Point-of-care Testing Technology Research Articles

A smartphone-based diagnostic analyzer for point-of-care milk somatic cell counting

BackgroundMastitis, a pervasive and detrimental disease in dairy farming, poses a significant challenge to the global dairy industry. Monitoring the milk somatic cell count (SCC) is vital for assessing the incidence of mastitis and the quality of raw cow's milk. However, existing SCC detection methods typically require large-scale instruments and specialized operators, limiting their application in resource-constrained settings such as dairy farms and small-scale labs. To address these limitations, this study introduces a novel, smartphone-based, on-site SCC testing method that leverages smartphone capabilities for milk somatic cell identification and enumeration, offering a portable and user-friendly testing platform. ResultsThe central findings of our study demonstrate the effectiveness of the proposed method for counting milk somatic cells. Its on-site applicability, facilitated by the microfluidic chip, optical system, and smartphone integration, heralds a paradigm shift in point-of-care testing (POCT) for dairy farms and smaller laboratories. This approach bypasses complex processing and presents a user-friendly solution for real-time SCC monitoring in resource-limited settings. This device boasts several unique features: small size, low cost (<$1,000 total manufacturing cost and <$1 per test), and high accuracy. Remarkably, it delivers test results within just 2 min. Actual-sample testing confirmed its consistency with results from the commercial Bentley FTS/FCM cytometer, affirming the reliability of the proposed method. Overall, these results underscore the potential for transformative change in dairy farm management and laboratory testing practices. SignificanceIn summary, this study concludes that the proposed smartphone-based method significantly contributes to the accessibility and ease of SCC testing in resource-limited environments. By fostering the use of POCT technology in food safety control, particularly in the dairy industry, this innovative approach has the potential to revolutionize the monitoring and management of mastitis, ultimately benefiting the global dairy sector.

Recent Advances in Acoustofluidics for Point-of-Care Testing.

Point-of-care testing (POCT) has played important role in clinical diagnostics, environmental assessment, chemical and biological analyses, and food and chemical processing due to its faster turnaround compared to laboratory testing. Dedicated manipulations of solutions or particles are generally required to develop POCT technologies that achieve a "sample-in-answer-out" operation. With the development of micro- and nanotechnology, many tools have been developed for sample preparation, on-site analysis and solution manipulations (mixing, pumping, valving, etc.). Among these approaches, the use of acoustic waves to manipulate fluids and particles (named acoustofluidics) has been applied in many researches. This review focuses on the recent developments in acoustofluidics for POCT. It starts with the fundamentals of different acoustic manipulation techniques and then lists some of representative examples to highlight each method in practical POC applications. Looking toward the future, a compact, portable, highly integrated, low power, and biocompatible technique is anticipated to simultaneously achieve precise manipulation of small targets and multimodal manipulation in POC applications.

Nucleic acid based point-of-care diagnostic technology for infectious disease detection using machine learning empowered smartphone-interfaced quantitative colorimetry

We report a nucleic acid-based point of care testing technology for infectious disease detection at resource limited settings by integrating a low-cost portable device with machine learning-empowered quantitative colorimetric analytics that can be interfaced via a smartphone application. We substantiate our proposition by demonstrating the efficacy of this technology in detecting COVID-19 infection from human swab samples, using the RT-LAMP protocol. Comparison with gold standard results from real-time PCR evidences high sensitivity and specificity, ensuring simplicity, portability, and user-friendliness of the technology at the same time. Colorimetric analytics of the reaction output without necessitating the opening of the reaction microchambers enables execution of the complete test workflow without any laboratory control that may otherwise be required stringently for safeguarding against carryover contamination. Seamless sample-to-answer workflow and machine learning-based readout further assures minimal human intervention for the test readout, thus eliminating inevitable inaccuracies stemming from erroneous execution of the test as well as subjectivity in interpreting the outcome. Our results further indicate the possibilities of upgrading the technology to predict the pathogenic load on the infected patients akin to the cyclic threshold value of the real-time PCR, when calibrated with reference to a wide range of ‘training’ data for the machine learner, thereby putting forward the same as viable alternative to the resource-intensive PCR tests that cannot be made readily accessible at underserved community settings.

