Point-of-care Testing Platform Research Articles

Quantitative assessment of disease markers using the naked eye: point-of-care testing with gas generation-based biosensor immunochromatographic strips

BackgroundImmunochromatographic strips (ICSs) are a practical tool commonly used in point-of-care testing (POCT) applications. However, ICSs that are currently available have low sensitivity and require expensive equipment for quantitative analysis. These limitations prohibit their extensive use in areas where medical resources are scarce.MethodsWe developed a novel POCT platform by integrating a gas generation biosensor with Au@Pt Core/Shell nanoparticle (Au@PtNPs)-based ICSs (G-ICSs). The resulting G-ICSs enabled the convenient and quantitative assessment of a target protein using the naked eye, without the need for auxiliary equipment or complicated computation. To assess this platform, C-reactive protein (CRP), a biomarker commonly used for the diagnosis of acute, infectious diseases was chosen as a proof-of-concept test.ResultsThe linear detection range (LDR) of the G-ICSs for CRP was 0.05–6.25 μg/L with a limit of detection (LOD) of 0.041 μg/L. The G-ICSs had higher sensitivity and wider LDR when compared with commonly used AuNPs and fluorescent-based ICSs. When compared with results from a chemiluminescent immunoassay, G-ICS concordance rates for CRP detection in serum samples ranged from 93.72 to 110.99%.ConclusionsThese results demonstrated that G-ICSs have wide applicability in family diagnosis and community medical institutions, especially in areas with poor medical resources.

Highly Sensitive Lab on a Chip (LOC) Immunoassay for Early Diagnosis of Respiratory Disease Caused by Respirable Crystalline Silica (RCS).

Respirable crystalline silica (RCS) produced in mining and construction industries can cause life-threatening diseases such as silicosis, lung cancer, and chronic obstructive pulmonary disease (COPD). These diseases could be more effectively treated and prevented if RCS-related biomarkers were identified and measured at an early stage of disease progression, which makes development of a point of care test (POCT) platform extremely desirable for early diagnosis. In this work, a new, highly sensitive lab on a chip (LOC) immunoassay has been designed, developed, and characterized for tumor necrosis factor α (TNF-α), a protein biomarker that causes lung inflammation due to RCS exposure. The designed LOC device is composed of four reservoirs for sample, enzyme conjugated detection antibody, wash buffer, and chemiluminescence substrate in liquid form, along with three spiral reaction chambers for test, positive control, and negative control. All reservoirs and spiral microchannels were connected in series and designed to perform sequential delivery of immunoassay reagents with minimal user intervention. The developed LOC measured TNF-α concentrations as low as 16 pg/mL in plasma from RCS-exposed rats and also had a limit of detection (LOD) of 0.5 pg/mL in spiked artificial serum. In addition, the analysis time was drastically reduced to about 30 min, as opposed to hours in conventional methods. Successful implementation of a highly sensitive, chemiluminescence-based immunoassay on a preloaded LOC with proper quality control, as reported in this work, can pave the way toward developing a new rapid POCT platform for in-field clinical diagnosis.

Development of a "Dual Gates" Locked, Target-Triggered Nanodevice for Point-of-Care Testing with a Glucometer Readout.

Developing a facile and sensitive sensing platform is of importance for point-of-care testing (POCT). Herein, a sensitive and portable POCT platform based on "dual gates" aminated magnetic mesoporous silica nanocomposites (AMMS) bearing polydopamine (PDA)-aptamer (Apt) two-tier shells, as a novel nanodevice, is designed for target detection through a target-triggered glucose (GO) release from AMMS with personal glucometer (PGM) readout. In the absence of target, GO can be firmly captured in pores by the designed "dual gates", which would decrease the high background signal of this system and ensure the accuracy of the detection results. Upon the introduction of the target molecules under acidic conditions (pH 5.5), the subsequent PDA self-degradation and the specific Apt-target reaction can cause the departure of "dual gates" and the opening of pores to release the loaded GO molecules, which could be quantitatively monitored by a portable PGM. It has been demonstrated that such POCT platform shows high sensitivity and excellent selectivity for aflatoxin B1 (AFB1) detection, accompanied by the well-presented reproducibility and stability. Importantly, this sensing platform was further validated by assaying contaminated samples, where the obtained results were well matched with that by HPLC. Regarding the features of portability, high sensitivity, and high throughput detection, the developed platform might find wide applications in POCT.

