Ultrasensitive, highly specific, colorimetric recognition of sulfide ions [S2−] in aqueous media: applications to environmental analysis

2015 ◽  
Vol 7 (6) ◽  
pp. 2547-2553 ◽  
Author(s):  
Uttam R. Kondekar ◽  
Laxman S. Walekar ◽  
Anil H. Gore ◽  
Prashant V. Anbhule ◽  
Sung H. Han ◽  
...  

Herein, we have demonstrated the simple, ultrasensitive and highly specific colorimetric assay for the detection of sulfide ions (S2−) based on interaction of the surface capped gold nanoparticles with S2− in aqueous media.

2020 ◽  
Vol 16 (5) ◽  
pp. 793-804
Author(s):  
Naimeh Mahheidari ◽  
Jamal Rashidiani ◽  
Hamid Kooshki ◽  
Khadijeh Eskandari

Background: Today, nanoparticles hold great promise in biomedical researches and applications including bacteria detection. The rapid and sensitive outcomes of bacteria detection strategies using nanoparticle conjugates become determinative, especially in bacterial outbreaks. In the current research, we focused on detecting V. cholera bacteria and its toxin using a thiocyanate/Au nanoparticle. Thiocyanate adsorbed strongly on the surface of gold nanoparticles and changed the surface by enhancing surface plasmon resonance of gold nanoparticles. Objective: This method is tried to introduce a simple and fast procedure to assay vibrio cholera. So, it is observed by the naked eyes as well. Methods: We used two antibodies (Ab) for V. cholera detection: a) a primary antibody conjugated to magnetic nanoparticles (MNPs) for trapping V. cholera bacterial cells, and b) a secondary Abconjugated thiocyanate-GNPs as a colorimetric detector. Then, an immuno-magnetic separation system connected to a colorimetric assay was designed based on the GNPs. The results were measured by ultraviolet-visible (UV-Vis) spectroscopy. Results: The results showed that gold nanoparticles are an appropriate optical assay for detecting biological samples in a minimum concentration and also it can be easily seen by the naked eyes. The linear range of this biosensor is 3.2×104 to 28×104 cells per ml. Conclusion: In this research, a colorimetric immune assay based on gold nanoparticles was designed to improve the sensitivity of V. cholera detection. Also, this method can be used for the detection of other biological agents.


RSC Advances ◽  
2021 ◽  
Vol 11 (37) ◽  
pp. 22691-22691
Author(s):  
Jinjin Yin ◽  
Jiuchao Wang ◽  
Xiyue Yang ◽  
Tao Wu ◽  
Huashan Wang ◽  
...  

Correction for ‘Poly(adenine)-mediated DNA-functionalized gold nanoparticles for sensitive detection of mercury ions in aqueous media’ by Jinjin Yin et al., RSC Adv., 2019, 9, 18728–18733, DOI: 10.1039/C9RA03041G.


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

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.


Biosensors ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 113 ◽  
Author(s):  
Chia-Chen Chang ◽  
Tsz-Lian Hsu ◽  
Chie-Pein Chen ◽  
Chen-Yu Chen

A colorimetric assay was developed for the detection of biothiols, based on the peroxidase-like activity of iodine-capped gold nanoparticles (AuNPs). These AuNPs show a synergetic effect in the form of peroxidase-mimicking activity at the interface of AuNPs, while free AuNPs and iodine alone have weak catalytic properties. Thus, iodine-capped AuNPs possess good intrinsic enzymatic activity and trigger the oxidation of 3,3’,5,5’-tetramethylbenzidine (TMB), leading to a change in color from colorless to yellow. When added to solution, biothiols, such as cysteine, strongly bind to the interface of AuNPs via gold-thiol bonds, inhibiting the catalytic activity of AuNPs, resulting in a decrease in oxidized TMB. Using this strategy, cysteine could be linearly determined, at a wide range of concentrations (0.5 to 20 μM), with a detection limit of 0.5 μM using UV-Vis spectroscopy. This method was applied for the detection of cysteine in diluted human urine.


ACS Sensors ◽  
2019 ◽  
Vol 4 (5) ◽  
pp. 1306-1312 ◽  
Author(s):  
Hanbi Kim ◽  
Minseon Park ◽  
Joonki Hwang ◽  
Jin Hwa Kim ◽  
Doo-Ryeon Chung ◽  
...  

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