scholarly journals Ti3C2 MXene-Based Nanobiosensors for Detection of Cancer Biomarkers

2021 ◽  
Author(s):  
Lenka Lorencova ◽  
Kishor Kumar Sadasivuni ◽  
Peter Kasak ◽  
Jan Tkac
Keyword(s):  
Limit Of Detection ◽  
Cancer Biomarkers ◽  
Final Part ◽  
Dna Aptamers ◽  
Dna Molecules ◽  
Sensitivity Limit ◽  
Operational Characteristics ◽  
Detection Assay ◽  
Assay Time ◽  
2D Nanomaterials

This chapter provides information about basic properties of MXenes (2D nanomaterials) that are attractive for a design of various types of nanobiosensors. The second part of the chapter discusses MXene synthesis and various protocols for modification of MXene making it a suitable matrix for immobilization of bioreceptors such as antibodies, DNA aptamers or DNA molecules. The final part of the chapter summarizes examples of MXene-based nanobiosensors developed using optical, electrochemical and nanomechanical transducing schemes. Operational characteristics of such devices such as sensitivity, limit of detection, assay time, assay reproducibility and potential for multiplexing are provided. In particular MXene-based nanobiosensors for detection of a number of cancer biomarkers are shown here.

Engineering DNA aptamers and DNA enzymes with fluorescence-signaling properties

2004 ◽  
Vol 76 (7-8) ◽  
pp. 1547-1561 ◽  
Author(s):  
R. Nutiu ◽  
Shirley Mei ◽  
Zhongjie Liu ◽  
Y. Li
Keyword(s):  
Dna Sequences ◽  
Rational Design ◽  
In Vitro Selection ◽  
Random Sequence ◽  
Pair Potential ◽  
Dna Aptamers ◽  
Dna Molecules ◽  
Dna Enzymes ◽  
Fluorescence Signaling

Single-stranded DNA molecules with ligand-binding ability and catalytic function, referred to as DNA aptamers and DNA enzymes, respectively, are special DNA sequences isolated from random-sequence DNA libraries by “in vitro selection”. These two new classes of artificial DNA molecules have the potential of being used as molecular tools in a variety of innovative applications ranging from biosensing to gene regulation. Our laboratory is interested in engineering fluorescence-signaling DNA aptamers and DNA enzymes that can be widely exploited for detection-directed applications. In this article, we will first discuss our recent efforts on the rational design of a new class of signaling aptamers denoted “structure- switching signaling aptamers”, which report target binding by switching structures from DNA/DNA duplex to DNA/target complex. We will then describe the in vitro selection of fluorescence-signaling DNA enzymes that exhibit a synchronized catalysis-signaling capability by cleaving a chimeric RNA/DNA substrate at the lone RNA linkage surrounded by closely spaced fluorophore-quencher pair. Potential utilities of these signaling DNA molecules will also be discussed.

scholarly journals Extraction-Chromogenic System for Cobalt Based on 5-Methyl-4-(2-thiazolylazo) Resorcinol and Benzalkonium Chloride

2021 ◽  
Vol 68 (1) ◽  
pp. 37-43
Author(s):  
Danail G. Georgiev Hristov ◽  
Petya Vassileva Racheva ◽  
Galya Konstantinova Toncheva ◽  
Kiril Blazhev Gavazov
Keyword(s):  
Benzalkonium Chloride ◽  
Limit Of Detection ◽  
Ion Association ◽  
Molar Absorptivity ◽  
Sensitivity Limit ◽  
Deprotonated Form ◽  
Limit Of Quantification ◽  
Optimum Ph ◽  
Ion Associate ◽  
Ph Range

The interaction between CoII and 5-methyl-4-(2-thiazolylazo)-resorcinol (MTAR) was studied in a water-chloroform system, in the presence or absence of benzalkonium chloride (BZC) as a cationic ion-association reagent. The optimum pH, concentration of the reagents and extraction time for the extraction of Co were found. In the presence of BZC, the extracted ion-associate could be represented by the formula (BZ+)[CoIII(MTAR2–)2], where MTAR is in its deprotonated form. The following extraction-spectrophotometric characteristics were determined: absorption maximum, molar absorptivity, Sandell’s sensitivity, limit of detection, limit of quantification, constant of extraction, distribution ratio and fraction extracted. In the absence of BZC, the extraction is incomplete and occurs in a narrow pH range. The extracted chelate contains one deprotonated and one monoprotonated ligand: [CoIII(MTAR2–)(HMTAR–)].

