Microfluidic paper-based analytical device using gold nanoparticles modified with N,N′-bis(2-hydroxyethyl)dithiooxamide for detection of Hg(ii) in air, fish and water samples

2020 ◽  
Vol 44 (43) ◽  
pp. 18662-18667
Author(s):  
Sattar Shariati ◽  
Gholamreza Khayatian
Keyword(s):  
Gold Nanoparticles ◽  
Water Samples ◽  
Visual Detection ◽  
Color Change ◽  
Digital Camera ◽  
New Method ◽  
Naked Eye ◽  
Analytical Device

A new method for visual detection of mercury by color change is developed that can detect Hg2+ by the naked eye or a digital camera.

Visual detection of 8-OHdG based on the aggregation of gold nanoparticles capped with the anti-8-OHdG antibody

2015 ◽  
Vol 7 (19) ◽  
pp. 8360-8365 ◽  
Author(s):  
Liping Wu ◽  
Wendan Pu ◽  
Yue Liu ◽  
Huawen Zhao ◽  
Weiqun Shu
Keyword(s):  
Gold Nanoparticles ◽  
Quantitative Determination ◽  
Rapid Method ◽  
Visual Detection ◽  
Color Change ◽  
Naked Eye ◽  
Absorption Wavelength

AuNPs, capped with anti-8-OHdG antibody, aggregate when 8-OHdG was added, resulting in color change and redshift of absorption wavelength. So a simple and rapid method to selectively determine 8-OHdG was developed and semi-quantitative determination could be achieved by the naked eye.

scholarly journals A Sensitive Near-Infrared Fluorescent Probe for Detecting Heavy Metal Ag+ in Water Samples

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 247 ◽  
Author(s):  
Yawen Zhang ◽  
Aiying Ye ◽  
Yuewei Yao ◽  
Cheng Yao
Keyword(s):  
Fluorescent Probe ◽  
Water Samples ◽  
Near Infrared ◽  
Color Change ◽  
World Health ◽  
Naked Eye ◽  
Real Water Samples ◽  
Frequent Use ◽  
The World ◽  
Health Organization

Silver is a common catalyst in industrial production, and the frequent use of Ag+ can cause water pollution. Thus, the detection of Ag+ in the environment is necessary to determine the level of pollution from silver. In this work, we designed a new, highly selective near-infrared (NIR) fluorescent probe QCy to detect Ag+. The probe exhibits “turn-off” fluorescence quenching responses at 760 nm towards Ag+ over other relevant cations, with outstanding sensitivity and a low detection limit (0.03 µM), which is considerably lower than the standard of the World Health Organization (WHO) for drinking water (0.9 µM). Meanwhile, QCy showed a very good linearity at a low concentration of Ag+ with a ‘naked eye’ visible color change of solution from blue to red. The probe has been applied successfully for the detection of Ag+ in real water samples.

Non-enzymatic colorimetric sensor strip based on melamine-functionalized gold nanoparticles assembled on polyamide nanofiber membranes for the detection of metronidazole

2019 ◽  
Vol 11 (29) ◽  
pp. 3706-3713 ◽  
Author(s):  
Mohammed Awad Abedalwafa ◽  
Yan Li ◽  
Chunfang Ni ◽  
Gang Yang ◽  
Lu Wang
Keyword(s):  
Gold Nanoparticles ◽  
Color Change ◽  
High Sensitivity ◽  
Colorimetric Sensor ◽  
Eye Detection ◽  
Naked Eye ◽  
Functionalized Gold Nanoparticles ◽  
Sensitivity And Selectivity ◽  
Nanofiber Membranes ◽  
Naked Eye Detection

Non-enzymatic colorimetric sensor strip for detection of metronidazole (MTZ) was designed and constructed, with high sensitivity and selectivity. Which can be used for naked-eye detection of MTZ with a visible color change from pink to purple.

scholarly journals A Facile Strategy for Immobilizing GOD and HRP onto Pollen Grain and Its Application to Visual Detection of Glucose

