Evaluation of up-converting phosphor technology-based lateral flow strips for rapid detection of Bacillus anthracis spore, Brucella spp., and Yersinia pestis

Abstract

Bacillus anthracis, Brucella spp., and Yersinia pestis are zoonotic pathogens and biowarfare- or bioterrorism-associated agents that must be detected rapidly on-site from various samples (e.g., viscera and powders). An up-converting phosphor technology-based lateral flow (UPT-LF) strip was developed as a point-of-care testing (POCT) to satisfy the requirements of first-level emergency response. We developed UPT-LF POCT to quantitatively detect the three pathogens within 15 min. Sample and operation-error tolerances of the assay were comprehensively evaluated. The sensitivity of UPT-LF assay to bacterial detection reached 10 4 cfu·mL -1 (100 cfu/test), with a linear quantitative range of 4 to 6 orders of magnitude. Results revealed that the UPT-LF assay exhibited a high specificity with the absence of false-positive results even at 10 9 cfu·mL -1 of non-specific bacterial contamination. The assay could tolerate samples with a wide pH range (2 to 12), high ion strengths (≥4 mol·L -1 of NaCl), high viscosities (≤25 mg·mL -1 of PEG20000 or ≥20% of glycerol), and high concentrations of bio-macromolecule (≤200 mg·mL -1 of bovine serum albumin or ≥80 mg·mL -1 of casein). The influence of various types of powders and viscera (fresh and decomposed) on the performance of UPT-LF assay was determined. The operational error of liquid measurement exhibited few effects on sensitivity and specificity. The developed UPT-LF POCT assay is applicable under field conditions with excellent tolerance to sample complexity and operational error. © 2014 Zhang et al.