In the realm of analysis, the lateral flow immunoassay (LFIA) is frequently utilized due to its capability to be fast and immediate. However, the biggest challenge of the LFIA is its low detection sensitivity and tolerance to matrix interference, making it impossible to enable accurate, qualitative analyses. In this study, we developed a new LFIA with higher affinity and sensitivity, based on a nanobody (G8-DIG) and CuS nanoflowers-Au (CuS NFs-Au), for the detection of aflatoxin B1(AFB1) in maize. We synthesized the immunoprobe G8-DIG@CuS NFs-Au, stimulated the in situ development of Au nanoparticles (Au NPs) on Cu NFs by electrical displacement, and obtained Cu NFs-Au for fixing the G8-DIG. G8-DIG@CuS NFs-Au probe-based LFIAs may, in ideal circumstances, use a strip chromatography reader to accomplish sensitive quantitative detection and qualitative visualization. AFB1has a detection range of 2.82–89.56 µg/L and a detection limit of 0.87 µg/L. When compared with an LFIA based on CuS NFs, this sensitivity is increased by 2.76 times. The practical application of this method in corn flour demonstrated a recovery rate of 81.7% to 117%. Therefore, CuS NFs-Au show great potential for detecting analytes.
Pengli Li,Min Wang,Mingzhe Jiang,Wenjing Lai,Jiajia Li,Kailin Liu,Hongling Li,Chenglin Hong
The early detection of tumour markers is essential for the timely treatment of cancer, and thus realising the sensitive detection of carcinoembryonic antigen (CEA) is significant. Herein, we employed an electrochemical immunosensor as a simple analytical method. The loading of precious metals significantly amplifies the signal of electrochemical immunosensors. In this study, the successful loading of Au NPs was achieved via the galvanic displacement method. Moreover, CuS nanoflowers possessed intrinsic peroxidase-like activity, which could catalyse the oxidation of o-phenylenediamine (OPD) to generate a light-orange product in the presence of hydrogen peroxide (H2O2). The flower-shaped CuS not only provided active sites for the catalytic reaction, but also possessed a large specific surface area, which could provide abundant sites for the placement of Au nanoparticles. Thus, it was suitable for the labelling of Ab2 for the sensitive detection of CEA. The instant current response (i–t) method detected CEA quantitatively, and the immunosensor prepared under the optimized conditions exhibited an excellent analytical performance. The detection range of the sensor prepared in this study was 0.1–80 ng mL−1 and its detection limit was 5.5 pg mL−1 (S/N = 3).
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