Microfluidic paper-based analysis device applying black phosphorus nanosheets@MWCNTs-COOH: A portable and efficient strategy for detection of -Lactoglobulin in dairy products

This study prepared a novel, portable and cost-effective microfluidic paper-based electrochemical analysis device (mu-PAD) using black phosphorus nanosheets@carboxylated multi-walled carbon nanotubes (BPNSs@MWCNTs-COOH) nanocomposites for beta-lactoglobulin (beta-LG) detection. At the appreciate ratio, the synthesized BPNSs@MWCNTs-COOH was demonstrated to not only serve as a high-quality substrate for the specific aptamer immobilization, but also improve the electron transfer capability of the sensing interface. The mu-PADs, utilizing BPNSs@MWCNTs-COOH and aptamer recognition, exhibited a wider detection range (10-1000 ng mL(-1)) and lower detection limit (LOD: 0.12 ng mL(-1)) for beta-LG, and demonstrated enhanced specificity, satisfactory anti-interference ability and stability. When applied to the beta-LG determination in dairy samples, the mu-PAD yielded beta-LG concentrations highly correlated with those obtained using the HPLC method (R-2: 0.9982). These results emphasized the reliable performance of the developed mu-PADs in beta-LG allergen quantification, highlighting their potential as an efficient platform for the rapid screening of beta-LG allergens.