scholarly journals A Highly Sensitive and Selective Colorimetric Hg2+ Ion Probe Using Gold Nanoparticles Functionalized with Polyethyleneimine

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Kyung Min Kim ◽  
Yun-Sik Nam ◽  
Yeonhee Lee ◽  
Kang-Bong Lee
Keyword(s):  
Gold Nanoparticles ◽  
Secondary Ion Mass Spectrometry ◽  
Color Change ◽  
Colorimetric Assay ◽  
Tap Water ◽  
Interparticle Distance ◽  
Pond Water ◽  
Assay Method ◽  
Tuna Fish ◽  
Highly Sensitive

A highly sensitive and selective colorimetric assay for the detection of Hg2+ ions was developed using gold nanoparticles (AuNPs) conjugated with polyethyleneimine (PEI). The Hg2+ ion coordinates with PEI, decreasing the interparticle distance and inducing aggregation. Time-of-flight secondary ion mass spectrometry showed that the Hg2+ ion was bound to the nitrogen atoms of the PEI in a bidentate manner (N–Hg2+–N), which resulted in a significant color change from light red to violet due to aggregation. Using this PEI-AuNP probe, determination of Hg2+ ion can be achieved by the naked eye and spectrophotometric methods. Pronounced color change of the PEI-AuNPs in the presence of Hg2+ was optimized at pH 7.0, 50°C, and 300 mM·NaCl concentration. The absorption intensity ratio (A700/A514) was correlated with the Hg2+ concentration in the linear range of 0.003–5.0 μM. The limits of detection were measured to be 1.72, 1.80, 2.00, and 1.95 nM for tap water, pond water, tuna fish, and bovine serum, respectively. Owing to its facile and sensitive nature, this assay method for Hg2+ ions can be applied to the analysis of water and biological samples.

scholarly journals Highly Sensitive Colorimetric Assay for Determining Fe3+Based on Gold Nanoparticles Conjugated with Glycol Chitosan

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Kyungmin Kim ◽  
Yun-Sik Nam ◽  
Yeonhee Lee ◽  
Kang-Bong Lee
Keyword(s):  
Gold Nanoparticles ◽  
Color Change ◽  
Colorimetric Assay ◽  
Tap Water ◽  
Interparticle Distance ◽  
Assay Method ◽  
Glycol Chitosan ◽  
Pharmaceutical Samples ◽  
Highly Sensitive ◽  
Oxygen Atoms

A highly sensitive and simple colorimetric assay for the detection of Fe3+ions was developed using gold nanoparticles (AuNPs) conjugated with glycol chitosan (GC). The Fe3+ion coordinates with the oxygen atoms of GC in a hexadentate manner (O-Fe3+-O), decreasing the interparticle distance and inducing aggregation. Time-of-flight secondary ion mass spectrometry showed that the bound Fe3+was coordinated to the oxygen atoms of the ethylene glycol in GC, which resulted in a significant color change from light red to dark midnight blue due to aggregation. Using this GC-AuNP probe, the quantitative determination of Fe3+in biological, environmental, and pharmaceutical samples could be achieved by the naked eye and spectrophotometric methods. Sensitive response and pronounced color change of the GC-AuNPs in the presence of Fe3+were optimized at pH 6, 70°C, and 300 mM NaCl concentration. The absorption intensity ratio (A700/A510) linearly correlated to the Fe3+concentration in the linear range of 0–180 μM. The limits of detection were 11.3, 29.2, and 46.0 nM for tap water, pond water, and iron supplement tablets, respectively. Owing to its facile and sensitive nature, this assay method for Fe3+ions can be applied to the analysis of drinking water and pharmaceutical samples.

scholarly journals A dual colorimetric probe for rapid environmental monitoring of Hg2+ and As3+ using gold nanoparticles functionalized with d-penicillamine

