Goat anti-mouse immunoglobulin as "crosslinker" assisted signal tracer assemble with intensive antibody utilization efficiency for sensitive paper-based strip nanobiosensors.

Engineered collaborative biochemical techniques and regulated nanomaterials (NMs) offer extraordinary opportunities for improving the analysis performance of lateral flow immunoassay (LFIA). Herein, inspired by the ability of macromolecules (e.g., proteins) to assemble into new functional units and the remarkable optical performance of engineered regulated NMs, goat anti-mouse immunoglobulin (GAMI) serves as the "crosslinker" to integrate gold‑manganese oxide (Au-MnOx ) to assemble the "signal tracers (STs)-crosslinker-antibody (mAb)" for elevating the mAb utilization efficiency. Notably, the "STs-crosslinker-mAb" assembly shows ~13.33-folds mAb utilization efficiency enhance, which perfectly response the challenge between limited sensitivity and sufficient signal intensity in competitive-type LFIA. The black color and rough structure of Au-MnOx offer higher colorimetric brightness (~2-folds than AuNPs) and enhanced mAb coupling efficiency (up to 92.47 %), which further improves sensitivity under the premise of functional assembly to intensify the competitive immunoreaction. Additionally, the convenient synthesis conditions (~13 min at room temperature) even comparable to direct purchase commercial products indicate that using Au-MnOx undoubtedly increases the cost-effectiveness. Encouragingly, the Au-MnOx -GAMI-mAb based LFIA exhibited high sensitivity (LOD: 0.063 ng mL-1 for clenbuterol (CLE) monitoring) by elevating mAb utilization efficiency with the attendant enhancing immune competition response in a cost-effective manner, which provides an invigorating reference pathway in point-of-care immunoassay.