Generational performance of three point-of-care testing devices compared with standard laboratory measurement of the international normalised ratio across extended ranges

Point-of-care testing (POCT) of the international normalised ratio (INR) is recognised as a rapid and reliable alternative to venous INR measurement for titration and monitoring of patients anticoagulated with vitamin...

A Portable Electrochemical Platform Integrated with a 3D AuNPs/CNTs Sponge for Point-of-Care Testing of Neurotransmitters

Point-of-care testing (POCT) of neurotransmitters, such as dopamine (DA) and 5-hydroxytryptamine (5-HT), can be used for early diagnosis of neurological diseases. Among various POCT platforms, electrochemical method-based platforms have attracted increasing interest owning to their high detection sensitivity and specificity as well as fast response time. In this work, we developed a portable electrochemical POCT platform for detection of neurotransmitters, which is based on integration of a three-dimensional (3D) gold nanoparticles/carbon nanotubes (AuNPs/CNTs) sponge synthesized by a simple in-situ growth and eco-friendly ice-templating method modified screen-printed electrode with a miniaturized USB electrochemical analyzer. We demonstrated the good performance of the portable electrochemical platform for detection of two typical neurotransmitters, i.e., DA and 5-HT, with detection sensitivities of 1.02 μA μM−1 cm−2 and 0.55 μA μM−1 cm−2, and detection limits of 0.06 μM and 0.30 μM for DA and 5-HT, respectively. We further verified the feasibility and practicability of the platform by simultaneous detection of DA and 5-HT in spiked saliva. The developed portable electrochemical platform provides a simple and user-friendly way for early diagnosis of neurological diseases in the future, especially at point of care.

Paper-Based Electrochemical Biosensors for Point-of-Care Testing of Neurotransmitters

Neurotransmitters are important biological molecules related to several nervous system diseases (NSDs). Point-of-care testing (POCT) of neurotransmitters is of great importance in preclinical research and early diagnosis of NSDs. Among various POCT platforms, paper-based electrochemical biosensors have achieved great advances in detection of neurotransmitters, thus taking a significant role in POCT of neurotransmitters nowadays. This review gives an overview of the recent advances of paper-based electrochemical biosensors for POCT of neurotransmitters. We first introduce the types of neurotransmitters and biological sample sources mainly used for neurotransmitter detection. Second, we review the components and the traditional fabrication technologies for paper-based electrochemical POCT biosensors, and then the functional modification methods of biosensor surfaces and three-dimensional fabrication methods for further enhancement of their detection performance. Then, we list examples of paper-based electrochemical biosensors used for detecting different neurotransmitters in biological samples. Last, we give a conclusion and promising development direction of paper-based electrochemical biosensors for neurotransmitters detection. The purpose of this review is to introduce the paper-based electrochemical biosensors as an emerging technology for POCT of neurotransmitters, offering a reference for readers and researchers for early diagnosis of NSDs using POCT technologies.

A Self-Contained Chemiluminescent Lateral Flow Assay for Point-of-Care Testing.

Immunoassays whose readouts rely on chemiluminescence are increasingly useful for a broad range of analytical applications, but they are rarely made into point-of-care (POC) format because of the complex reagents required (some reagents have to be stored in low temperatures, and some reagents have to be freshly made right before the assay). This study reports a self-contained chemiluminescent lateral flow assay (CLFA), which prestores all necessary reagents. This CLFA contains three parts: the normal lateral flow assay (LFA) strip, the chemiluminescence substrate pad, and the polycarbonate (PC) holder. On the LFA strip, we simultaneously labeled horseradish peroxidase (HRP) and antibody on the gold nanoparticles (AuNPs) for the conjugate pad. For the substrate pad, we used sodium perborate as the oxidant and lyophilized the chemiluminescence substrate on the glass fiber, which allows long-term storage. After the transfer of substrate from the substrate pad to the nitrocellulose (NC) membrane, we captured the chemiluminescence signal for the quantification of the targets. The HRP on the AuNPs can amplify the chemiluminescence signal efficiently. We used this CLFA system to detect both macromolecules and small molecules successfully. This self-contained and easily processable device is exceedingly appropriate for rapid detection and is a convenient platform for POC testing.

Healthcare worker feedback on a prototype smartphone-based point-of-care test platform for use in episodic care.

