scholarly journals A two-colour multiplexed lateral flow immunoassay system to differentially detect human malaria species on a single test line

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Jinsu Kim ◽  
Xiangkun Elvis Cao ◽  
Julia L. Finkelstein ◽  
Washington B. Cárdenas ◽  
David Erickson ◽  
...  

Abstract Background Malaria continues to impose a tremendous burden in terms of global morbidity and mortality, yet even today, a large number of diagnoses are presumptive resulting in lack of or inappropriate treatment. Methods In this work, a two-colour lateral flow immunoassay (LFA) system was developed to identify infections by Plasmodium spp. and differentiate Plasmodium falciparum infection from the other three human malaria species (Plasmodium vivax, Plasmodium ovale, Plasmodium malariae). To achieve this goal, red and blue colours were encoded to two markers on a single test line of strips, for simultaneous detection of PfHRP2 (red), a marker specific for P. falciparum infection, and pLDH (blue), a pan-specific marker for infections by all species of Plasmodium. The assay performance was first optimized and evaluated with recombinant malarial proteins spiked in washing buffer at various concentrations from 0 to 1000 ng mL−1. The colour profiles developed on the single test line were discriminated and quantified: colour types corresponded to malaria protein species; colour intensities represented protein concentration levels. Results The limit of detection (the lowest concentrations of malaria antigens that can be distinguished from blank samples) and the limit of colour discrimination (the limit to differentiate pLDH from PfHRP2) were defined for the two-colour assay from the spiked buffer test, and the two limits were 31.2 ng mL−1 and 7.8 ng mL−1, respectively. To further validate the efficacy of the assay, 25 human whole blood frozen samples were tested and successfully validated against ELISA and microscopy results: 15 samples showed malaria negative; 5 samples showed P. falciparum positive; 5 samples showed P. falciparum negative, but contained other malaria species. Conclusions The assay provides a simple method to quickly identify and differentiate infection by different malarial parasites at the point-of-need and overcome the physical limitations of traditional LFAs, improving the multiplexing potential for simultaneous detection of various biomarkers.

Talanta ◽  
2019 ◽  
Vol 192 ◽  
pp. 288-294 ◽  
Author(s):  
Fabio Di Nardo ◽  
Eugenio Alladio ◽  
Claudio Baggiani ◽  
Simone Cavalera ◽  
Cristina Giovannoli ◽  
...  

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 768
Author(s):  
Hyung-Mo Kim ◽  
Chiwoo Oh ◽  
Jaehyun An ◽  
Seungki Baek ◽  
Sungje Bock ◽  
...  

Exosomes are attracting attention as new biomarkers for monitoring the diagnosis and prognosis of certain diseases. Colorimetric-based lateral-flow assays have been previously used to detect exosomes, but these have the disadvantage of a high limit of detection. Here, we introduce a new technique to improve exosome detection. In our approach, highly bright multi-quantum dots embedded in silica-encapsulated nanoparticles (M–QD–SNs), which have uniform size and are brighter than single quantum dots, were applied to the lateral flow immunoassay method to sensitively detect exosomes. Anti-CD63 antibodies were introduced on the surface of the M–QD–SNs, and a lateral flow immunoassay with the M–QD–SNs was conducted to detect human foreskin fibroblast (HFF) exosomes. Exosome samples included a wide range of concentrations from 100 to 1000 exosomes/µL, and the detection limit of our newly designed system was 117.94 exosome/μL, which was 11 times lower than the previously reported limits. Additionally, exosomes were selectively detected relative to the negative controls, liposomes, and newborn calf serum, confirming that this method prevented non-specific binding. Thus, our study demonstrates that highly sensitive and quantitative exosome detection can be conducted quickly and accurately by using lateral immunochromatographic analysis with M–QD–SNs.


RSC Advances ◽  
2020 ◽  
Vol 10 (49) ◽  
pp. 29156-29170
Author(s):  
Ji Xia ◽  
Yifan Liu ◽  
Menglin Ran ◽  
Wenbo Lu ◽  
Liyan Bi ◽  
...  

Based on SERS-based lateral flow immunoassay, nano-Ag polydopamine nanospheres was used for detecting squamous cell carcinoma antigen and cancer antigen 125 simultaneously in cervical cancer serum.


2020 ◽  
Vol 92 (23) ◽  
pp. 15542-15549
Author(s):  
Chongwen Wang ◽  
Xingsheng Yang ◽  
Bing Gu ◽  
Haifeng Liu ◽  
Zihui Zhou ◽  
...  

