scholarly journals Highly Sensitive and Selective Copper (II)-Catalyzed Dual-DNAzyme Colorimetric Biosensor Based on Exonuclease III-Mediated Cyclical Assembly

Catalysts ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1352
Author(s):  
Baiqiang Zhai ◽  
Kunlun Huang ◽  
Hongtao Wang ◽  
Dongmin Su ◽  
Yuancong Xu
Keyword(s):  
Metal Ion ◽  
Limit Of Detection ◽  
Rapid Determination ◽  
High Sensitivity ◽  
General Purpose ◽  
Exonuclease Iii ◽  
Dna Cleaving ◽  
Transition Sequence ◽  
Highly Sensitive ◽  
Exo Iii

“Cu-DNAzyme” and “G4-DNAzyme” were used to develop a “turn-off” dual-DNAzyme colorimetric biosensor, which could be used to detect Cu2+ by employing exonuclease III-mediated cyclical assembly (EMCA). EMCA was based on the cleavage activity of Cu2+ to transfer the linkage sequences of the substrate strand and enzyme strand into the transition sequence. The horseradish peroxidase (HRP)-mimicking activity of the G4-DNAzyme was lost after binding with the complementary transition sequence and was hydrolyzed by Exo III. These results demonstrate that the proposed colorimetric biosensor was an effective method for ultradetection of trace metals in a high original signal background. Due to the high sensitivity of the biosensor, the limit of detection (LOD) of Cu2+ is 0.16 nM. This design offers a general purpose platform that could be applied for the detection of any metal ion target through adjustment of metal-dependent DNA-cleaving DNAzymes, which is of great significance for the rapid determination of food safety.

Label-free DNA detection based on oligonucleotide-stabilized silver nanoclusters and exonuclease III-catalyzed target recycling amplification

2014 ◽  
Vol 6 (15) ◽  
pp. 6082-6087 ◽  
Author(s):  
Hui Ma ◽  
Wei Wei ◽  
Qian Lu ◽  
Zhixin Zhou ◽  
Henan Li ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Silver Nanoclusters ◽  
Label Free ◽  
Exonuclease Iii ◽  
Target Recycling ◽  
Free Dna ◽  
Sensitivity And Selectivity ◽  
Exo Iii ◽  
Ag Ncs ◽  
Recycling Amplification

A label-free DNA biosensor with high sensitivity and selectivity is constructed by using DNA–Ag NCs and Exo III-catalyzed target recycling amplification.

scholarly journals A Highly Sensitive Cell-Based TLR Reporter Platform for the Specific Detection of Bacterial TLR Ligands

2022 ◽  
Vol 12 ◽  
Author(s):  
Katharina Radakovics ◽  
Claire Battin ◽  
Judith Leitner ◽  
Sabine Geiselhart ◽  
Wolfgang Paster ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Ectopic Expression ◽  
High Sensitivity ◽  
High Specificity ◽  
Reporter System ◽  
Specificity And Sensitivity ◽  
Highly Sensitive ◽  
Definition Of ◽  
The Individual ◽  
Allergen Extracts

Toll-like receptors (TLRs) are primary pattern recognition receptors (PRRs), which recognize conserved microbial components. They play important roles in innate immunity but also in the initiation of adaptive immune responses. Impurities containing TLR ligands are a frequent problem in research but also for the production of therapeutics since TLR ligands can exert strong immunomodulatory properties even in minute amounts. Consequently, there is a need for sensitive tools to detect TLR ligands with high sensitivity and specificity. Here we describe the development of a platform based on a highly sensitive NF-κB::eGFP reporter Jurkat JE6-1 T cell line for the detection of TLR ligands. Ectopic expression of TLRs and their coreceptors and CRISPR/Cas9-mediated deletion of endogenously expressed TLRs was deployed to generate reporter cell lines selectively expressing functional human TLR2/1, TLR2/6, TLR4 or TLR5 complexes. Using well-defined agonists for the respective TLR complexes we could demonstrate high specificity and sensitivity of the individual reporter lines. The limit of detection for LPS was below 1 pg/mL and ligands for TLR2/1 (Pam3CSK4), TLR2/6 (Fsl-1) and TLR5 (flagellin) were detected at concentrations as low as 1.0 ng/mL, 0.2 ng/mL and 10 pg/mL, respectively. We showed that the JE6-1 TLR reporter cells have the utility to characterize different commercially available TLR ligands as well as more complex samples like bacterially expressed proteins or allergen extracts. Impurities in preparations of microbial compounds as well as the lack of specificity of detection systems can lead to erroneous results and currently there is no consensus regarding the involvement of TLRs in the recognition of several molecules with proposed immunostimulatory functions. This reporter system represents a highly suitable tool for the definition of structural requirements for agonists of distinct TLR complexes.

