Mobile device for disease diagnosis and data tracking in resource-limited settings

Leveraging a smartphone to perform time-gated luminescence measurements

Empowered by advanced on-board sensors, high-performance optics packages and ever-increasing computational power, smartphones have democratized data generation, collection, and analysis. Building on this capacity, many platforms have been developed to enable its use as an optical sensing platform for colorimetric and fluorescence measurements. In this paper, we report the ability to enable a smartphone to perform laboratory quality time-resolved analysis of luminescent samples via the exploitation of the rolling shutter mechanism of the native CMOS imager. We achieve this by leveraging the smartphone's standard image capture applications, commercially available image analysis software, and housing the device within a UV-LED containing case. These low-cost modifications enable us to demonstrate the smartphone's analytical potential by performing tasks ranging from authentication and encryption to the interrogation of packaging, compounds, and physical phenomena. This approach underscores the power of repurposing existing technologies to extend the reach and inclusivity of scientific exploration, opening new avenues for data collection and analysis.

Assessment of Immune Status Using Inexpensive Cytokines: A Literature Review and Learning Approaches

The emergence of point-of-care (POC) testing has lately been promoted to deliver rapid, reliable medical tests in critical life-threatening situations, especially in resource-limited settings. Recently, POC tests have witnessed further advances due to the technological revolution in smartphones. Smartphones are integrated as reliable readers to the POC results to improve their quantitative detection. This has enabled the use of more complex medical tests by the patient him/herself at home without the need for professional staff and sophisticated equipment. Cytokines, the important immune system biomarkers, are still measured today using the time-consuming Enzyme-Linked Immunosorbent Assay (ELISA), which can only be performed in specially equipped laboratories. Therefore, in this study, we investigate the current development of POC technologies suitable for the home testing of cytokines by conducting a PRISMA literature review. Then, we classify the collected technologies as inexpensive and expensive depending on whether the cytokines can be measured easily at home or not. Additionally, we propose a machine learning-based solution to even increase the efficiency of the cytokine measurement by leveraging the cytokines that can be inexpensively measured to predict the values of the expensive ones. In total, we identify 12 POCs for cytokine quantification. We find that Interleukin 1β (IL-1β), Interleukin 3 (IL-3), Interleukin 6 (IL-6), Interleukin 8 (IL-8) and Tumor necrosis factor (TNF) can be measured with inexpensive POC technology, namely at home. We build machine-learning models to predict the values of other expensive cytokines such as Interferon-gamma (IFN-γ), IL-10, IL-2, IL-17A, IL-17F, IL-4 and IL-5 by relying on the identified inexpensive ones in addition to the age of the individual. We evaluate to what extent the built machine learning models can use the inexpensive cytokines to predict the expensive ones on 351 healthy subjects from the public dataset 10k Immunomes. The models for IFN-γ show high results for the coefficient of determination: R2 = 0.743. The results for IL-5 and IL-4 are also promising, whereas the predictive model of IL-10 achieves only R2 = 0.126. Lastly, the results demonstrate the vital role of TNF and IL-6 in the immune system due to its high importance in the predictions of all the other expensive cytokines.

Nanotechnology Fundamentals Applied to Clinical Infectious Diseases and Public Health

Nanotechnology involves the discovery and fabrication of nanoscale materials possessing unique physicochemical properties that are being employed in industry and medicine. Infectious Diseases clinicians and public health scientists utilize nanotechnology applications to diagnose, treat, and prevent infectious diseases. However, fundamental principles of nanotechnology are often presented in technical formats that presuppose an advanced knowledge of chemistry, physics, and engineering, thereby limiting the clinician’s grasp of the underlying science. While nanoscience is technically complex, it need not be out of reach of the clinical practitioner. The aim of this review is to introduce fundamental principles of nanotechnology in an accessible format, describe examples of current clinical infectious diseases and public health applications, and provide a foundation that will aid understanding of and appreciation for this burgeoning and important field of science.

Call to action for health systems integration of point-of-care testing to mitigate the transmission and burden of sexually transmitted infections

Objectives

In 2016, WHO estimated 376 million new cases of the four main curable STIs: gonorrhoea, chlamydia, trichomoniasis and syphilis. Further, an estimated 290 million women are infected with human papillomavirus. STIs may lead to severe reproductive health sequelae. Low-income and middle-income countries carry the highest global burden of STIs. A large proportion of urogenital and the vast majority of extragenital non-viral STI cases are asymptomatic. Screening key populations and early and accurate diagnosis are important to provide correct treatment and to control the spread of STIs. This article paints a picture of the state of technology of STI point-of-care testing (POCT) and its implications for health system integration.