Community pharmacist‐provided test and treat programs for acute infectious conditions

AbstractCommunity pharmacists' roles have expanded in recent years to include offering test and treat programs where they perform testing on Clinical Laboratory Improvement Amendment (CLIA)‐waived point‐of‐care testing (POCT) devices to diagnose specific acute infectious conditions, such as influenza and group A streptococcus (GAS) pharyngitis, and then potentially prescribe and dispense appropriate antimicrobials. Availability of these services in pharmacies has several benefits, including increased access to care, decreased overutilization of other health care services, and decreased antimicrobial resistance. States have different requirements for collaborative practice agreements and reimbursement for these clinical services in community pharmacies. Several studies have looked at outcomes related to community pharmacies implementing test and treat programs for influenza and/or GAS. Other studies looked at outcomes related to implementing testing for SARS‐CoV‐2 and referring for treatment. Most studies described successful implementation and barriers to integration of these programs into pharmacy workflow. Some studies showed that patients want these services to be offered in community pharmacies and are willing to pay for the services. Data show that these services are cost effective compared to physician provider‐based treatment. Newer CLIA‐waived POCT technology may increase implementation of these services, but studies are needed to evaluate their utility in community pharmacies. Pharmacy schools should implement widespread training on these devices, and research should continue in this area to test the use of newer technology (i.e., multiplexed devices) and their economic impact.

The application of nanoparticles in point-of-care testing (POCT) immunoassays.

The Covid-19 pandemic has led to greater recognition of the importance of the fast and timely detection of pathogens. Recent advances in point-of-care testing (POCT) technology have shown promising results for rapid diagnosis. Immunoassays are among the most extensive POCT assays, in which specific labels are used to indicate and amplify the immune signal. Nanoparticles (NPs) are above the rest because of their versatile properties. Much work has been devoted to NPs to find more efficient immunoassays. Herein, we comprehensively describe NP-based immunoassays with a focus on particle species and their specific applications. This review describes immunoassays along with key concepts surrounding their preparation and bioconjugation to show their defining role in immunosensors. The specific mechanisms, microfluidic immunoassays, electrochemical immunoassays (ELCAs), immunochromatographic assays (ICAs), enzyme-linked immunosorbent assays (ELISA), and microarrays are covered herein. For each mechanism, a working explanation of the appropriate background theory and formalism is articulated before examining the biosensing and related point-of-care (POC) utility. Given their maturity, some specific applications using different nanomaterials are discussed in more detail. Finally, we outline future challenges and perspectives to give a brief guideline for the development of appropriate platforms.

Artificial intelligence reinforced upconversion nanoparticle-based lateral flow assay via transfer learning

The combination of upconverting nanoparticles (UCNPs) and immunochromatography has become a widely used and promising new detection technique for point-of-care testing (POCT). However, their low luminescence efficiency, non-specific adsorption, and image noise have always limited their progress toward practical applications. Recently, artificial intelligence (AI) has demonstrated powerful representational learning and generalization capabilities in computer vision. We report for the first time a combination of AI and upconversion nanoparticle-based lateral flow assays (UCNP-LFAs) for the quantitative detection of commercial internet of things (IoT) devices. This universal UCNPs quantitative detection strategy combines high accuracy, sensitivity, and applicability in the field detection environment. By using transfer learning to train AI models in a small self-built database, we not only significantly improved the accuracy and robustness of quantitative detection, but also efficiently solved the actual problems of data scarcity and low computing power of POCT equipment. Then, the trained AI model was deployed in IoT devices, whereby the detection process does not require detailed data preprocessing to achieve real-time inference of quantitative results. We validated the quantitative detection of two detectors using eight transfer learning models on a small dataset. The AI quickly provided ultra-high accuracy prediction results (some models could reach 100% accuracy) even when strong noise was added. Simultaneously, the high flexibility of this strategy promises to be a general quantitative detection method for optical biosensors. We believe that this strategy and device have a scientific significance in revolutionizing the existing POCT technology landscape and providing excellent commercial value in the in vitro diagnostics (IVD) industry.

