scholarly journals Colorimetric detection of organophosphates with cysteamine capped gold nanoparticle sensors

2020 ◽  
Author(s):  
Muhammad Musaddiq Shah ◽  
Wen Ren ◽  
Bashir Ahmad ◽  
Joseph Irudayaraj
Keyword(s):  
Gold Nanoparticle ◽  
Limit Of Detection ◽  
Colorimetric Detection ◽  
High Sensitivity ◽  
Food Samples ◽  
Quantitative Detection ◽  
Enzyme Mimics ◽  
Nanoparticle Probes ◽  
Site Monitoring ◽  
20 Nm

Nanozyme biosensors have the potential to provide high sensitivity, multiple functionality, and tunable activity. A facile colorimetric biosensor for the detection of organophosphates (OPs) using cysteamine capped gold nanoparticle probes (C-AuNPs) as enzyme mimics is proposed. Parathion ethyl (PE) a class of OPs is a potent insecticide that functions by inhibiting the acetylcholinesterase (AChE) in the nervous system of insects. The inhibition kinetics of AChE using PE enables the development of a PE sensor. C-AuNPs possess the ability to catalyze the oxidization of 3, 3’, 5, 5’-tetramethylbenzidine (TMB) to a blue-colored product without peroxidase. The detection of PE was monitored by the inability of AChE to generate choline. Choline causes the aggregation of C-AuNPs and the aggregated C-AuNPs has decreased ability to catalyze the oxidization of TMB. A calibration was developed in the 40-320 nM range for the quantitative detection of PE. The limit of detection observed was 20 nM and the method had excellent specificity. The proposed sensor provides an excellent platform for on-site monitoring of PE in environmental and food samples with high sensitivity and greater selectivity.

scholarly journals Dramatically Enhancing the Sensitivity of Immunoassay for Ochratoxin A Detection by Cascade-Amplifying Enzyme Loading

Toxins ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 781
Author(s):  
Zhuolin Song ◽  
Lin Feng ◽  
Yuankui Leng ◽  
Mingzhu Huang ◽  
Hao Fang ◽  
...  
Keyword(s):  
Ochratoxin A ◽  
Limit Of Detection ◽  
High Sensitivity ◽  
Cross Reaction ◽  
Molar Ratio ◽  
Quantitative Detection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Enzyme Loading ◽  
M13 Bacteriophage ◽  
Mimic Peptide

Enzyme-linked immunosorbent assay (ELISA) is widely used in the routine screening of mycotoxin contamination in various agricultural and food products. Herein, a cascade-amplifying system was introduced to dramatically promote the sensitivity of an immunoassay for ochratoxin A (OTA) detection. Specifically, a biotinylated M13 bacteriophage was introduced as a biofunctional competing antigen, in which a seven-peptide OTA mimotope fused on the p3 protein of M13 was used to specifically recognize an anti-OTA monoclonal antibody, and the biotin molecules modified on capsid p8 proteins were used in loading numerous streptavidin-labeled polymeric horseradish peroxidases (HRPs). Owing to the abundance of biotinylated p8 proteins in M13 and the high molar ratio between HRP and streptavidin in streptavidin-polyHRP, the loading amount of HRP enzymes on the M13 bacteriophage were greatly boosted. Hence, the proposed method exhibited high sensitivity, with a limit of detection of 2.0 pg/mL for OTA detection, which was 250-fold lower than that of conventional ELISA. In addition, the proposed method showed a slight cross-reaction of 2.3% to OTB, a negligible cross-reaction for other common mycotoxins, and an acceptable accuracy for OTA quantitative detection in real corn samples. The practicability of the method was further confirmed with a traditional HRP-based ELISA method. In conclusion, the biotinylated bacteriophage and polyHRP structure showed potential as a cascade-amplifying enzyme loading system for ultra-trace OTA detemination, and its application can be extended to the detection of other analytes by altering specific mimic peptide sequences.

scholarly journals Validation of a novel FRET real-time PCR assay for simultaneous quantitative detection and discrimination of human Plasmodium parasites

