scholarly journals A Paper-Based Analytical Device for Analysis of Paraquat in Urine and Its Validation with Optical-Based Approaches

Diagnostics ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 6
Author(s):  
Tse-Yao Wang ◽  
Yi-Tzu Lee ◽  
Hsien-Yi Chen ◽  
Cheng-Hao Ko ◽  
Chi-Tsung Hong ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Diagnostic Tools ◽  
Point Of Care Testing ◽  
Timely Initiation ◽  
Standard Curve ◽  
Colorimetric Measurements ◽  
Concentration Measurements ◽  
Analytical Device

Paraquat is a highly toxic herbicide. Paraquat poisoning is often fatal and is an important public health threat in many places. The quick identification and timely initiation of treatment based on timely analysis of the paraquat concentration in urine/serum could improve the prognosis for patients. However, current paraquat concentration measurements are time-consuming and difficult to implement due to the expensive and bulky equipment required. To address these practical challenges, paper-based devices have emerged as alternative diagnostic tools for improving point-of-care testing. In this study, we demonstrate the successful use of a paper-based analytical device for the accurate detection of urine paraquat concentration. The developed paper-based analytical device employs colorimetric paraquat concentration measurements. The R2 value for the urine paraquat standard curve was 0.9989, with a dynamic range of 0–100 ppm. The limit of detection was 3.01 ppm. Two other optical-based approaches, Spectrochip and NanoDrop, were used for comparison. The results suggest that the developed paper-based analytical device is comparable to other colorimetric measurements, as determined by Bland–Altman analysis. The device was clinically validated using urine from six paraquat-poisoned patients. The results prove that the developed paper-based analytical device is accurate, easy-to-use, and efficient for urine paraquat concentration measurement, and may enable physicians to improve clinical management.

scholarly journals A Smartphone Camera Colorimetric Assay of Acetylcholinesterase and Butyrylcholinesterase Activity

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1796
Author(s):  
Miroslav Pohanka ◽  
Jitka Zakova
Keyword(s):  
Limit Of Detection ◽  
Colorimetric Assay ◽  
Point Of Care ◽  
Specific Treatment ◽  
Point Of Care Testing ◽  
Analytical Instruments ◽  
Colorimetric Test ◽  
3D Printed ◽  
Butyrylcholinesterase Activity ◽  
Additional Education

Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) can serve as biochemical markers of various pathologies like liver disfunction and poisonings by nerve agents. Ellman’s assay is the standard spectrophotometric method to measure cholinesterase activity in clinical laboratories. The authors present a new colorimetric test to assess AChE and BChE activity in biological samples using chromogenic reagents, treated 3D-printed measuring pads and a smartphone camera as a signal detector. Multiwell pads treated with reagent substrates 2,6-dichlorophenolindophenyl acetate, indoxylacetate, ethoxyresorufin and methoxyresorufin were prepared and tested for AChE and BChE. In the experiments, 3D-printed pads containing indoxylacetate as a chromogenic substrate were optimal for analytical purposes. The best results were achieved using the red (R) channel, where the limit of detection was 4.05 µkat/mL for BChE and 4.38 µkat/mL for AChE using a 40 µL sample and a 60 min assay. The major advantage of this method is its overall simplicity, as samples are applied directly without any specific treatment or added reagents. The assay was also validated to the standard Ellman’s assay using human plasma samples. In conclusion, this smartphone camera-based colorimetric assay appears to have practical applicability and to be a suitable method for point-of-care testing because it does not require specific manipulation, additional education of staff or use of sophisticated analytical instruments.

scholarly journals Wave-shaped microfluidic chip assisted point-of-care testing for accurate and rapid diagnosis of infections

2021 ◽  
Author(s):  
Binfeng Yin ◽  
Xinhua Wan ◽  
Mingzhu Yang ◽  
Changcheng Qian ◽  
A S M Muhtasim Fuad Sohan
Keyword(s):  
Microfluidic Chip ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Simultaneous Detection ◽  
Accurate Diagnosis ◽  
Point Of Care Testing ◽  
Promising Alternative ◽  
Reactive Protein ◽  
Linear Relationships ◽  
Multiple Biomarkers

