Two Potential Clinical Applications of Origami-Based Paper Devices

Detecting small amounts of analyte in clinical practice is challenging because of deficiencies in specimen sample availability and unsuitable sampling environments that prevent reliable sampling. Paper-based analytical devices (PADs) have successfully been used to detect ultralow amounts of analyte, and origami-based PADs (O-PADs) offer advantages that may boost the overall potential of PADs in general. In this study, we investigated two potential clinical applications for O-PADs. The first O-PAD we investigated was an origami-based enzyme-linked immunosorbent assay (ELISA) system designed to detect different concentrations of rabbit IgG. This device was designed with four wing structures, each of which acted as a reagent loading zone for pre-loading ELISA reagents, and a central test sample loading zone. Because this device has a low limit of detection (LOD), it may be suitable for detecting IgG levels in tears from patients with a suspected viral infection (such as herpes simplex virus (HSV)). The second O-PAD we investigated was designed to detect paraquat levels to determine potential poisoning. To use this device, we sequentially folded each of two separate reagent zones, one preloaded with NaOH and one preloaded with ascorbic acid (AA), over the central test zone, and added 8 µL of sample that then flowed through each reagent zone and onto the central test zone. The device was then unfolded to read the results on the test zone. The three folded layers of paper provided a moist environment not achievable with conventional paper-based ELISA. Both O-PADs were convenient to use because reagents were preloaded, and results could be observed and analyzed with image analysis software. O-PADs expand the testing capacity of simpler PADs while leveraging their characteristic advantages of convenience, cost, and ease of use, particularly for point-of-care diagnosis.

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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 ◽

10.3390/diagnostics10080605 ◽

2020 ◽

Vol 10 (8) ◽

pp. 605 ◽

Cited By ~ 3

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.

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Perioperative Ultrasonography Review

Journal of Perioperative Echocardiography ◽

10.5005/jp-journals-10034-1044 ◽

2016 ◽

Vol 4 (1) ◽

pp. 3-9

Author(s):

Nicholas J Schott ◽

Christopher K Schott

Keyword(s):

Patient Care ◽

Assessment Tool ◽

Point Of Care ◽

Modern Medicine ◽

Clinical Applications ◽

Ease Of Use ◽

Clinical Use ◽

Patient Assessment ◽

Point Of Care Ultrasonography ◽

Device Technology

ABSTRACT Point-of-care ultrasonography (POCUS) has become increasingly utilized in modern medicine. Advancements in device technology and ease of use have dramatically broadened its clinical applications. The role in acute care specialties of a pointof- care device has allowed increased opportunities for patient assessment and management. The specialties of emergency medicine and critical care medicine have accepted POCUS in many aspects of clinical use as well as trainee education. Anesthesiology has begun to implement the use of POCUS, specifically transthoracic echocardiography, in the perioperative setting. Many elements of patient care can be addressed and modified using this as an assessment tool. This has led to in growth in ultrasonography training and the potential to be a staple of future anesthesiology care. Point-of-care ultrasonography may become vital to the forefront of management for improving perioperative patient care. How to cite this article Schott NJ, Schott CK. Perioperative Ultrasonography Review. J Perioper Echocardiogr 2016; 4(1):3-9.

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Mobile platform for rapid sub–picogram-per-milliliter, multiplexed, digital droplet detection of proteins

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1814110116 ◽

2019 ◽

Vol 116 (10) ◽

pp. 4489-4495 ◽

Cited By ~ 36

Author(s):

Venkata Yelleswarapu ◽

Joshua R. Buser ◽

Margalit Haber ◽

Jonathan Baron ◽

Eshwar Inapuri ◽

...

Keyword(s):