Individual versus collective strategies in system building - The case of point-of-care diagnostics in Germany

• This paper analyses how large companies and SMEs choose between individual and collective system building activities and how it impacts the development and diffusion of point-of-care diagnostics technology in Germany. Innovative entrepreneurs often need to engage in different system building activities in order to overcome the barriers to successful market introduction of an innovative technology. There is a large body of literature on individual system building strategies by single actors, as well as on the collective nature of system building by different actors. Yet, only limited research has been done into what type of system building activities innovative entrepreneurs undertake individually or collectively, how it depends on their size and resources, and what the trade-off between these different strategies is. This paper shows how firms', choice between individual and collective strategies depends on the availability of resources and the type of system building activity in the point-of-care testing (POCT) sector in Germany. Furthermore, we highlight the role of hospitals as end-user, whose specific needs influence the collaboration strategies of entrepreneurs along the whole value chain of POCT technology development.

Understanding Healthcare Professionals' Perspectives on Point-of-Care Testing.

Point-of-care testing (POCT) is an emerging technology that provides crucial assistance in delivering healthcare. The COVID-19 pandemic led to the accelerated importance of POCT technology due to its in-home accessibility. While POCT use and implementation has increased, little research has been published about how healthcare professionals perceive these technologies. The objective of our study was to examine the current perspectives of healthcare professionals towards POCT. We surveyed healthcare professionals to quantify perceptions of POCT usage, adoption, benefits, and concerns between October 2020 and November 2020. Questions regarding POCT perception were assessed on a 5-point Likert Scale. We received a total of 287 survey responses. Of the respondents, 53.7% were male, 66.6% were white, and 30.7% have been in practice for over 20 years. We found that the most supported benefit was POCTs ability to improve patient management (92%) and that the most supported concern was that POCTs lead to over-testing (30%). This study provides a better understanding of healthcare workers’ perspectives on POCT. To improve patient outcomes through the usage of POCT, greater research is needed to assess the needs and concerns of industry and healthcare stakeholders.

Microfluidic technology and its application in the point-of-care testing field

Since the outbreak of the coronavirus disease 2019 (COVID-19), countries around the world have suffered heavy losses of life and property. The global pandemic poses a challenge to the global public health system, and public health organizations around the world are actively looking for ways to quickly and efficiently screen for viruses. Point-of-care testing (POCT), as a fast, portable, and instant detection method, is of great significance in infectious disease detection, disease screening, pre-disease prevention, postoperative treatment, and other fields. Microfluidic technology is a comprehensive technology that involves various interdisciplinary disciplines. It is also known as a lab-on-a-chip (LOC), and can concentrate biological and chemical experiments in traditional laboratories on a chip of several square centimeters with high integration. Therefore, microfluidic devices have become the primary implementation platform of POCT technology. POCT devices based on microfluidic technology combine the advantages of both POCT and microfluids, and are expected to shine in the biomedical field. This review introduces microfluidic technology and its applications in combination with other technologies.

Instant Preparation of Ultraclean Gold Nanothorns under Ambient Conditions for SERS Kit-Enabled Mobile Diagnosis.

