
responses for detecting cypermethrin and 3-PBA ranging from 1 to 100
ng/mL and from 0.1 to 100 ng/mL, respectively, and the limits of detection
were calculated to be ∼0.35 ng/mL for cypermethrin and ∼0.04
ng/mL for 3-PBA. The results demonstrate that the ICTS device is promising
for accurate point-of-care biomonitoring of pesticide exposure.