Abstract Background: Simultaneous and timely detection of C-reactive protein (CRP), procalcitonin (PCT), and interleukin-6 (IL-6) provides effective information for the accurate diagnosis of infections. Early diagnosis and classification of infections increase the cure rate while decreasing complications, which is significant for severe infections, especially for war surgery. However, traditional methods rely on laborious operations and bulky devices. On the other hand, point-of-care (POC) methods suffer from limited robustness and accuracy. Therefore, it is of urgent demand to develop POC devices for rapid and accurate diagnosis of infections to fulfill on-site militarized requirements.Methods: We developed a wave-shaped microfluidic chip (WMC) assisted multiplexed detection platform (WMC-MDP). WMC-MDP reduces detection time and improves repeatability through premixing of the samples and reaction of the reagents. We further combined the detection platform with the streptavidin-biotin (SA-B) amplified system to enhance the sensitivity while using chemiluminescence (CL) intensity as signal readout. We realized simultaneous detection of CRP, PCT, and IL-6 on the detection platform and evaluated the sensitivity, linear range, selectivity, and repeatability. Finally, we finished detecting 15 samples from volunteers and compared the results with commercial ELISA kits.Results: Detection of CRP, PCT, and IL-6 exhibited good linear relationships between CL intensities and concentrations in the range of 1.25-40 μg/mL, 0.4-12.8 ng/mL, and 50-1600 pg/mL. The limit of detection (LOD) of CRP, PCT, and IL-6 were 0.54 μg/mL, 0.11 ng/mL, and 16.25 pg/mL, respectively. WMC-MDP is capable of good adequate selectivity and repeatability. The whole detection procedure takes only 22 minutes that meets the requirements of a POC device. Results of 15 samples from volunteers were consistent with the results detected by commercial ELISA kits.Conclusion: WMC-MDP allows simultaneous, rapid, and sensitive detection of CRP, PCT, and IL-6 with satisfactory selectivity and repeatability, requiring minimal manipulation. However, WMC-MDP takes advantage of being a microfluidic device showing the coefficients of variation less than 10% enabling WMC-MDP to be a type of POCT. Therefore, WMC-MDP provides a promising alternative to point-of-care testing (POCT) of multiple biomarkers. We believe the practical application of WMC-MDP in militarized fields will revolutionize infection diagnosis for soldiers.

scholarly journals Point-of-Care Testing-the Key in the Battle against SARS-CoV-2 Pandemic

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1464
Author(s):  
Florina Silvia Iliescu ◽  
Ana Maria Ionescu ◽  
Larisa Gogianu ◽  
Monica Simion ◽  
Violeta Dediu ◽  
...  
Keyword(s):  
Clinical Decision Making ◽  
Point Of Care ◽  
Low Cost ◽  
Diagnostic Testing ◽  
Clinical Decision ◽  
Rapid Screening ◽  
Diagnostic Tools ◽  
Point Of Care Testing ◽  
Qrt Pcr ◽  
User Friendly

The deleterious effects of the coronavirus disease 2019 (COVID-19) pandemic urged the development of diagnostic tools to manage the spread of disease. Currently, the “gold standard” involves the use of quantitative real-time polymerase chain reaction (qRT-PCR) for SARS-CoV-2 detection. Even though it is sensitive, specific and applicable for large batches of samples, qRT-PCR is labour-intensive, time-consuming, requires trained personnel and is not available in remote settings. This review summarizes and compares the available strategies for COVID-19: serological testing, Point-of-Care Testing, nanotechnology-based approaches and biosensors. Last but not least, we address the advantages and limitations of these methods as well as perspectives in COVID-19 diagnostics. The effort is constantly focused on understanding the quickly changing landscape of available diagnostic testing of COVID-19 at the clinical levels and introducing reliable and rapid screening point of care testing. The last approach is key to aid the clinical decision-making process for infection control, enhancing an appropriate treatment strategy and prompt isolation of asymptomatic/mild cases. As a viable alternative, Point-of-Care Testing (POCT) is typically low-cost and user-friendly, hence harbouring tremendous potential for rapid COVID-19 diagnosis.

scholarly journals Direct-RT-qPCR Detection of SARS-CoV-2 without RNA Extraction as Part of a COVID-19 Testing Strategy: From Sample to Result in One Hour

Diagnostics ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 605 ◽  
Author(s):  
Eva Kriegova ◽  
Regina Fillerova ◽  
Petr Kvapil
Keyword(s):  
High Throughput Screening ◽  
High Speed ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Rna Extraction ◽  
Rna Isolation ◽  
High Sensitivity ◽  
Ease Of Use ◽  
Diagnostic Tools ◽  
Heat Inactivation

