scholarly journals Restriction Endonuclease-Based Assays for DNA Detection and Isothermal Exponential Signal Amplification

Sensors ◽  
2020 ◽  
Vol 20 (14) ◽  
pp. 3873 ◽  
Author(s):  
Maria Smith ◽  
Kenneth Smith ◽  
Alan Olstein ◽  
Andrew Oleinikov ◽  
Andrey Ghindilis
Keyword(s):  
Restriction Endonuclease ◽  
Signal Amplification ◽  
Low Cost ◽  
The Self ◽  
Specific Detection ◽  
Assay Sensitivity ◽  
Reaction Solution ◽  
Target Probe ◽  
Probe Hybridization ◽  
Nanomolar Range

Application of restriction endonuclease (REase) enzymes for specific detection of nucleic acids provides for high assay specificity, convenience and low cost. A direct restriction assay format is based on the specific enzymatic cleavage of a target–probe hybrid that is accompanied with the release of a molecular marker into the solution, enabling target quantification. This format has the detection limit in nanomolar range. The assay sensitivity is improved drastically to the attomolar level by implementation of exponential signal amplification that is based on a cascade of self-perpetuating restriction endonuclease reactions. The cascade is started by action of an amplification “trigger”. The trigger is immobilized through a target-specific probe. Upon the target probe hybridization followed with specific cleavage, the trigger is released into the reaction solution. The solution is then added to the assay amplification stage, and the free trigger induces cleavage of amplification probes, thus starting the self-perpetuating cascade of REase-catalyzed events. Continuous cleavage of new amplification probes leads to the exponential release of new triggers and rapid exponential signal amplification. The proposed formats exemplify a valid isothermal alternative to qPCR with similar sensitivity achieved at a fraction of the associated costs, time and labor. Advantages and challenges of the approach are discussed.

A simple method to construct a low-cost immunosensor based on a dithiol-functionalized polydopamine platform

2021 ◽  
Author(s):  
Bo Liu ◽  
Luanying Yang ◽  
Gang Wang ◽  
Sha He ◽  
Xiaobo Wang ◽  
...  
Keyword(s):  
Detection Limit ◽  
Linear Response ◽  
Low Cost ◽  
Covalent Immobilization ◽  
The Self ◽  
Simple Method ◽  
Low Detection Limit

A simple and low-cost electrochemical CEA immunosensor was investigated via the self-polymerization of dopamine and a dithiol compound spacer for the covalent immobilization of antibodies. The designed CEA immunosensor exhibited a linear response and a low detection limit.

scholarly journals Contribution of Nanomaterials to the Development of Electrochemical Aptasensors for the Detection of Antimicrobial Residues in Food Products

Chemosensors ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 69
Author(s):  
Valérie Gaudin
Keyword(s):  
Signal Amplification ◽  
Electrochemical Sensors ◽  
Low Cost ◽  
Food Products ◽  
Animal Origin ◽  
Screening Methods ◽  
Chemical Methods ◽  
Portable Instrumentation ◽  
Physico Chemical ◽  
Antimicrobial Residues

The detection of antimicrobial residues in food products of animal origin is of utmost importance. Indeed antimicrobial residues could be present in animal derived food products because of animal treatments for curative purposes or from illegal use. The usual screening methods to detect antimicrobial residues in food are microbiological, immunological or physico-chemical methods. The development of biosensors to propose sensitive, cheap and quick alternatives to classical methods is constantly increasing. Aptasensors are one of the major trends proposed in the literature, in parallel with the development of immunosensors based on antibodies. The characteristics of electrochemical sensors (i.e., low cost, miniaturization, and portable instrumentation) make them very good candidates to develop screening methods for antimicrobial residues in food products. This review will focus on the recent advances in the development of electrochemical aptasensors for the detection of antimicrobial residues in food products. The contribution of nanomaterials to improve the performance characteristics of electrochemical aptasensors (e.g., Sensitivity, easiness, stability) in the last ten years, as well as signal amplification techniques will be highlighted.

scholarly journals Antioxidant Determination with the Use of Carbon-Based Electrodes

Chemosensors ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 72
Author(s):  
Aurelia Magdalena Pisoschi ◽  
Aneta Pop ◽  
Florin Iordache ◽  
Loredana Stanca ◽  
Liviu Bilteanu ◽  
...  
Keyword(s):  
Surface Area ◽  
Oxidation Process ◽  
Low Cost ◽  
Oxidative Enzymes ◽  
Adaptation Mechanisms ◽  
Chain Breaking ◽  
Nanomolar Range ◽  
Quench Singlet Oxygen ◽  
Carbon Based

