ABSTRACT
The quantification of neutralising antibodies (NAb) for SARS-CoV-2 has become an important tool for monitoring protective immunity following infection or immunisation. In this study, we evaluated using World-Health-Organisation-standard immunoglobulin preparations, a novel point-of-care test that quantitates NAb by time-resolved fluorescent immunoassay. The assay provided robust data of binding antibody units (BAU) in 15 min that were well correlated with NAb values obtained by traditional in vitro neutralisation assay. The data also correlated well to spike-receptor-binding domain-binding antibodies over a broad range of plasma dilutions. The assay was extremely sensitive, able to detect positive samples after dilution 1:10,000 and over a wide range of BAU. Assay specificity was estimated at 96% using Pre-COVID-19 serum samples when applying a cut-off value of 47 BAU/mL, although readings of up to 100 BAU/mL could be considered borderline. This point-of-care diagnostic test is useful for rapid population screening and includes the use of capillary blood samples. Furthermore, it provides results for SARS-CoV-2 NAb in 15 min, which can inform immediate decisions regarding protective immunity levels and the need for continued COVID immunisations.
ABSTRACT
The demonic progression of the SARS-CoV-2 (severe acute respiratory syndrome coronavirus) worldwide points out the need to develop innovative, rapid, and sensitive detection of microbial pathogens. Conventional molecular diagnostic techniques often require sophisticated, expensive instrumentation in addition to the high cost and shorter shelf life of some reagents. In contrast, the use of fluorescent quantum dots, carbon nanotube, etc., for pathogen detection can be tailored by changing surface charge ratio and particle size, which may provide global accessibility. The operating principle behind pathogen identification is the surface marker recognition of bacterial or viral nucleic acid sequences. Therefore this chapter aims to focus on the comprehensive utilization of nanotechnology in pathogen identification. The emerging technology of nano-based point-of-care detection and its association with the neural network is believed to mark a blueprint for diagnosing infectious diseases and improving human existence. © 2022 Elsevier Inc. All rights reserved.
ABSTRACT
The COVID-19 pandemic has demonstrated the need for better understanding of the kinetics of anti-SARSCoV-2 antibody production and development of serological assays for multiple viral antigens. Electrochemical (EC) sensor platforms offer the potential to develop rapid, sensitive, point-of-care (POC) diagnostics for this type of application. Here, we describe multiplexed EC biosensors with novel antifouling properties that detect anti-SARSCoV-2 immunoglobulin G (IgG) against spike protein (S), spike receptor-binding domain (RBD), and nucleocapsid (NC) antigens. This POC assay was validated using 69 clinical blood samples and obtained 96% sensitivity and 100% specificity with area under the curve (AUC) of 0.98 for multiplexed detection of anti-SARS-CoV-2 IgG. © 2021 MicroTAS 2021 - 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences. All rights reserved.
ABSTRACT
We present a nucleic acid-based point-of-care diagnostic for the detection of the SARS-CoV-2 from saliva using an additively manufactured microfluidic cartridge. The assay uses reverse transcriptase loop-mediated isothermal amplification (RT-LAMP) to detect the presence of SARS-CoV-2 RNA on-cartridge in a point-of-care optical detection system based on a smartphone. We show positive results within the 10-30 minutes range and integrated biological controls on the cartridge. We demonstrate the microfluidic diagnostic with human patient samples, with results that are consistent with the off-cartridge validation. © 2021 MicroTAS 2021 - 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences. All rights reserved.
ABSTRACT
We present a multiplexed, electronic enzyme-linked immunosorbent assay (E2LISA) microchip for direct electrical detection and quantitation of multiple biomarkers from a single microliter-scale drop of sample. Spatially distinct spots on the microchip, each containing an interdigitated microelectrode array, are coated with specific capture agents and used to bind different analytes. Enzyme-labeled probes are then used to convert this analyte binding to an electrical impedance signal via the amplified, localized deposition of silver on the nanostructured, catalytic surface of the chip prepared using gold nanoparticles. We use this microchip with a custom handheld, cellphone interfaced reader to detect COVID-19 biomarkers including antigen-specific antibodies and viral antigens. Further, we demonstrate the multiplexed measurement of distinct antibody responses in serum samples from convalescent COVID-19 patients versus uninfected vaccine recipients. © 2021 MicroTAS 2021 - 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences. All rights reserved.