Due to the lack of protective immunity in the general population and the absence of effective antivirals and vaccines, the Coronavirus disease 2019 (COVID-19) pandemic continues in some countries, with local epicentres emerging in others. Due to the great demand for effective COVID-19 testing programmes to control the spread of the disease, we have suggested such a testing programme that includes a rapid RT-qPCR approach without RNA extraction. The Direct-One-Step-RT-qPCR (DIOS-RT-qPCR) assay detects severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in less than one hour while maintaining the high sensitivity and specificity required of diagnostic tools. This optimised protocol allows for the direct use of swab transfer media (14 μL) without the need for RNA extraction, achieving comparable sensitivity to the standard method that requires the time-consuming and costly step of RNA isolation. The limit of detection for DIOS-RT-qPCR was lower than seven copies/reaction, which translates to 550 virus copies/mL of swab. The speed, ease of use and low price of this assay make it suitable for high-throughput screening programmes. The use of fast enzymes allows RT-qPCR to be performed under standard laboratory conditions within one hour, making it a potential point-of-care solution on high-speed cycling instruments. This protocol also implements the heat inactivation of SARS-CoV-2 (75 °C for 10 min), which renders samples non-infectious, enabling testing in BSL-2 facilities. Moreover, we discuss the critical steps involved in developing tests for the rapid detection of COVID-19. Implementing rapid, easy, cost-effective methods can help control the worldwide spread of the COVID-19 infection.

scholarly journals Rapid Detection of Bacillus anthracis Bloodstream Infections by Use of a Novel Assay in the GeneXpert System

2017 ◽  
Vol 55 (10) ◽  
pp. 2964-2971 ◽  
Author(s):  
Padmapriya P. Banada ◽  
Srinidhi Deshpande ◽  
Riccardo Russo ◽  
Eric Singleton ◽  
Darshini Shah ◽  
...  
Keyword(s):  
Bacillus Anthracis ◽  
Dynamic Range ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Severe Disease ◽  
Automated System ◽  
Bacterial Isolates ◽  
Sample Processing ◽  
Blood Samples ◽  
Content Type

ABSTRACT Bacillus anthracis is a tier 1 select agent with the potential to quickly cause severe disease. Rapid identification of this pathogen may accelerate treatment and reduce mortality in the event of a bioterrorism attack. We developed a rapid and sensitive assay to detect B. anthracis bacteremia using a system that is suitable for point-of-care testing. A filter-based cartridge that included both sample processing and PCR amplification functions was loaded with all reagents needed for sample processing and multiplex nested PCR. The assay limit of detection (LOD) and dynamic range were determined by spiking B. anthracis DNA into individual PCR mixtures and B. anthracis CFU into human blood. One-milliliter blood samples were added to the filter-based detection cartridge and tested for B. anthracis on a GeneXpert instrument. Assay specificity was determined by testing blood spiked with non-anthrax bacterial isolates or by testing blood samples drawn from patients with concurrent non- B. anthracis bacteremia or nonbacteremic controls. The assay LODs were 5 genome equivalents per reaction and 10 CFU/ml blood for both the B. anthracis Sterne and V1B strains. There was a 6-log 10 dynamic range. Assay specificity was 100% for tests of non- B. anthracis bacterial isolates and patient blood samples. Assay time was less than 90 min. This automated system suitable for point-of-care detection rapidly identifies B. anthracis directly from blood with high sensitivity. This assay might lead to early detection and more rapid therapy in the event of a bioterrorism attack.

scholarly journals Performance evaluation of the point-of-care SAMBA II SARS-CoV-2 Test for detection of SARS-CoV-2

2020 ◽  
Author(s):  
Sonny M Assennato ◽  
Allyson V Ritchie ◽  
Cesar Nadala ◽  
Neha Goel ◽  
Hongyi Zhang ◽  
...  
Keyword(s):  
Public Health ◽  
Infection Control ◽  
Sensitivity And Specificity ◽  
Patient Management ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Clinical Samples ◽  
Analytical Sensitivity ◽  
Point Of Care Testing ◽  
Clinical Sensitivity