Antioxidants are compounds that prevent or delay the oxidation process, acting at a much smaller concentration, in comparison to that of the preserved substrate. Primary antioxidants act as scavenging or chain breaking antioxidants, delaying initiation or interrupting propagation step. Secondary antioxidants quench singlet oxygen, decompose peroxides in non-radical species, chelate prooxidative metal ions, inhibit oxidative enzymes. Based on antioxidants’ reactivity, four lines of defense have been described: Preventative antioxidants, radical scavengers, repair antioxidants, and antioxidants relying on adaptation mechanisms. Carbon-based electrodes are largely employed in electroanalysis given their special features, that encompass large surface area, high electroconductivity, chemical stability, nanostructuring possibilities, facility of manufacturing at low cost, and easiness of surface modification. Largely employed methods encompass voltammetry, amperometry, biamperometry and potentiometry. Determination of key endogenous and exogenous individual antioxidants, as well as of antioxidant activity and its main contributors relied on unmodified or modified carbon electrodes, whose analytical parameters are detailed. Recent advances based on modifications with carbon-nanotubes or the use of hybrid nanocomposite materials are described. Large effective surface area, increased mass transport, electrocatalytical effects, improved sensitivity, and low detection limits in the nanomolar range were reported, with applications validated in complex media such as foodstuffs and biological samples.

scholarly journals Highly specific detection of genetic modification events using an enzyme-linked probe hybridization chip

2015 ◽  
Vol 14 (3) ◽  
pp. 9298-9305
Author(s):  
M.Z. Zhang ◽  
X.F. Zhang ◽  
X.M. Chen ◽  
X. Chen ◽  
S. Wu ◽  
...  
Keyword(s):  
Genetic Modification ◽  
Specific Detection ◽  
Probe Hybridization

scholarly journals Delivering strong 1H nuclear hyperpolarization levels and long magnetic lifetimes through signal amplification by reversible exchange

2017 ◽  
Vol 114 (16) ◽  
pp. E3188-E3194 ◽  
Author(s):  
Peter J. Rayner ◽  
Michael J. Burns ◽  
Alexandra M. Olaru ◽  
Philip Norcott ◽  
Marianna Fekete ◽  
...  
Keyword(s):  
Clinical Diagnosis ◽  
Signal Amplification ◽  
Low Cost ◽  
Building Blocks ◽  
Biologically Relevant ◽  
Polarization Level

Hyperpolarization turns typically weak NMR and MRI responses into strong signals so that ordinarily impractical measurements become possible. The potential to revolutionize analytical NMR and clinical diagnosis through this approach reflect this area's most compelling outcomes. Methods to optimize the low-cost parahydrogen-based approach signal amplification by reversible exchange with studies on a series of biologically relevant nicotinamides and methyl nicotinates are detailed. These procedures involve specific 2H labeling in both the agent and catalyst and achieve polarization lifetimes of ca. 2 min with 50% polarization in the case of methyl-4,6-d2-nicotinate. Because a 1.5-T hospital scanner has an effective 1H polarization level of just 0.0005% this strategy should result in compressed detection times for chemically discerning measurements that probe disease. To demonstrate this technique’s generality, we exemplify further studies on a range of pyridazine, pyrimidine, pyrazine, and isonicotinamide analogs that feature as building blocks in biochemistry and many disease-treating drugs.

scholarly journals Single-ribonucleotide repair-mediated ligation-dependent cycling signal amplification for sensitive and specific detection of DNA methyltransferase

2018 ◽  
Vol 9 (28) ◽  
pp. 6053-6061 ◽  
Author(s):  
Li-juan Wang ◽  
Xiao Han ◽  
Chen-chen Li ◽  
Chun-yang Zhang
Keyword(s):  
Signal Amplification ◽  
Dna Methyltransferase ◽  
Sensitive Detection ◽  
Specific Detection ◽  
Mtase Activity

Specific and sensitive detection of DNA MTase activity can be achieved by a single-ribonucleotide repair-mediated ligation-dependent cycling signal amplification approach.