With a growing list of new platforms, end-user acceptability is an evolving topic in point-of-care (POC) test development. While technical reports of new experimental POC tests are common, it is rare to find reports which evaluate the end-user acceptability of such innovations. This work illustrates an example of bridging that gap by evaluating the end-user acceptability of an experimental POC test platform with novel technical features. A prototype smartphone-based STI tests was evaluated by ED technicians, followed by a survey of acceptability factors. Our findings suggest that the end-user acceptability of some design features implemented in the prototype.

A portable microfluidic platform for rapid molecular diagnostic testing of patients with myeloproliferative neoplasms

The ability to simultaneously detect JAK2 V617F and MPL W515K/L mutations would substantially improve the early diagnosis of myeloproliferative neoplasms (MPNs) and decrease the risk of arterial thrombosis. The goal of this study is to achieve a point of care testing platform for simultaneous analysis of major genetic alterations in MPN. Here, we report a microfluidic platform including a glass capillary containing polypropylene matrix that extracts genomic DNA from a drop of whole blood, a microchip for simultaneous multi-gene mutation screening, and a handheld battery-powered heating device. The µmLchip system was successfully used for point-of-care identification of the JAK2 V617F and MPL W515K/L mutations. The µmLchip assays were then validated by mutation analysis with samples from 100 MPN patients who had previously been analyzed via unlabeled probe melting curve analysis or real-time PCR. The results from the µmLchip were in perfect agreement with those from the other methods, except for one discrepant result that was negative in the unlabeled probe melting curve analysis but positive in the µmLchip. After T-A cloning, sequences of cloned PCR products revealed JAK2 V617F mutation in the sample. The portable microfluidic platform may be very attractive in developing point-of-care diagnostics for MPL W515K/L and JAK2 V617F mutations.

Application of nanodiagnostics in point-of-care tests for infectious diseases

Although tremendous efforts have been put into the treatment of infectious diseases to prevent epidemics and mortality, it is still one of the major health care issues that have a profound impact on humankind. Therefore, the development of specific, sensitive, accurate, rapid, low-cost, and easy-to-use diagnostic tools is still in urgent demand. Nanodiagnostics, defined as the application of nanotechnology to medical diagnostics, can offer many unique opportunities for more successful and efficient diagnosis and treatment for infectious diseases. In this review, we provide an overview of the nanodiagnostics for infectious diseases from nanoparticle-based, nanodevice-based, and point-of-care test (POCT) platforms. Most importantly, emphasis focused on the recent trends in the nanotechnology-based POCT system. The current state-of-the-art and most promising point-of-care nanodiagnostic technologies, including miniaturized diagnostic magnetic resonance platform, magnetic barcode assay system, cell phone-based polarized light microscopy platform, cell phone-based dongle platform, and paper-based POCT platform, for infectious diseases were fully examined. The limitations, challenges, and future trends of the nanodiagnostics in POCTs for infectious diseases are also discussed.

A new algorithm of suspected stroke patient management with brain natriuretic peptide/N-terminal pro-brain natriuretic peptide point of care testing platform in the emergency department.

A new algorithm of suspected stroke patient management with brain natriuretic peptide/N-terminal pro-brain natriuretic peptide point of care testing platform in the emergency department.

Evaluation of point of care testing platform (ePLEX) for respiratory viral diagnosis

Evaluation of point of care testing platform (ePLEX) for respiratory viral diagnosis

Challenges of development and implementation of point of care pharmacogenetic testing

ABSTRACTIntroduction: Just as technology was the underlying driver of the sequencing of the human genome and subsequent generation of volumes of genome sequence data from healthy and affected individuals, animal, plant, and microbial species alike, so too will technology revolutionize diagnostic testing. One area of intense interest is the use of genetic data to inform decisions regarding drug selection and drug dosing, known as pharmacogenetic (PGx) testing, to improve likelihood of successful treatment outcomes with minimal risks.Areas covered: This commentary will provide an overview of implementation research of PGx testing, the benefits of point-of-care (POC) testing and overview of POC testing platforms, available PGx tests, and barriers and facilitators to the development and integration of POC-PGx testing into clinical settings. Sources include the published literature, and databases from the Centers for Medicaid and Medicare Services, Food and Drug Administration.Expert commentary: The utilization of POC PGx testing may enable more routine test use, but the development and implementation of such tests will face some barriers before personalized medicine is available to every patient. In particular, provider training, availability of clinical decision supports, and connectivity will be key areas to facilitate routine use.

