Special Issue "Microsystems for Point-of-Care Testing"

A special issue of Micromachines (ISSN 2072-666X). This special issue belongs to the section "B:Biology and Biomedicine".

Deadline for manuscript submissions: closed (31 January 2020) | Viewed by 39181

Special Issue Editor

Prof. Dr. Zulfiqur Ali
E-Mail Website
Guest Editor
School of Health, Social Care, Teesside University, Middlesbrough, Tees Valley TS1 3BX, UK
Interests: micro and nanofabrication; microfluidics; lab-on-chip; point-of-care diagnostic; pattern recognition
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Point-of-care (POC) testing offers the opportunity to move healthcare away from the symptomatic treatment of diseases towards more predictive, preventive and personalised medicine. POC testing has advantages over centralised rapid analysis laboratories with no requirement for expensive capital infrastructure or staff with specialist technical expertise. These devices are applicable in a variety of settings including within primary, secondary and tertiary care as well as within low to medium income countries (LMICs). A wide range of advances—including in assays, transducers, microfluidics, and device fabrication, connected instrumentation and data analytics—have allowed the development of a variety of applications including for chronic and infectious disease conditions. These advances are reflected in an increasing number of scientific publications, patents and commercial products that demonstrate high sensitivity, selectivity and reliability, as well as fast, accurate, cost-effective and user-friendly assays.

On this research topic, we welcome review articles and original research papers aimed at the related key issues of basic research, materials development, system integration and data management with new POC diagnostic technologies in the frame of emerging and demanding clinical and biotechnological applications.

Prof. Zulfiqur Ali
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Micromachines is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Microfluidics
  • Lab-on-a-Chip
  • Point-of-Care Diagnostics
  • Rapid Diagnostics
  • Cancer Detection
  • Infectious and Chronic Diseases
  • Connected Instrumentation
  • Data Analytics
  • Device Fabrication

Published Papers (9 papers)