Availability of surface-enhanced Raman scattering (SERS) substrates with good stability, high sensitivity, and a clean surface is crucial for the practical usefulness of the SERS technology in biochemical sensing, especially for point-of-care testing (POCT). Hereby, we develop a "ready-to-use" SERS kit, which requires only 20 s to fabricate ultraclean gold nanothorn (AuNT)-based SERS chips under ambient conditions with simple solution processing steps. By varying the thickness of the pre-coated platinum (Pt) nanolayer, we can control the size and number density of the grown AuNT. Taking advantage of the ultraclean surface of the instantly obtained fresh AuNT, Raman reporter molecules can also be immediately modified, by means of which specific detection of three analytes including H2O2, NO2-, and ClO- is realized. Furthermore, we propose the concept of an SERS kit and apply it to smartphone-based Raman analysis for POCT applications. This on-site preparation method solves the long-standing challenges hindering the practical use of SERS substrates, such as complicated fabrication processes, interference of residual surfactants, poor surface stability, and easy contamination. Besides performing SERS analysis conveniently and quickly, this SERS kit-enabled POCT technology can integrate remote data terminals and medical resources, which shows great potential for environmental protection or online-healthcare systems.

Scaling up sexually transmissible infections point-of-care testing in remote Aboriginal and Torres Strait Islander communities: healthcare workers\u2019 perceptions of the barriers and facilitators

BackgroundSexually transmissible infections (STIs), such as gonorrhoea and chlamydia, are highly prevalent, particularly in remote Aboriginal and Torres Strait Islander communities in Australia. In these settings, due to distance to centralised laboratories, the return of laboratory test results can take a week or longer, and many young people do not receive treatment, or it is considerably delayed. Point-of-care testing (POCT) provides an opportunity for same day diagnosis and treatment. Molecular POC testing for STIs was available at 31 regional or remote primary health care clinic sites through the Test-Treat-And-GO (TANGO2) program. This qualitative study sought to identify barriers and facilitators to further scaling up STI POCT in remote Aboriginal communities within Australia.MethodsA total of 15 healthcare workers (including nurses and Aboriginal health practitioners) and five managers (including clinic coordinators and practice managers) were recruited from remote health services involved in the TTANGO2 program to participate in semi-structured in-depth interviews. Health services’ clinics were purposively selected to include those with high or low STI POCT uptake. Personnel participants were selected via a hybrid approach including nomination by clinic managers and purposive sampling to include those in roles relevant to STI testing and treatment and those who had received TTANGO2 training for POCT technology. Milat’s scaling up guide informed the coding framework and analysis.ResultsAcceptability of STI POCT technology among healthcare workers and managers was predominantly influenced by self-efficacy and perceived effectiveness of POCT technology as well as perceptions of additional workload burden associated with POCT. Barriers to integration of STI POCT included retention of trained staff to conduct POCT. Patient reach (including strategies for patient engagement) was broadly considered an enabler for STI testing scale up using POCT technology.ConclusionsRemote healthcare clinics should be supported by both program and clinic management throughout scaling up efforts to ensure broad acceptability of STI POCT as well as addressing local health systems’ issues and identifying and enhancing opportunities for patient engagement.

Application of Lab-on-Chip for Detection of Microbial Nucleic Acid in Food and Environment.

Various diseases caused by food-borne or environmental pathogenic microorganisms have been a persistent threat to public health and global economies. It is necessary to regularly detect microorganisms in food and environment to prevent infection of pathogenic microorganisms. However, most traditional detection methods are expensive, time-consuming, and unfeasible in practice in the absence of sophisticated instruments and trained operators. Point-of-care testing (POCT) can be used to detect microorganisms rapidly on site and greatly improve the efficiency of microbial detection. Lab-on-chip (LOC) is an emerging POCT technology with great potential by integrating most of the experimental steps carried out in the laboratory into a single monolithic device. This review will primarily focus on principles and techniques of LOC for detection of microbial nucleic acid in food and environment, including sample preparation, nucleic acid amplification and sample detection.

After Theranos: Using point-of-care testing to advance measures of health biomarkers in human biology research.