Modular development of a prototype point of care molecular diagnostic platform for sexually transmitted infections

This paper presents the design of a modular point of care test platform that integrates a proprietary sample collection device directly with a microfluidic cartridge. Cell lysis, within the cartridge, is conducted using a chemical method and nucleic acid purification is done on an activated cellulose membrane. The microfluidic device incorporates passive mixing of the lysis-binding buffers and sample using a serpentine channel. Results have shown extraction efficiencies for this new membrane of 69% and 57% compared to the commercial Qiagen extraction method of 85% and 59.4% for 0.1ng/µL and 100ng/µL salmon sperm DNA respectively spiked in phosphate buffered solution. Extraction experiments using the serpentine passive mixer cartridges incorporating lysis and nucleic acid purification showed extraction efficiency around 80% of the commercial Qiagen kit. Isothermal amplification was conducted using thermophillic helicase dependant amplification and recombinase polymerase amplification. A low cost benchtop real-time isothermal amplification platform has been developed capable of running six amplifications simultaneously. Results show that the platform is capable of detecting 1.32×106 of sample DNA through thermophillic helicase dependant amplification and 1×105 copy numbers Chlamydia trachomatis genomic DNA within 10min through recombinase polymerase nucleic acid amplification tests.

A dual-readout chemiluminescent-gold lateral flow test for multiplex and ultrasensitive detection of disease biomarkers in real samples.

Even though the gold lateral flow test (GLFT) is low-cost and allows for point-of-care testing (POCT), its intrinsic limitations including low sensitivity and incapability of quantification significantly hinder the clinical application of GLFT for assaying disease biomarkers. To improve the performance of the GLFT without sacrificing its simplicity, we develop a chemiluminescent-gold lateral flow test (C-mode GLFT) for quantitative and multiplex detection of disease biomarkers with an ultrahigh sensitivity at a picomolar level. Horseradish peroxidase (HRP) and antibody (Ab) are simultaneously labeled onto the surface of gold nanoparticles (AuNPs) to achieve a dual-readout (chemiluminescent and visual, C&V-mode GLFT). A red color appears at the test line caused by the accumulation of captured AuNPs in the presence of targets, while HRP on the surface of AuNPs catalyzes the chemiluminescence reaction of luminol to amplify the signal. C-mode GLFT is successfully used for detecting tumor biomarkers (alpha fetoprotein, AFP, and carcino embryonic antigen, CEA) and bacterial infection biomarkers (procalcitonin, PCT) in serum samples as well as whole blood. The excellent features of C-mode GLFT such as straightforward operation, ultrahigh sensitivity and quantitative detection, make it a promising platform for POCT of a variety of disease biomarkers in real samples.

P193 Development of a handheld point of care molecular diagnostic device for sexually transmitted infections

<h3>Background/introduction</h3> Brunel DoCLab is part of the <i>e</i>STI2 Consortium which is developing electronic self-testing and portable instruments for sexually transmitted infections using nucleic acid amplification test technologies. We have designed a point of care test platform that integrates a proprietary sample collection device directly with a microfluidic cartridge. A low cost benchtop real-time isothermal amplification platform has been developed capable of running six amplifications simultaneously. <h3>Aim(s)/objectives</h3> To evaluate the sample preparation and isothermal amplification within the low cost diagnostic platform. <h3>Methods</h3> The microfluidic device incorporates passive mixing of the lysis-binding buffers and sample. Cell lysis, within the cartridge, is conducted using a chemical method and nucleic acid purification is done on an activated cellulose membrane. Isothermal amplification was conducted using recombinase polymerase amplification (RPA). <h3>Results</h3> Preliminary results have shown extraction efficiencies for this new membrane of 69% and 57% compared to the commercial Qiagen extraction method of 85% and 59.4% for 0.1 ng/µL and 100 ng/µL salmon sperm DNA respectively spiked in phosphate buffered solution. Extraction experiments in the passive mixer cartridges with lysis and nucleic acid purification showed extraction efficiency around 80% of the commercial Qiagen kit. The platform is capable of detecting <i>Chlamydia trachomatis</i> genomic DNA within 10 min using RPA for 100,000 copies/µL. <h3>Discussion/conclusion</h3> The work presented here shows a low cost, rapid nucleic acid extraction, isothermal amplification and detection platform for diagnosing C. trachomatis. Work is on-going to fully integrate the sample-in to result platform for rapid diagnosis of STIs using genital samples.

Optimization of a cell counting algorithm for mobile point-of-care testing platforms.