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Research

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Article
Improved Enumeration of Weakly Fluorescent CD4+ T-lymphocytes by Confining Cells in a Spinning Sample Cartridge with a Helical Minichannel
Micromachines 2020, 11(6), 618; https://doi.org/10.3390/mi11060618 - 25 Jun 2020
Viewed by 911
Abstract
The CD4 (cluster of differentiation 4) counting method is used to measure the number of CD4+ T-lymphocytes per microliter of blood and to evaluate the timing of the initiation of antiretroviral therapy as well as the effectiveness of treatment in patients with human [...] Read more.
The CD4 (cluster of differentiation 4) counting method is used to measure the number of CD4+ T-lymphocytes per microliter of blood and to evaluate the timing of the initiation of antiretroviral therapy as well as the effectiveness of treatment in patients with human immunodeficiency virus. We developed a three-dimensional helical minichannel-based sample cartridge in which a thread-like microgroove formed in the cylindrical surface and configured a particle-positioning and imaging system equipped with a single DC (direct current) motor that can be controlled by a smartphone application. Confinement and enrichment of CD4 cells within a sharp focal depth along the helical minichannel is accomplished by spinning the cylindrical sample cartridge at high speed before acquiring cell images and thus CD4+ cells with weak fluorescence intensity can be detected even in a channel much deeper than existing two-dimensional flat chambers without an autofocusing module. By detecting more cells in a larger sample volume, the accuracy of the CD4 cell count is improved by a factor of 5.8 with a channel of 500 μm depth and the precision is enhanced by a factor of 1.5 with a coefficient of variation of 2.6%. Full article
(This article belongs to the Special Issue Microsystems for Point-of-Care Testing)
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Article
Impedance-Based Biosensing of Pseudomonas putida via Solution Blow Spun PLA: MWCNT Composite Nanofibers
Micromachines 2019, 10(12), 876; https://doi.org/10.3390/mi10120876 - 13 Dec 2019
Cited by 4 | Viewed by 1513
Abstract
Quantifiable sensing of common microbes in chronic wounds has the potential to enable an objective assessment of wound healing for diagnostic applications. Sensing platforms should be robust, simple, and flexible to provide clinicians with a point-of-care tool. In this work, solution blow spun [...] Read more.
Quantifiable sensing of common microbes in chronic wounds has the potential to enable an objective assessment of wound healing for diagnostic applications. Sensing platforms should be robust, simple, and flexible to provide clinicians with a point-of-care tool. In this work, solution blow spun poly (lactic acid)/multiwalled carbon nanotube nanofiber composites are used to detect the presence and concentration of Pseudomonas putida in vitro using changes in impedance. Impedance microbiology (IM) is a well-documented diagnostic technique used in many applications, including cancer detection, tuberculosis screening and pregnancy tests. Twenty-four hour real-time measurements of the equivalent circuit of three culture media were taken with an inductance, capacitance, and resistance (LCR) meter. Variations in impedance were calculated to correspond to the growth of P. putida. Additionally, instantaneous measurements of bacterial cultures were taken over a one-minute time point to display the fast sensing of bacterial load via IM. This proof-of-concept shows that conductive solution blow spun fiber mats is a valid fabrication technique to develop in situ wound dressing impedance sensors. Study results indicate successful measurement and quantification of bacterial growth in this proof-of-concept study. Full article
(This article belongs to the Special Issue Microsystems for Point-of-Care Testing)
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Article
Automated Pre-Analytic Processing of Whole Saliva Using Magnet-Beating for Point-of-Care Protein Biomarker Analysis
Micromachines 2019, 10(12), 833; https://doi.org/10.3390/mi10120833 - 30 Nov 2019
Cited by 10 | Viewed by 2258
Abstract
Saliva offers many advantages for point-of-care (PoC) diagnostic applications due to non-invasive, easy, and cost-effective methods of collection. However, the complex matrix with its non-Newtonian behavior and high viscosity poses handling challenges. Several tedious and long pre-analytic steps, incompatible with PoC use, are [...] Read more.
Saliva offers many advantages for point-of-care (PoC) diagnostic applications due to non-invasive, easy, and cost-effective methods of collection. However, the complex matrix with its non-Newtonian behavior and high viscosity poses handling challenges. Several tedious and long pre-analytic steps, incompatible with PoC use, are required to liquefy and homogenize saliva samples before protein analysis can be performed. We apply magnet-beating to reduce hands-on time and to simplify sample preparation. A magnet in a chamber containing the whole saliva is actuated inside a centrifugal microfluidic cartridge by the interplay of centrifugal and magnetic forces. Rigorous mixing, which homogenizes the saliva sample, is then initiated. Consequently, fewer manual steps are required to introduce the whole saliva into the cartridge. After 4 min of magnet-beating, the processed sample can be used for protein analysis. The viscosity of whole saliva has been reduced from 10.4 to 2.3 mPa s. Immunoassay results after magnet-beating for three salivary periodontal markers (MMP-8, MMP-9, TIMP-1) showed a linear correlation with a slope of 0.99 when compared to results of reference method treated samples. Conclusively, magnet-beating has been shown to be a suitable method for the pre-analytic processing of whole saliva for fully automated PoC protein analysis. Full article
(This article belongs to the Special Issue Microsystems for Point-of-Care Testing)
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Article
Fast and Parallel Detection of Four Ebola Virus Species on a Microfluidic-Chip-Based Portable Reverse Transcription Loop-Mediated Isothermal Amplification System
Micromachines 2019, 10(11), 777; https://doi.org/10.3390/mi10110777 - 14 Nov 2019
Cited by 12 | Viewed by 1604
Abstract
Considering the lack of official vaccines and medicines for Ebola virus infection, reliable diagnostic methods are necessary for the control of the outbreak and the spread of the disease. We developed a microfluidic-chip-based portable system for fast and parallel detection of four Ebola [...] Read more.
Considering the lack of official vaccines and medicines for Ebola virus infection, reliable diagnostic methods are necessary for the control of the outbreak and the spread of the disease. We developed a microfluidic-chip-based portable system for fast and parallel detection of four Ebola virus species. The system is based on reverse transcription loop-mediated isothermal amplification (RT-LAMP) and consists of four specific LAMP primers, a disc microfluidic chip, and a portable real-time fluorescence detector. It could specifically and parallelly distinguish four species of the Ebola virus after only one sampling, including the Zaire Ebola virus, the Sudan Ebola virus, the Bundibugyo Ebola virus, and the Tai Forest Ebola virus, without cross-contamination. The limit of detection was as small as 10 copies per reaction, while the total consumption of sample and reagent was 0.94 μL per reaction. The final results could be obtained in 50 min after one addition of sample and reagent mixture. This approach provides simplicity, high sensitivity, and multi-target parallel detection at a low cost, which could enable convenient and effective on-site detections of the Ebola virus in the outdoors, remote areas, and modern hospitals. Full article
(This article belongs to the Special Issue Microsystems for Point-of-Care Testing)
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Review

