scholarly journals A Reverse Transcription Recombinase-Aided Amplification Method for Rapid and Point-of-Care Detection of SARS-CoV-2, including Variants

Viruses ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1875
Author(s):  
Fengyun Li ◽  
Ping He ◽  
Dongyan Xiong ◽  
Yakun Lou ◽  
Qiaosheng Pu ◽  
...  
Keyword(s):  
Reverse Transcription ◽  
Large Scale ◽  
Point Of Care ◽  
High Sensitivity ◽  
High Agreement ◽  
Amplification Method ◽  
In Situ Methods ◽  
Diagnostic Applications ◽  
Point Of Care Detection

The worldwide pandemic caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and its emergence of variants needs rapid and point-of-care testing methods for a broad diagnosis. The regular RT-qPCR is time-consuming and limited in central laboratories, so a broad and large-scale screening requirement calls for rapid and in situ methods. In this regard, a reverse transcription recombinase-aided amplification (RT-RAA) is proposed here for the rapid and point-of-care detection of SARS-CoV-2. A set of highly conserved primers and probes targeting more than 98% of SARS-CoV-2 strains, including currently circulating variants (four variants of concerns (VOCs) and three variants of interest (VOIs)), was used in this study. With the preferred primers, the RT-RAA assay showed a 100% specificity to SARS-CoV-2 from eight other respiratory RNA viruses. Moreover, the assay here is of a high sensitivity and 0.48 copies/μL can be detected within 25 min at a constant temperature (42 °C), which can be realized on portable equipment. Furthermore, the RT-RAA assay demonstrated its high agreement for the detection of SARS-CoV-2 in clinical specimens compared with RT-qPCR. The rapid, simple and point-of-care RT-RAA method is expected to be an appealing detection tool to detect SARS-CoV-2, including variants, in clinical diagnostic applications.

Trends in Diagnosis for Active Tuberculosis Using Nanomaterials

2019 ◽  
Vol 26 (11) ◽  
pp. 1946-1959 ◽  
Author(s):  
Le Minh Tu Phan ◽  
Lemma Teshome Tufa ◽  
Hwa-Jung Kim ◽  
Jaebeom Lee ◽  
Tae Jung Park
Keyword(s):  
Sensitivity And Specificity ◽  
High Efficiency ◽  
Point Of Care ◽  
High Sensitivity ◽  
Signs And Symptoms ◽  
Diagnostic Methods ◽  
Advantages And Disadvantages ◽  
Treatment And Prevention ◽  
Clinical Tools ◽  
Diagnostic Applications

Background:Tuberculosis (TB), one of the leading causes of death worldwide, is difficult to diagnose based only on signs and symptoms. Methods for TB detection are continuously being researched to design novel effective clinical tools for the diagnosis of TB.Objective:This article reviews the methods to diagnose TB at the latent and active stages and to recognize prospective TB diagnostic methods based on nanomaterials.Methods:The current methods for TB diagnosis were reviewed by evaluating their advantages and disadvantages. Furthermore, the trends in TB detection using nanomaterials were discussed regarding their performance capacity for clinical diagnostic applications.Results:Current methods such as microscopy, culture, and tuberculin skin test are still being employed to diagnose TB, however, a highly sensitive point of care tool without false results is still needed. The utilization of nanomaterials to detect the specific TB biomarkers with high sensitivity and specificity can provide a possible strategy to rapidly diagnose TB. Although it is challenging for nanodiagnostic platforms to be assessed in clinical trials, active TB diagnosis using nanomaterials is highly expected to achieve clinical significance for regular application. In addition, aspects and future directions in developing the high-efficiency tools to diagnose active TB using advanced nanomaterials are expounded.Conclusion:This review suggests that nanomaterials have high potential as rapid, costeffective tools to enhance the diagnostic sensitivity and specificity for the accurate diagnosis, treatment, and prevention of TB. Hence, portable nanobiosensors can be alternative effective tests to be exploited globally after clinical trial execution.

scholarly journals Colorimetric Nanoplasmonics to Spot Hyperglycemia From Saliva

2020 ◽  
Vol 8 ◽  
Author(s):  
Paolo Donati ◽  
Tania Pomili ◽  
Luca Boselli ◽  
Pier P. Pompa
Keyword(s):  
Large Scale ◽  
Point Of Care ◽  
High Sensitivity ◽  
Diabetic Patients ◽  
Visual Response ◽  
Colorimetric Sensing ◽  
Chronic Patients ◽  
Self Monitoring ◽  
Sensing Platform ◽  
Signal Color

