In-situ growth of highly stable CsPbBr3@MSN@PbBr(OH) through water-assisted strategy for high sensitivity immunochromatographic assay

Classical gold nanoparticle-based colorimetric immunochromatographic assay (ICA) exhibits moderate performance, limiting their application in trace detection. In this study, perovskite-MSN nanocomposites with high quantum yield (74.7 %), a narrow full width at half maximum (29.5 nm) and excellent water stability were synthesized using in situ crystallization growth and a water-assisted strategy. Carboxyl-modified perovskite-MSN nanocomposites were employed to label anti-gliadin monoclonal antibody (mAb) and construct dual-mode fluorescent ICA (FICA) for determination of gliadin in milk and beef samples. Compared to the traditional AuNP-based colorimetric ICA strips, the CsM-H-based FICA demonstrated improved sensitivity, with a limit of detection (LOD) of 3.62 ng/mL in quantitative analysis. The CsM-H-based FICA strips exhibited average recoveries ranging from 90.2 % to 110.0 %, with coefficients of variation (CVs) between 3.3 % and 7.4 % for milk and beef samples. The ultra-stable perovskite-MSN nanocomposites provided the FICA strip with excellent stability, enabling storage for up to six months at room temperature. This study highlights the advantages of CsM-H-based FICA, including its rapidity, simplicity, and cost-effectiveness, as a promising POCT biosensor.