The rise and fall of the health technology startup Theranos is emblematic of the promise and peril of point-of-care testing (POCT). Instruments that deliver immediate results from minimally invasive samples at the location of collection can provide powerful tools to deliver health data in clinical and public health contexts. Yet, POCT availability is driven largely by market interests, which limits the development of inexpensive tests for diverse health conditions that can be used in resource-limited settings. These constraints, combined with complex regulatory hurdles and substantial ethical challenges, have contributed to the underutilization of POCT in human biology research. We evaluate current POCT capabilities and limitations, discuss promising applications for POCT devices in resource-limited settings, and discuss the future of POCT. As evidenced by publication trends, POCT platforms have rapidly advanced in recent years, gaining traction among clinicians and health researchers. We highlight POCT devices of potential interest to population-based researchers and present specific examples of POCT applications in human biology research. Several barriers can limit POCT applications, including cost, lack of regulatory approval for non-clinical use, requirements for expensive equipment, and the dearth of validation in remote field conditions. Despite these issues, we see immense potential for emerging POCT technology capable of analyzing new sample types and used in conjunction with increasingly common technology (e.g., smart phones). We argue that the fallout from Theranos may ultimately provide an opportunity to advance POCT, leading to more ethical data collection and novel opportunities in human biology research.

1654. Evaluation of a rapid detection method of clarithromycin resistance genes in Mycobacterium avium using the Amplification Refractory Mutation System-Loop-Mediated Isothermal Amplification method

BackgroundClarithromycin (CLR) is the key drug in multidrug therapy for Mycobacterium avium complex (MAC) diseases and the only drug for which drug susceptibility is correlated with a clinical response in these diseases. In the case of CLR-resistant MAC, a point mutation is present at either position 2058 or 2059 of the peptidyl transferase active center in the domain V region of 23S rRNA at the macrolide binding site. Using conventional investigation, we clarified the correlation between drug susceptibility testing and mutation of drug resistance genes. In this study, we adapted a rapid detection method using the amplification refractory mutation system (ARMS)-loop-mediated isothermal amplification (LAMP) to identify a mutation in the 23S rRNA gene in M. avium isolates (Figure 1). Furthermore, we evaluated the usefulness as point-of-care testing (POCT) technology using clinical isolates.Figure 1. The designs of CLR resistance A2058G mutant-type mismatch primers used for the ARMS-LAMP assay. a) A strand-displacing DNA polymerase extends the DNA from FIP while separating from the DNA chain. The primer F3 binds to its complementary region on the DNA to displace the newly synthesized DNA. An analogous reaction is performed by BIP and B3. α (α = A, wild type; G, A2058G) and β (β = A, wild type; C, A2058G) are indicated by the point mutation at position 2058 of the 23S rRNA gene. The bold area indicates the mismatched base C (cytosine). b) The synthesized DNA self-anneals because of the complementary region at both ends and forms ‘dumbbell’ structures. c) After repeated rounds, a complementary region on the same chain is amplified. MethodsPrimers for ARMS-LAMP were designed using PrimerExplorerV5 software based on the nucleotide sequence data for 23S rRNA in M. avium strain 104 (Figure 2). Using the minimum inhibitory concentration of CLR, drug susceptibility was determined for 18 clinical M. avium isolates. Of these, eight CLR-susceptible and 10 CLR-resistant strains were analyzed by sequencing the 23S rRNA gene and ARMS-LAMP.Figure 2. Alignment of the nucleotide sequences including the domain V region of 23S rRNA at the macrolide binding site. The constructed LAMP primer sets are shown in solid boxes (forward primers, F1-3) and dashed boxes (backward primers, B1-3). The bold area indicates the point mutation at position 2058 or 2059 of the 23S rRNA gene. ResultsSequence analysis revealed that all eight CLR-sensitive strains tested were wild type, whereas all 10 CLR-resistant strains were mutants. Using ARMS-LAMP, no amplification with the mutant-type mismatch primer sets (MTPS) was observed in the eight wild-type strains, but amplification was observed with MTPS in the 10 mutant strains (Table 1).Table 1. MICs of CLR and results of ARMS–LAMP using Mycobacterium avium isolates. ConclusionThe developed rapid detection method for the CLR resistance gene using ARMS-LAMP can determine drug resistance in a few hours without the need for special equipment. ARMS-LAMP may be a new clinically beneficial POCT technology for examination that is novel and extremely practical.Disclosures All Authors: No reported disclosures

Point-of-Care Testing for D-Dimer in the Diagnosis of Venous Thromboembolism in Primary Care: A Narrative Review.