2020 ◽  
Vol 21 (24) ◽  
pp. 9529
Author(s):  
Shanxia Jin ◽  
Liping Liu ◽  
Mengying Fan ◽  
Yaru Jia ◽  
Ping Zhou
Keyword(s):  
Visual Detection ◽  
Color Change ◽  
Cost Effective ◽  
Pollen Grain ◽  
Practical Application ◽  
Horse Radish Peroxidase ◽  
Experimental Conditions ◽  
Naked Eye ◽  
Cost Effective Approach ◽  
Affinity Interaction

Pollen grain was explored as a new carrier for enzyme immobilization. After being modified with boric acid-functionalized titania, the pollen grain was able to covalently immobilize glycosylated enzymes by boronate affinity interaction under very mild experimental conditions (e.g., pH 7.0, ambient temperature and free of organic solvent). The glucose oxidase and horse radish peroxidase-immobilized pollen grain became a bienzyme system. The pollen grain also worked as an indicator of the cascade reaction by changing its color. A rapid, simple and cost-effective approach for the visual detection of glucose was then developed. When the glucose concentration exceeded 0.5 mM, the color change was observable by the naked eye. The assay of glucose in body fluid samples exhibited its great potential for practical application.

Colorimetric Detection of Melamine Based on Poly-Thymine Stabilized Gold Nanoparticles

2013 ◽  
Vol 790 ◽  
pp. 619-622
Author(s):  
Chong Jin ◽  
Hui Min Zhao ◽  
Meng Liu ◽  
Jun Ping Tian ◽  
Xie Quan
Keyword(s):  
Gold Nanoparticles ◽  
Color Change ◽  
Limit Of Detection ◽  
Pure Water ◽  
Colorimetric Detection ◽  
Colorimetric Method ◽  
Milk Powder ◽  
Aggregation Process ◽  
Naked Eye ◽  
Fresh Milk

A simple, fast and reliable colorimetric method for melamine detection based on gold nanoparticles (AuNPs) and poly-thymine (poly-T) is reported. Poly-T strands attract AuNPs through static electricity and keep them stable against aggregation in the presence of NaCl. The affinity between melamine and poly-T, hydrogen bond, frees AuNP from the protection provided by poly-T and thus makes AuNPs aggregate in the presence of NaCl. The color change of AuNPs from wine red to blue can be observed immediately by the naked eye during the aggregation process, and can be accurately recorded with the help of a UV/vis spetrophotometer within 5 minutes. The limit of detection (LOD) of melamine in pure water is 0.146 μmol/L with a linear range from 0.2×10-7 mol/L to 10.0×10-7 mol/L. In fresh milk and milk powder, the LOD is respectively as low as 2.37 μmol/L and 5.36 μmol/L.

Ultrasensitive visual detection of Hg2+ ions via the Tyndall effect of gold nanoparticles

2021 ◽  
Author(s):  
Zihao Deng ◽  
Wenying Jin ◽  
Qiaobo Yin ◽  
Jinkun Huang ◽  
Ziheng Huang ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Visual Detection ◽  
Eye Detection ◽  
Naked Eye ◽  
Tyndall Effect ◽  
One Step ◽  
Naked Eye Detection

This work describes a new nanosensor for one-step ultrasensitive naked-eye detection of Hg2+ ions based on the target-triggered aggregation of gold nanoparticles showing a dramatically enhanced Tyndall effect.

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.

scholarly journals A simple, fast, and sensitive colorimetric assay for visual detection of berberine in human plasma by NaHSO4-optimized gold nanoparticles

RSC Advances ◽  
2017 ◽  
Vol 7 (55) ◽  
pp. 34746-34754 ◽  
Author(s):  
Ziwei Hu ◽  
Mingshan Xie ◽  
Danting Yang ◽  
Dong Chen ◽  
Jingyi Jian ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Human Plasma ◽  
Visual Detection ◽  
Colorimetric Assay ◽  
Naked Eye ◽  
Vis Spectroscopy ◽  
Colorimetric Visualization

Herein, we report a simple, fast and sensitive colorimetric visualization of berberine in human plasma using NaHSO4-optimized gold nanoparticles. The LOD in human plasma is 0.24 μg mL−1by the naked eye and 0.06 μg mL−1by UV-vis spectroscopy.

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