scholarly journals High specificity antibodies and detection methods for quantifying phosphorylated tau from clinical samples

2021 ◽  
Author(s):  
Monika Arbaciauskaite ◽  
Yu Lei ◽  
Yong Ku Cho
Keyword(s):  
Neurodegenerative Diseases ◽  
Memory Loss ◽  
High Sensitivity ◽  
High Specificity ◽  
Detection Methods ◽  
Clinical Samples ◽  
Phosphorylated Tau ◽  
Comprehensive Survey ◽  
Low Levels ◽  
Development Engineering

Abstract The ability to measure total and phosphorylated tau levels in clinical samples is transforming the detection of Alzheimer’s disease (AD) and other neurodegenerative diseases. In particular, recent reports indicate that accurate detection of low levels of phosphorylated tau (p-tau) in plasma provides a reliable biomarker of AD long before sensing memory loss. Therefore, the diagnosis and monitoring of neurodegenerative diseases progression using blood samples is becoming a reality. These major advances were achieved by using antibodies specific to p-tau as well as sophisticated high sensitivity immunoassay platforms. This review focuses on these enabling advances in high-specificity antibody development, engineering, and novel signal detection methods. We will draw insights from structural studies on p-tau antibodies, engineering efforts to improve their binding properties, and efforts to validate their specificity. A comprehensive survey of high-sensitivity p-tau immunoassay platforms along with sensitivity limits will be provided. We conclude that although robust approaches for detecting certain p-tau species have been established, systematic efforts to validate antibodies for assay development is still needed for the recognition of biomarkers for AD and other neurodegenerative diseases.

scholarly journals SARS-CoV-2 Direct Detection Without RNA Isolation With Loop-Mediated Isothermal Amplification (LAMP) and CRISPR-Cas12

2021 ◽  
Vol 8 ◽  
Author(s):  
Alfredo Garcia-Venzor ◽  
Bertha Rueda-Zarazua ◽  
Eduardo Marquez-Garcia ◽  
Vilma Maldonado ◽  
Angelica Moncada-Morales ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Direct Detection ◽  
Direct Method ◽  
Rna Extraction ◽  
Rna Isolation ◽  
High Sensitivity ◽  
High Specificity ◽  
Isothermal Amplification ◽  
Clinical Samples ◽  
Loop Mediated Isothermal Amplification

As to date, more than 49 million confirmed cases of Coronavirus Disease 19 (COVID-19) have been reported worldwide. Current diagnostic protocols use qRT-PCR for viral RNA detection, which is expensive and requires sophisticated equipment, trained personnel and previous RNA extraction. For this reason, we need a faster, direct and more versatile detection method for better epidemiological management of the COVID-19 outbreak. In this work, we propose a direct method without RNA extraction, based on the Loop-mediated isothermal amplification (LAMP) and Clustered Regularly Interspaced Short Palindromic Repeats-CRISPR associated protein (CRISPR-Cas12) technique that allows the fast detection of SARS-CoV-2 from patient samples with high sensitivity and specificity. We obtained a limit of detection of 16 copies/μL with high specificity and at an affordable cost. The diagnostic test readout can be done with a real-time PCR thermocycler or with the naked eye in a blue-light transilluminator. Our method has been evaluated on a small set of clinical samples with promising results.

scholarly journals Long Noncoding RNAs as Novel Biomarkers Have a Promising Future in Cancer Diagnostics

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Ting Shi ◽  
Ge Gao ◽  
Yingli Cao
Keyword(s):  
Noncoding Rnas ◽  
High Sensitivity ◽  
High Specificity ◽  
Body Fluids ◽  
Cancer Diagnostics ◽  
Long Noncoding Rnas ◽  
Detection Methods ◽  
Tumor Biomarkers ◽  
Biological Functions ◽  
Sample Collection

Cancers have a high mortality rate due to lack of suitable specific early diagnosis tumor biomarkers. Emerging evidence is accumulating that lncRNAs (long noncoding RNAs) are involved in tumorigenesis, tumor cells proliferation, invasion, migration, apoptosis, and angiogenesis. Furthermore, extracellular lncRNAs can circulate in body fluids; they can be detected and strongly resist RNases. Many researchers have found that lncRNAs could be good candidates for tumor biomarkers and possessed high specificity, high sensitivity, and noninvasive characteristics. In this review, we summarize the detection methods and possible sources of circulating lncRNAs and outline the biological functions and expression level of the most significant lncRNAs in tissues, cell lines, and body fluids (whole blood, plasma, urine, gastric juice, and saliva) of different kinds of tumors. We evaluate the diagnostic performance of lncRNAs as tumor biomarkers. However, the biological functions and the mechanisms of circulating lncRNAs secretion have not been fully understood. The uniform normalization protocol of sample collection, lncRNAs extraction, endogenous control selection, quality assessment, and quantitative data analysis has not been established. Therefore, we put forward some recommendations that might be investigated in the future if we want to adopt lncRNAs in clinical practice.

