scholarly journals Quantum Dot Doping-Induced Photoluminescence for Facile, Label-Free, and Sensitive Pyrophosphatase Activity Assay and Inhibitor Screening

Nanomaterials ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 111 ◽  
Author(s):  
Yishen Tian ◽  
Lijie Hao ◽  
Chao Wang ◽  
Xiaoyan Yang ◽  
Shufeng Liu
Keyword(s):  
Quantum Dot ◽  
Disease Diagnosis ◽  
Label Free ◽  
Sensitive Assay ◽  
Activity Assay ◽  
Inhibitor Screening ◽  
Assay Methods ◽  
Pyrophosphatase Activity ◽  
Hydrolysis Of ◽  
Promising Avenue

Development of simple, convenient, and sensitive assay methods for pyrophosphatase (PPase) activity is of importance, for disease diagnosis and drug discovery. Herein, a simple, rapid, label-free, and sensitive fluorescence sensor for PPase activity assay is developed, using Cu2+ doping-induced quantum dot (QD) photoluminescence as a signal reporter. The Cu2+ doping of ZnSe QD can induce a dopant-dependent emission response, which will be inhibited after the premixing of Cu2+ with pyrophosphate (PPi), to form a Cu2+-PPi complex. Then, the hydrolysis of PPi into phosphate (Pi), specifically catalyzed by PPase, liberates the free Cu2+ to regain the QD doping for the fluorescence response, which is highly dependent on the PPase activity. The PPase can be sensitively and selectively assayed, with a detection limit of 0.1 mU/mL. The developed sensing strategy can be also employed for the PPase inhibitor screening. Thus, the current QD doping-based sensing strategy offers an efficient and promising avenue for Cu2+, PPi, or PPase-related target analysis, and might hold great potential for the further applications in the clinical disease diagnosis.

Label–free, turn–on fluorescent sensor for trypsin activity assay and inhibitor screening

Talanta ◽  
2016 ◽  
Vol 161 ◽  
pp. 535-540 ◽  
Author(s):  
Lufeng Zhang ◽  
Haiyan Qin ◽  
Wanwan Cui ◽  
Yang Zhou ◽  
Jianxiu Du
Keyword(s):  
Fluorescent Sensor ◽  
Label Free ◽  
Trypsin Activity ◽  
Activity Assay ◽  
Inhibitor Screening ◽  
Turn On

scholarly journals Construction of a Turn Off-On-Off Fluorescent System Based on Competitive Coordination of Cu2+between 6,7-Dihydroxycoumarin and Pyrophosphate Ion for Sensitive Assay of Pyrophosphatase Activity

2016 ◽  
Vol 2016 ◽  
pp. 1-10
Author(s):  
Lingzhi Zhao ◽  
Liu Zhao ◽  
Yanqing Miao ◽  
Chunye Liu ◽  
Chenxiao Zhang
Keyword(s):  
Fluorescent Probe ◽  
Reaction System ◽  
Water Soluble ◽  
Sensitive Assay ◽  
Optimum Conditions ◽  
Activity Assay ◽  
Competitive Coordination ◽  
Hydrolysis Of ◽  
Subsequent Addition

The detection of pyrophosphatase (PPase) activity is of great significance in diagnosing diseases and understanding the function of PPase-related biological events. This study constructed a turn off-on-off fluorescent system for PPase activity assay based on PPase-regulated competitive coordination of Cu2+between a water-soluble fluorescent probe 6,7-dihydroxycoumarin (DHC) and pyrophosphate (PPi). The probe DHC can coordinate with Cu2+and consequently display on-off type fluorescence response. Furthermore, the in situ formed nonfluorescent Cu2+-DHC complex can act as an effective off-on type fluorescent probe for sensing PPi due to the higher coordination reactivity between Cu2+and PPi than that between Cu2+and DHC. The subsequent addition of PPase to the mixture containing Cu2+, DHC, and PPi leads to the fluorescence requenching of the system again (an off state) because PPase catalyzes the hydrolysis of PPi into orthophosphate in the reaction system. Under the optimum conditions, the decrease of the fluorescence intensity of DHC-Cu2+-PPi system was linear with the increase of the PPase activity in the range from 0.1 to 0.3 U. The detection limit was down to 0.028 U PPase (S/N=3). Moreover, the as-established system was also applied to evaluate PPase inhibitor. This study offers a simple yet effective method for the detection of PPase activity.

scholarly journals Photonic Crystal Nanobeam Cavities for Nanoscale Optical Sensing: A Review

Micromachines ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 72 ◽  
Author(s):  
Da-Quan Yang ◽  
Bing Duan ◽  
Xiao Liu ◽  
Ai-Qiang Wang ◽  
Xiao-Gang Li ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Optical Waveguides ◽  
Optical Sensing ◽  
Early Stage ◽  
Disease Diagnosis ◽  
Label Free ◽  
Quality Factors ◽  
Integrated Sensor ◽  
Early Stage Disease ◽  
Wide Range