Single Molecule ◽

Gold Standard ◽

Limit Of Detection ◽

Human Subjects ◽

Point Of Care ◽

Parallel Operation ◽

Single Chip ◽

Elisa System ◽

Gm Csf ◽

Digital Elisa

Digital droplet assays—in which biological samples are compartmentalized into millions of femtoliter-volume droplets and interrogated individually—have generated enormous enthusiasm for their ability to detect biomarkers with single-molecule sensitivity. These assays have untapped potential for point-of-care diagnostics but are currently mainly confined to laboratory settings, due to the instrumentation necessary to serially generate, control, and measure tens of millions of droplets/compartments. To address this challenge, we developed an optofluidic platform that miniaturizes digital assays into a mobile format by parallelizing their operation. This technology is based on three key innovations: (i) the integration and parallel operation of a hundred droplet generators onto a single chip that operates >100× faster than a single droplet generator, (ii) the fluorescence detection of droplets at >100× faster than conventional in-flow detection using time domain-encoded mobile phone imaging, and (iii) the integration of on-chip delay lines and sample processing to allow serum-to-answer device operation. To demonstrate the power of this approach, we performed a duplex digital ELISA. We characterized the performance of this assay by first using spiked recombinant proteins in a complex media (FBS) and measured a limit of detection, 0.004 pg/mL (300 aM), a 1,000× improvement over standard ELISA and matching that of the existing laboratory-based gold standard digital ELISA system. We additionally measured endogenous GM-CSF and IL6 in human serum fromn= 14 human subjects using our mobile duplex assay, and showed excellent agreement with the gold standard system (R2=0.96).

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Advanced Signal-Amplification Strategies for Paper-Based Analytical Devices: A Comprehensive Review

Biomedicines ◽

10.3390/biomedicines9050540 ◽

2021 ◽

Vol 9 (5) ◽

pp. 540

Author(s):

Thi Xoan Hoang ◽

Le Minh Tu Phan ◽

Thuy Anh Thu Vo ◽

Sungbo Cho

Keyword(s):

Signal Amplification ◽

Point Of Care ◽

Clinical Applications ◽

Clinical Diagnostics ◽

Ease Of Use ◽

Rapid Responses ◽

Surface Enhanced ◽

Surface Enhanced Raman ◽

Enhanced Raman Scattering ◽

User Friendly

Paper-based analytical devices (PADs) have emerged as a promising approach to point-of-care (POC) detection applications in biomedical and clinical diagnosis owing to their advantages, including cost-effectiveness, ease of use, and rapid responses as well as for being equipment-free, disposable, and user-friendly. However, the overall sensitivity of PADs still remains weak, posing a challenge for biosensing scientists exploiting them in clinical applications. This review comprehensively summarizes the current applicable potential of PADs, focusing on total signal-amplification strategies that have been applied widely in PADs involving colorimetry, luminescence, surface-enhanced Raman scattering, photoacoustic, photothermal, and photoelectrochemical methods as well as nucleic acid-mediated PAD modifications. The advances in signal-amplification strategies in terms of signal-enhancing principles, sensitivity, and time reactions are discussed in detail to provide an overview of these approaches to using PADs in biosensing applications. Furthermore, a comparison of these methods summarizes the potential for scientists to develop superior PADs. This review serves as a useful inside look at the current progress and prospective directions in using PADs for clinical diagnostics and provides a better source of reference for further investigations, as well as innovations, in the POC diagnostics field.

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Point-of-Need Disposable ELISA System for COVID-19 Serology Testing

10.33774/chemrxiv-2021-c4bmd-v3 ◽

2021 ◽

Author(s):

Cody Carrell ◽

Jeremy Link ◽

Ilhoon Jang ◽

James Terry ◽

Michael Scherman ◽

...

Keyword(s):

Clinical Laboratory ◽

Point Of Care ◽

Lateral Flow ◽

World Health ◽

Clinical Samples ◽

Enzyme Linked Immunosorbent Assay ◽

Elisa System ◽

Health Organization ◽

Care Technology ◽

Serology Testing

A disposable enzyme-linked immunosorbent assay (dELISA) device for ate-home or doctor’s office use was developed to detect SARS-CoV-2 antibodies. Serology testing for SARS-CoV-2 antibodies is currently run using well-plate ELISAs in centralized laboratories. However, the scale of serology testing needed for epidemiological and clinical screening studies will overwhelm existing clinical laboratory resources. Instead, a point-of-need device that can be used at home or in doctor’s offices for COVID-19 serology testing must be developed and is one of four target products prioritized by the World Health Organization. Lateral flow assays are common and easy to use, but lack the sensitivity needed to reliably detect SARS-CoV-2 antibodies in clinical samples. This work describes a disposable ELISA device that is as simple to use as a lateral flow assay, but as sensitive as a well-plate ELISA. The device utilizes capillary-driven flow channels made of transparency films and double-sided adhesive combined with paper pumps to drive flow. The geometry of the channels and storage pads enables automated sequential washing and reagent addition steps with two simple end-user steps. An enzyme label is used to produce a colorimetric signal instead of a nanoparticle label in order to amplify signal and increase sensitivity, while the integrated washing steps decrease false positives and increase reproducibility. Naked-eye detection can be used for qualitative results or a smartphone camera for quantitative analysis. The device can detect antibodies at 2.8 ng/mL from whole blood, which was very close the concentration of detectable target in a well-plate ELISA (1.2 ng/mL). In this study the dELISA system was used to detect SARS-CoV-2 antibodies, but we believe that the device represents a fundamental step forward in point-of-care technology that will enable sensitive detection of many other analytes outside of a centralized laboratory.

