1 research outputs found
Size-Dependent Immunochromatographic Assay with Quantum Dot Nanobeads for Sensitive and Quantitative Detection of Ochratoxin A in Corn
Fluorescent microspheres
are a novel luminescent nanomaterial proposed
as an alternative probe to improve the detection sensitivity of competitive
immunochromatographic assay (ICA). Quantum dot nanobeads (QBs) possess
strong luminescence and resistance to matrix interference. Theoretically,
large-sized QBs exhibit stronger luminescent intensity than small-sized
QBs and are beneficial to ICA sensitivity. However, oversized QBs
may reduce the sensitivity of competitive ICA. Thus, the relationship
between the size and luminescent intensity of QBs and the competitive
ICA sensitivity must be elucidated. In this study, QBs of different
sizes (58, 124, 255, 365, and 598 nm) were synthesized. Ochratoxin
A (OTA) was selected as the model analyte for competitive ICA. The
effects of QB size on the detection performance of competitive ICA
were then evaluated. The cutoff limit of QB-ICA for naked eye detection
was used for qualitative analysis, and the half-maximal inhibitory
concentration (IC<sub>50</sub>) and LOD were employed for quantitative
analysis. Results indicated that 124 nm QBs used as labeling probes
for competitive ICA showed the optimal detection performance and the
lowest cutoff value of 5 ng/mL for qualitative detection and IC<sub>50</sub> (0.39 ng/mL) for quantitative detection. Similar to commercial
ELISA, QB<sub>124</sub>-ICA displayed good accuracy, specificity,
reproducibility, and practicability. In summary, 124 nm QBs can be
used as a new labeling probe for competitive ICA