The ability to detect nanoscale objects is particular crucial for a wide range of applications, such as environmental protection, early-stage disease diagnosis and drug discovery. Photonic crystal nanobeam cavity (PCNC) sensors have attracted great attention due to high-quality factors and small-mode volumes (Q/V) and good on-chip integrability with optical waveguides/circuits. In this review, we focus on nanoscale optical sensing based on PCNC sensors, including ultrahigh figure of merit (FOM) sensing, single nanoparticle trapping, label-free molecule detection and an integrated sensor array for multiplexed sensing. We believe that the PCNC sensors featuring ultracompact footprint, high monolithic integration capability, fast response and ultrahigh sensitivity sensing ability, etc., will provide a promising platform for further developing lab-on-a-chip devices for biosensing and other functionalities.

A label-free and enzyme-free signal amplification strategy for a sensitive RNase H activity assay

Nanoscale ◽  
2017 ◽  
Vol 9 (42) ◽  
pp. 16149-16153 ◽  
Author(s):  
Chang Yeol Lee ◽  
Hyowon Jang ◽  
Ki Soo Park ◽  
Hyun Gyu Park
Keyword(s):  
Signal Amplification ◽  
Rnase H ◽  
Label Free ◽  
Activity Assay ◽  
G Quadruplex ◽  
Catalytic Hairpin Assembly ◽  
Amplification Strategy

A target-triggered catalytic hairpin assembly with a G-quadruplex specific fluorescent binder, NMM, is employed to develop a novel and sensitive RNase H activity assay.

Label-Free Sickle Cell Disease Diagnosis using a Low-Cost, Handheld Platform

2016 ◽  
Vol 1 (5) ◽  
pp. 1600100 ◽  
Author(s):  
Bekir Yenilmez ◽  
Stephanie Knowlton ◽  
Chu Hsiang Yu ◽  
Matthew M. Heeney ◽  
Savas Tasoglu
Keyword(s):  
Sickle Cell Disease ◽  
Sickle Cell ◽  
Low Cost ◽  
Disease Diagnosis ◽  
Label Free ◽  
Cell Disease

scholarly journals A label-free RTP sensor based on aptamer/quantum dot nanocomposites for cytochrome c detection

RSC Advances ◽  
2019 ◽  
Vol 9 (55) ◽  
pp. 31953-31959
Author(s):  
Dongxia Li ◽  
Junping Guo ◽  
Liang Zhao ◽  
Guoxian Zhang ◽  
Guiqin Yan
Keyword(s):  
Cytochrome C ◽  
Quantum Dot ◽  
Label Free ◽  
Mn Doped

In this study, the nanocomposites from polyethyleneimine-capped Mn-doped ZnS QDs (PEI-QDs) and Cyt c binding aptamer (CBA) were prepared and used as Cyt c RTP sensors..

THE METABOLISM OF THE ERYTHROCYTE: X. THE INORGANIC PYROPHOSPHATASE OF THE ERYTHROCYTE

1956 ◽  
Vol 34 (1) ◽  
pp. 121-129 ◽  
Author(s):  
A. Malkin ◽  
O. F. Denstedt
Keyword(s):  
Enzyme Activity ◽  
Calcium Ions ◽  
Human Erythrocyte ◽  
Inorganic Pyrophosphatase ◽  
Magnesium Ions ◽  
Constant Ratio ◽  
Inorganic Pyrophosphate ◽  
Noncompetitive Inhibitor ◽  
Pyrophosphatase Activity ◽  
Hydrolysis Of

The activity of the pyrophosphatase which catalyzes the hydrolysis of inorganic pyrophosphate in the erythrocyte of the human, the rabbit, and the chicken is confined entirely to the cytoplasm of the cell. Following preincubation, the enzyme activity in the human erythrocyte is diminished, but pre-incubation in the presence of cysteine or glutathione prevents the diminution of the enzyme activity. Aging of the hemolyzate of the human erythrocytes results in a marked loss of the inorganic pyrophosphatase activity. The diminished activity can be restored by the addition of cysteine or glutathione to the reaction mixture; but after the hemolyzate has aged for five or six days at 5 °C, the loss in the enzyme activity can no longer be restored with these reagents. Fluoride and calcium ions inhibit the activity of the enzyme, while magnesium ions are essential for its activity. Calcium is a noncompetitive inhibitor, while the inhibition by fluoride is of a "quadratic" nature. If a constant ratio of magnesium to pyrophosphate is maintained, the quadratic inhibition can be converted to the "uncompetitive" type of inhibition.

Sign in / Sign up

Export Citation Format

Share Document