Methods

The material for the STI POCT landscape was gathered from publicly available information, published and unpublished reports and prospectuses, and interviews with developers and manufacturers.

Results

The development of STI POCT is moving rapidly, and there are much more tests in the pipeline than in 2014, when the first STI POCT landscape analysis was published on the website of WHO. Several of the available tests need to be evaluated independently both in the laboratory and, of particular importance, in different points of care.

Conclusion

This article reiterates the importance of accurate, rapid and affordable POCT to reach universal health coverage. While highlighting the rapid technical advances in this area, we argue that insufficient attention is being paid to health systems capacity and conditions to ensure the swift and rapid integration of current and future STI POCT. Unless the complexity of health systems, including context, institutions, adoption systems and problem perception, are recognised and mapped, simplistic approaches to policy design and programme implementation will result in poor realisation of intended outcomes and impact.

A Multiplexed Serologic Test for Diagnosis of Lyme Disease for Point-of-Care Use

Single multiplexed assays could replace the standard 2-tiered (STT) algorithm recommended for the laboratory diagnosis of Lyme disease if they perform with a specificity and a sensitivity superior or equal to those of the STT algorithm. We used human serum rigorously characterized to be sera from patients with acute- and convalescent-phase early Lyme disease, Lyme arthritis, and posttreatment Lyme disease syndrome, as well as the necessary controls (n = 241 samples), to select the best of 12 Borrelia burgdorferi proteins to improve our microfluidic assay (mChip-Ld). We then evaluated its serodiagnostic performance in comparison to that of a first-tier enzyme immunoassay and the STT algorithm. We observed that more antigens became positive as Lyme disease progressed from early to late stages. We selected three antigens (3Ag) to include in the mChip-Ld: VlsE and a proprietary synthetic 33-mer peptide (PepVF) to capture sensitivity in all disease stages and OspC for early Lyme disease. With the specificity set at 95%, the sensitivity of the mChip-Ld with 3Ag ranged from 80% (95% confidence interval [CI], 56% to 94%) and 85% (95% CI, 74% to 96%) for two panels of serum from patients with early Lyme disease and was 100% (95% CI, 83% to 100%) for serum from patients with Lyme arthritis; the STT algorithm detected early Lyme disease in the same two panels of serum from patients with early Lyme disease with a sensitivity of 48.5% and 75% and Lyme arthritis in serum from patients with Lyme arthritis with a sensitivity of 100%, and the specificity was 97.5% to 100%. The mChip-Ld platform outperformed the STT algorithm according to sensitivity. These results open the door for the development of a single, rapid, multiplexed diagnostic test for point-of-care use that can be designed to identify the Lyme disease stage.

Towards Resilient Health Systems in Sub-Saharan Africa: A Systematic Review of the English Language Literature on Health Workforce, Surveillance, and Health Governance Issues for Health Systems Strengthening

Background:

Meeting health security capacity in sub-Saharan Africa will require strengthening existing health systems to prevent, detect, and respond to any threats to health. The purpose of this review was to examine the literature on health workforce, surveillance, and health governance issues for health systems strengthening.

Methods:

We searched PubMed, Science Direct, Cochrane library, CINAHL, Web of Science, EMBASE, EBSCO, Google scholar, and the WHO depository library databases for English-language publications between January 2007 and February 2017. Electronic searches for selected articles were supplemented by manual reference screening. The review followed the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines.

Results:

Out of 1,548 citations retrieved from the electronic searches, 31 articles were included in the review. Any country health system that trains a cadre of health professionals on the job, reduces health workforce attrition levels, and builds local capacity for health care workers to apply innovative mHealth technologies improves health sector performance. Building novel surveillance systems can improve clinical care and improve health system preparedness for health threats. Effective governance processes build strong partnerships for health and create accountability mechanisms for responding to health emergencies.

Conclusions:

Overall, policy shifts in African countries’ health systems that prioritize training a cadre of willing and able workforce, invest in robust and cost-effective surveillance capacity, and create financial accountability and good governance are vital in health strengthening efforts.