scholarly journals Rapid-Response and Highly Sensitive Boronate Derivative-Based Fluorescence Probe for Detecting H2O2 in Living Cells

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Muthusamy Selvaraj ◽  
Kanagaraj Rajalakshmi ◽  
Yun-Sik Nam ◽  
Yeonhee Lee ◽  
Byoung Chan Kim ◽  
...  
Keyword(s):  
Functional Group ◽  
Fluorescence Probe ◽  
Limit Of Detection ◽  
High Sensitivity ◽  
Rapid Identification ◽  
Oxygen Species ◽  
Human Breast ◽  
Highly Sensitive ◽  
Whatman Paper ◽  
Mcf 7

Intracellular H2O2 monitoring is important and has driven researchers to pursue advancements for the rapid identification of H2O2, since H2O2 is short-lived in cell lines. An arylboronate derivative has been investigated as a chemospecific fluorescence recognition agent for H2O2. Triphenylimidazoleoxadiazolephenyl (TPIOP) boronate was contrived as a novel candidate for the rapid and sensitive recognition of H2O2. The probe was conjugated using the TPIOP functional group acting as an excellent fluorescent enhancer. The TPIOP group stimulated the polarization of C–B bond due to its extended π-conjugation, which included heteroatoms, and induced the production of rapid signal because of the highly polar C–B bond along with the corresponding boronate unit. While H2O2 reacts with TPIOP boronate, its nucleophilic addition to the boron generates a charged tetrahedral boronate complex, and then the C–B bond migrates toward one of the electrophilic peroxide oxygen atoms. The resulting boronate ester is then hydrolyzed by water into a phenol, which significantly enhances fluorescence through aggregation-induced emission. The TPIOP boronate probe responded to H2O2 rapidly, within 2 min, and exhibited high sensitivity with a limit of detection of 8 nM and a 1000-fold selectivity in the presence of other reactive oxygen species. Therefore, the developed TPIOP boronate chemodosimeter was successfully utilized to visualize and quantify intracellular H2O2 from human breast cancer (MCF-7) cells, as well as gaseous and aqueous H2O2 from environmental samples using Whatman paper strips coated with TPIOP boronate.

scholarly journals Flexible and Highly Sensitive Pressure Sensors Based on Microstructured Carbon Nanowalls Electrodes

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 496 ◽  
Author(s):  
Xi Zhou ◽  
Yongna Zhang ◽  
Jun Yang ◽  
Jialu Li ◽  
Shi Luo ◽  
...  
Keyword(s):  
Pressure Sensor ◽  
High Performance ◽  
Limit Of Detection ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Physiological Signals ◽  
Healthcare Applications ◽  
Highly Sensitive ◽  
Carbon Nanowalls ◽  
Pressure Regime

Wearable pressure sensors have attracted widespread attention in recent years because of their great potential in human healthcare applications such as physiological signals monitoring. A desirable pressure sensor should possess the advantages of high sensitivity, a simple manufacturing process, and good stability. Here, we present a highly sensitive, simply fabricated wearable resistive pressure sensor based on three-dimensional microstructured carbon nanowalls (CNWs) embedded in a polydimethylsiloxane (PDMS) substrate. The method of using unpolished silicon wafers as templates provides an easy approach to fabricate the irregular microstructure of CNWs/PDMS electrodes, which plays a significant role in increasing the sensitivity and stability of resistive pressure sensors. The sensitivity of the CNWs/PDMS pressure sensor with irregular microstructures is as high as 6.64 kPa−1 in the low-pressure regime, and remains fairly high (0.15 kPa−1) in the high-pressure regime (~10 kPa). Both the relatively short response time of ~30 ms and good reproducibility over 1000 cycles of pressure loading and unloading tests illustrate the high performance of the proposed device. Our pressure sensor exhibits a superior minimal limit of detection of 0.6 Pa, which shows promising potential in detecting human physiological signals such as heart rate. Moreover, it can be turned into an 8 × 8 pixels array to map spatial pressure distribution and realize array sensing imaging.

