scholarly journals Strong binding and fluorescence sensing of bisphosphonates by guanidinium-modified calix[5]arene

2018 ◽  
Vol 14 ◽  
pp. 1840-1845 ◽  
Author(s):  
Jie Gao ◽  
Zhe Zheng ◽  
Lin Shi ◽  
Si-Qi Wu ◽  
Hongwei Sun ◽  
...  
Keyword(s):  
Salt Bridge ◽  
Quantitative Detection ◽  
Label Free ◽  
Fluorescence Sensing ◽  
Buffer Solution ◽  
Biologically Relevant ◽  
Strong Binding ◽  
Label Free Detection ◽  
Artificial Urine ◽  
Set Up

Based on the indicator displacement assay (IDA) approach, we herein report the fluorescence “switch-on” sensing and quantitative detection of bisphosphonates (BPs), a class of drugs extensively used in the treatment of patients with various skeletal diseases. Guanidinium-modified calix[5]arene (GC5A) affords strong binding on the micromolar to nanomolar level towards BPs dominantly via multiple salt bridge interactions, which was evaluated by fluorescence competitive titrations. Fluorescent IDA enables the highly sensitive and label-free detection of BPs in buffer solution, and more importantly, in artificial urine. Calibration lines were therefore set up in untreated artificial urine, allowing for quantifying the concentrations of BPs in the biologically relevant low range.

Cobalt oxyhydroxide nanoflake based fluorescence sensing platform for label-free detection of DNA

The Analyst ◽  
2016 ◽  
Vol 141 (15) ◽  
pp. 4719-4724 ◽  
Author(s):  
Yaqing Chang ◽  
Zhe Zhang ◽  
Huiqing Liu ◽  
Nan Wang ◽  
Jilin Tang
Keyword(s):  
Fluorescence Quenching ◽  
Label Free ◽  
Quenching Mechanism ◽  
Fluorescence Sensing ◽  
Single Stranded Dna ◽  
Cobalt Oxyhydroxide ◽  
Sensing Platform ◽  
Label Free Detection ◽  
Fluorescence Quenching Mechanism ◽  
Coooh Nanoflakes

In this study, we investigated the interaction of cobalt oxyhydroxide (CoOOH) nanoflakes with DNA and their fluorescence quenching mechanism of a FAM-labeled single-stranded DNA (ssDNA) probe.

scholarly journals A Simple and Label-Free Detection of As3+ using 3-nitro-L-tyrosine as an As3+-chelating Ligand

Sensors ◽  
2019 ◽  
Vol 19 (13) ◽  
pp. 2857 ◽  
Author(s):  
Jin-Ho Park ◽  
Gyuho Yeom ◽  
Donggu Hong ◽  
Eun-Jung Jo ◽  
Chin-Ju Park ◽  
...  
Keyword(s):  
Detection Method ◽  
Color Change ◽  
Specific Property ◽  
Quantitative Detection ◽  
Label Free ◽  
Real Samples ◽  
Real Water Samples ◽  
Label Free Detection ◽  
Reaction Stoichiometry ◽  
Site Binding

A simple and rapid As3+ detection method using 3-nitro-L-tyrosine (N-Tyr) is reported. We discovered the specific property of N-Tyr, which specifically chelates As3+. The reaction between As3+ and N-Tyr induces a prompt color change to vivid yellow, concomitantly increasing the absorbance at 430 nm. The selectivity for As3+ is confirmed by competitive binding experiments with various metal ions (Hg2+, Pb2+, Cd2+, Cr3+, Mg2+, Ni2+, Cu2+, Fe2+, Ca2+, Zn2+, and Mn2+). Also, the N-Tyr binding site, binding affinity, and As3+/N-Tyr reaction stoichiometry are investigated. The specific reaction is utilized to design a sensor that enables the quantitative detection of As3+ in the 0.1–100 μM range with good linearity (R2 = 0.995). Furthermore, the method’s applicability for the analysis of real samples, e.g., tap and river water, is successfully confirmed, with good recoveries (94.32–109.15%) using As3+-spiked real water samples. We believe that our discovering and its application for As3+ analysis can be effectively utilized in environmental analyses such as those conducted in water management facilities, with simplicity, rapidity, and ease.

scholarly journals Instrument for Label-Free Detection of Noncoding RNAs

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Peter Noy ◽  
Roger Steiner ◽  
Joerg Voelkle ◽  
Martin Hegner ◽  
Christof Fattinger
Keyword(s):  
Noncoding Rnas ◽  
Analysis Tool ◽  
Label Free ◽  
Cantilever Arrays ◽  
Label Free Detection ◽  
Before And After ◽  
Direct Binding ◽  
Experimental Protocols ◽  
Set Up ◽  
User Friendly

We set up a label-free direct binding assay for the detection of noncoding RNAs. The assay is based on nanomechanical cantilever arrays for the detection of surface stress induced by immobilized biomolecules and their interaction partners. We used various means to significantly reduce the drift of the cantilever readout that was a prominent feature in experiments with readout in stationary fluid before and after sample injection. Major improvements were achieved by focusing on a faster system equilibration (for instance temperature control and diffusion independence). Experimental protocols were improved to provide user-friendly and less time-consuming measurements. Further enhancements were achieved by, for example, using pre-gold-coated cantilever array wafers compared to individually prepared ones and a directly implemented data analysis tool as real-time feature of the measurement software. We have demonstrated picomolar specific biomarker target detection and can easily distinguish modified targets with single-nucleotide mismatches that hybridize with lower affinity.

