Colorimetric and fluorescence “turn-on” methods for the sensitive detection of bromelain using carbon dots functionalized gold nanoparticles as a dual probe

RSC Advances ◽  
2016 ◽  
Vol 6 (38) ◽  
pp. 32025-32036 ◽  
Author(s):  
Karuna A. Rawat ◽  
Rakesh Kumar Singhal ◽  
Suresh Kumar Kailasa
Keyword(s):  
Gold Nanoparticles ◽  
Fluorescence Spectroscopy ◽  
Fluorescence Detection ◽  
Carbon Dots ◽  
Limit Of Detection ◽  
Functionalized Gold Nanoparticles ◽  
Turn On ◽  
Uv Visible ◽  
Fluorescence Turn On ◽  
Dual Probe

Carbon dots were functionalized on the surfaces of gold nanoparticles for the colorimetric and fluorescence detection of bromelain. The limit of detection for bromelain was 18.9 nM and 0.52 nM using UV-visible and fluorescence spectroscopy, respectively.

Fabrication of an “ion-imprinting” dual-emission quantum dot nanohybrid for selective fluorescence turn-on and ratiometric detection of cadmium ions

The Analyst ◽  
2016 ◽  
Vol 141 (20) ◽  
pp. 5886-5892 ◽  
Author(s):  
Jing Wang ◽  
Chenxing Jiang ◽  
Xiaoqi Wang ◽  
Ligeng Wang ◽  
Aimin Chen ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Fluorescence Detection ◽  
Ratiometric Fluorescence ◽  
Dual Emission ◽  
Cadmium Ions ◽  
Turn On ◽  
Ratiometric Detection ◽  
Ion Imprinting ◽  
Fluorescence Turn On

A new CdTe@SiO2@CdSe nanohybrid was demonstrated for the ratiometric fluorescence detection of Cd2+via the turn-on model and “ion-imprinting” technique.

A benzothiazole-based fluorescence turn-on sensor for copper(II)

2021 ◽  
Author(s):  
Gyeongjin Kim ◽  
Donghwan Choi ◽  
Cheal Kim
Keyword(s):  
Charge Transfer ◽  
Limit Of Detection ◽  
Theoretical Calculations ◽  
Enhanced Fluorescence ◽  
Turn On ◽  
Fluorescent Response ◽  
Chelation Enhanced Fluorescence ◽  
Fluorescence Turn On ◽  
Internal Charge Transfer ◽  
Internal Charge

Abstract A new benzothiazole-based chemosensor BTN (1-((Z)-(((E)-3-methylbenzo[d]thiazol-2(3H)-ylidene)hydrazono)methyl)naphthalen-2-ol) was synthesized for the detection of Cu2+. BTN could detect Cu2+ with “off-on” fluorescent response from colorless to yellow irrespective of presence of other cations. Limit of detection for Cu2+ was determined to be 3.3 µM. Binding ratio of BTN and Cu2+ turned out to be a 1:1 with the analysis of Job plot and ESI-MS. Sensing feature of Cu2+ by BTN was explained with theoretical calculations, which might be owing to internal charge transfer and chelation-enhanced fluorescence processes.

Near-infrared carbon dots-based fluorescence turn on aptasensor for determination of carcinoembryonic antigen in pleural effusion

2019 ◽  
Vol 1068 ◽  
pp. 52-59 ◽  
Author(s):  
Kang Shao ◽  
Lanfang Wang ◽  
Yingting Wen ◽  
Tao Wang ◽  
Yuanjie Teng ◽  
...  
Keyword(s):  
Pleural Effusion ◽  
Carcinoembryonic Antigen ◽  
Carbon Dots ◽  
Near Infrared ◽  
Turn On ◽  
Fluorescence Turn On

para-Hydroxy Thiophenol-Coated CdSe/ZnS Quantum Dots as a Turn-On Fluorescent Probe for H2O2 Detection in Aqueous Media

2018 ◽  
Vol 71 (12) ◽  
pp. 971 ◽  
Author(s):  
Xiaomei Wang ◽  
Yong Luo ◽  
Hu Xu ◽  
Dan Li ◽  
Yuhong Wang
Keyword(s):  
Quantum Dots ◽  
Limit Of Detection ◽  
Aqueous Media ◽  
Hydroxy Ketone ◽  
Hole Transfer ◽  
Turn On ◽  
H2o2 Detection ◽  
Potential Alternative ◽  
Fluorescence Turn On ◽  
Optimized Conditions

Since hydrogen peroxide plays an important role in various fields, a facile, simple, highly selective, and stable analytic method for H2O2 is desirable. Semiconductor quantum dots (QDs) have acted as a potential alternative for organic fluorophores in fluorescence analytical fields due to their superior optical properties. Herein, we report hydrophilic p-hydroxy thiophenol (p-HTP) coated CdSe/ZnS QDs (denoted as p-HTP-QDs) acting as a selective fluorescence ‘turn-on’ probe for H2O2 in aqueous media. The obtained p-HTP-QD probe exhibits weak fluorescence, which stems from hole transfer from the QDs to p-HTP. The presence of H2O2 induces an oxidative structural transformation of p-HTP in p-HTP-QDs from a phenol structure to an α-hydroxy ketone derivative, which extremely reduces the driving force for hole transfer. Thus, the QDs photoluminescence (PL) was re-switched on. Under optimized conditions, an excellent linear relationship between fluorescence response and H2O2 concentration could be produced with a linear range from 0.309 to 4.900mM. The limit of detection of this probe was found to be 0.135mM. Moreover, the present probe exhibited a high selectivity of H2O2 over other reactive oxygen species/reactive nitrogen species (ROS/RNS) and was successfully used in the detection of H2O2 in real water samples.

Improved Detection of Hg2+ in Aqueous Solution with High Sensitivity and Selectivity by Using Mercury-Specific DNA, Sybr Green I and Gold Nanoparticles

2011 ◽  
Vol 239-242 ◽  
pp. 934-939
Author(s):  
Hui Xu ◽  
Shuli Gao ◽  
Jian Nong Chen ◽  
Quan Wen Liu
Keyword(s):  
Gold Nanoparticles ◽  
High Sensitivity ◽  
Sybr Green ◽  
Sybr Green I ◽  
Fluorescence Signal ◽  
Potassium Ions ◽  
Label Free ◽  
Turn On ◽  
Sensitivity And Selectivity ◽  
Fluorescence Turn On

We report a label-free, fast, fluorescence turn on assay for Hg2+detecton by using mercury-specific DNA (MSD), Sybr Green I (SG) and gold nanoparticles (AuNPs). SG efficiently discriminates MSD and MSD/Hg2+complex. The addition of gold nanoparticle decreases the background fluorescence signal further for MSD. The fluorescence intensity of MSD/Hg2+complex keeps constant after addition of AuNPs. This property improves the signal-to-background ratio and decreases the detection limitation further. In addition, the method shows improved selectivity compared with that in the absence of AuNPs. This strategy could be applied to the detection of potassium ions and showed good generality.

“Turn-on” Fluorescence Detection of Lead Ions Based on Accelerated Leaching of Gold Nanoparticles on the Surface of Graphene

2012 ◽  
Vol 4 (2) ◽  
pp. 1080-1086 ◽  
Author(s):  
Xiuli Fu ◽  
Tingting Lou ◽  
Zhaopeng Chen ◽  
Meng Lin ◽  
Weiwei Feng ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Fluorescence Detection ◽  
Lead Ions ◽  
Turn On ◽  
Accelerated Leaching
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