ABSTRACT
Without global mass vaccination, COVID-19 will continue to infect and cause serious illness, disproportionately in low- and middle-income countries. Point-of-care and home-based nucleic acid amplification tests (NAATs) are valuable tools to control COVID-19 transmission. Here we present a rapid isothermal NAAT for duplexed detection of SARS-CoV-2 and an MS2 bacteriophage internal control. This assay amplifies RNA in less than 15 minutes, utilizes a low temperature of 39°C, and has fluorescence or visual lateral flow readout. This positions our assay for use in low-cost paper-based nucleic acid diagnostic devices for ultrasensitive and reliable COVID-19 detection in POC or home-based settings. © 2021 MicroTAS 2021 - 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences. All rights reserved.
ABSTRACT
Rapid polymerase chain reaction (PCR) utilizing plasmon-driven photothermal cycling requires real-time quantification of amplicons during PCR and miniaturization of real-time PCR (qPCR) system for point-of-care (POC) diagnostics. In this work, we have demonstrated handheld photothermal qPCR system with disposable aluminum PCR chips for the ultrafast amplification and real-time quantification of plasmids expressing SARSCoV-2 envelope protein within 5 min. This novel system provides stable and useful point-of-care diagnostic platform for prevention of fast-spreading pandemic in airport and harbor. © 2021 MicroTAS 2021 - 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences. All rights reserved.
ABSTRACT
As the COVID-19 pandemic continues, there remains a need for fast, accurate and low-cost diagnostic tests to prevent outbreaks. We have developed an electrochemical capillary-flow driven immunoassay (eCaDI) capable of detecting SARS-CoV-2 nucleocapsid (N) protein in self-administered nasal samples at the point of care (POC). The low-cost device is made of polyester and adhesive films and provides sequential delivery of sample and reagents to a detection zone integrating a screen-printed carbon electrode (SPCE) modified with anti-N protein antibodies from a single addition of sample, automating the steps of an ELISA. The modified electrodes are highly sensitive and selective for COVID-19 N protein and were successfully applied to test clinical samples. The novelty of this work resides in the integration of sensitive electrochemical detection with pump-free capillary-flow assay, providing accuracy at the POC. Previously reported systems are slow and/or require multiple user steps reducing the utility for POC applications relative to the system reported here. © 2021 MicroTAS 2021 - 25th International Conference on Miniaturized Systems for Chemistry and Life Sciences. All rights reserved.
ABSTRACT
The novel coronavirus disease of 2019 (COVID-19) is associated with significant morbidity and mortality, as well as large numbers of patients requiring endotracheal intubation. While much of the literature has focused on the intubation technique, there is scant discussion of intubation confirmation. Herein, we discuss the limitations of traditional confirmatory approaches, summarize the literature supporting a role for point-of-care ultrasound in this application, and propose an algorithm for intubation confirmation among COVID-19 patients. [West J Emerg Med. 2020;21(5)1042-1045.]
ABSTRACT
Desirable biosensing assays need to be sensitive, specific, cost‐effective, instrument‐free, and versatile. Herein we report a new strategy termed CLIPON (CRISPR and Large DNA assembly Induced Pregnancy strips for signal‐ON detection) that can deliver these traits. CLIPON integrates a commercial pregnancy test strip (PTS) with four biological elements: the human chorionic gonadotropin (hCG), CRISPR‐Cas12a, crRNA and cauliflower‐like large‐sized DNA assemblies (CLD). CLIPON uses the Cas12a/crRNA complex both to recognize a target of interest and to release CLD‐bound hCG so that target presence can translate into a colorimetric signal on the PTS. We demonstrate the versatility of CLIPON through sensitive and specific detection of HPV genomic DNA, SARS‐CoV‐2 genomic RNA and adenosine. We also engineer a cell phone app and a hand‐held microchip to achieve signal quantification. CLIPON represents an attractive option for biosensing and point‐of‐care diagnostics.