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0252887
Author(s):  
Renate Schneider ◽  
Aline Lamien-Meda ◽  
Herbert Auer ◽  
Ursula Wiedermann-Schmidt ◽  
Peter L. Chiodini ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Limit Of Detection ◽  
Melting Curve ◽  
Resonance Energy ◽  
High Sensitivity ◽  
Significant Rise ◽  
Quantitative Detection ◽  
Melting Curve Analysis ◽  
Nucleotide Polymorphisms

Increasing numbers of travelers returning from endemic areas, migrants, and refugees have led to a significant rise in the number of imported malaria cases in non-endemic countries. Real- time PCR serves as an excellent diagnostic tool, especially in regions where experience in microscopy is limited. A novel fluorescence resonance energy transfer-based real-time PCR (FRET-qPCR) was developed and evaluated using 56 reference samples of the United Kingdom National External Quality Assessment Service (UK NEQAS) for molecular detection of malaria, including P. falciparum, P. vivax, P. ovale, P. malariae, and P. knowlesi. Species identification is based on single nucleotide polymorphisms (SNPs) within the genome where the MalLC640 probe binds, lowering the melting temperature in the melting curve analysis. The novel FRET-qPCR achieved 100% (n = 56) correct results, compared to 96.43% performing nested PCR. The high sensitivity, with a calculated limit of detection of 199.97 parasites/mL blood for P. falciparum, is a significant advantage, especially if low-level parasitemia has to be ruled out. Even mixed infections of P. falciparum with P. vivax or P. ovale, respectively, were detected. In contrast to many other real-time PCR protocols, this novel FRET-qPCR allows the quantitative and species-specific detection of Plasmodium spp. in one single run. Solely, P. knowlesi was detected but could not be differentiated from P. vivax. The turnaround time of this novel FRET-qPCR including DNA extraction is less than two hours, qualifying it for routine clinical applications, including treatment monitoring.

scholarly journals A FRET-ICT Dual-Modulated Ratiometric Fluorescence Sensor for Monitoring and Bio-Imaging of Cellular Selenocysteine

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 4999
Author(s):  
Zongcheng Wang ◽  
Chenhong Hao ◽  
Xiaofang Luo ◽  
Qiyao Wu ◽  
Chengliang Zhang ◽  
...  
Keyword(s):  
Real Time ◽  
Limit Of Detection ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
High Sensitivity ◽  
Fluorescence Sensor ◽  
Quantitative Detection ◽  
Fluorescence Signal ◽  
Ratiometric Fluorescence ◽  
Sensitivity And Selectivity

Since the fluctuation of cellular selenocysteine (Sec) concentration plays an all-important role in the development of numerous human disorders, the real-time fluorescence detection of Sec in living systems has attracted plenty of interest during the past decade. In order to obtain a faster and more sensitive small organic molecule fluorescence sensor for the Sec detection, a new ratiometric fluorescence sensor Q7 was designed based on the fluorescence resonance energy transfer (FRET) strategy with coumarin fluorophore as energy donor and 4-hydroxy naphthalimide fluorophore (with 2,4-dinitrobenzene sulfonate as fluorescence signal quencher and Sec-selective recognition site) as an energy acceptor. The sensor Q7 exhibited only a blue fluorescence signal, and displayed two well distinguished emission bands (blue and green) in the presence of Sec with ∆λ of 68 nm. Moreover, concentrations ranging of quantitative detection of Sec of Q7 was from 0 to 45 μM (limit of detection = 6.9 nM), with rapid ratiometric response, high sensitivity and selectivity capability. Impressively, the results of the living cell imaging test demonstrated Q7 has the potentiality of being an ideal sensor for real-time Sec detection in biosystems.

scholarly journals Comparison of Nanosized Markers in Lateral Flow Immunoassay of Antibiotic Lincomycin

Proceedings ◽  
2020 ◽  
Vol 60 (1) ◽  
pp. 41
Author(s):  
Olga D. Hendrickson ◽  
Kseniya V. Serebrennikova ◽  
Elena A. Zvereva ◽  
Demid S. Popravko ◽  
Anatoly V. Zherdev ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Gold Nanoparticle ◽  
Limit Of Detection ◽  
Cost Effective ◽  
Lateral Flow ◽  
Lateral Flow Immunoassay ◽  
Quantitative Detection ◽  
Site Testing ◽  
Limits Of Detection ◽  
Chemical Contaminants