scholarly journals Guidance for Studies Evaluating the Accuracy of Rapid Tuberculosis Drug-Susceptibility Tests

2019 ◽  
Vol 220 (Supplement_3) ◽  
pp. S126-S135 ◽  
Author(s):  
Sophia B Georghiou ◽  
Samuel G Schumacher ◽  
Timothy C Rodwell ◽  
Rebecca E Colman ◽  
Paolo Miotto ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Evaluation Studies ◽  
Drug Susceptibility ◽  
Drug Susceptibility Testing ◽  
World Health ◽  
Policy Recommendations ◽  
Operational Characteristics ◽  
Susceptibility Tests ◽  
Health Organization ◽  
Intended Use

Abstract The development and implementation of rapid molecular diagnostics for tuberculosis (TB) drug-susceptibility testing is critical to inform treatment of patients and to prevent the emergence and spread of resistance. Optimal trial planning for existing tests and those in development will be critical to rapidly gather the evidence necessary to inform World Health Organization review and to support potential policy recommendations. The evidence necessary includes an assessment of the performance for TB and resistance detection as well as an assessment of the operational characteristics of these platforms. The performance assessment should include analytical studies to confirm the limit of detection and assay ability to detect mutations conferring resistance across globally representative strains. The analytical evaluation is typically followed by multisite clinical evaluation studies to confirm diagnostic performance in sites and populations of intended use. This paper summarizes the considerations for the design of these analytical and clinical studies.

Tropomyosin Analysis in Foods Using an Electrochemical Immunosensing Approach

2021 ◽  
Vol 5 (1) ◽  
pp. 62
Author(s):  
Ricarda Torre ◽  
Maria Freitas ◽  
Estefanía Costa-Rama ◽  
Henri P. A. Nouws ◽  
Cristina Delerue-Matos
Keyword(s):  
Limit Of Detection ◽  
Polyclonal Antibodies ◽  
Analytical Signal ◽  
Food Samples ◽  
Electrochemical Immunosensor ◽  
Screen Printed Carbon Electrode ◽  
Sandwich Type ◽  
Assay Time ◽  
Electrochemical Immunosensing

A screen-printed carbon electrode was used as the transducer for the development of an electrochemical immunosensor for the determination of tropomyosin (a major shrimp allergen) in food samples. Monoclonal and polyclonal antibodies were used in a sandwich-type immunoassay. The analytical signal was electrochemically obtained using an alkaline phosphatase-labelled secondary antibody and a 3-indoxyl phosphate/silver nitrate substrate. The total assay time was 2 h 50 min and allowed the quantification of tropomyosin between 2.5 and 20 ng mL−1, with a limit of detection of 1.7 ng mL−1 The immunosensor was successfully applied to the analysis of commercial food products.

A laboratory and clinical evaluation of an immunochemiluminometric assay of thyrotropin in serum.

1988 ◽  
Vol 34 (10) ◽  
pp. 2087-2090 ◽  
Author(s):  
D J Berry ◽  
P M Clark ◽  
C P Price
Keyword(s):  
Magnetic Particles ◽  
Magnetic Particle ◽  
External Quality Assessment ◽  
Limit Of Detection ◽  
Particle Separation ◽  
Reference Interval ◽  
External Quality ◽  
Analytical Recovery ◽  
Luminescence Assay ◽  
Assay Time

