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 104 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 109 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.

Calibration of an Upconverting Phosphor-Based Quantitative Immunochromatographic Assay for Detecting Yersinia pestis, Brucella spp., and Bacillus anthracis Spores

“…(Zhao et al, 2016). Our UPT-LF assays showed robust performance using many clinical and environmental samples such as biochemical reagents and various types of powders and viscera samples (Zhang P. et al, 2014;Hua et al, 2015a,b), as well as field water samples (Hao et al, 2017). After the samples are loaded onto the strip, upconverting phosphor (UCP) particles that have first been combined with monoclonal antibodies (mAbs) against bacteria can capture the corresponding bacteria and are then captured by the other antibodies against bacteria fixed onto the test band (T band), while the remaining UCP-mAbs complexes are captured by goat anti-mouse IgG on the control band (C band).…”

“…The bacterial purity and activity, including the cellular integrity and surface constituents, were critical for evaluating the accuracy of the immunoassay. This study primarily focused on the bacterial quality for calibration because the specificity of the UPT-LF assay for detecting Y. pestis, B. abortus S19, and B. anthracis had been demonstrated in a previous study (Zhang P. et al, 2014). For B. anthracis, B. atrophaeus, B. subtilis, and B. cereus, the bacterial spores can be dyed green by malachite green stain, whereas for the Grampositive bacteria, their vegetative forms were recognized via crystal violet-iodine using a Gram stain.…”

Development and evaluation of an up-converting phosphor technology-based lateral flow assay for the rapid, simultaneous detection of Vibrio cholerae serogroups O1 and O139

“…The overall scheme used for operating the device was the same as that described previously [29]. Detection samples were diluted in sample-treating buffer (pH7.2 0.03 mol L −1 phosphate buffer containing 0.5 mol L −1 NaCl, 0.5% NP-40) at a ratio of 1:9, and then 140 μL of the mixture was applied to the UPT-LF strip.…”

Development and evaluation of an up-converting phosphor technology-based lateral flow assay for rapid detection of Francisella tularensis

“…Its optical signals can be collected and transformed into electrical signals, so the target is detected quantitatively with high sensitivity. UPT-LF assay has also been successively utilized for the detection of parasites 16 and bacteria 17 18 19 . Given UCP’s stable optical properties and strong covalent combination with antibodies, UPT-LF assay shows robust performance for many practical samples, such as blood, urine, and saliva 16 20 .…”

“…Given UCP’s stable optical properties and strong covalent combination with antibodies, UPT-LF assay shows robust performance for many practical samples, such as blood, urine, and saliva 16 20 . This assay is especially suitable for the surveillance of natural foci and first-level emergency responses in biowarfare and bioterrorism, because it is tolerant to highly complex samples (such as viscera collected from surveillance and various “white powders” present in anti-terrorist applications) and presents low operation error caused by nonprofessionals 17 18 . Thus, UPT-LF may be a feasible method for on-site detection of F. tularensis .…”