ABSTRACT
Microfluidic biochips are being adopted today in point-of-care diagnostics, e.g., COVID-19 testing;therefore, it is critical to ensure integrity of bio-sample before bioassays are run on-chip. A security technique called molecular barcoding was recently proposed to thwart sample-forgery attacks in DNA forensics. Molecular barcoding refers to addition of unique DNA molecules in bio-samples, and the sequence of the added DNA sample serves as a distinct 'barcode' for the sample. The existence of the added molecule can be validated using polymerase chain reaction (PCR) and gel electrophoresis. However, this security solution has several limitations: (1) the lack of robustness of the barcode molecules when they are added to other genomic DNA (e.g., samples collected for diagnostics);(2) the need for special bulk instrumentation for validation;(3) the need for human intervention during the overall process. To overcome the limitations, we design a set of robust molecular barcodes that can be validated using both traditional polymerase chain reaction and loop mediated isothermal amplification (LAMP). The validation using LAMP can be executed on a small-in-size and portable digital microfluidic biochip (DMFB). Our LAMP workflow includes a color-changing visual indicator for simple, rapid identification of the barcode existence in solutions. We first demonstrate the proposed security workflow using benchtop techniques. Next, we fabricate a printed circuit board (PCB)-based DMFB with heaters and demonstrate, for the first time, the LAMP assay on a DMFB. © 2021 IEEE.
ABSTRACT
The importance of medical diagnostics, and specifically, tests for infectious agents such as viruses, is well recognized, and in fact, are a crucial component of efforts to control pandemics and mitigate their effects on public health. A long-established trend is the development of low-cost, easy-to-use point-of-care (POC) diagnostics to provide pervasive, timely testing independent of laboratories and other medical infrastructure. The technology of POC tests is widely accessible to engineering students, and there are many opportunities and avenues for innovation, including Smartphone-based platforms and integration with the Internet of Medical Things (IoMT). We discuss the design, demonstration, and testing of POC virus testing, including tests applicable to COVID-19, as Senior Design Projects for undergraduate mechanical, electrical, and manufacturing engineering majors. Copyright © 2021 by ASME
ABSTRACT
BACKGROUND: Point of care (POC) testing has enabled rapid coronavirus disease 2019 (COVID-19) diagnosis in resource-limited settings with limited laboratory infrastructure and high disease burden. However, the accessibility of the tests is not optimal in these settings. This scoping review mapped evidence on supply chain management (SCM) systems for POC diagnostic services to reveal evidence that can help guide future research and inform the improved implementation of SARS-CoV-2 POC diagnostics in resource-limited settings. METHODOLOGY: This scoping review was guided by an adapted version of the Arksey and O'Malley methodological framework. We searched the following electronic databases: Medline Ovid, Medline EBSCO, Scopus, PubMed, PsychInfo, Web of Science and EBSCOHost. We also searched grey literature in the form of dissertations/theses, conference proceedings, websites of international organisations such as the World Health Organisation and government reports. A search summary table was used to test the efficacy of the search strategy. The quality of the included studies was appraised using the mixed method appraisal tool (MMAT) version 2018. RESULTS: We retrieved 1206 articles (databases n = 1192, grey literature n = 14). Of these, 31 articles were included following abstract and full-text screening. Fifteen were primary studies conducted in LMICs, and 16 were reviews. The following themes emerged from the included articles: availability and accessibility of POC diagnostic services; reasons for stockouts of POC diagnostic tests (procurement, storage, distribution, inventory management and quality assurance) and human resources capacity in POC diagnostic services. Of the 31 eligible articles, 15 underwent methodological quality appraisal with scores between 90% and 100%. CONCLUSIONS: Our findings revealed limited published research on SCM systems for POC diagnostic services globally. We recommend primary studies aimed at investigating the barriers and enablers of SCM systems for POC diagnostic services for highly infectious pathogens such SARS-CoV-2 in high disease-burdened settings with limited laboratory infrastructures.