scholarly journals Recent advances of fluorescent biosensors based on cyclic signal amplification technology in biomedical detection

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Hongke Qu ◽  
Chunmei Fan ◽  
Mingjian Chen ◽  
Xiangyan Zhang ◽  
Qijia Yan ◽  
...  
Keyword(s):  
Signal Amplification ◽  
Low Cost ◽  
Rolling Circle Amplification ◽  
High Sensitivity ◽  
High Specificity ◽  
Detection Methods ◽  
Research Progress ◽  
Rolling Circle ◽  
Displacement Reactions ◽  
Short Time

AbstractThe cyclic signal amplification technology has been widely applied for the ultrasensitive detection of many important biomolecules, such as nucleic acids, proteins, enzymes, adenosine triphosphate (ATP), metal ions, exosome, etc. Due to their low content in the complex biological samples, traditional detection methods are insufficient to satisfy the requirements for monitoring those biomolecules. Therefore, effective and sensitive biosensors based on cyclic signal amplification technology are of great significance for the quick and simple diagnosis and treatment of diseases. Fluorescent biosensor based on cyclic signal amplification technology has become a research hotspot due to its simple operation, low cost, short time, high sensitivity and high specificity. This paper introduces several cyclic amplification methods, such as rolling circle amplification (RCA), strand displacement reactions (SDR) and enzyme-assisted amplification (EAA), and summarizes the research progress of using this technology in the detection of different biomolecules in recent years, in order to provide help for the research of more efficient and sensitive detection methods. Graphical Abstract

Microarray Analysis Reveals the Actual Specificity of Enrichment Media Used for Food Safety Assessment

2011 ◽  
Vol 74 (6) ◽  
pp. 1030-1034 ◽  
Author(s):  
TANJA KOSTIĆ ◽  
BEATRIX STESSL ◽  
MARTIN WAGNER ◽  
ANGELA SESSITSCH
Keyword(s):  
Food Safety ◽  
Food Analysis ◽  
Safety Assessment ◽  
Marker Gene ◽  
Simultaneous Detection ◽  
High Sensitivity ◽  
High Specificity ◽  
Microarray Platform ◽  
Detection Methods ◽  
Indicator Organisms

Microbial diagnostic microarrays are tools for simultaneous detection and identification of microorganisms in food, clinical, and environmental samples. In comparison to classic methods, microarray-based systems have the potential for high throughput, parallelism, and miniaturization. High specificity and high sensitivity of detection have been demonstrated. A microbial diagnostic microarray for the detection of the most relevant bacterial food- and waterborne pathogens and indicator organisms was developed and thoroughly validated. The microarray platform based on sequence-specific end labeling of oligonucleotides and the phylogenetically robust gyrB marker gene allowed a highly specific (resolution on genus and/or species level) and sensitive (0.1% relative and 104 CFU absolute sensitivity) detection of the target pathogens. In initial challenge studies of the applicability of microarray-based food analysis, we obtained results demonstrating the questionable specificity of standardized culture-dependent microbiological detection methods. Taking into consideration the importance of reliable food safety assessment methods, comprehensive performance assessment is essential. Results demonstrate the potential of this new pathogen diagnostic microarray to evaluate culture-based standard methods in microbiological food analysis.

scholarly journals Quantum dot biosensor combined with antibody and aptamer for tracing food-borne pathogens

2021 ◽  
Vol 5 ◽  
Author(s):  
Feifei Sun ◽  
Jing Zhang ◽  
Qingli Yang ◽  
Wei Wu
Keyword(s):  
Quantum Dots ◽  
Pathogen Detection ◽  
High Sensitivity ◽  
High Specificity ◽  
Detection Methods ◽  
Food Borne Pathogens ◽  
Food Borne ◽  
Recognition Elements ◽  
Different Characteristics ◽  
And Control

Abstract Due to the increasing number of food-borne diseases, more attention is being paid to food safety. Food-borne pathogens are the main cause of food-borne diseases, which seriously endanger human health, so it is necessary to detect and control them. Traditional detection methods cannot meet the requirements of rapid detection of food due to many shortcomings, such as being time-consuming, laborious or requiring expensive instrumentation. Quantum dots have become a promising nanotechnology in pathogens tracking and detection because of their excellent optical properties. New biosensor detection methods based on quantum dots are have been gradually developed due to their high sensitivity and high specificity. In this review, we summarize the different characteristics of quantum dots synthesized by carbon, heavy metals and composite materials firstly. Then, attention is paid to the principles, advantages and limitations of the quantum dots biosensor with antibodies and aptamers as recognition elements for recognition and capture of food-borne pathogens. Finally, the great potential of quantum dots in pathogen detection is summarized.