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Review
Quantum Dots: An Emerging Tool for Point-of-Care Testing
Micromachines 2020, 11(12), 1058; https://doi.org/10.3390/mi11121058 - 29 Nov 2020
Cited by 7 | Viewed by 1379
Abstract
Quantum dots (QDs) are semiconductor crystals in the nanodimension having unique optical and electronic properties that differ from bulk material due to quantum mechanics. The QDs have a narrow emission peak, size-dependent emission wavelength, and broad excitation range which can be utilized for [...] Read more.
Quantum dots (QDs) are semiconductor crystals in the nanodimension having unique optical and electronic properties that differ from bulk material due to quantum mechanics. The QDs have a narrow emission peak, size-dependent emission wavelength, and broad excitation range which can be utilized for diverse biomedical applications such as molecular imaging, biosensing, and diagnostic systems. This article reviews the current developments of biomedical applications of QDs with special reference to point-of-care testing. Full article
(This article belongs to the Special Issue Microsystems for Point-of-Care Testing)
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Review
Biomarkers for Point-of-Care Diagnosis of Sepsis
Micromachines 2020, 11(3), 286; https://doi.org/10.3390/mi11030286 - 10 Mar 2020
Cited by 26 | Viewed by 3340
Abstract
Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection. In 2017, almost 50 million cases of sepsis were recorded worldwide and 11 million sepsis-related deaths were reported. Therefore, sepsis is the focus of intense research to [...] Read more.
Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to infection. In 2017, almost 50 million cases of sepsis were recorded worldwide and 11 million sepsis-related deaths were reported. Therefore, sepsis is the focus of intense research to better understand the complexities of sepsis response, particularly the twin underlying concepts of an initial hyper-immune response and a counter-immunological state of immunosuppression triggered by an invading pathogen. Diagnosis of sepsis remains a significant challenge. Prompt diagnosis is essential so that treatment can be instigated as early as possible to ensure the best outcome, as delay in treatment is associated with higher mortality. In order to address this diagnostic problem, use of a panel of biomarkers has been proposed as, due to the complexity of the sepsis response, no single marker is sufficient. This review provides background on the current understanding of sepsis in terms of its epidemiology, the evolution of the definition of sepsis, pathobiology and diagnosis and management. Candidate biomarkers of interest and how current and developing point-of-care testing approaches could be used to measure such biomarkers is discussed. Full article
(This article belongs to the Special Issue Microsystems for Point-of-Care Testing)
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Other

