Color-selective labyrinth-like quantum dot nanobeads enable point-of-care dual assay of of Mycotoxins

Complex nanoparticles with hybrid forms of quantum dots and nano-scale templates are highly interesting due to various functionalities and broad applications in point-of-care testing (POCT). High sensitivity and throughput are significant for POCT in clinical applications and food safety, especially for determining multiple targets in complex matrices. Here, we developed the labyrinth-like quantum dot nanobeads (LQDBs) with controlled size, enhanced loading capacity and an intelligent mobile detection format. We reported a smartphone readout using color-selective LQDBs as fluorescent labels for POCT of dual targets in paper-test format. The labyrinth-like nanobeads assembled with QDs provided high colloidal stability, facile functionalization, and a rough surface for more binding sites to monoclonal antibodies enabled by a thin silica layer coating. Using LQDB, the POCT of dual targets was developed assisted with an in-house application on a smartphone. This assay detected aflatoxin B1 (AFB1) and zearalenone (ZEN) within 10 min using a competitive immunoassay. The LODs for urine and agricultural products were recorded as 0.002 and 0.02 ng/mL for AFB1 and ZEN, respectively. Reasonable specificity, repeatability, reproducibility, and validation results were recorded in real samples. This biosensing platform can be widely suitable in clinical healthcare and food safety applications.