scholarly journals Large Number Hexagonal Cavities Microfluidic Digital Chip for Gene Mutation Ultrasensitive Analysis in Lung Cancer

2020 ◽  
Author(s):  
Fei Liu ◽  
Pan Feng ◽  
Mingjing Guo ◽  
Gang Li ◽  
Tengbao Xie ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Gene Mutation ◽  
Malignant Tumors ◽  
High Reliability ◽  
Growth Factor Receptor ◽  
High Sensitivity ◽  
High Specificity ◽  
Digital Pcr ◽  
Detection Methods ◽  
Egfr Gene

Abstract Lung cancer is the highest incidence of malignant tumors in the world. Targeted therapy based on gene mutation detection including epidermal growth factor receptor (EGFR) gene mutation is one of the first-line treatments. In this work, took EGFR gene G719S mutation as a representative object, a large number hexagonal cavities microfluidic chip (LHMC) platform based on digital PCR (dPCR) for the absolute quantification of gene mutation in lung cancer was established. In this chip, 113,137 cavities chip was designed to increase the number of absolute quantitative, which was 2~5 times higher than the traditional one. The hexagonal shape of cavities elevates the filling rate and filling speed. A set of primers and probes for G719S with high sensitivity, high specificity and high reliability were designed and screened. Then the PCR parameters were optimized. The results demonstrated that the chip platform shows good performance. The minimum detection concentration of the gene mutant was 3.01 copies/μL, and a good correlation (Y= 0.725X- 0.581, R2= 0.984) was noted between the measured value and the expected value. This chip possesses sensitively detect positive mutations in G719S and completely negative when detecting other substances. The developed LHMC-dPCR chip is a rapid and accurate gene mutation analysis platform, which has faster speed and lower price than classic detection methods, for instance, droplet dPCR, DNA sequencing method. Moreover, LHMC-dPCR is not limited by the number of nucleic acids and droplets and there is no need to estimate the nucleic acid concentration of the sample. This chip platform could also detect other gene mutations, for example, L858R, exon 19 deletions, in other tumors including lung cancer.

Novel Detection of Norovirus and Double Clostridium difficile in a Closed Cartridge System

2020 ◽  
Vol 16 (6) ◽  
pp. 954-964
Author(s):  
Hui Chen ◽  
Ziqi Xiao ◽  
Zhou Chu ◽  
Lian Jin ◽  
Song Li ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Supervisory Control ◽  
Detection Efficiency ◽  
High Sensitivity ◽  
High Specificity ◽  
Automatic Testing ◽  
Detection Sensitivity ◽  
Detection Methods ◽  
Testing System ◽  
Automatic Testing System

Clostridium difficile infection (CDI) has become the main cause of diarrhea-related diseases in domestic (China) inpatients. High-sensitivity and high-specificity detection methods for CDI must be applied clinically for CDI supervisory control. In this paper, we introduce a detection method for C. difficile and Norovirus based on real-time PCR. We developed and optimized a primer–probe for Norovirus targets tcdA and tcdB with remarkably increased detection sensitivity. We then used this method in an integrated cassette, and found increased detection efficiency for Norovirus standards in the cassette compared to C. difficile samples. These results provide a basis for further exploration of automatic testing system design.

scholarly journals Chiral Resolution of a New Agent against Memory Impairment Connected to Neurodegenerative Diseases

Proceedings ◽  
2019 ◽  
Vol 22 (1) ◽  
pp. 15
Author(s):  
Cavalloro ◽  
Rui ◽  
Rossino ◽  
Rossi ◽  
Rapetti ◽  
...  
Keyword(s):  
Public Health ◽  
Neurodegenerative Diseases ◽  
Memory Impairment ◽  
Memory Loss ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Chiral Resolution ◽  
Low Levels

Nowadays, the incidence of neurodegenerative diseases is increasing, and these disorders will become one of the main challenges for medicine and public health in future years. Particularly, memory loss characterizes many neurodegenerative pathologies, and it is often related to low levels of cyclic adenosine monophosphate (cAMP). [...]

scholarly journals Clinical validation of engineered CRISPR/Cas12a for rapid SARS-CoV-2 detection