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Evaluation of accuracy, exclusivity, limit-of-detection and ease-of-use of LumiraDx™ - Antigen-detecting point-of-care device for SARS-CoV-2

10.1101/2021.03.02.21252430 ◽

2021 ◽

Author(s):

Lisa Johanna Krüger ◽

Julian A.F. Klein ◽

Frank Tobian ◽

Mary Gaeddert ◽

Federica Lainati ◽

...

Keyword(s):

Viral Load ◽

Limit Of Detection ◽

Point Of Care ◽

Scale Up ◽

Cross Reactivity ◽

Ease Of Use ◽

Analytical Sensitivity ◽

Rt Pcr ◽

Clinical Sensitivity ◽

Lateral Flow Assays

Background: Rapid antigen-detecting tests (Ag-RDTs) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can transform pandemic control. Thus far, sensitivity (≤85%) of lateral-flow assays has limited scale-up. Conceivably, microfluidic immunofluorescence Ag-RDTs could increase sensitivity for SARS-CoV-2 detection. Materials and Methods: This multi-centre diagnostic accuracy study investigated performance of the microfluidic immunofluorescence LumiraDx™ assay, enrolling symptomatic and asymptomatic participants with suspected SARS-CoV-2 infection. Participants collected a supervised nasal mid-turbinate (NMT) self-swab for Ag-RDT testing, in addition to a professionally-collected nasopharyngeal (NP) swab for routine testing with reverse transcriptase polymerase chain reaction (RT-PCR). Results were compared to calculate sensitivity and specificity. Sub-analyses investigated the results by viral load, symptom presence and duration. An analytical study assessed exclusivity and limit-of-detection (LOD). In addition, we evaluated ease-of-use. Results: Study conduct was between November 2nd 2020 and January 21st 2021. 761 participants were enrolled, with 486 participants reporting symptoms on testing day. 120 out of 146 RT-PCR positive cases were detected positive by LumiraDx™, resulting in a sensitivity of 82.2% (95% CI: 75.2%-87.5%). Specificity was 99.3% (CI: 98.3-99.7%). Sensitivity was increased in individuals with viral load ≥ 7 log10 SARS-CoV2 RNA copies/ml (93.8%; CI: 86.2%-97.3%). Testing against common respiratory commensals and pathogens showed no cross-reactivity and LOD was estimated to be 2-56 PFU/mL. The ease-of-use-assessment was favourable for lower throughput settings. Conclusion: The LumiraDx™ assay showed excellent analytical sensitivity, exclusivity and clinical specificity with good clinical sensitivity using supervised NMT self-sampling.

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A Systematic Study and Potential Limitations of Proton-ELISA Platform for α-Synuclein Antigen Detection

Chemosensors ◽

10.3390/chemosensors10010005 ◽

2021 ◽

Vol 10 (1) ◽

pp. 5

Author(s):

Chia-Ming Yang ◽

Jia-Yuan Chang ◽

Min-Yi Chen ◽

Chao-Sung Lai

Keyword(s):

Limit Of Detection ◽

Point Of Care ◽

Low Cost ◽

Systematic Investigation ◽

Antigen Detection ◽

Enzyme Linked Immunosorbent Assay ◽

Testing Environment ◽

Ph Changes ◽

Speed Up ◽

Detection Of Biomarkers

To evaluate point-of-care testing (POCT) for the potential early detection of biomarkers of Parkinson’s disease, a systematic investigation of portable and low-cost platforms is performed based on the Proton-enzyme-linked immunosorbent assay (Proton-ELISA) methodology. The detection of the α-synuclein antigen was first presented by biotin-relative linkers, and glucose substrate solution was first performed with a systematic experimental design to optimize the sensing results. All materials in this study are commercially available. Three different experiments with the partitional check were performed to investigate the Proton-ELISA platform, including proton catalyzed efficiency, blocking efficiency, and full Proton-ELISA procedure. The response time was selected as 15 min by the time-dependent curves of a full reaction. The limit of detection of conventional ELISA kits is 0.169 ng/mL, which is much lower than the Proton-ELISA results. The final response of the full Proton-ELISA procedure to pH changes was approximately 0.60 and 0.12 for α-synuclein antigen concentrations of 100 ng/mL and 4 ng/mL, respectively. With the partitional check, pH changes of pure glucose substrate and conjugated oxidase and interference of the nonspecific binding are 1.7 and 0.04, respectively. The lower pH changes far from the partitional check results can be concluded for the properties of glucose oxidase conjugation, including the isoelectric point and binding affinity modification by the testing environment. This preliminary guideline can be used as a lesson learnt to speed up following studies of the evaluation and optimization of other antigen detection. Therefore, Proton-ELISA can be suggested for some special applications with the help of custom-designed conjugation in the environment with less degradation or interference and a proper detection concentration range.