Venous thromboembolism (VTE) is regarded as a significant cause of mortality and disability, affecting 1–2 per 1000 people annually, presenting with a relatively wide range of symptoms, which can pose a diagnostic challenge. Historically, people in whom VTE is suspected will have been taken to hospital for diagnosis and treatment; however, a high proportion of patients are found not to have VTE. Concerns have been expressed about potential delays in treatment, with the risk of additional morbidity and disability, and death. Diagnostic strategies are typically based on the use of a clinical prediction rule to determine the pre-test probability, complemented with a measurement of D-dimer, with confirmation by imaging assessment. This narrative review explores the literature on the use of point-of-care testing (POCT) for the measurement of D-dimer, as part of a clinical decision rule, for the diagnosis of deep vein thrombosis (DVT) and pulmonary embolism (PE) in the primary care setting. In the two main prospective management (validation) studies that included D-dimer POCT or similar technologies, with a total cohort of 1600 participants, DVT was ruled out in 49% of patients, with a false negative rate of 1.4%, whereas PE was ruled out in 45% of patients, with a false negative rate of 1.5%. This suggests that uptake of POCT D-dimer in primary care has the potential to reduce the number of referrals to hospitals for imaging confirmatory investigation, with consequent cost savings. Thus, adopting POCT for D-dimer in primary care can offer clinical and cost benefits, particularly when quantitative POCT assays are being used. Furthermore, POCT should be undertaken in collaboration with the local laboratories to ensure the harmonisation of D-dimer methods and quality assurance to improve the diagnosis of VTE.

Recent Trends in Nanomaterial-Based Biosensors for Point-of-Care Testing.

In recent years, nanomaterials of different shape, size, and composition have been prepared and characterized, such as gold and silver nanoparticles, quantum dots, mesoporous silica nanoparticles, carbon nanomaterials, and hybrid nanocomposites. Because of their unique physical and chemical properties, these nanomaterials are increasingly used in point-of-care testing (POCT) to improve analytical performance and simplify detection process. They are used either as carriers for immobilizing biorecognition elements, or as labels for signal generation, transduction and amplification. In this commentary, we highlight recent POCT technologies that employ nanotechnology for the analysis of disease biomarkers, including small-molecule metabolites, enzymes, proteins, nucleic acids, cancer cells, and pathogens. Recent advances in lateral flow tests, printable electrochemical biosensors, and microfluidics-based devices are summarized. Existing challenges and future directions are also discussed.

Current Status of Clinical Application of Point-of-Care Testing.

The clinical applications of point-of-care testing (POCT) are gradually increasing in many health care systems. Recently, POCT devices using molecular genetic method techniques have been developed. We need to examine clinical pathways to see where POCT can be applied to improve them. To introduce up-to-date POCT items and equipment and to provide the content that should be prepared for clinical application of POCT. Literature review based on PubMed searches containing the terms point-of-care testing, clinical chemistry, diagnostic hematology, and clinical microbiology. If medical resources are limited, POCT can help clinicians make quick medical decisions. As POCT technology improves and menus expand, areas where POCT can be applied will also increase. We need to understand the limitations of POCT so that it can be optimally used to improve patient management.