2022 ◽  
Vol 2 (1) ◽  
Author(s):  
Long T. Nguyen ◽  
Santosh R. Rananaware ◽  
Brianna L. M. Pizzano ◽  
Brandon T. Stone ◽  
Piyush K. Jain
Keyword(s):  
High Sensitivity ◽  
High Specificity ◽  
Detection Methods ◽  
Clinical Validation ◽  
Respiratory Pathogens ◽  
Detection Capability ◽  
Guide Rna ◽  
Assay Optimization ◽  
Dual Reporter ◽  
Wide Range

Abstract Background The coronavirus disease (COVID-19) caused by SARS-CoV-2 has swept through the globe at an unprecedented rate. CRISPR-based detection technologies have emerged as a rapid and affordable platform that can shape the future of diagnostics. Methods We developed ENHANCEv2 that is composed of a chimeric guide RNA, a modified LbCas12a enzyme, and a dual reporter construct to improve the previously reported ENHANCE system. We validated both ENHANCE and ENHANCEv2 using 62 nasopharyngeal swabs and compared the results to RT-qPCR. We created a lyophilized version of ENHANCEv2 and characterized its detection capability and stability. Results Here we demonstrate that when coupled with an RT-LAMP step, ENHANCE detects COVID-19 samples down to a few copies with 95% accuracy while maintaining a high specificity towards various isolates of SARS-CoV-2 against 31 highly similar and common respiratory pathogens. ENHANCE works robustly in a wide range of magnesium concentrations (3 mM-13 mM), allowing for further assay optimization. Our clinical validation results for both ENHANCE and ENHANCEv2 show 60/62 (96.7%) sample agreement with RT-qPCR results while only using 5 µL of sample and 20 minutes of CRISPR reaction. We show that the lateral flow assay using paper-based strips displays 100% agreement with the fluorescence-based reporter assay during clinical validation. Finally, we demonstrate that a lyophilized version of ENHANCEv2 shows high sensitivity and specificity for SARS-CoV-2 detection while reducing the CRISPR reaction time to as low as 3 minutes while maintaining its detection capability for several weeks upon storage at room temperature. Conclusions CRISPR-based diagnostic platforms offer many advantages as compared to conventional qPCR-based detection methods. Our work here provides clinical validation of ENHANCE and its improved form ENHANCEv2 for the detection of COVID-19.

scholarly journals Development of an ELAA kit to detect neomycin in milk

2021 ◽  
Vol 18 (4) ◽  
pp. 745-754
Author(s):  
Nguyen Truong Giang ◽  
Tran Thi Bich Dao ◽  
Le Quang Huan ◽  
La Thi Huyen
Keyword(s):  
High Sensitivity ◽  
High Specificity ◽  
Detection Methods ◽  
Assay Method ◽  
Resistant Bacteria ◽  
Growth Promoter ◽  
Bicarbonate Buffer ◽  
Specificity And Sensitivity ◽  
Resistant Infection ◽  
Ethanesulfonic Acid

Antibiotics used in livestock production offer various benefits as an antimicrobial agent, growth promoter, and feed effective improvement. However, the abuse of antibiotics leads to antibiotic resistance which may seriously threaten human and animal welfare, and growing levels of antibiotics or antibiotic-resistant bacteria in the environment increase the numbers of drug-resistant infection outbreaks. Therefore, many detection methods have been being developed to quickly assess antibiotic content and its residues in foods. Among many analytical methods, the aptamer-based biosensor has considerable attention for its outstanding advantages such as high specificity, high sensitivity, and good selectivity. We use the ELAA (Enzyme-Linked Aptamer Assay) method - a variant of ELISA - which has a high affinity with neomycin. Firstly, we investigated different buffers to create the Neo-BSA complex. As result, 2-(N-morpholino) ethanesulfonic acid (MES) buffer pH 7 was found with the best results. Next, to help the Neo-BSA complex be fixed well on polystyrene wells, we surveyed various buffers and found the coating buffer (50mM Bicarbonate buffer, pH 9.6) rated as the most suitable for this process. In addition, the quality of the kit is also assessed through competitive ELAA reaction components. Therefore, we have investigated and optimized conditions such as aptamer concentration 25 nM in PBS buffer, and the biotinized aptamers did not need heat treatment prior to joining the reaction. From the results, we have successfully developed a calibration curve for antibiotic residue in milk using the ELAA technique, linear range 0,1 ng/mL and 100 ng/mL. Then, we initially surveyed 20 milk samples found that the ELAA method was consistent with the results from LC-MS/MS was obtained showing no difference between the two methods. We continued to test the samples to determine the kit’s sensitivity and specificity. The results showed that the kit has a specificity and sensitivity of 100%. Finally, LOD and LOQ value had xavg = 0.448; SD = 0.22, LOD = xavg + 3SD = 1.11 (ng / ml); LOQ = x tb + 10SD = 2.65 (ng / mL). We will continue to optimize the kit before being brought to the market.

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