Colorimetric Sensing of Methyl Parathion Using Nanozymatic Activity of Gold Nanoparticles

In this study, we have used new approach for detection of the methyl parathion residues i.e., by inhibiting half of the peroxidase-like activity of gold nanoparticles. We have investigated the peroxidase like activity of gold nanoparticles by colorimetric assay and optimized the pH, temperature, incubation time and different concentrations of H2O2 by using TMB as substrate as well as organophosphates effect on their enzyme mimetic activity. Kinetic study of gold nanoparticles has shown better catalytic activity than horseradish peroxidase at pH 3.5. The peroxidase substrate TMB (3,3,5,5-tetramethylbenzidine) can be oxidized by H2O2 by the enzymatic action of the gold nanoparticles resulting in a blue-coloured product, oxidized TMB. The principle involved behind the inhibition of enzymatic activity of nanozyme is due to hindrance of electron transfer mechanism TMB-H2O2-Au NPs system by the methyl parathion. The peroxidase activity is selectively reduced with increasing methyl parathion concentration. This sensing method has lowest limit of detection of 78.95 nM. This study can be used for development of sensitive and cost effective technique for sensing of harmful pesticides.

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A Critical Factor for Quantifying Proteins in Unmodified Gold Nanoparticles-Based Aptasensing: The Effect of pH

Chemosensors ◽

10.3390/chemosensors8040098 ◽

2020 ◽

Vol 8 (4) ◽

pp. 98

Author(s):

Dai Lu ◽

Dong Zhang ◽

Qian Zhao ◽

Xiangyang Lu ◽

Xingbo Shi

Keyword(s):

Gold Nanoparticles ◽

Limit Of Detection ◽

Protein Detection ◽

Critical Factor ◽

Cost Effective ◽

Protein Corona ◽

Target Protein ◽

Universal Method ◽

Salt Addition ◽

Positively Charged

Unmodified gold nanoparticles (AuNPs)-based aptasensing (uGA) assay has been widely implemented in the determination of many different targets, but there are few reports on protein detection using uGA. Here, we designed a uGA assay for protein detection including the elimination of interfering proteins. Positively charged protein can be absorbed directly on the surface of AuNPs to form “protein corona”, which results in the aggregation of AuNPs even without salt addition, thereby preventing target protein detection. To overcome this problem, we systematically investigated the effect of modifying the pH of the solution during the uGA assay. A probe solution with a pH slightly higher than the isoelectric points (pI) of the target protein was optimal for protein detection in the uGA assay, allowing the aptamer to selectively detect the target protein. Three proteins (beta-lactoglobulin, lactoferrin, and lysozyme) with different pI were chosen as model proteins to validate our method. Positively charged interfering proteins (with pIs higher than the optimal pH) were removed by centrifugation of protein corona/AuNPs aggregates before the implementation of actual sample detection. Most importantly, the limit of detection (LOD) for all three model proteins was comparable to that of other methods, indicating the significance of modulating the pH. Moreover, choosing a suitable pH for a particular target protein was validated as a universal method, which is significant for developing a novel, simple, cost-effective uGA assay for protein detection.

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Sensitive and selective colorimetric sensing of Fe3+ion by using p-amino salicylic acid dithiocarbamate functionalized gold nanoparticles

New Journal of Chemistry ◽

10.1039/c3nj01468a ◽

2014 ◽

Vol 38 (4) ◽

pp. 1503-1511 ◽

Cited By ~ 40

Author(s):

Vaibhavkumar N. Mehta ◽

Suresh Kumar Kailasa ◽

Hui-Fen Wu

Keyword(s):

Gold Nanoparticles ◽

Salicylic Acid ◽

Biological Samples ◽

Colorimetric Sensing ◽

Au Nps ◽

Functionalized Gold Nanoparticles ◽

Amino Salicylic Acid

DTC-PAS-Au NPs successfully acted as probes for the selective and sensitive colorimetric sensing of Fe3+ions in biological samples.

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Colorimetric Detection of Trace Arsenic(III) in Aqueous Solution Using Arsenic Aptamer and Gold Nanoparticles

Australian Journal of Chemistry ◽

10.1071/ch13512 ◽

2014 ◽

Vol 67 (5) ◽

pp. 813 ◽

Cited By ~ 49

Author(s):

Minglei Yu

Keyword(s):

Aqueous Solution ◽

Gold Nanoparticles ◽

Detection Limit ◽

Colorimetric Assay ◽

Colorimetric Detection ◽

Colour Change ◽

Colorimetric Sensing ◽

Detection Range ◽

Colorimetric Indicator ◽

Blue Solution

In this study, trace arsenic(iii) (AsIII) in aqueous solution was detected by applying a classical aptamer-based gold nanoparticles colorimetric sensing strategy. An arsenic aptamer was used as a sensing probe and gold nanoparticles as a colorimetric indicator. In the absence of AsIII, the gold nanoparticles were stabilised by the arsenic aptamer and remained dispersed at high NaCl concentrations, displaying a red solution. Contrarily, in the presence of AsIII, the gold nanoparticles were prone to aggregation, owing to the formation of aptamer–AsIII complex between the arsenic aptamer and AsIII, and thus exhibited a blue solution. By monitoring the colour change, a simple and fast colorimetric assay for AsIII was established with a detection range of 1.26–200 ppb and a detection limit of 1.26 ppb. Because this colorimetric assay only involves common reagents and can be assessed visually, it holds great potential for arsenic(iii) monitoring in environment-related and other applications.