Early diagnostics and point-of-care (POC) devices can save people’s lives or drastically improve their quality. In particular, millions of diabetic patients worldwide benefit from POC devices for frequent self-monitoring of blood glucose. Yet, this still involves invasive sampling processes, which are quite discomforting for frequent measurements, or implantable devices dedicated to selected chronic patients, thus precluding large-scale monitoring of the globally increasing diabetic disorders. Here, we report a non-invasive colorimetric sensing platform to identify hyperglycemia from saliva. We designed plasmonic multibranched gold nanostructures, able to rapidly change their shape and color (naked-eye detection) in the presence of hyperglycemic conditions. This “reshaping approach” provides a fast visual response and high sensitivity, overcoming common detection issues related to signal (color intensity) losses and bio-matrix interferences. Notably, optimal performances of the assay were achieved in real biological samples, where the biomolecular environment was found to play a key role. Finally, we developed a dipstick prototype as a rapid home-testing kit.

scholarly journals Accessible LAMP-Enabled Rapid Test (ALERT) for Detecting SARS-CoV-2

Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 742
Author(s):  
Ali Bektaş ◽  
Michael F. Covington ◽  
Guy Aidelberg ◽  
Anibal Arce ◽  
Tamara Matute ◽  
...  
Keyword(s):  
Large Scale ◽  
Point Of Care ◽  
False Negative ◽  
Rapid Test ◽  
High Sensitivity ◽  
Surface Proteins ◽  
Influenza B ◽  
True Negative ◽  
Free Concentration ◽  
Primer Sets

The coronavirus disease 2019 (COVID-19) pandemic has highlighted bottlenecks in large-scale, frequent testing of populations for infections. Polymerase chain reaction (PCR)-based diagnostic tests are expensive, reliant on centralized labs, can take days to deliver results, and are prone to backlogs and supply shortages. Antigen tests that bind and detect the surface proteins of a virus are rapid and scalable but suffer from high false negative rates. To address this problem, an inexpensive, simple, and robust 60-minute do-it-yourself (DIY) workflow to detect viral RNA from nasal swabs or saliva with high sensitivity (0.1 to 2 viral particles/μL) and specificity (>97% true negative rate) utilizing reverse transcription loop-mediated isothermal amplification (RT-LAMP) was developed. ALERT (Accessible LAMP-Enabled Rapid Test) incorporates the following features: (1) increased shelf-life and ambient temperature storage, compared to liquid reaction mixes, by using wax layers to isolate enzymes from other reagents; (2) improved specificity compared to other LAMP end-point reporting methods, by using sequence-specific QUASR (quenching of unincorporated amplification signal reporters); (3) increased sensitivity, compared to methods without purification through use of a magnetic wand to enable pipette-free concentration of sample RNA and cell debris removal; (4) quality control with a nasopharyngeal-specific mRNA target; and (5) co-detection of other respiratory viruses, such as influenza B, by multiplexing QUASR-modified RT-LAMP primer sets. The flexible nature of the ALERT workflow allows easy, at-home and point-of-care testing for individuals and higher-throughput processing for labs and hospitals. With minimal effort, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific primer sets can be swapped out for other targets to repurpose ALERT to detect other viruses, microorganisms, or nucleic acid-based markers.

scholarly journals Zika virus lateral flow assays using reverse transcription-loop-mediated isothermal amplification

RSC Advances ◽  
2021 ◽  
Vol 11 (29) ◽  
pp. 17800-17808
Author(s):  
Gna Ahn ◽  
SeonHyung Lee ◽  
Se Hee Lee ◽  
Yun Hee Baek ◽  
Min-Suk Song ◽  
...  
Keyword(s):  
Reverse Transcription ◽  
Zika Virus ◽  
Detection Method ◽  
Point Of Care ◽  
Lateral Flow ◽  
Isothermal Amplification ◽  
Independent Point ◽  
Loop Mediated Isothermal Amplification ◽  
Lateral Flow Assays ◽  
Point Of Care Detection

Our study suggest that ZIKV RT-LAMP combined with LFA could serve as a rapid, accurate, and independent point-of-care detection method for ZIKV outbreaks.

scholarly journals Rapid and Sensitive Point of Care Detection of MRSA gDNA by Nanoelectrokinetic Sensors

2021 ◽  
Author(s):  
Rania Oueslati ◽  
Yu Jiang ◽  
Jiangang Chen ◽  
Jie Jayne Wu
Keyword(s):  
Point Of Care ◽  
Low Cost ◽  
High Sensitivity ◽  
High Specificity ◽  
Hybridization Chain Reaction ◽  
Sensor Surface ◽  
Ac Electrokinetics ◽  
Interdigitated Microelectrodes ◽  
Nanostructured Sensor ◽  
Point Of Care Detection