Improving the sensitivity of the competitive lateral flow immunoassay (LFIA) is important, given the increasing demands for the monitoring of chemical contaminants in food. The choice of nanosized marker is an essential task for improving the LFIA sensitivity. In this study, a CdSe/ZnS quantum dot (QD)-based LFIA combined with a portable reader was developed for rapid and quantitative detection of an antibiotic lincomycin (LIN). The performance of the proposed fluorescence LFIA was compared to the conventional gold nanoparticle (AuNP)-based LFIA realized with the same immunoreagents. The visual cutoff values were 10 ng/mL for AuNP-based LFIA and 20 ng/mL for QD-based LFIA. Furthermore, the instrumental limits of detection have been shown to be comparable for both nanosized markers and amounted to 0.4 ng/mL for AuNPs and 0.2 ng/mL for QDs, respectively. According to the results obtained, both LFIAs may be used for rapid, cost-effective, on-site testing of antibiotics, in particular LIN. However, the QD-based LFIA exhibits lowest limit of detection with the least immunoreagent consumption, which makes it economically beneficial.

Self-Assembly Strategy for Reducing Non-Specific Adsorption on Substrates and Application for Quantitative Immunoassay

2021 ◽  
Author(s):  
Yanbing lv ◽  
Man Zhao ◽  
Jinjin Fan ◽  
Ruili Wu ◽  
Yanxia Xu ◽  
...  
Keyword(s):  
Self Assembly ◽  
Glass Substrate ◽  
Limit Of Detection ◽  
Substrate Surface ◽  
High Sensitivity ◽  
Specific Adsorption ◽  
Quantitative Detection ◽  
Glass Substrates ◽  
Functionalized Surfaces ◽  
Substrate Surfaces

Abstract Background The development of functionalized surfaces with low non-specific adsorption is important for biomedical applications. To inhibit non-specific adsorption on a substrate, we prepared a novel optical biochip based on a quantum dot fluorescence immunosorbent assay (QD-FLISA), specifically by modifying a layer of dense negatively charged film (SO32−) on the glass substrate surface via self-assembly. Results Using optimized conditions, we constructed a biochip on functionalized glass substrates to achieve quantitative detection of C-reactive protein (CRP). We subsequently achieved quantitative determination of CRP in the range of 1-1,000 ng/mL, with a limit of detection (LOD) of 1.26 ng/mL or 5.17 ng/mL, using poly(styrene sulfonic acid) sodium salt (PSS) or meso-tetra (4-sulfonatophenyl) porphine dihydrochloride (TSPP) on individually modified glass substrate biochips. The experimental protocol was further optimized and the LOD achieved a sensitivity of 0.69 ng/mL using functionalized TSPP and PSS co-treated glass substrate surfaces for the quantitative detection of CRP. Conclusions This work demonstrated an effective and convenient strategy to obtain biochips with low non-specific adsorption properties on functionalized surfaces, thus providing a new approach for creating ultra-high sensitivity microchannels or microarrays on glass substrates.

Analyte-triggered autocatalytic amplification combined with gold nanoparticle probes for colorimetric detection of heavy-metal ions

2017 ◽  
Vol 53 (54) ◽  
pp. 7477-7480 ◽  
Author(s):  
Juanhua Yang ◽  
Yun Zhang ◽  
Lang Zhang ◽  
Huili Wang ◽  
Jinfang Nie ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Gold Nanoparticles ◽  
Metal Ions ◽  
Gold Nanoparticle ◽  
Heavy Metal Ions ◽  
Colorimetric Detection ◽  
Detection Limits ◽  
Label Free ◽  
Nanoparticle Probes ◽  
Free Gold

This work reports a new nanosensor based on analyte-triggered autocatalytic amplification and label-free gold nanoparticles for the colorimetric detection of Hg2+, Cu2+and Ag+with detection limits less than 3 nM.

scholarly journals Highly Sensitive and Selective Colorimetric Detection of Creatinine Based on Synergistic Effect of PEG/Hg2+–AuNPs

Nanomaterials ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1424 ◽  
Author(s):  
Xia ◽  
Zhu ◽  
Bian ◽  
Li ◽  
Liu ◽  
...  
Keyword(s):  
Color Change ◽  
Limit Of Detection ◽  
Colorimetric Detection ◽  
High Sensitivity ◽  
Peak Shift ◽  
Creatinine Concentration ◽  
Highly Sensitive ◽  
Coordination Effect ◽  
Bovine Serum Sample