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Dicoumarol assisted synthesis of water dispersible gold nanoparticles for colorimetric sensing of cysteine and lysozyme in biofluids

RSC Advances ◽

10.1039/c5ra06814b ◽

2015 ◽

Vol 5 (49) ◽

pp. 39182-39191 ◽

Cited By ~ 30

Author(s):

Betha Saineelima B. Kasibabu ◽

Jigna R. Bhamore ◽

Stephanie L. D'souza ◽

Suresh Kumar Kailasa

Keyword(s):

Gold Nanoparticles ◽

Colorimetric Sensing ◽

Schematic Representation ◽

Au Nps ◽

Water Dispersible

A schematic representation of the mechanism for the colorimetric sensing of Cys and Lys using DIC–Au NPs as a probe.

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2,3,4-Trihydroxy benzophenone as a novel reducing agent for one-step synthesis of size-optimized gold nanoparticles and their application in colorimetric sensing of adenine at nanomolar concentration

RSC Advances ◽

10.1039/c5ra21634f ◽

2016 ◽

Vol 6 (14) ◽

pp. 11099-11108 ◽

Cited By ~ 13

Author(s):

Karuna A. Rawat ◽

Suresh Kumar Kailasa

Keyword(s):

Gold Nanoparticles ◽

Reducing Agent ◽

Colorimetric Sensing ◽

Au Nps ◽

Stabilizing Agent ◽

Nanomolar Concentration ◽

One Step

2,3,4-trihydroxy benzophenone acts as a novel reducing and stabilizing agent for one-step synthesis of size-optimized Au NPs and used as a probe for colorimetric sensing of adenine.

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Amplified visual immunosensor integrated with nanozyme for ultrasensitive detection of avian influenza virus

10.1101/128538 ◽

2017 ◽

Author(s):

Syed Rahin Ahmed ◽

Suresh Neethirajan

Keyword(s):

Gold Nanoparticles ◽

Influenza Virus ◽

Catalytic Activity ◽

Avian Influenza ◽

Avian Influenza Virus ◽

Limit Of Detection ◽

Blue Color ◽

Au Nps ◽

Influenza Virus A ◽

Practical Applications

ABSTRACTNanomaterial-based artificial enzymes or nanozymes exhibits superior properties such as stability, cost effectiveness and ease of preparation in comparison to conventional enzymes. However, the lower catalytic activity of nanozymes limits their sensitivity and thereby practical applications in the bioanalytical field. To overcome this drawback, herein we propose a very simple but highly sensitive, specific and low-cost dual enhanced colorimetric immunoassay for the detection of avian influenza virus A (H5N1) through facile in situ synthesis of gold nanoparticles and their peroxidase-like enzymatic activity. 3,3’,5,5’-Tetramethylbenzidine (TMBZ) was used as a reducing agent to produce gold nanoparticles (Au NPs) from a viral target-specific antibody-gold ion complex. The developed blue color from the sensing design was further amplified through catalytic activity of Au NPs in presence of TMBZ–hydrogen peroxide (H2O2) complex. The developed dual enhanced colorimetric immunosensor enables the detection of avian influenza virus A (H5N1) with a limit of detection (LOD) of 1.11 pg/mL. Our results further confirms that the developed assay has superior sensitivity than the conventional ELISA method, plasmonic-based bioassay and commercial flu diagnostic kits.

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Malonamide dithiocarbamate functionalized gold nanoparticles for colorimetric sensing of Cu2+ and Hg2+ ions

RSC Advances ◽

10.1039/c4ra11640b ◽

2015 ◽

Vol 5 (6) ◽

pp. 4245-4255 ◽

Cited By ~ 32

Author(s):

Vaibhavkumar N. Mehta ◽

Suresh Kumar Kailasa

Keyword(s):

Gold Nanoparticles ◽

Colorimetric Detection ◽

Colorimetric Sensing ◽

Au Nps ◽

Colorimetric Probe ◽

Functionalized Gold Nanoparticles

In this study, a colorimetric probe was developed based on malonamide dithiocarbamate functionalized gold nanoparticles (MA–DTC–Au NPs) for the simultaneous colorimetric detection of Cu2+ and Hg2+ ions.

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