Biosensors have shown great potential in realizing rapid, low cost and portable on-site detection for diseases. This work reports the development of a new bioelectronic sensor called AC electrokinetics-based capacitive (ABC) biosensor, for the detection of genomic DNA (gDNA) of methicillin-resistant Staphylococcus aureus (MRSA). The ABC sensor is based on interdigitated microelectrodes biofunctionalized with oligonucleotide probes. It uses a special AC signal for direct capacitive monitoring of topological change on nanostructured sensor surface, which simultaneously induce dieletrophoretic enrichment of target gDNAs. As a result, rapid and specific detection of gDNA/probe hybridization can be realized with high sensitivity. It requires no signal amplification such as labelling, hybridization chain reaction, or nucleic acid sequence-based amplification. This method involves only simple sample preparation. After optimization of nano-structured sensor surface and signal processing, the ABC sensor demonstrated fast turnaround of results (~10 s detection), excellent sensitivity (a detection limit of 4.7 DNA copies /µL MRSA gDNA) and high specificity, suitable for point of care diagnosis. As a bioelectronic sensor, the developed ABC sensors can be easily adapted for detection of other infectious agents.

scholarly journals A Sensitive, Point-of-Care Detection of Small Molecules Based on a Portable Barometer: Aflatoxins In Agricultural Products

Toxins ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 158
Author(s):  
Weiqi Zhang ◽  
Wenqin Wu ◽  
Chong Cai ◽  
Xiaofeng Hu ◽  
Hui Li ◽  
...  
Keyword(s):  
Food Safety ◽  
High Performance ◽  
Large Scale ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Detection Methods ◽  
Relative Standard ◽  
Microplate Reader ◽  
Assay Precision ◽  
Point Of Care Detection

Sensitive and point-of-care detection of small toxic molecules plays a key role in food safety. Aflatoxin, a typical small toxic molecule, can cause serious healthcare and economic issues, thereby promoting the development of sensitive and point-of-care detection. Although ELISA is one of the official detection methods, it cannot fill the gap between sensitivity and point-of-care application because it requires a large-scale microplate reader. To employ portable readers in food safety, Pt-catalysis has attracted increasing attention due to its portability and reliability. In this study, we developed a sensitive point-of-care aflatoxin detection (POCAD) method via a portable handheld barometer. We synthesized and characterized Au@PtNPs and Au@PtNPs conjugated with a second antibody (Au@PtNPs-IgG). A competitive immunoassay was established based on the homemade monoclonal antibody against aflatoxins. Au@PtNPs-IgG was used to catalyze the production of O2 from H2O2 in a sealed vessel. The pressure of O2 was then recorded by a handheld barometer. The aflatoxin concentration was inversely proportional to the pressure recorded via the barometer reading. After optimization, a limit of detection of 0.03 ng/mL and a linear range from 0.09 to 16.0 ng/mL were achieved. Recovery was recorded as 83.1%–112.0% along with satisfactory results regarding inner- and inter-assay precision (relative standard deviation, RSD < 6.4%). Little cross-reaction was observed. Additionally, the POCAD was validated by high-performance liquid chromatography (HPLC) by using peanut and corn samples. The portable POCAD exhibits strong potential for applications in the on-site detection of small toxic molecules to ensure food safety.

scholarly journals In-Situ Integration of 3D C-MEMS Microelectrodes with Bipolar Exfoliated Graphene for Label-Free Electrochemical Cancer Biomarkers Aptasensor

Micromachines ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 104
Author(s):  
Shahrzad Forouzanfar ◽  
Nezih Pala ◽  
Chunlei Wang
Keyword(s):  
High Performance ◽  
Microelectromechanical Systems ◽  
Point Of Care ◽  
High Sensitivity ◽  
Label Free ◽  
Lab On Chip ◽  
Electrochemical Label ◽  
Mems Technology ◽  
On Chip