In a point-of-care (POC) setting, it is critically important to reliably count the number of specific cells in a blood sample. Software-based cell counting, which is far faster than manual counting, while much cheaper than hardware-based counting, has emerged as an attractive solution potentially applicable to mobile POC testing. However, the existing software-based algorithm based on the normalized cross-correlation (NCC) method is too time- and, thus, energy-consuming to be deployed for battery-powered mobile POC testing platforms. In this paper, we identify inefficiencies in the NCC-based algorithm and propose two synergistic optimization techniques that can considerably reduce the runtime and, thus, energy consumption of the original algorithm with negligible impact on counting accuracy. We demonstrate that an Android™ smart phone running the optimized algorithm consumes 11.5× less runtime than the original algorithm.

Improving Patient Flow in Acute Coronary Syndromes in the Face of Hospital Crowding

BackgroundThe current paradigm for the evaluation of patients with suspected acute coronary syndromes (ACS) in the emergency department (ED) is focused on the identification of patients with active underlying coronary disease. The majority of patients evaluated in the ED setting do not have active underlying cardiac disease. ObjectiveTo measure the effect of bedside point-of-care (POC) cardiac biomarker testing on telemetry unit admissions from the ED. Furthermore, to evaluate the effect telemetry admissions have on ED length of stay (LOS) and overall hospital LOS. MethodsPrimary data were collected over two 6-month periods in an urban teaching hospital ED. This was an observational cohort study conducted pre- and post- availability of a POC testing platform for cardiac biomarkers. Major measures included number of overall telemetry admissions, ED LOS, hospital LOS, and disposition. Patients were followed at 30 days for significant cardiac events, repeat ED visit or admission, and death. ResultsIn the post-implementation period there was a 30% (95% confidence interval [CI] 36–44%) reduction in admissions to telemetry with a 33% (95% CI 26–39%) reduction in ED LOS and a 20% (95% CI 7–34%) reduction in hospital LOS. There was a 62% reduction in overall mortality between the pre-implementation period and the post-implementation period (p=0.001). ConclusionThe focused use of a rapid cardiac disposition protocol can dramatically impact resource utilization, expedite patient flow, and improve short-term outcomes for patients with suspected ACS.

Paper based point-of-care testing disc for multiplex whole cell bacteria analysis

Point-of-care testing (POCT) of infectious bacterial agents offers substantial benefits for disease diagnosis, mainly by shortening the time required to obtain results and by making the test available bedside or at remote care centers. Immunochromatographic lateral flow biosensors offer a low cost, highly sensitive platform for POCT. In this article, we describe the fabrication and testing of a multiplex immuno-disc sensor for the specific detection of Pseudomonas aeruginosa and Staphylococcus aureus. Antibody conjugated gold nanoparticles were used as the signaling agents. The detection range of the bacteria lies within 500–5000 CFU/ml. The advantage of the immuno-disc sensor is that it does not require any preprocessing of biological sample and is capable of whole cell bacterial detection. We also describe the design and fabrication of a compact portable device which converts the color intensity of the gold nanoparticles that accumulate at the test region into a quantitative voltage reading proportional to the bacterial concentration in the sample. The combination of the immuno-disc and the portable color reader provides a rapid, sensitive, low cost, and quantitative tool for the detection of a panel of infectious agents present in the patient sample.

Development of a Point-of-Care Testing Platform With a Nanogap-Embedded Separated Double-Gate Field Effect Transistor Array and Its Readout System for Detection of Avian Influenza

Label-free electrical detection of avian influenza (AI) is demonstrated for the development of a point-of-care testing (POCT) platform. For a new POCT platform, a novel field effect transistor (FET)-based biosensor array was fabricated with conventional complementary metal-oxide-semiconductor (CMOS) technology. Nanogap-embedded separated double-gate FETs (nanogap-DGFETs) were realized in a 6 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\,\times\,$</tex> </formula> 6 array as a biosensor cartridge. Moreover, the low-noise readout circuit was designed and fabricated using a 0.35- <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">$\mu$</tex></formula> m standard CMOS process. The AI antigen and antibody were bound with the aid of silica-binding proteins (SBP) in the nanogap of the biosensor device. Because the gate dielectric constant was increased by the immobilized biomolecules, the threshold voltage of the nanogap-DGFET was reduced while the drain-to-source current was enhanced. Drain-to-source currents of the nanogap-DGFET array were successfully acquired using the fabricated readout circuitry and measurement setup. This platform is suitable for a simple and effective label-free detection of AI in POCT applications.