ABSTRACT
A novel severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) emerged in China in December 2019, causing an ongoing, rapidly spreading global pandemic. Worldwide, vaccination is now expected to provide containment of the novel virus, resulting in an antibody-mediated immunity. To verify this, serological antibody assays qualitatively as well as quantitatively depicting the amount of generated antibodies are of great importance. Currently available test methods are either laboratory based or do not have the ability to indicate an estimation about the immune response. To overcome this, a novel and rapid serological magnetic immunodetection (MID) point-of-care (PoC) assay was developed, with sensitivity and specificity comparable to laboratory-based DiaSorin Liaison SARS-CoV-2 S1/S2 IgG assay. To specifically enrich human antibodies against SARS-CoV-2 in immunofiltration columns (IFCs) from patient sera, a SARS-CoV-2 S1 antigen was transiently produced in plants, purified and immobilized on the IFC. Then, an IgG-specific secondary antibody could bind to the retained antibodies, which was finally labeled using superparamagnetic nanoparticles. Based on frequency magnetic mixing technology (FMMD), the magnetic particles enriched in IFC were detected using a portable FMMD device. The obtained measurement signal correlates with the amount of SARS-CoV-2-specific antibodies in the sera, which could be demonstrated by titer determination. In this study, a MID-based assay could be developed, giving qualitative as well as semiquantitative results of SARS-CoV-2-specific antibody levels in patient's sera within 21 min of assay time with a sensitivity of 97% and a specificity of 92%, based on the analysis of 170 sera from hospitalized patients that were tested using an Food and Drug Administration (FDA)-certified chemiluminescence assay.
ABSTRACT
COVID-19 pandemic will continue to pose a major public health threat until vaccination-mediated herd immunity is achieved. Most projections predict vaccines will reach a large subset of the population late in 2021 or early 2022. In the meantime, countries are exploring options to remove strict lockdown measures and allow society and the economy to return to normal function. One possibility is to expand on existing COVID-19 testing strategies by including large-scale rapid point-of-care diagnostic tests (POCTs). Currently, there is significant variability in performance and features of available POCTs, making selection and procurement of an appropriate test for specific use case difficult. In this review, we have used the World Health Organization's (WHO) recently published target product profiles (TPPs) for specific use cases of COVID-19 diagnostic tests to screen for top-performing POCTs on the market. Several POCTs, based on clinical sensitivity/specificity, the limit of detection, and time to results, which meet WHO TPP criteria for direct detection of SARS-CoV-2 (acute infection) or indirect diagnosis of past infection (host antibodies), are highlighted here.
ABSTRACT
Point-of-care (POC) diagnostic device is an instrument that is used to acquire particular clinical information of patients in clinical as well as resource-limited settings. The conventional clinical diagnostic procedure requires high-end and costly instruments, an expert technician for operation and result interpretation, longer time, etc. that ultimately makes it exhausting and expensive. Although there are a lot of improvements in the medical facilities in the Indian healthcare system, the use of POC diagnostic devices is still in its nascent phase. This review illustrates the status of POC diagnostic devices currently used in clinical setups along with constraints in their use. The devices and technologies that are in the research and development phase across the country that has tremendous potential to elevate the clinical diagnostics scenario along with the diagnosis of ongoing COVID-19 pandemic are emphasized. The implications of using POC diagnostic devices and the future objectives for technological advancements that may eventually uplift the status of healthcare and related sectors in India are also discussed here.