Novel “turn on–off” paper sensor based on nonionic conjugated polythiophene-coated CdTe QDs for efficient visual detection of cholinesterase activity

The Analyst ◽  
2020 ◽  
Vol 145 (12) ◽  
pp. 4305-4313 ◽  
Author(s):  
Qi Ou ◽  
Salah M. Tawfik ◽  
Xinfeng Zhang ◽  
Yong-Ill Lee

A novel conjugated polythiophene (CP) compound was successfully combined with CdTe quantum dots to improve their selectivity and sensitivity for the efficient visual detection of AChE activity via the color variation of CdTe/CP.

RSC Advances ◽  
2015 ◽  
Vol 5 (55) ◽  
pp. 44173-44182 ◽  
Author(s):  
Xuanping Tan ◽  
Qin Li ◽  
Xiaoning Zhang ◽  
Yizhong Shen ◽  
Jidong Yang

A new fluorescence sensor for the determination of thioctic acid (TA) in aqueous media based on the recovered fluorescence of N-acetyl-l-cysteine capped CdTe quantum dots [NALC-CdTe QDs]–Cu2+ system was proposed.


Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 713
Author(s):  
Yuefeng Gao ◽  
Sai Xu ◽  
Zhijian Liu ◽  
Kezhen Yu ◽  
Xinxiang Pan

It is urgent that a convenient and sensitive technique of detecting Hg2+ be developed because of its toxicity. Conventional fluorescence analysis works with a single fluorescence probe, and it often suffers from signal fluctuations which are influenced by external factors. In this research, a novel dual-emission probe assembled through utilizing CdTe quantum dots (QDs) and rhodamine B was designed to detect Hg2+ visually. Only the emission of CdTe QDs was quenched after adding Hg2+ in the dual-emission probe, which caused an intensity ratio change of the two different emission wavelengths and hence facilitated the visual detection of Hg2+. Compared to single emission QDs-based probe, a better linear relationship was shown between the variation of fluorescence intensity and the concentration of Hg2+, and the limit of detection (LOD) was found to be11.4 nM in the range of 0–2.6 μM. Interestingly, the intensity of the probe containing Hg2+ could be recovered in presence of glutathione (GSH) due to the stronger binding affinity of Hg2+ towards GSH than that towards CdTe QDs. Based on this phenomenon, an IMPLICATION logic gate using Hg2+/GSH as inputs and the fluorescence signal of QDs as an output was constructed.


Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2605 ◽  
Author(s):  
Liyun Ding ◽  
Bing Xu ◽  
Tao Li ◽  
Jun Huang ◽  
Wei Bai

A novel “turn-on” fluorescent copper biosensor is developed successfully based on the graphene oxide (GO)-dsDNA-CdTe quantum dots (QDs) complex via chemical crosslink method. The optical and structure properties of GO-dsDNA-CdTe QDs complex are studied by fluorescence (FL) spectra and transmission electron microscopy (TEM) in detail. It is demonstrated that the fluorescence quenching of CdTe QDs is a process of fluorescence resonance energy transfer (FRET) due to the essential surface and quenching properties of two-dimensional GO. Copper ions induce the catalytic reaction of DNA chain and irreversibly break at the cleavage site, which will cause the G-quadruplex formation, moreover further result in the CdTe QDs separated from GO and restored its fluorescence. Therefore, a significant recovery effect on the fluorescence of the GO-dsDNA-CdTe QDs complex is observed in the presence of copper ions. The fluorescence responses are concentration-dependent and can be well described by a linear equation. Compared with other metal ions, the sensor performs good selectivity for copper ions.


The Analyst ◽  
2015 ◽  
Vol 140 (23) ◽  
pp. 7859-7863 ◽  
Author(s):  
Xiaohui Lu ◽  
Yunjie Zhao ◽  
Jinjun Zhang ◽  
Xiaozhen Lu ◽  
Yucong Wang ◽  
...  

Visual detection of Cu2+ is realized based on a copper-induced fluorescence band shift rather than an intensity change of CdTe QDs.


2021 ◽  
Author(s):  
Yifei Guo ◽  
Jingjing Du ◽  
Jianjun Li ◽  
Ran Yang ◽  
Peter B. de Harrington ◽  
...  

In this work, cysteamine-coated CdTe quantum dots (CA-CdTe QDs) were synthesized by a simple hydrothermal method employing cadmium chloride as the cadmium source and cysteamine hydrochloride as the functional monomer....


2020 ◽  
Vol 12 (21) ◽  
pp. 2718-2726
Author(s):  
Oraphan Thepmanee ◽  
Kanlaya Prapainop ◽  
Obnithi Noppha ◽  
Nuanlaor Rattanawimanwong ◽  
Weena Siangproh ◽  
...  

Paper-based device with MSA-CdTe QDs as arsenic detection probe is presented.


RSC Advances ◽  
2020 ◽  
Vol 10 (64) ◽  
pp. 38965-38973
Author(s):  
Huazheng Li ◽  
Wangwei Lu ◽  
Gaoling Zhao ◽  
Bin Song ◽  
Jing Zhou ◽  
...  

Ag-doped CdTe QDs emit multiple-fluorescence peaks, and the relationship between fluorescence intensity and the concentration of Hg2+ is established. Two linear relationships are obtained, which is benefit to the extension of detection range.


2017 ◽  
Vol 9 (6) ◽  
pp. 929-936 ◽  
Author(s):  
Fan Zhang ◽  
Miaomiao Chen ◽  
Haiqing Zhang ◽  
Huayu Xiong ◽  
Wei Wen ◽  
...  

A sensitive, convenient and rapid fluorescent sensor for effectively and directly detecting propranolol was proposed based on the fluorescence suppression of 3-mercaptopropionic acid stabilized CdTe quantum dots.


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