Abstract We evaluated an immunochemiluminometric assay for human thyrotropin. A chemiluminescent acridinium ester is used as a label, with magnetic-particle separation. The lower limit of detection of the assay (mean + 3 SD of the zero standard) was 0.07 milli-int. unit/L, with a working range of 0.5 to greater than 60.0 milli-int. units/L. Assay accuracy was good as judged from analytical recovery, analysis of external quality-assessment samples, and comparison with an enzyme-amplified immunoassay. There were no significant interferences or cross-reactivities. Twenty-four samples assayed showed aggregation of the magnetic particles. On re-assay, four of these samples showed a significant increase in the measured TSH by the luminescence assay. Assay time for 60 tubes was approximately 3.5 h with the use of a semi-automated luminometer. The reference interval, determined from data on 144 healthy euthyroid subjects, was 0.3-4.0 milli-int. units/L. Sixteen of 19 thyrotoxic patients showed clearly suppressed concentrations of thyrotropin in serum.

scholarly journals Optomagnetic detection of DNA triplex nanoswitches

The Analyst ◽  
2017 ◽  
Vol 142 (4) ◽  
pp. 582-585 ◽  
Author(s):  
Gabriel Antonio S. Minero ◽  
Jeppe Fock ◽  
John S. McCaskill ◽  
Mikkel F. Hansen
Keyword(s):  
Limit Of Detection ◽  
Low Cost ◽  
Triplex Dna ◽  
Assay Time ◽  
Dna Triplex ◽  
Dose Dependent

Triplex DNA formation is studied using rapid low-cost and dose-dependent optomagnetic method with an assay time of max 10 min and limit of detection of 100 pM.

scholarly journals Flow-Through Electrochemical Biosensor for the Detection of Listeria monocytogenes Using Oligonucleotides

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3754
Author(s):  
Cheryl M. Armstrong ◽  
Joe Lee ◽  
Andrew G. Gehring ◽  
Joseph A. Capobianco
Keyword(s):  
Listeria Monocytogenes ◽  
Limit Of Detection ◽  
Regulatory Agencies ◽  
Escherichia Coli O157 ◽  
Hospitalization Rates ◽  
Low Concentrations ◽  
Detection Assay ◽  
Culture Enrichment ◽  
Flow Through ◽  
Genetic Detection

Consumption of food contaminated by Listeria monocytogenes can result in Listeriosis, an illness with hospitalization rates of 94% and mortality rates up to 30%. As a result, U.S. regulatory agencies governing food safety retain zero-tolerance policies for L. monocytogenes. However, detection at such low concentrations often requires strategies such as increasing sample size or culture enrichment. A novel flow-through immunoelectrochemical biosensor has been developed for Escherichia coli O157:H7 detection in 1 L volumes without enrichment. The current work further augments this biosensor’s capabilities to (1) include detection of L. monocytogenes and (2) accommodate genetic detection to help overcome limitations based upon antibody availability and address specificity errors in phenotypic assays. Herein, the conjugation scheme for oligo attachment and the conditions necessary for genetic detection are laid forth while results of the present study demonstrate the sensor’s ability to distinguish L. monocytogenes DNA from L. innocua with a limit of detection of ~2 × 104 cells/mL, which agrees with prior studies. Total time for this assay can be constrained to <2.5 h because a timely culture enrichment period is not necessary. Furthermore, the electrochemical detection assay can be performed with hand-held electronics, allowing this platform to be adopted for near-line monitoring systems.

scholarly journals Multiple Bacteria Identification in the Point-of-Care: an Old Method Serving a New Approach

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3351
Author(s):  
Sara Viveiros ◽  
Mónica Rodrigues ◽  
Débora Albuquerque ◽  
Sofia A. M. Martins ◽  
Susana Cardoso ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Limit Of Detection ◽  
Detection System ◽  
Point Of Care ◽  
Bovine Mastitis ◽  
Cross Reactivity ◽  
Superparamagnetic Nanoparticles ◽  
Nucleic Acid Amplification ◽  
Streptococcus Uberis ◽  
Detection Assay