Integrating user behavior with engineering design of point-of-care diagnostic devices: theoretical framework and empirical findings

With point-of-care (POC) diagnostic devices becoming increasingly available to untrained users, it will be critical to understand how real-world user behavior can best inform and guide the engineering design process. Social sciences present frameworks for analyzing user behavior, but they have not yet been applied to POC diagnostics in a methodical manner. Here, we develop a framework that synthesizes two models that can collectively account for user behavior and experience with POC diagnostic devices: a social psychological information-motivation-behavior (IMB) model (first described by Fisher and Fisher) for identifying determinants for health-related behavior, and user experience (UX) elements for studying interactions between users and products. Based on studies of 40 naïve users of our smartphone-enabled microfluidics device that can be used for HIV home-testing, we found that untrained participants could perform 90% of steps correctly, with engineering design elements that provided feedback that was either direct (e.g., a light or click) or binary (e.g., a switch) enhancing usability. Interestingly, of the steps performed incorrectly, over 70% were due not to errors in the device or user operation, but user-to-user variability (e.g. time in collecting fingerstick and force applied to initiate vacuum), which could be addressed by further modifications to the device. Overall, this study suggests that microfluidic POC HIV home-testing is likely to benefit from smartphone integration, and that engineering design of POC diagnostic devices can benefit from a structured evaluation of user behavior and experience, as guided by a social-psychological framework, which emphasizes user credibility, accessibility, acceptability, usability, and value.

Designing Paper-Based Immunoassays for Biomedical Applications

Paper-based sensors and assays have been highly attractive for numerous biological applications, including rapid diagnostics and assays for disease detection, food safety, and clinical care. In particular, the paper immunoassay has helped drive many applications in global health due to its low cost and simplicity of operation. This review is aimed at examining the fundamentals of the technology, as well as different implementations of paper-based assays and discuss novel strategies for improving their sensitivity, performance, or enabling new capabilities. These innovations can be categorized into using unique nanoparticle materials and structures for detection via different techniques, novel biological species for recognizing biomarkers, or innovative device design and/or architecture.

Smartphone-based clinical diagnostics: towards democratization of evidence-based health care

Recent advancements in bioanalytical techniques have led to the development of novel and robust diagnostic approaches that hold promise for providing optimal patient treatment, guiding prevention programs and widening the scope of personalized medicine. However, these advanced diagnostic techniques are still complex, expensive and limited to centralized healthcare facilities or research laboratories. This significantly hinders the use of evidence-based diagnostics for resource-limited settings and the primary care, thus creating a gap between healthcare providers and patients, leaving these populations without access to precision and quality medicine. Smartphone-based imaging and sensing platforms are emerging as promising alternatives for bridging this gap and decentralizing diagnostic tests offering practical features such as portability, cost-effectiveness and connectivity. Moreover, towards simplifying and automating bioanalytical techniques, biosensors and lab-on-a-chip technologies have become essential to interface and integrate these assays, bringing together the high precision and sensitivity of diagnostic techniques with the connectivity and computational power of smartphones. Here, we provide an overview of the emerging field of clinical smartphone diagnostics and its contributing technologies, as well as their wide range of areas of application, which span from haematology to digital pathology and rapid infectious disease diagnostics.

From Point-of-Care Testing to eHealth Diagnostic Devices (eDiagnostics)

Point-of-care devices were originally designed to allow medical testing at or near the point of care by health-care professionals. Some point-of-care devices allow medical self-testing at home but cannot fully cover the growing diagnostic needs of eHealth systems that are under development in many countries. A number of easy-to-use, network-connected diagnostic devices for self-testing are needed to allow remote monitoring of patients' health. This Outlook highlights the essential characteristics of diagnostic devices for eHealth settings and indicates point-of-care technologies that may lead to the development of new devices. It also describes the most representative examples of simple-to-use, point-of-care devices that have been used for analysis of untreated biological samples.

Immunoassay Multiplexing on a Complementary Metal Oxide Semiconductor Photodiode Array

Scalable immunoassay multiplexing offers a route to creating rapid point-of-care (POC) diagnostics. We present a method for multiplexing immunoassays on the surface of a complementary metal oxide semiconductor (CMOS) sensor array integrated circuit (IC) without the use of physical separators such as wells or channels. Major advantages of using a CMOS sensor array include low mass-manufacturing costs, the possibility to multiplex multiple assays on a single IC, and improved signal when averaging multiple sensors, along with providing a platform where wash steps can be incorporated to maximize selectivity and sensitivity compared to paper based lateral flow immunoassay. The device was able to differentiate between samples containing either, neither, or both rabbit anti-mouse (RAM) antibodies and/or anti-HIV gp120 antibodies in serum using a gold-nanoparticle promoted silver enhancement immunoassay. HIV antibody concentrations down to 100 μg/mL were readily detected, which is three times lower than those typically found in infected humans (300-500 μg/mL), and the limit of detection was 10 μg/mL.