RSC Advances ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 5456-5465
Author(s):  
Su-Jin Yoon ◽  
Yun-Sik Nam ◽  
Yeonhee Lee ◽  
In Hwan Oh ◽  
Kang-Bong Lee
Keyword(s):  
Gold Nanoparticles ◽  
Environmental Monitoring ◽  
Colorimetric Assay ◽  
Colorimetric Probe ◽  
Highly Sensitive ◽  
Dual Detection

A highly sensitive and selective colorimetric assay for the dual detection of Hg2+ and As3+ using gold nanoparticles (AuNPs) conjugated with d-penicillamine (DPL) was developed.

scholarly journals A Simple Colorimetric Assay for Sensitive Cu2+ Detection Based on the Glutathione-Mediated Etching of MnO2 Nanosheets

2021 ◽  
Vol 9 ◽  
Author(s):  
Shurong Tang ◽  
Qiao Liu ◽  
Jie Hu ◽  
Wei Chen ◽  
Fengping An ◽  
...  
Keyword(s):  
Copper Ions ◽  
Colorimetric Assay ◽  
Detection System ◽  
Tap Water ◽  
High Specificity ◽  
Optimum Conditions ◽  
Deep Blue ◽  
Highly Sensitive ◽  
Layered Nanostructures ◽  
Highly Sensitive Detection

In this paper, we developed a quick, economical and sensitive colorimetric strategy for copper ions (Cu2+) quantification via the redox response of MnO2 nanosheets with glutathione (GSH). This reaction consumed MnO2 nanosheets, which acted as a catalyst for the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) to a blue product (oxTMB). In the presence of Cu2+, the GSH was catalyzed to GSSG (oxidized glutathione), and the solution changed from colorless to deep blue. Under the optimum conditions, the absorption signal of the oxidized product (oxTMB) became proportional to Cu2+ concentration in the range from 10 to 300 nM with a detection limit of 6.9 nM. This detection system showed high specificity for Cu2+. Moreover, the system has been efficaciously implemented for Cu2+ detection in actual tap water samples. The layered-nanostructures of MnO2 nanosheets make it possess high chemical and thermal stability. TMB can be quickly oxidized within 10 min by the catalyzing of MnO2 nanosheets with high oxidase-like activity. There is no need of expensive reagents, additional H2O2 and complicated modification processes during the colorimetric assay. Therefore, the strategy primarily based on MnO2 nanosheets is promising for real-time, rapid and highly sensitive detection of Cu2+ under practical conditions.

Selective colorimetric detection of Cr(iii) and Cr(vi) using gallic acid capped gold nanoparticles

2016 ◽  
Vol 45 (20) ◽  
pp. 8347-8354 ◽  
Author(s):  
Chen Dong ◽  
Genhua Wu ◽  
Zhuqing Wang ◽  
Wenzhi Ren ◽  
Yujie Zhang ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Gallic Acid ◽  
Color Change ◽  
Colorimetric Assay ◽  
Colorimetric Detection ◽  
Selective Detection

A colorimetric assay is proposed for the selective detection of Cr(iii) and Cr(vi) via the aggregation-induced color change of gallic acid capped gold nanoparticles (GA-AuNPs).

scholarly journals A Nanocomposite Based on Reduced Graphene and Gold Nanoparticles for Highly Sensitive Electrochemical Detection of Pseudomonas aeruginosa through Its Virulence Factors

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1180 ◽  
Author(s):  
Islem Gandouzi ◽  
Mihaela Tertis ◽  
Andreea Cernat ◽  
Dalila Saidane-Mosbahi ◽  
Aranka Ilea ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Gold Nanoparticles ◽  
Bacterial Infections ◽  
Electrochemical Sensors ◽  
Tap Water ◽  
Low Cost ◽  
Biological Contamination ◽  
Reduced Graphene ◽  
Highly Sensitive ◽  
Higher Sensitivity