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Opinion
2019 Novel Coronavirus Disease (COVID-19): Paving the Road for Rapid Detection and Point-of-Care Diagnostics
Micromachines 2020, 11(3), 306; https://doi.org/10.3390/mi11030306 - 14 Mar 2020
Cited by 162 | Viewed by 23143
Abstract
We believe a point-of-care (PoC) device for the rapid detection of the 2019 novel Coronavirus (SARS-CoV-2) is crucial and urgently needed. With this perspective, we give suggestions regarding a potential candidate for the rapid detection of the coronavirus disease 2019 (COVID-19), as well [...] Read more.
We believe a point-of-care (PoC) device for the rapid detection of the 2019 novel Coronavirus (SARS-CoV-2) is crucial and urgently needed. With this perspective, we give suggestions regarding a potential candidate for the rapid detection of the coronavirus disease 2019 (COVID-19), as well as factors for the preparedness and response to the outbreak of the COVID-19. Full article
(This article belongs to the Special Issue Microsystems for Point-of-Care Testing)
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Opinion
How to Ease the Pain of Taking a Diagnostic Point of Care Test to the Market: A Framework for Evidence Development
Micromachines 2020, 11(3), 291; https://doi.org/10.3390/mi11030291 - 10 Mar 2020
Cited by 11 | Viewed by 2935
Abstract
Bringing a diagnostic point of care test (POCT) to a healthcare market can be a painful experience as it requires the manufacturer to meet considerable technical, financial, managerial, and regulatory challenges. In this opinion article we propose a framework for developing the evidence [...] Read more.
Bringing a diagnostic point of care test (POCT) to a healthcare market can be a painful experience as it requires the manufacturer to meet considerable technical, financial, managerial, and regulatory challenges. In this opinion article we propose a framework for developing the evidence needed to support product development, marketing, and adoption. We discuss each step in the evidence development pathway from the invention phase to the implementation of a new POCT in the healthcare system. We highlight the importance of articulating the value propositions and documenting the care pathway. We provide guidance on how to conduct care pathway analysis as little has been published on this. We summarize the clinical, economic and qualitative studies to be considered for developing evidence, and provide useful links to relevant software, on-line applications, websites, and give practical advice. We also provide advice on patient and public involvement and engagement (PPIE), and on product management. Our aim is to help device manufacturers to understand the concepts and terminology used in evaluation of in vitro diagnostics (IVDs) so that they can communicate effectively with evaluation methodologists, statisticians, and health economists. Manufacturers of medical tests and devices can use the proposed framework to plan their evidence development strategy in alignment with device development, applications for regulatory approval, and publication. Full article
(This article belongs to the Special Issue Microsystems for Point-of-Care Testing)
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Concept Paper
Efficient Development of Integrated Lab-On-A-Chip Systems Featuring Operational Robustness and Manufacturability
Micromachines 2019, 10(12), 886; https://doi.org/10.3390/mi10120886 - 17 Dec 2019
Cited by 15 | Viewed by 1435
Abstract
The majority of commercially oriented microfluidic technologies provide novel point-of-use solutions for laboratory automation with important areas in the context of the life sciences such as health care, biopharma, veterinary medicine and agrifood as well as for monitoring of the environment, infrastructures and [...] Read more.
The majority of commercially oriented microfluidic technologies provide novel point-of-use solutions for laboratory automation with important areas in the context of the life sciences such as health care, biopharma, veterinary medicine and agrifood as well as for monitoring of the environment, infrastructures and industrial processes. Such systems are often composed of a modular setup exhibiting an instrument accommodating rather conventional actuation, detection and control units which interfaces with a fluidically integrated “Lab-on-a-Chip” device handling (bio-)sample(s) and reagents. As the complex network of tiny channels, chambers and surface-functionalised zones can typically not be properly cleaned and regenerated, these microfluidic chips are mostly devised as single-use disposables. The availability of cost-efficient materials and associated structuring, functionalisation and assembly schemes thus represents a key ingredient along the commercialisation pipeline and will be a first focus of this work. Furthermore, and owing to their innate variability, investigations on biosamples mostly require the acquisition of statistically relevant datasets. Consequently, intermediate numbers of consistently performing chips are already needed during application development; to mitigate the potential pitfalls of technology migration and to facilitate regulatory compliance of the end products, manufacture of such pilot series should widely follow larger-scale production schemes. To expedite and de-risk the development of commercially relevant microfluidic systems towards high Technology Readiness Levels (TRLs), we illustrate a streamlined, manufacturing-centric platform approach employing the paradigms of tolerance-forgiving Design-for-Manufacture (DfM) and Readiness for Scale-up (RfS) from prototyping to intermediate pilot series and eventual mass fabrication. Learning from mature industries, we further propose pursuing a platform approach incorporating aspects of standardisation in terms of specification, design rules and testing methods for materials, components, interfaces, and operational procedures; this coherent strategy will foster the emergence of dedicated commercial supply chains and also improve the economic viability of Lab-on-a-Chip systems often targeting smaller niche markets by synergistically bundling technology development. Full article
(This article belongs to the Special Issue Microsystems for Point-of-Care Testing)
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