AbstractNucleic acid amplification for the detection of SARS-CoV-2 RNA in respiratory samples is the standard method for diagnosis. These tests are centralised and therefore turnaround times can be 2-5 days. Point-of-care testing with rapid turnaround times would allow more effective triage in settings where patient management and infection control decisions need to be made rapidly.Inclusivity and specificity of the SAMBA II SARS-CoV-2 assay was determined by in silico analyses of the primers and probes. Analytical and clinical sensitivity and specificity of the SAMBA II SARS-CoV-2 Test was evaluated for analytical sensitivity and specificity. Clinical performance was evaluated in residual clinical samples compared to the Public Health England reference tests.The limit of detection of the SAMBA II SARS-CoV-2 Test is 250 cp/mL and is specific for detection of 2 regions of the SARS-CoV-2 genome. The clinical sensitivity was evaluated in 172 clinical samples provided by the Clinical Microbiology and Public Health Laboratory, Addenbrooke’s Hospital, Cambridge (CMPHL), which showed a sensitivity of 98.9% (95% CI 94.03-99.97%), specificity of 100% (95% CI 95.55-100%), PPV of 100% and NPV of 98.78% (92.02-99.82%) compared to testing by CMPHLSAMBA detected 3 positive samples that were initially negative by PHE Test. The data shows that the SAMBA II SARS-CoV-2 Test performs equivalently to the centralised testing methods with a much quicker turnaround time. Point of care testing, such as SAMBA, should enable rapid patient management and effective implementation of infection control measures.

scholarly journals A Rapid Immunochromatographic Method Based on a Secondary Antibody-Labelled Magnetic Nanoprobe for the Detection of Hepatitis B preS2 Surface Antigen

Biosensors ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 161
Author(s):  
Yangyang Cai ◽  
Jun Yan ◽  
Li Zhu ◽  
Hengliang Wang ◽  
Ying Lu
Keyword(s):  
Hepatitis B ◽  
Large Scale ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Secondary Antibody ◽  
Serum Samples ◽  
Standard Curve ◽  
Signal Characteristics ◽  
Viral Infectious Disease ◽  
The Stability

Hepatitis B is a globally prevalent viral infectious disease caused by the hepatitis B virus (HBV). In this study, an immunochromatographic assay (ICA) for the rapid detection of hepatitis B preS2 antigen (preS2Ag) was established. The magnetic nanoparticles (MNPs) indirectly labelled with goat anti-mouse (GAM) secondary antibody were applied as a nanoprobe for free preS2 antibody (preS2Ab) capturing and signal amplification. By employing sample pre-incubation processing as well, preS2Ag-preS2Ab was sufficiently caught by the GAM-MNPs probe in 5 min. A qualitative sensitivity of 625 ng/mL was obtained by naked-eye observation within 15–20 min. A standard curve (0–5000 ng/mL) was established, with a quantitative limit of detection (LOD) of 3.6 ng/mL, based on the stability and penetrability of the magnetic signal characteristics. The proposed method for preS2Ag was rapid (~25 min, cf. ELISA ~4 h) and had a good accuracy, which was verified using an ELISA kit (relative error < 15%). Large equipment and skilled technicians were not required. The sensitivity and specificity of the developed GAM-MNPs-ICA method were 93.3% and 90% in clinical serum samples (n = 25), respectively. A good detection consistency (84%) was observed between the developed ICA method and 2 types of commercial ELISA kits, indicating that the GAM-MNPs-ICA has a potential application in large-scale screening for and point-of-care diagnosis of hepatitis B or other infectious diseases.

scholarly journals Multiplex Detection of Three Select Agents Directly from Blood by Use of the GeneXpert System

2019 ◽  
Vol 57 (5) ◽  
Author(s):  
Padmapriya P. Banada ◽  
Srinidhi Deshpande ◽  
Sukalyani Banik ◽  
Darshini Shah ◽  
Ranie Koshy ◽  
...  
Keyword(s):  
Rapid Detection ◽  
Dynamic Range ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Severe Disease ◽  
High Sensitivity ◽  
Negative Control ◽  
Blood Samples ◽  
Content Type ◽  
Clinical Patient

