A novel electro-driven immunochromatography assay based on upconversion nanoparticles for rapid pathogen detection.

Immunochromatography assays are simple and low-cost point-of-care diagnostics. However, the dependence on paper-based capillary forces limits improvements in speed of the assay. An electro-driven immunochromatography assay (EICA) is described that uses electroosmotic flow (EOF) to increase the driving force, as well as upconversion nanoparticles for high-sensitivity detection. EOF increased the signal intensity by 64.0% and reduced the assay time from 15 min to 5 min, and the EICA exhibited good specificity and sensitivity (1.2 × 103 CFU/mL) for pure cultures of Yersinia pestis EV76. It also had a strong tolerance to acid-base conditions (pH 2-12), salt solutions (NaCl ≤ 0.5 mol/L), viscous materials (polyethylene glycol 20,000 ≤ 25 mg/mL), and proteins (bovine serum albumin ≤200 mg/mL). For real soil samples, the EICA exhibited a low limit of detection (LOD) of 1.2 × 104 CFU/mL with good repeatability and reliability. Thus, EICA is applicable for detection of Y. pestis in soil, and should provide a rapid and sensitive tool for point-of-care diagnosis and detection.