A QCM Immunosensor for Rapid Determination of Ractopamine in Food Based on Enzyme-AuNPs for Signal Amplification and Magnetic β-Cyclodextrins for Extraction

2015 ◽  
Vol 738-739 ◽  
pp. 56-60
Author(s):  
Shu Xian Chen ◽  
Jing Liu ◽  
Dao Dong Pan ◽  
Ning Gan
Keyword(s):  
Signal Amplification ◽  
Rapid Determination ◽  
Screening Method ◽  
High Sensitivity ◽  
The Novel ◽  
Highly Sensitive ◽  
Reliable Quantification ◽  
Highly Sensitive Detection ◽  
Amplification Strategy

An enzyme amplified immunosensor for highly sensitive detection of Ractopamine (RAC) in foodstuff was developed based on quartz crystal microbalance (QCM). The high sensitivity was achieved by enzyme-AuNPs signal amplification strategy and magnetic β-cyclodextrins (β-CD) enrichment capacity. The novel QCM immunosensor which combines with the advantages of high selectivity of immunoassays and the high sensitivity of QCM has been developed for the determination of trace residues of RAC in food production. Under optimum conditions, the differences in the frequencies (∆f) of the QCM were proportional to the concentration of RAC over the range from 0.01 to 10 ng mL-1. The minimal detection limit was 0.01 ng mL-1. Due to its high sensitivity, acceptable stability and good selectivity, the immunosensor realized reliable quantification of RAC in real foodstuff. The proposed project has the potential to become a successful on-site screening method in food safety.

scholarly journals Novel Highly Sensitive Protein Sensors Based on Tapered Optical Fibres Modified with Au-Based Nanocoatings

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Aitor Urrutia ◽  
Kartheka Bojan ◽  
Leonel Marques ◽  
Kevin Mullaney ◽  
Javier Goicoechea ◽  
...  
Keyword(s):  
Binding Constant ◽  
Limit Of Detection ◽  
High Sensitivity ◽  
Optical Fibres ◽  
Layer By Layer ◽  
Measured Concentration ◽  
Au Nps ◽  
Layer Deposition ◽  
Highly Sensitive ◽  
Protein Sensors

Novel protein sensors based on tapered optical fibres modified with Au coatings deposited using two different procedures are proposed. Au-based coatings are deposited onto a nonadiabatic tapered optical fibre using (i) a novel facile method composed of layer-by-layer deposition consisting of polycation (poly(allylamine hydrochloride), PAH) and negatively charged SiO2nanoparticles (NPs) followed by the deposition of the charged Au NPs and (ii) the sputtering technique. The Au NPs and Au thin film surfaces are then modified with biotin in order to bind streptavidin (SV) molecules and detect them. The sensing principle is based on the sensitivity of the transmission spectrum of the device to changes in the refractive index of the coatings induced by the SV binding to the biotin. Both sensors showed high sensitivity to SV, with the lowest measured concentration levels below 2.5 nM. The calculated binding constant for the biotin-SV pair was2.2×10-11 M−1when a tapered fibre modified with the LbL method was used, with a limit of detection (LoD) of 271 pM. The sensor formed using sputtering had a binding constant of1.01×10-10 M−1with a LoD of 806 pM. These new structures and their simple fabrication technique could be used to develop other biosensors.

Highly Sensitive Picric Acid Chemical Sensor Based on Samarium (Sm) Doped ZnO Nanorods

2019 ◽  
Vol 19 (6) ◽  
pp. 3637-3642 ◽  
Author(s):  
Yas Al-Hadeethi ◽  
Ahmad Umar ◽  
Kulvinder Singh ◽  
Ahmed A Ibrahim ◽  
Saleh. H Al-Heniti ◽  
...  
Keyword(s):  
Large Scale ◽  
Chemical Sensor ◽  
Limit Of Detection ◽  
Picric Acid ◽  
Zno Nanorods ◽  
Hydrothermal Process ◽  
High Sensitivity ◽  
Highly Sensitive ◽  
Doped Zno ◽  
Facile Hydrothermal Process

Herein, we report the synthesis, characterization and picric acid chemical sensing application of samarium (Sm) doped ZnO nanorods. The Sm-doped ZnO nanorods were synthesized by facile hydrothermal process and characterized using various analytical methods which confirmed the large-scale synthesis and wurtzite hexagonal crystal structure for the synthesized nanorods. The doping of Sm ions in the lattices of the synthesized nanorods was evaluated by the energy dispersive X-ray spectroscopy (EDS). The synthesized Sm-doped ZnO nanorods were used as potential scaffold to fabricate high sensitive and reproducible picric acid chemical sensor based on I–V technique. The fabricated picric acid chemical sensor based on Sm-doped ZnO nanorods exhibited a high sensitivity of 213.9 mA mM−1 cm−2 with the limit of detection of ∼0.228 mM and correlation coefficient of R═0.9889. The obtained results revealed that the facile grown Sm-doped ZnO nanorods can efficiently be used to fabricate high sensitive and reproducible chemical sensors.