ABSTRACT Francisella tularensis, Bacillus anthracis, and Yersinia pestis are tier 1 select agents with the potential to rapidly cause severe disease. Rapid detection of these bacteria from patient samples at the point of care could contribute to improved clinical outcomes in the event of a bioterrorism attack. A multiplex nested PCR assay for detection of F. tularensis, B. anthracis, and Y. pestis directly from patient blood samples was developed using the GeneXpert system. The multiplex GeneXpert cartridge-based assay includes all necessary sample processing and amplification reagents. Blood samples spiked with different numbers of CFU were used to measure the analytical limit of detection (LOD) and dynamic range. Sensitivity was determined by testing spiked blood samples and negative-control blood in a blind manner. Specificity was determined by testing against nontarget pathogens and blood samples from clinical patients. The assay LOD was 8.5 CFU/ml for F. tularensis, 10 CFU/ml for B. anthracis, and 4.5 CFU/ml for Y. pestis. The sensitivity was 100% at the LOD for all three select agent bacteria in spiked patient blood samples. The assay specificity was 100% when it was tested against both nontarget pathogens and clinical patient blood samples. The total assay time was approximately 100 min. This automated assay, which is suitable for use at the point of care, identifies three select agents directly in blood without the need for enrichment with a high sensitivity within 100 min. This assay may enable rapid detection and treatment of patients infected with the target organisms in the event of a bioterrorism attack.

scholarly journals Digital immunoassay for biomarker concentration quantification using solid-state nanopores

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Liqun He ◽  
Daniel R. Tessier ◽  
Kyle Briggs ◽  
Matthaios Tsangaris ◽  
Martin Charron ◽  
...  
Keyword(s):  
Solid State ◽  
Single Molecule ◽  
Dynamic Range ◽  
Point Of Care ◽  
Magnetic Bead ◽  
Thyroid Stimulating Hormone ◽  
Target Protein ◽  
Diagnostic Tools ◽  
Dna Nanostructures ◽  
Serum Samples

ABSTRACTSingle-molecule counting is the most accurate and precise method for determining the concentration of a biomarker in solution and is leading to the emergence of digital diagnostic platforms enabling precision medicine. In principle, solid-state nanopores—fully electronic sensors with single-molecule sensitivity—are well suited to the task. Here we present a digital immunoassay scheme capable of reliably quantifying the concentration of a target protein in complex biofluids that overcomes specificity, sensitivity, and consistency challenges associated with the use of solid-state nanopores for protein sensing. This is achieved by employing easily-identifiable DNA nanostructures as proxies for the presence (“1”) or absence (“0”) of the target protein captured via a magnetic bead-based sandwich immunoassay. As a proof-of-concept, we demonstrate quantification of the concentration of thyroid-stimulating hormone from human serum samples down to the high femtomolar range. Further optimization to the method will push sensitivity and dynamic range, allowing for development of precision diagnostic tools compatible with point-of-care format.

scholarly journals Polystyrene Microsphere-Based Immunochromatographic Assay for Detection of Aflatoxin B1 in Maize

Biosensors ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 200
Author(s):  
Jin Wang ◽  
Xiangmei Li ◽  
Xing Shen ◽  
Ang Zhang ◽  
Jinxiu Liu ◽  
...  
Keyword(s):  
Aflatoxin B1 ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Immunochromatographic Assay ◽  
Quantitative Detection ◽  
Point Of Care Testing ◽  
Polystyrene Microsphere ◽  
Accuracy And Precision ◽  
Wide Range ◽  
Liquid Chromatography Tandem Mass

Aflatoxin B1 (AFB1), a mycotoxin, is hepatotoxic, carcinogenic, and nephrotoxic in humans and animals, and contaminate a wide range of maize. In this study, an immunochromatographic assay (ICA) based on polystyrene microspheres (PMs) was developed for sensitive and quantitative detection of AFB1 in maize. The amounts of PMs, the condition for activating carboxyl groups of PMs, the amount of monoclonal antibody (mAb), and the volume of the immune probe were optimized to enhance the performance PMs-ICA for point-of-care testing of AFB1 in maize. The PMs-ICA showed the cut-off value of 1 ng/mL in phosphate buffer (PB) and 6 µg/kg in maize samples, respectively. The quantitative limit of detection (qLOD) was 0.27 and 1.43 µg/kg in PB and maize samples, respectively. The accuracy and precision of the PMs-ICA were evaluated by analysis of spiked maize samples with recoveries of 96.0% to 107.6% with coefficients of variation below 10%. In addition, the reliability of PMs-ICA was confirmed by the liquid chromatography-tandem mass spectrometry method. The results indicated that the PMs-ICA could be used as a sensitive, simple, rapid point-of-care testing of AFB1 in maize.

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