The accurate diagnosis of bacterial infections is of critical importance for effective treatment decisions. Due to the multietiologic nature of most infectious diseases, multiplex assays are essential for diagnostics. However, multiplexability in nucleic acid amplification-based methods commonly resorts to multiple primers and/or multiple reaction chambers, which increases analysis cost and complexity. Herein, a polymerase chain reaction (PCR) offer method based on a universal pair of primers and an array of specific oligonucleotide probes was developed through the analysis of the bacterial 16S ribosomal RNA gene. The detection system consisted of DNA hybridization over an array of magnetoresistive sensors in a microfabricated biochip coupled to an electronic reader. Immobilized probes interrogated single-stranded biotinylated amplicons and were obtained using asymmetric PCR. Moreover, they were magnetically labelled with streptavidin-coated superparamagnetic nanoparticles. The benchmarking of the system was demonstrated to detect five major bovine mastitis-causing pathogens: Escherichia coli, Klebsiella sp., Staphylococcus aureus, Streptococcus uberis, and Streptococcus agalactiae. All selected probes proved to specifically detect their respective amplicon without significant cross reactivity. A calibration curve was performed for S. agalactiae, which demonstrates demonstrating a limit of detection below 30 fg/µL. Thus, a sensitive and specific multiplex detection assay was established, demonstrating its potential as a bioanalytical device for point-of-care applications.

scholarly journals Analytical Validation of a COVID-19 qRT-PCR Detection Assay Using a 384-well Format and Three Extraction Methods

2020 ◽  
Author(s):  
Andrew C. Nelson ◽  
Benjamin Auch ◽  
Matthew Schomaker ◽  
Daryl M. Gohl ◽  
Patrick Grady ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Extraction Methods ◽  
Detection Sensitivity ◽  
Acid Extraction ◽  
Analytical Validation ◽  
Qrt Pcr ◽  
Global Pandemic ◽  
Detection Assay ◽  
Effective Public Health ◽  
Local Laboratory

AbstractThe COVID-19 global pandemic is an unprecedented health emergency. Insufficient access to testing has hampered effective public health interventions and patient care management in a number of countries. Furthermore, the availability of regulatory-cleared reagents has challenged widespread implementation of testing. We rapidly developed a qRT-PCR SARS-CoV-2 detection assay using a 384-well format and tested its analytic performance across multiple nucleic acid extraction kits. Our data shows robust analytic accuracy on residual clinical biospecimens. Limit of detection sensitivity and specificity was confirmed with currently available commercial reagents. Our methods and results provide valuable information for other high-complexity laboratories seeking to develop effective, local, laboratory-developed procedures with high-throughput capability to detect SARS-CoV-2.

scholarly journals Highly Sensitive Immunochromatographic Identification of Tetracycline Antibiotics in Milk

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
N. A. Taranova ◽  
A. S. Kruhlik ◽  
E. A. Zvereva ◽  
V. V. Shmanai ◽  
I. I. Vashkevich ◽  
...  
Keyword(s):  
Colloidal Gold ◽  
Limit Of Detection ◽  
Polyclonal Antibodies ◽  
Detection Sensitivity ◽  
Assay Sensitivity ◽  
Highly Sensitive ◽  
Effective Inhibition ◽  
Test Zone ◽  
Assay Time ◽  
Strip Test

A rapid immunochromatographic assay was developed for the control of tetracycline (TC). The assay is based on the competition between immobilized TC-protein conjugate and TC in a tested sample for binding with polyclonal anti-TC antibodies conjugated to colloidal gold during the flow of the sample along a membrane strip with immobilized reactants. Conjugation of colloidal gold and the total immunoglobulin (IgG) fraction of polyclonal antibodies was used to increase the assay sensitivity to ensure low content of specific antibodies in the conjugate. This allowed effective inhibition of free TC and conjugate binding in the strip test zone. Photometric marker registration allows control of the reduction of binding, thereby enhancing detection sensitivity. The proposed assay allows TC to be detected at concentrations up to 20 ng/mL, exceeding the limit of detection of the known analogues, in a wide working range (more than two orders) of 60 pg/mL to 10 ng/mL, ensured through the use of polyclonal antibodies. The assay time is 10 min. The efficiency of the designed assay is shown to identify TC in milk; the degree of recovery of TC ranges from 90 to 112%. The precision of the concentrations measurements was no more than 10%.

Sign in / Sign up

Export Citation Format

Share Document