2016 ◽  
Vol 79 (3) ◽  
pp. 477-483 ◽  
Author(s):  
JONGKIT MASIRI ◽  
BRIANDA BARRIOS-LOPEZ ◽  
LORA BENOIT ◽  
JOSHUA TAMAYO ◽  
JEFFREY DAY ◽  
...  

ABSTRACT Allergies to cow's milk are very common and can present as life-threatening anaphylaxis. Consequently, food labeling legislation mandates that foods containing milk residues, including casein and/or β-lactoglobulin, provide an indication of such on the product label. Because contamination with either component independent of the other can occur during food manufacturing, effective allergen management measures for containment of milk residues necessitates the use of dual screening methods. To assist the food industry in improving food safety practices, we have developed a rapid lateral flow immunoassay test kit that reliably reports both residues down to 0.01 μg per swab and 0.1 ppm of protein for foods. The assay utilizes both sandwich and competitive format test lines and is specific for bovine milk residues. Selectivity testing using a panel of matrices with potentially interfering substances, including commonly used sanitizing agents, indicated reduction in the limit of detection by one-to fourfold. With food, residues were easily detected in all cow's milk–based foods tested, but goat and sheep milk residues were not detected. Specificity analysis revealed no cross-reactivity with common commodities, with the exception of kidney beans when present at high concentrations (>1%). The development of a highly sensitive and rapid test method capable of detecting trace amounts of casein and/or β-lactoglobulin should aid food manufacturers and regulatory agencies in monitoring for milk allergens in environmental and food samples.


2021 ◽  
Vol 13 (34) ◽  
pp. 40342-40353
Author(s):  
Chongwen Wang ◽  
Xiaodan Cheng ◽  
Liyan Liu ◽  
Xiaochang Zhang ◽  
Xingsheng Yang ◽  
...  

2020 ◽  
Author(s):  
Vasily Panferov ◽  
Irina V. Safenkova ◽  
Anatoly V. Zherdev ◽  
Boris B. Dzantiev

<div>The approach to inhibit endogenous peroxidases by elevated concentrations of hydrogen peroxide while maintaining the high peroxidase-mimicking activity of Au@Pt nanozymes was developed. The approach facilitates selective and highly-sensitive detection of peroxidase-mimicking nanozyme nanozymes in the background of endogenous peroxidases. Au@Pt nanozyme was used as the colorimetric and catalytic label in lateral flow immunoassay of an important plant pathogen – potato virus X. The inhibition of endogenous peroxidases in plant extracts and selective detection of Au@Pt nanozyme provides the lowest limit of detection among immunochemical assays of potato virus X (up to 500 times lower compared to the assay with conventional gold nanoparticles). </div><div>The proposed approach uses the fundamental principle of enzyme inhibition by the substrate. It is universal and applicable to all matrixes with peroxidase activity. </div>


F1000Research ◽  
2019 ◽  
Vol 8 ◽  
pp. 1042
Author(s):  
Tien Viet Tran ◽  
Binh Nhu Do ◽  
Thao Phuong Thi Nguyen ◽  
Tung Thanh Tran ◽  
Son Cao Tran ◽  
...  

Fumonisins are among the most prevalent mycotoxins in maize, causing substantial economic losses and potential health risks in humans and animals. In the present study, in-house polyclonal IgY antibody against fumonisin B1 (FB1) and B2 (FB2) was applied for the development of a competitive lateral flow immunoassay detecting these mycotoxins in maize grains with the limit of detection of 4000 µg/kg, which corresponds to the maximum residue limit adopted by the European Commission. To this end, factors affecting the test performance including nitrocellulose membrane type, dilution factor of maize homogenates in running buffer, amount of detection conjugate, and incubation time between detection conjugate and samples were optimized. Under the optimal condition (UniSart® CN140 nitrocellulose membrane, FB1-BSA immobilized at 1 µg/cm, 1:10 dilution factor, 436 ng of gold nanoparticle conjugate, 30 minutes of incubation), the developed test could detect both FB1 and FB2 in maize with limit of detection of 4000 µg/kg, and showed no cross-reactivity to deoxynivalenol, ochratoxin A, aflatoxin B1 and zearalenone. When applied to detect FB1 and FB2 in naturally contaminated maize samples, results obtained from the developed assay were in good agreement with those from the high-performance liquid chromatography method. This lateral flow immunoassay is particularly suitable for screening of fumonisins in maize because of its simplicity and cost-effectiveness.


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