The high performance photoelectrochemical sensor for specific detection of H2O2 and glucose based on an organic conjugated microporous polymer

2021 ◽  
Author(s):  
Qiqi Sun ◽  
Qi Liu ◽  
Wen Gao ◽  
Chuanwang Xing ◽  
Jingshun Shen ◽  
...  
Keyword(s):  
High Performance ◽  
Low Cost ◽  
Specific Detection ◽  
Sensing Applications ◽  
Conjugated Microporous Polymer ◽  
Microporous Polymer ◽  
Photoelectrochemical Sensor

The cathodic photoelectrochemical (PEC) biosensor, is one of ideal systems for sensing applications owing to its advantages in the low-cost, simplicity of the detection and miniaturization of the sensors with...

scholarly journals Open-Source Grinding Machine for Compression Screw Manufacturing

Inventions ◽  
2020 ◽  
Vol 5 (3) ◽  
pp. 26
Author(s):  
Jacob Franz ◽  
Joshua M. Pearce
Keyword(s):  
Open Source ◽  
Circular Economy ◽  
Low Cost ◽  
The Self ◽  
Compression Screw ◽  
Waste Plastic ◽  
Abrasive Disk ◽  
Technical Systems ◽  
Grinding Machine ◽  
1045 Steel

Some of the most promising distributed recycling and additive manufacturing (DRAM) technical systems use fused particle fabrication (FPF) or fused granular fabrication (FGF), where compression screws force post-consumer waste plastic through a heated nozzle for direct 3D printing. To assist the technical evolution of these systems, this study provided the details of an invention for a low-cost, easily replicable open-source grinding machine for compression screw manufacturing. The system itself can be largely fabricated using FPF/FGF following the self-replicating rapid prototyper (RepRap) methodology. This grinding machine can be made from a cordless cut-off grinder and < $155 in parts. The new invention is demonstrated to be able to cut custom screws with variable (i) channel depths, (ii) screw diameters, (iii) screw lengths, (iv) pitches, (v) abrasive disk thicknesses, (vi) handedness of the screws, (vii) and materials (three types of steel tested: 1045 steel, 1144 steel, and 416 stainless steel). The results show that the device is more than capable of replicating commercial screws as well as providing makers with a much greater flexibility to make custom screws. This invention enables the DRAM toolchain to become even more self-sufficient, which assists the goals of the circular economy.

Hedonic and Utilitarian Values Behind Engagement of Online Consumers

2021 ◽  
pp. 1242-1263
Author(s):  
Farrah Zeba ◽  
Musarrat Shaheen ◽  
Raveesh Krishnankutty
Keyword(s):  
Lived Experience ◽  
Airline Industry ◽  
Low Cost ◽  
Marketing Strategies ◽  
The Self ◽  
Customer Engagement ◽  
Third Order ◽  
Diary Method ◽  
Low Cost Carriers ◽  
Order Construct

In the hyper-competitive Indian airline industry, the low-cost carriers as well as full-service airlines are in dire need of innovative marketing strategies to engage their customers. To understand the dynamics behind the process of customer engagement, the purpose of this paper is to gain insights into the lived experience of consumers about their online air-ticket bookings experiences. In total, 60 frequent air travellers were approached to participate in the study and the self-completion diary method was incorporated to record their ticket booking experiences. The responses recorded in the diaries were analyzed on the basis of their content from which eight themes were derived. The findings bring forth the importance of hedonic experiential values along with utilitarian experiential values toward the engagement of customers during the online air-ticket booking process. The current study is one of the pioneers in conceptualization of customer engagement as a third-order construct by uncovering the sub-dimensions of the second order factors—utilitarian and hedonic experiential values.

Feasibility Analysis of Self-Reactive Spray Forming TiC-TiB2-Based Composite Ceramic Preforms

2008 ◽  
Vol 368-372 ◽  
pp. 1126-1129 ◽  
Author(s):  
Hong Wei Liu ◽  
Long Zhang ◽  
Jian Jiang Wang ◽  
Xin Kang Du
Keyword(s):  
Low Cost ◽  
New Technology ◽  
Composite Ceramic ◽  
Spray Forming ◽  
The Self ◽  
High Temperature Synthesis ◽  
Near Net Shape ◽  
Columnar Grain ◽  
Metal Spray ◽  
Base Phase

A new near-net-shape technology, namely, self-reactive spray forming, to prepare ceramic preforms with low cost was proposed by combining the self-propagating high-temperature synthesis (SHS) with the metal spray forming. The feasibility of the technology was illustrated. And TiC-TiB2 -based structural ceramic was prepared by the new technology. The microstructure of the self-reactive spray formed preforms was analyzed. It was shown that the self-reactive spray formed preforms are composed of four kinds of structure, which takes on the characteristics of rapid solidification. They are griseous continuous base phase TiC0.3N0.7, black columnar grain TiB2 with the size of 100nm-1μm, white by-product phase TiO2 distributing along the boundary of the base phase, and a few of black anomalous pores respectively.

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