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.

An ultra-sensitive colorimetric assay for reliable visual detection of telomerase activity

The Analyst ◽  
2017 ◽  
Vol 142 (17) ◽  
pp. 3235-3240 ◽  
Author(s):  
Yaocai Wang ◽  
Luzhu Yang ◽  
Yanjun Wang ◽  
Wei Liu ◽  
Baoxin Li ◽  
...  
Keyword(s):  
Hela Cell ◽  
Visual Detection ◽  
Colorimetric Assay ◽  
Telomerase Activity ◽  
Cell Lysates ◽  
Naked Eye ◽  
Vis Spectroscopy

We proposed a sensitive colorimetric assay for detecting telomerase activity. The telomerase activity of 5 and 20 HeLa cell lysates can be detected via UV-vis spectroscopy and the naked eye, respectively.

An Effort to Making a Colorimitric Nano-Biosensor for Vibrio cholera Detection

2020 ◽  
Vol 16 (5) ◽  
pp. 793-804
Author(s):  
Naimeh Mahheidari ◽  
Jamal Rashidiani ◽  
Hamid Kooshki ◽  
Khadijeh Eskandari
Keyword(s):  
Gold Nanoparticles ◽  
Colorimetric Assay ◽  
Au Nanoparticle ◽  
Bacteria Detection ◽  
Great Promise ◽  
Bacterial Cells ◽  
Vibrio Cholera ◽  
Minimum Concentration ◽  
Vis Spectroscopy ◽  
Fast Procedure

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.

scholarly journals Enhancement of the Peroxidase-Like Activity of Iodine-Capped Gold Nanoparticles for the Colorimetric Detection of Biothiols

Biosensors ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 113 ◽  
Author(s):  
Chia-Chen Chang ◽  
Tsz-Lian Hsu ◽  
Chie-Pein Chen ◽  
Chen-Yu Chen
Keyword(s):  
Gold Nanoparticles ◽  
Catalytic Activity ◽  
Detection Limit ◽  
Enzymatic Activity ◽  
Catalytic Properties ◽  
Colorimetric Assay ◽  
Colorimetric Detection ◽  
Synergetic Effect ◽  
Vis Spectroscopy ◽  
Wide Range

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.

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.

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 cancer cells by using in situ grown functional Cu2−xSe/reduced graphene oxide hybrids acting as an efficient nanozyme

The Analyst ◽  
2019 ◽  
Vol 144 (2) ◽  
pp. 716-721 ◽  
Author(s):  
Qing Juan Guo ◽  
Zi Yu Pan ◽  
Chen Men ◽  
Wen Yi Lv ◽  
Hong Yan Zou ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Cancer Cells ◽  
Reduced Graphene Oxide ◽  
Visual Detection ◽  
Colorimetric Assay ◽  
Signal Transducer ◽  
Naked Eye ◽  
Reduced Graphene ◽  
Se Nanoparticles

Cu2−xSe nanoparticles grown in situ on reduced graphene oxide (Cu2−xSe/rGO) acted as an efficient nanozyme. Using the Cu2−xSe/rGO as a signal transducer, a colorimetric assay for cancer cells with the naked eye has been developed.

scholarly journals Theranostic Nanoplatforms of Thiolated Reduced Graphene Oxide Nanosheets and Gold Nanoparticles

2020 ◽  
Vol 10 (16) ◽  
pp. 5529 ◽  
Author(s):  
Pascal Tomasella ◽  
Vanessa Sanfilippo ◽  
Carmela Bonaccorso ◽  
Lorena Maria Cucci ◽  
Giuseppe Consiglio ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Graphene Oxide ◽  
Density Functional ◽  
Metal Salt ◽  
Colorimetric Assay ◽  
Neuroblastoma Cells ◽  
Human Neuroblastoma ◽  
Force Microscopy ◽  
Vis Spectroscopy

In this study, graphene oxide (GO) and reduced-thiolated GO (rGOSH) were used as 2D substrate to fabricate nanocomposites with nanoparticles of gold nanospheres (AuNS) or nanorods (AuNR), via in situ reduction of the metal salt precursor and seed-mediated growth processes. The plasmonic sensing capability of the gold-decorated nanosheets were scrutinized by UV-visible (UV-VIS) spectroscopy. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), thermogravimetric analyses (TGA), and atomic force microscopy (AFM) were performed in order to prove the actual reduction that occurred concomitantly with the thiolation of GO, the increase in the hydrophobic character as well as the size, and preferential gathering of the gold nanoparticles onto the nanosheet substrates, respectively. Moreover, the theoretical electronic and infrared absorption (UV-VIS and IR) spectra were calculated within a time-dependent approach of density functional theory (DFT). Eventually, in vitro cellular experiments on human neuroblastoma cells (SH-SY5Y line) were carried out in order to evaluate the nanotoxicity of the nanocomposites by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide tetrazolium reduction (MTT) colorimetric assay. Results pointed out the promising potential of these hybrids as plasmonic theranostic platforms with different hydrophilic or hydrophobic features as well as cytotoxic effects against cancer cells.

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.

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