Poly(thymine)-templated fluorescent copper nanoparticles for label-free detection of N-acetylcysteine in pharmaceutical samples

2015 ◽  
Vol 7 (15) ◽  
pp. 6372-6377 ◽  
Author(s):  
Hai-Bo Wang ◽  
Hong-Ding Zhang ◽  
Ying Chen ◽  
Li-Juan Ou ◽  
Yan-Ming Liu
Keyword(s):  
Copper Nanoparticles ◽  
Fluorescent Probes ◽  
Label Free ◽  
Fluorescence Sensing ◽  
Pharmaceutical Samples ◽  
Label Free Detection

A simple, label-free, sensitive fluorescence sensing strategy is reported for N-acetylcysteine detection by using poly T-templated Cu NPs as fluorescent probes.

scholarly journals Development of an Impedimetric Aptasensor for Label Free Detection of Patulin in Apple Juice

Molecules ◽  
2019 ◽  
Vol 24 (6) ◽  
pp. 1017 ◽  
Author(s):  
Reem Khan ◽  
Sondes Ben Aissa ◽  
Tauqir Sherazi ◽  
Gaelle Catanante ◽  
Akhtar Hayat ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Apple Juice ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Diazonium Salt ◽  
Specific Interaction ◽  
Quantitative Detection ◽  
Label Free ◽  
Analytical Technique ◽  
Label Free Detection

In the present work, an aptasensing platform was developed for the detection of a carcinogenic mycotoxin termed patulin (PAT) using a label-free approach. The detection was mainly based on a specific interaction of an aptamer immobilized on carbon-based electrode. A long linear spacer of carboxy-amine polyethylene glycol chain (PEG) was chemically grafted on screen-printed carbon electrodes (SPCEs) via diazonium salt in the aptasensor design. The NH2-modified aptamer was then attached covalently to carboxylic acid groups of previously immobilized bifunctional PEG to build a diblock macromolecule. The immobilized diblocked molecules resulted in the formation of long tunnels on a carbon interface, while the aptamer was assumed as the gate of these tunnels. Upon target analyte binding, the gates were assumed to be closed due to conformational changes in the structure of the aptamer, increasing the resistance to the charge transfer. This increase in resistance was measured by electrochemical impedance spectroscopy, the main analytical technique for the quantitative detection of PAT. Encouragingly, a good linear range between 1 and 25 ng was obtained. The limit of detection and limit of quantification was 2.8 ng L−1 and 4.0 ng L−1, respectively. Selectivity of the aptasensor was confirmed with mycotoxins commonly occurring in food. The developed apta-assay was also applied to a real sample, i.e., fresh apple juice spiked with PAT, and toxin recovery up to 99% was observed. The results obtained validated the suitability and selectivity of the developed apta-assay for the identification and quantification of PAT in real food samples.

A smartphone-based fiber-optic aptasensor for label-free detection of Plasmodium falciparum glutamate dehydrogenase

2020 ◽  
Vol 12 (10) ◽  
pp. 1333-1341
Author(s):  
Manoharan Sanjay ◽  
Naveen K. Singh ◽  
Lightson Ngashangva ◽  
Pranab Goswami
Keyword(s):  
Plasmodium Falciparum ◽  
Glutamate Dehydrogenase ◽  
Fiber Optic ◽  
Quantitative Detection ◽  
Optic Fiber ◽  
Label Free ◽  
Label Free Detection

A novel smartphone-based, multi-channel, optic fiber platform for quantitative detection of Plasmodium falciparum glutamate dehydrogenase (PfGDH) has been explored in this study.

A microfluidic device with integrated impedance detection for λ-DNA

2003 ◽  
Vol 773 ◽  
Author(s):  
Myung-Il Park ◽  
Jonging Hong ◽  
Dae Sung Yoon ◽  
Chong-Ook Park ◽  
Geunbae Im
Keyword(s):  
Microfluidic Device ◽  
Electrochemical Impedance ◽  
Direct Detection ◽  
Full Potential ◽  
Label Free ◽  
Buffer Solution ◽  
Detection Systems ◽  
Significant Difference ◽  
Detection Of Biomolecules ◽  
Impedance Magnitude

AbstractThe large optical detection systems that are typically utilized at present may not be able to reach their full potential as portable analysis tools. Accurate, early, and fast diagnosis for many diseases requires the direct detection of biomolecules such as DNA, proteins, and cells. In this research, a glass microchip with integrated microelectrodes has been fabricated, and the performance of electrochemical impedance detection was investigated for the biomolecules. We have used label-free λ-DNA as a sample biomolecule. By changing the distance between microelectrodes, the significant difference between DW and the TE buffer solution is obtained from the impedance-frequency measurements. In addition, the comparison for the impedance magnitude of DW, the TE buffer, and λ-DNA at the same distance was analyzed.

A label-free fluorescent aptasensor based on HCR and G-quadruplex DNAzymes for the detection of prostate-specific antigen

The Analyst ◽  
2021 ◽  
Author(s):  
Ruirui Zhao ◽  
Lu Zhao ◽  
Haidi Feng ◽  
Xiaoliang Chen ◽  
Huilin Zhang ◽  
...  
Keyword(s):  
Prostate Specific Antigen ◽  
Specific Antigen ◽  
Label Free ◽  
Fluorescence Sensing ◽  
Sensing Platforms ◽  
G Quadruplex ◽  
Fluorescent Aptasensor

Fluorescence sensing platforms based on HCR and G-quadruplex DNAzyme amplification strategies for the detection of prostate-specific antigen.

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.

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