scholarly journals Highly sensitive two-dimensional MoS 2 gas sensor decorated with Pt nanoparticles

2018 ◽  
Vol 5 (12) ◽  
pp. 181462 ◽  
Author(s):  
Jaeseo Park ◽  
Jihun Mun ◽  
Jae-Soo Shin ◽  
Sang-Woo Kang
Keyword(s):  
Gas Sensor ◽  
Vapour Deposition ◽  
Limit Of Detection ◽  
Pt Nanoparticles ◽  
High Sensitivity ◽  
Two Dimensional ◽  
Stencil Mask ◽  
Highly Sensitive ◽  
Metal Organic ◽  
Metal Decoration

A two-dimensional molybdenum disulfide (MoS 2 )-based gas sensor was decorated with Pt nanoparticles (NPs) for high sensitivity and low limit of detection (LOD) for specific gases (NH 3 and H 2 S). The two-dimensional MoS 2 film was grown at 400°C using metal organic gas vapour deposition. To fabricate the MoS 2 gas sensor, an interdigitated Au/Ti electrode was deposited using the electron beam (e-beam) evaporation method with a stencil mask. The MoS 2 gas sensor without metal decoration sensitively detects NH 3 and H 2 S gas down to 2.5 and 30 ppm, respectively, at room temperature (RT). However, for improved detection of NH 3 and H 2 S gas, we investigated the functionalization strategy using metal decoration. Pt NP decoration modulated the electronic properties of MoS 2 , significantly improving the sensitivity of NH 3 and H 2 S gas by 5.58× and 4.25×, respectively, compared with the undecorated MoS 2 gas sensor under concentrations of 70 ppm. Furthermore, the Pt NP-decorated MoS 2 sensor had lower LODs for NH 3 and H 2 S gas of 130 ppb and 5 ppm, respectively, at RT.

Highly sensitive detection of nucleic acids using a cascade amplification strategy based on exonuclease III-assisted target recycling and conjugated polyelectrolytes

The Analyst ◽  
2018 ◽  
Vol 143 (18) ◽  
pp. 4267-4272 ◽  
Author(s):  
Biqing Bao ◽  
Yanrui Pan ◽  
Bingbing Gu ◽  
Jia Chen ◽  
Yu Xu ◽  
...  
Keyword(s):  
Nucleic Acids ◽  
Signal Amplification ◽  
Conjugated Polyelectrolytes ◽  
Exonuclease Iii ◽  
Target Recycling ◽  
Highly Sensitive ◽  
Exo Iii ◽  
Highly Sensitive Detection ◽  
Amplification Strategy ◽  
Cascade Amplification

A ratiometric and cascade amplification strategy that combines the signal amplification and effecitive FRET property of CPEs with the Exo III-assisted target recycling method has been developed for DNA detection.

scholarly journals Schiff-Based Fluorescent-ON Sensor L Synthesis and Its Application for Selective Determination of Cerium in Aqueous Media

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Maria Sadia ◽  
Jehangir Khan ◽  
Robina Naz ◽  
Muhammad Zahoor ◽  
Ezzat Khan ◽  
...  
Keyword(s):  
Metal Ion ◽  
Limit Of Detection ◽  
Fluorescent Sensor ◽  
Aqueous Media ◽  
High Sensitivity ◽  
Transition Metal Ions ◽  
Acetonitrile Solution ◽  
Selective Determination ◽  
Sensitivity And Selectivity

In the present study, a fluorescent sensor L for sensing of Ce3+ ion was designed and characterized by XRD, 1HNMR, and FTIR. Its fluorescence behavior towards metal ion was examined by fluorescence spectroscopy. Chelation-enhanced fluorescence was shown by the sensor L upon interaction with Ce3+ ion. This fluorescent sensor exhibits high sensitivity and selectivity towards Ce3+ ion in acetonitrile solution, forming 2 : 1 (L : M) complex as determined by Job’s plot. Association constant was found to be 1×107 M−1 estimated from the Benesi-Hildebrand plot. No significant interference was observed in the presence of other studied alkali, alkaline, and transition metal ions. A rapid response was observed when employed for the determination of Ce3+ ion in spiked water samples with a limit of detection equal to 3.4×10−8 M.

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