An ultrasensitive lateral flow immunoassay platform for foodborne biotoxins and pathogenic bacteria based on carbon-dots embedded mesoporous silicon nanoparticles fluorescent reporter probes

Abstract

Lateral flow immunoassays (LFIAs) are routine methods for rapid foodborne pollutants screening, with detection limits that are closely associated with the label probes used. The exploitation of high performance and robust probe is highly desirable, and remains a great challenge. Herein, we reported an emerging fluorescent nanobeads i.e. carbon-dots (CD) covalently incorporated mesoporous silicon nanoparticles (CD-MSNs) for LFIAs. CD-MSNs revealed brighter fluorescence, larger particle size and more modification sites in comparison with those of single CD. After bio-functionalisation, CD-MSNs probes were introduced to construct LFIA test strips, and designed for ultrasensitive detection of aflatoxin B1 (AFB1) and Staphylococcus aureus (S. aureus), two representative foodborne pollutants, based on the competitive and sandwich models, respectively. Very competitive quantitative detection limits i.e. 0.05 ng/mL and 10² cfu/mL were correspondingly obtained. Additionally, the test strips were successfully applied to rapidly and accurately screen AFB1 and S. aureus in food samples, highlighting their practicality.

Keywords: Carbon-Dots; Fluorescence probe; Foodborne pollutants; Lateral flow immunoassay; Mesoporous silicon nanoparticles.