Fluorescent Carrier Ampholytes Assay for Portable, Label-Free Detection of Chemical Toxins in Tap Water

2010 ◽  
Vol 82 (5) ◽  
pp. 1858-1866 ◽  
Author(s):  
M. Bercovici ◽  
G. V. Kaigala ◽  
C. J. Backhouse ◽  
J. G. Santiago
Keyword(s):  
Tap Water ◽  
Label Free ◽  
Label Free Detection ◽  
Carrier Ampholytes

Selective, Sensitive and Label-Free Detection of Fe3+ Ion in Tap Water Using Highly Fluorescent Graphene Quantum Dots

2019 ◽  
Vol 29 (3) ◽  
pp. 541-548 ◽  
Author(s):  
Yuanyuan Zhang ◽  
Xiangyue Yang ◽  
Yunxun Pu ◽  
Wei Cheng ◽  
Song Lin ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Tap Water ◽  
Graphene Quantum Dots ◽  
Label Free ◽  
Label Free Detection

scholarly journals A Cationic Surfactant-Decorated Liquid Crystal-Based Aptasensor for Label-Free Detection of Malathion Pesticides in Environmental Samples

Biosensors ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 92
Author(s):  
Duy Khiem Nguyen ◽  
Chang-Hyun Jang
Keyword(s):  
Liquid Crystal ◽  
Cationic Surfactant ◽  
Environmental Samples ◽  
Tap Water ◽  
High Specificity ◽  
Optical Image ◽  
Label Free ◽  
Optical Images ◽  
Label Free Detection ◽  
Homeotropic Orientation

We report a liquid crystal (LC)-based aptasensor for the detection of malathion using a cationic surfactant-decorated LC interface. In this method, LCs displayed dark optical images when in contact with aqueous cetyltrimethylammonium bromide (CTAB) solution due to the formation of a self-assembled CTAB monolayer at the aqueous/LC interface, which induced the homeotropic orientation of LCs. With the addition of malathion aptamer, the homeotropic orientation of LCs changed to a planar one due to the interactions between CTAB and the aptamer, resulting in a bright optical image. In the presence of malathion, the formation of aptamer-malathion complexes caused a conformational change of the aptamers, thereby weakening the interactions between CTAB and the aptamers. Therefore, CTAB is free to induce a homeotropic ordering of the LCs, which corresponds to a dark optical image. The developed sensor exhibited high specificity for malathion determination and a low detection limit of 0.465 nM was achieved. Moreover, the proposed biosensor was successfully applied to detect malathion in tap water, river water, and apple samples. The proposed LC-based aptasensor is a simple, rapid, and convenient platform for label-free monitoring of malathion in environmental samples.

scholarly journals The Role of Surface Chemistry in the Efficacy of Protein and DNA Microarrays for Label-Free Detection: An Overview

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1026
Author(s):  
Elisa Chiodi ◽  
Allison M. Marn ◽  
Matthew T. Geib ◽  
M. Selim Ünlü
Keyword(s):  
Surface Chemistry ◽  
Surface Functionalization ◽  
Dna Microarrays ◽  
Label Free ◽  
Polymeric Coatings ◽  
Label Free Detection ◽  
Particle Imaging ◽  
Single Particle Imaging ◽  
The Impact

The importance of microarrays in diagnostics and medicine has drastically increased in the last few years. Nevertheless, the efficiency of a microarray-based assay intrinsically depends on the density and functionality of the biorecognition elements immobilized onto each sensor spot. Recently, researchers have put effort into developing new functionalization strategies and technologies which provide efficient immobilization and stability of any sort of molecule. Here, we present an overview of the most widely used methods of surface functionalization of microarray substrates, as well as the most recent advances in the field, and compare their performance in terms of optimal immobilization of the bioreceptor molecules. We focus on label-free microarrays and, in particular, we aim to describe the impact of surface chemistry on two types of microarray-based sensors: microarrays for single particle imaging and for label-free measurements of binding kinetics. Both protein and DNA microarrays are taken into consideration, and the effect of different polymeric coatings on the molecules’ functionalities is critically analyzed.

Label-free and Simple Detection of Trace Pb(II) in Tap Water Using Non-faradaic Impedimetric Sensors

2021 ◽  
pp. 112833
Author(s):  
Abdulaziz K. Assaifan ◽  
Mahmoud Hezam ◽  
Mahmoud A. Al-Gawati ◽  
Khaled E. Alzahrani ◽  
Abdullah Alswieleh ◽  
...  
Keyword(s):  
Tap Water ◽  
Label Free ◽  
Simple Detection

scholarly journals Label-Free Electrochemical Sensor for Rapid Bacterial Pathogen Detection Using Vancomycin-Modified Highly Branched Polymers

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1872
Author(s):  
Holger Schulze ◽  
Harry Wilson ◽  
Ines Cara ◽  
Steven Carter ◽  
Edward N. Dyson ◽  
...  
Keyword(s):  
Pathogen Detection ◽  
Electrochemical Impedance ◽  
Point Of Care ◽  
Branched Polymers ◽  
Label Free ◽  
Conformation Change ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Staphylococcus Carnosus ◽  
Label Free Detection

Rapid point of care tests for bacterial infection diagnosis are of great importance to reduce the misuse of antibiotics and burden of antimicrobial resistance. Here, we have successfully combined a new class of non-biological binder molecules with electrochemical impedance spectroscopy (EIS)-based sensor detection for direct, label-free detection of Gram-positive bacteria making use of the specific coil-to-globule conformation change of the vancomycin-modified highly branched polymers immobilized on the surface of gold screen-printed electrodes upon binding to Gram-positive bacteria. Staphylococcus carnosus was detected after just 20 min incubation of the sample solution with the polymer-functionalized electrodes. The polymer conformation change was quantified with two simple 1 min EIS tests before and after incubation with the sample. Tests revealed a concentration dependent signal change within an OD600 range of Staphylococcus carnosus from 0.002 to 0.1 and a clear discrimination between Gram-positive Staphylococcus carnosus and Gram-negative Escherichia coli bacteria. This exhibits a clear advancement in terms of simplified test complexity compared to existing bacteria detection tests. In addition, the polymer-functionalized electrodes showed good storage and operational stability.

H2O2-sensitive quantum dots for the label-free detection of glucose

Talanta ◽  
2010 ◽  
Vol 82 (3) ◽  
pp. 997-1002 ◽  
Author(s):  
Mei Hu ◽  
Jing Tian ◽  
Hao-Ting Lu ◽  
Li-Xing Weng ◽  
Lian-Hui Wang
Keyword(s):  
Quantum Dots ◽  
Label Free ◽  
Label Free Detection
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