The electrochemical label-free aptamer-based biosensors (also known as aptasensors) are highly suitable for point-of-care applications. The well-established C-MEMS (carbon microelectromechanical systems) platforms have distinguishing features which are highly suitable for biosensing applications such as low background noise, high capacitance, high stability when exposed to different physical/chemical treatments, biocompatibility, and good electrical conductivity. This study investigates the integration of bipolar exfoliated (BPE) reduced graphene oxide (rGO) with 3D C-MEMS microelectrodes for developing PDGF-BB (platelet-derived growth factor-BB) label-free aptasensors. A simple setup has been used for exfoliation, reduction, and deposition of rGO on the 3D C-MEMS microelectrodes based on the principle of bipolar electrochemistry of graphite in deionized water. The electrochemical bipolar exfoliation of rGO resolves the drawbacks of commonly applied methods for synthesis and deposition of rGO, such as requiring complicated and costly processes, excessive use of harsh chemicals, and complex subsequent deposition procedures. The PDGF-BB affinity aptamers were covalently immobilized by binding amino-tag terminated aptamers and rGO surfaces. The turn-off sensing strategy was implemented by measuring the areal capacitance from CV plots. The aptasensor showed a wide linear range of 1 pM–10 nM, high sensitivity of 3.09 mF cm−2 Logc−1 (unit of c, pM), and a low detection limit of 0.75 pM. This study demonstrated the successful and novel in-situ deposition of BPE-rGO on 3D C-MEMS microelectrodes. Considering the BPE technique’s simplicity and efficiency, along with the high potential of C-MEMS technology, this novel procedure is highly promising for developing high-performance graphene-based viable lab-on-chip and point-of-care cancer diagnosis technologies.

scholarly journals Accessible LAMP-Enabled Rapid Test (ALERT) for detecting SARS-CoV-2

2021 ◽  
Author(s):  
Ali Bektaş ◽  
Michael F. Covington ◽  
Guy Aidelberg ◽  
Anibal Arce ◽  
Tamara Matute ◽  
...  
Keyword(s):  
Large Scale ◽  
Point Of Care ◽  
False Negative ◽  
Rapid Test ◽  
High Sensitivity ◽  
Surface Proteins ◽  
Influenza B ◽  
True Negative ◽  
Free Concentration ◽  
Primer Sets

AbstractThe COVID-19 pandemic has highlighted bottlenecks in large-scale, frequent testing of populations for infections. PCR-based diagnostic tests are expensive, reliant on expensive centralized labs, can take days to deliver results, and are prone to backlogs and supply shortages. Antigen tests, that bind and detect the surface proteins of a virus, are rapid and inexpensive but suffer from high false negative rates. To address this problem, we have created an inexpensive, simple, and robust 60-minute Do-It-Yourself (DIY) workflow to detect viral RNA from nasal swabs or saliva with high sensitivity (0.1 to 2 viral particles/µl) and specificity (>97% True Negative Rate) utilizing reverse transcription loop-mediated isothermal amplification (RT-LAMP).Our workflow, ALERT (Accessible LAMP-Enabled Rapid Test), incorporates the following features: 1) Increased shelf-life and ambient temperature storage by using wax layers to isolate enzymes from reaction, 2) Improved specificity by using sequence-specific QUASR reporters, 3) Increased sensitivity through use of a magnetic wand to enable pipette-free concentration of sample RNA and cell debris removal, 4) Quality control with a nasopharyngeal-specific mRNA target, and 5) Co-detection of other respiratory viruses, such as Influenza B, by duplexing QUASR-modified RT-LAMP primer sets.The flexible nature of the ALERT workflow allows easy, at-home and point-of-care testing for individuals and higher-throughput processing for centralized labs and hospitals. With minimal effort, SARS-CoV-2-specific primer sets can be swapped out for other targets to repurpose ALERT to detect other viruses, microorganisms or nucleic acid-based markers.

TO SEPARATELY ASSESS THE DIAGNOSTIC POTENTIAL OF TVS & MRI IN THE TERMS OF SENSITIVITY AND SPECIFICITY BY CORRELATING THE IMAGING FINDINGS WITH HISTOPATHOLOGY

2020 ◽  
Vol 4 (6) ◽  
Author(s):  
Suraj Mathur
Keyword(s):  
Transvaginal Ultrasound ◽  
High Sensitivity ◽  
Imaging Evaluation ◽  
Medical College ◽  
Conventional Mri ◽  
Diagnostic Potential ◽  
Adc Mapping ◽  
Malignant Lesions ◽  
Sensitivity Specificity

This prospective study was done in the Department of Radio diagnosis Govt. Medical College, Kozhikode. A total of 65 patients who were referred to our department with clinical suspicion of endometrial lesions and incidentally detected endometrial lesions on ultrasonography underwent transvaginal ultrasound and subsequent Imaging evaluation of pelvis MRI has very high sensitivity (95%) and specificity (98%) and is almost as accurate (97%) as histopathology in differentiating benign from malignant lesions. Addition of DWI with ADC mapping to conventional MRI increases its accuracy even more. However there is inherent limitation to MRI in detecting carcinoma in situ and micrometastasis. Keywords: TVS, MRI, Sensitivity, Specificity, Histopathology.

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