A colorimetric sensor, based on the synergistic coordination effect on a gold nanoparticle (AuNP) platform has been developed for the determination of creatinine. The sensor selects citrate stabilized AuNPs as a platform, polyethylene glycol (PEG) as a decorator, and Hg2+ as a linkage to form a colorimetric probe system (PEG/Hg2−–AuNPs). By forming hydrogen bond between the oxygen-containing functional groups of PEG and citrate ions on the surface of AuNPs, this probe shows good stability. PEG coordinated with Hg2+ synergistically and specifically on the surface of dispersed AuNPs, and the existence of creatinine could induce the aggregation of AuNPs with a corresponding color change and an obvious absorption peak shift within 5 min. This PEG/Hg2+–AuNPs probe towards creatinine shows high sensitivity, and a good linear relationship (R2 = 0.9948) was obtained between A620–522 nm and creatinine concentration, which can achieve the quantitative calculations of creatinine. The limit of detection (LOD) of this PEG/Hg2+–AuNPs probe was estimated to be 9.68 nM, lower than that of many other reported methods (Supplementary Materials Table S3). Importantly, the sensitive probe can be successfully applied in a urine simulating fluid sample and a bovine serum sample. The unique synergistic coordination sensing mechanism applied in the designation of this probe further improves its high selectivity and specificity for the detection of creatinine. Thus, the proposed probe may give new inspirations for colorimetric detection of creatinine and other biomolecules.

Highly sensitive detection of nitrite by using gold nanoparticle-decorated α-Fe2O3 nanorod arrays as self-supporting photo-electrodes

2019 ◽  
Vol 6 (6) ◽  
pp. 1432-1441 ◽  
Author(s):  
Shenghong Kang ◽  
Haimin Zhang ◽  
Guozhong Wang ◽  
Yunxia Zhang ◽  
Huijun Zhao ◽  
...  
Keyword(s):  
Gold Nanoparticle ◽  
Limit Of Detection ◽  
High Sensitivity ◽  
Sensitive Detection ◽  
Nanorod Arrays ◽  
Highly Sensitive ◽  
Highly Sensitive Detection

Gold nanoparticle (Au NP)-decorated-Fe2O3 nanorod arrays (AuNPs-Fe2O3) as a photoelectrode are applied to the detection of nitrite solution with a low limit of detection and high sensitivity.

scholarly journals Smartphone-Based Colorimetric Detection of Chromium (VI) by Maleic Acid-Functionalized Gold Nanoparticles

2021 ◽  
Vol 11 (22) ◽  
pp. 10894
Author(s):  
Ahmed Mohamed ◽  
Xuemeng Li ◽  
Chengfei Li ◽  
Xuegang Li ◽  
Chao Yuan ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Maleic Acid ◽  
Colorimetric Detection ◽  
High Sensitivity ◽  
Quantitative Detection ◽  
Resource Constrained ◽  
Functionalized Gold Nanoparticles ◽  
Chromium Vi ◽  
Red Color ◽  
Sensitivity And Selectivity

Because of the significant environmental pollution produced by human activities, there is an ongoing need to develop transportable, simple, and reliable techniques for determining trace contaminants on the spot. This work reported a colorimetric detection method for aqueous Cr(VI) sensing by maleic acid-functionalized gold nanoparticles with high sensitivity and selectivity. The wine-red color of the probe solution can change to gray even in the presence of 1.0 µg L−1 of aqueous Cr(VI). Moreover, with the assistance of a smartphone installed with a commercially available color scan application software, its concentration of could be readily quantified on the spot without the help of UV-Vis spectrometer. The detection limit could reach as low as 0.1 µg L−1 with linear range from 0.2 to 2.0 µg L−1. Most importantly, the coefficient variation of the proposed smartphone-based method was equivalent to that of colorimetry, demonstrating the high accuracy of the proposed method for accurate detection of Cr(VI) in resource-constrained countries. Conclusively, with the help of the smartphone, this nanomaterials-based probe demonstrated the potential in the field of environment monitoring for on-site quantitative detection of any pollutants in resource-constrained countries.

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