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Fully integrated rapid microfluidic device translated from conventional 96-well ELISA kit

Scientific Reports ◽

10.1038/s41598-021-81433-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

M. Jalal Uddin ◽

Nabil H. Bhuiyan ◽

Joon S. Shim

Keyword(s):

Microfluidic Device ◽

Troponin I ◽

Limit Of Detection ◽

Point Of Care ◽

Sample Volume ◽

Elisa Test ◽

Enzyme Linked Immunosorbent Assay ◽

Fully Integrated ◽

Assay Time ◽

On Chip

AbstractIn this work, a fully integrated active microfluidic device transforming a conventional 96-well kit into point-of-care testing (POCT) device was implemented to improve the performance of traditional enzyme-linked immunosorbent assay (ELISA). ELISA test by the conventional method often requires the collection of 96 samples for its operation as well as longer incubation time from hours to overnight, whereas our proposed device conducts ELISA immediately individualizing a 96-well for individual patients. To do that, a programmable and disposable on-chip pump and valve were integrated on the device for precise control and actuation of microfluidic reagents, which regulated a reaction time and reagent volume to support the optimized protocols of ELISA. Due to the on-chip pump and valve, ELISA could be executed with reduced consumption of reagents and shortening the assay time, which are crucial for conventional ELISA using 96-well microplate. To demonstrate highly sensitive detection and easy-to-use operation, this unconventional device was successfully applied for the quantification of cardiac troponin I (cTnI) of 4.88 pg/mL using a minimum sample volume of 30 µL with a shorter assay time of 15 min for each ELISA step. The limit of detection (LOD) thus obtained was significantly improved than the conventional 96-well platform.

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Point-of-Need Disposable ELISA System for COVID-19 Serology Testing

10.26434/chemrxiv.13050539 ◽

2020 ◽

Author(s):

Cody Carrell ◽

Jeremy Link ◽

Ilhoon Jang ◽

James Terry ◽

Michael Scherman ◽

...

Keyword(s):

Clinical Laboratory ◽

Point Of Care ◽

Lateral Flow ◽

World Health ◽

Clinical Samples ◽

Enzyme Linked Immunosorbent Assay ◽

Elisa System ◽

Health Organization ◽

Care Technology ◽

Serology Testing

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Pipetting-based immunoassay for point-of-care testing: Application for detection of the influenza A virus

Scientific Reports ◽

10.1038/s41598-019-53083-8 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 4

Author(s):

Ji Yeong Noh ◽

Sun-Woo Yoon ◽

Youngji Kim ◽

Thi Van Lo ◽

Min-Ju Ahn ◽

...

Keyword(s):

Influenza A Virus ◽

Influenza A ◽

Flow System ◽

Limit Of Detection ◽

Point Of Care ◽

Lateral Flow ◽

Ease Of Use ◽

Target Antigen ◽

Enzymatic Reactions

Abstract Point-of-care tests (POCT) for pathogens are considered important for low-resource countries and facilities. Although lateral flow immunoassays (LFIA) have many advantages including speed and ease of use, their sensitivity is limited without specific equipment. Furthermore, their response cannot be enhanced through enzymatic reactions. Owing to these limitations, LFIAs have not yet been generally adopted as the standard protocol for in vitro analysis of infectious pathogens. We aimed to develop a novel pipetting-based immunoassay using a removable magnetic ring-coupled pipette tip. The “magnetic bead-capture antibody-targeted protein complex” was simply purified by pipetting and quantified by enzymatic colour development or using a lateral flow system. This pipetting-based immunoassay was applied to detect the nucleoprotein (NP) of the influenza A virus. Using an HRP-conjugated monoclonal antibody as a probe, the assay allowed for specific and sensitive detection. Furthermore, when this assay was applied exclusively for antigen capture in the lateral flow system, the limit of detection improved 100-fold and displayed greater sensitivity than the lateral flow system alone. Therefore, the pipetting-based immunoassay may be potentially used as a sensitive POCT to clinically detect a target antigen.

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