Application of paper-based microfluidics in point-of-care testing

Point-of-care testing (POCT) is a test method performed on the sampling site or patient bedside. Accurate results can be achieved rapidly by the application of portable analytical instruments and compatible reagents. It has been widely used in the field of in vitro diagnosis (IVD). Paper-based microfluidics technology has great potential in developing POCT due to its advantages in low cost, simple operation, rapid detection, portable equipment, and unrestricted application conditions. In recent years, the development of paper-based microfluidic technology and its integration with various new technologies and methods have promoted the substantial development of POCT technology and methods. The classification and characteristic of the paper are summarized in this review. Paper-based microfluidic sample pretreatment methods, the flow control in the process of reaction and the signal detecting and analyzing methods for the testing results are introduced. The research progress of various kinds of microfluidic paper-based analytical devices (μPADs) toward POCT in recent years is reviewed. Finally, remaining problems and the future prospects in POCT application of paper-based microfluidics are discussed.

Hand-powered centrifugal microfluidic disc with magnetic chitosan bead-based ELISA for antibody quantitation

Extreme point-of-care testing (POCT) is a medical test performed at or near patients at a resource-limited condition. POCT technology has advantages over traditional medical lab tests for molecular detection and infection diagnosis, such as being simple, portable, low-cost, and user-friendly. However, some POCT devices might rely on bulky equipment, and some might be easily influenced by components in biofluid, which might result in higher prices and lower accuracy. In this paper, we demonstrated a low-cost method for detecting bacterial infection in the early stage. We designed a hand-powered centrifugal microfluidic (CMF) disc with magnetic chitosan beads (MCBs) to detect specific circulating antibodies in human whole blood. Nine identical units was used for calibration curve plotting and sample testing. The MCBs, generated with another microfluidic chip and coated with MBL proteins (biomarker of drug-resistant Streptococcus pneumoniae, DRSP, taken as an example for bacterial infection), were served as the substrate of sandwich-structured enzyme-linked immunosorbent assays (ELISA) and as the micro stirring sphere at the same time. The limit of detection (LOD) in PBS and human whole blood were 22.67 ng/mL and 24.83 ng/mL, respectively. The comparison between calibration curves from the antibody spiked in human whole blood and that in PBS was shown to prove the high compatibility and low interference of biofluid, and the recovery rate was 92 %. In conclusion, since our low-cost, time-saving, and user-friendly hand-powered CMF device with minimally consumed electricity detected the target antibody precisely, we believe that other similar assays would be feasible as well. Therefore, we are firmly convinced that this alternative POCT device may lead to the development of next-generation healthcare diagnoses.

Fluorescent microbeads for point-of-care testing: a review.

Microbead-based point-of-care testing (POCT) has demonstrated great promise in translating detection modalities from bench-side to bed-side. This is due to the ease of visualization, high surface area-to-volume ratio of beads for efficient target binding, andefficient encoding capability for simultaneous detection of multiple analytes. This review (with 112 references) summarizes the progress made in the field of fluorescent microbead-based POCT. Following an introduction into the field, a first large section sums up techniques and materials for preparing microbeads, typically of dye-labelled particles, various kinds of quantum dots and upconversion materials. Further subsections cover the encapsulation of nanoparticles into microbeads, decoration of nanoparticles on microbeads, and in situ embedding of nanoparticles during microbead synthesis. A next large section summarizes microbead-based fluorometric POCT, with subsections on detection of nucleic acids, proteins, circulating tumor cells and bacteria. A further section covers emerging POCT based on the use of smartphones or flexible microchips. The last section gives conclusions and an outlook on current challenges and possible solutions. Aside from giving an overview on the state of the art, we expect this article to boost the further development of POCT technology. Graphical Abstract Schematic presentation of the fabrication of microbeads, the detection targets of interest including bacteria, circulating tumor cells (CTCs), protein and nucleic acid, and the emerging point-of-care testing (POCT) platform. The colored wheels of the bus represent the fluorescent materials embedded in (red color) or decorated on the surface of microbeads (green color).