Pyoverdine is a fluorescent siderophore produced by Pseudomonas aeruginosa that can be considered as a detectable marker in nosocomial infections. The presence of pyoverdine in water can be directly linked to the presence of the P. aeruginosa, thus being a nontoxic and low-cost marker for the detection of biological contamination. A novel platform was developed and applied for the electrochemical selective and sensitive detection of pyoverdine, based on a graphene/graphite-modified screen-printed electrode (SPE) that was electrochemically reduced and decorated with gold nanoparticles (NPs). The optimized sensor presenting higher sensitivity towards pyoverdine was successfully applied for its detection in real samples (serum, saliva, and tap water), in the presence of various interfering species. The excellent analytical performances underline the premises for an early diagnosis kit of bacterial infections based on electrochemical sensors.

Gold nanoparticle-based exonuclease III signal amplification for highly sensitive colorimetric detection of folate receptor

Nanoscale ◽  
2014 ◽  
Vol 6 (6) ◽  
pp. 3055-3058 ◽  
Author(s):  
Xinjian Yang ◽  
Zhiqiang Gao
Keyword(s):  
Gold Nanoparticles ◽  
Small Molecule ◽  
Signal Amplification ◽  
Colorimetric Assay ◽  
Folate Receptor ◽  
Colorimetric Detection ◽  
Label Free ◽  
Exonuclease Iii ◽  
Highly Sensitive ◽  
Highly Sensitive Detection

By combining terminal protection of small molecule (folate)-capped DNA probes, exonuclease III signal amplification and gold nanoparticles, we developed a simple and label-free colorimetric assay for highly sensitive detection of folate receptor.

A colorimetric assay method for invA gene of Salmonella using DNAzyme probe self-assembled gold nanoparticles as single tag

2014 ◽  
Vol 198 ◽  
pp. 87-93 ◽  
Author(s):  
Rong Luo ◽  
Yahui Li ◽  
Xiaojuan Lin ◽  
Fang Dong ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Colorimetric Assay ◽  
Assay Method ◽  
Inva Gene ◽  
Self Assembled

scholarly journals Portable on-chip colorimetric biosensing platform integrated with a smartphone for label/PCR-free detection of Cryptosporidium RNA

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
George S. Luka ◽  
Ephraim Nowak ◽  
Quin Robert Toyata ◽  
Nishat Tasnim ◽  
Homayoun Najjaran ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Color Change ◽  
Colorimetric Assay ◽  
Cost Effective ◽  
Naked Eye ◽  
Sensing Platform ◽  
3D Printed ◽  
Protozoan Pathogen ◽  
On Chip ◽  
Colorimetric Biosensing

AbstractCryptosporidium, a protozoan pathogen, is a leading threat to public health and the economy. Herein, we report the development of a portable, colorimetric biosensing platform for the sensitive, selective and label/PCR-free detection of Cryptosporidium RNA using oligonucleotides modified gold nanoparticles (AuNPs). A pair of specific thiolated oligonucleotides, complementary to adjacent sequences on Cryptosporidium RNA, were attached to AuNPs. The need for expensive laboratory-based equipment was eliminated by performing the colorimetric assay on a micro-fabricated chip in a 3D-printed holder assembly. A smartphone camera was used to capture an image of the color change for quantitative analysis. The detection was based on the aggregation of the gold nanoparticles due to the hybridization between the complementary Cryptosporidium RNA and the oligonucleotides immobilized on the AuNPs surface. In the complementary RNA’s presence, a distinctive color change of the AuNPs (from red to blue) was observed by the naked eye. However, in the presence of non-complementary RNA, no color change was observed. The sensing platform showed wide linear responses between 5 and 100 µM with a low detection limit of 5 µM of Cryptosporidium RNA. Additionally, the sensor developed here can provide information about different Cryptosporidium species present in water resources. This cost-effective, easy-to-use, portable and smartphone integrated on-chip colorimetric biosensor has great potential to be used for real-time and portable POC pathogen monitoring and molecular diagnostics.

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