Sliding-strip microfluidic device enables ELISA on paper

This article describes a 3D microfluidic paper-based analytical device that can be used to conduct an enzyme-linked immunosorbent assay (ELISA). The device comprises two parts: a sliding strip (which contains the active sensing area) and a structure surrounding the sliding strip (which holds stored reagents—buffers, antibodies, and enzymatic substrate—and distributes fluid). Running an ELISA involves adding sample (e.g. blood) and water, moving the sliding strip at scheduled times, and analyzing the resulting color in the sensing area visually or using a flatbed scanner. We demonstrate that this device can be used to detect C-reactive protein (CRP)—a biomarker for neonatal sepsis, pelvic inflammatory disease, and inflammatory bowel diseases—at a concentration range of 1–100 ng/mL in 1000-fold diluted blood (1–100 µg/mL in undiluted blood). The accuracy of the device (as characterized by the area under the receiver operator characteristics curve) is 89% and 83% for cut-offs of 10 ng/mL (for neonatal sepsis and pelvic inflammatory disease) and 30 ng/mL (for inflammatory bowel diseases) CRP in 1000-fold diluted blood respectively. In resource-limited settings, the device can be used as a part of a kit (containing the device, a fixed-volume capillary, a pre-filled tube, a syringe, and a dropper); this kit would cost ~ $0.50 when produced in large scale (>100,000 devices/week). This kit has the technical characteristics to be employed as a pre-screening tool, when combined with other data such as patient history and clinical signs.

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3D microfluidic paper-based analytical device performs ELISA with colorimetric results.

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Two components enable separation of reagents in the device: a sliding-strip and a functional dock.

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All required reagents (antibodies, enzyme, substrate, buffers) are stored in the device.

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User only needs to add sample and water using the provided kit.

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Device can detect C-reactive protein for possible pre-screening of neonatal sepsis, pelvic inflammatory disease, or inflammatory bowel diseases.

Pre-concentration by liquid intake by paper (P-CLIP): a new technique for large volumes and digital microfluidics

Microfluidic platforms are an attractive option for incorporating complex fluid handling into low-cost and rapid diagnostic tests. A persistent challenge for microfluidics, however, is the mismatch in the "world-to-chip" interface - it is challenging to detect analytes present at low concentrations in systems that can only handle small volumes of sample. Here we describe a new technique termed pre-concentration by liquid intake by paper (P-CLIP) that addresses this mismatch, allowing digital microfluidics to interface with volumes on the order of hundreds of microliters. In P-CLIP, a virtual microchannel is generated to pass a large volume through the device; analytes captured on magnetic particles can be isolated and then resuspended into smaller volumes for further processing and analysis. We characterize this method and demonstrate its utility with an immunoassay for Plasmodium falciparum lactate dehydrogenase, a malaria biomarker, and propose that the P-CLIP strategy may be useful for a wide range of applications that are currently limited by low-abundance analytes.

Multiplexed Point-of-Care Testing - xPOCT

Multiplexed point-of-care testing (xPOCT), which is simultaneous on-site detection of different analytes from a single specimen, has recently gained increasing importance for clinical diagnostics, with emerging applications in resource-limited settings (such as in the developing world, in doctors’ offices, or directly at home). Nevertheless, only single-analyte approaches are typically considered as the major paradigm in many reviews of point-of-care testing. Here, we comprehensively review the present diagnostic systems and techniques for xPOCT applications. Different multiplexing technologies (e.g., bead- or array-based systems) are considered along with their detection methods (e.g., electrochemical or optical). We also address the unmet needs and challenges of xPOCT. Finally, we critically summarize the in-field applicability and the future perspectives of the presented approaches.

Simultaneous on-site measurement of different substances from a single sample, called multiplexed point-of-care testing, has recently become more and more important for in vitro diagnostics.

The major aim for the development of xPOCT systems is the smart combination of a high-performing device with a low system complexity. Thus, the on-site tests are realized in a short time by non-experts and ensure comparable results with clinical and central laboratory findings.

A multiplexing capability of up to 10 analytes has been sufficient for many recent xPOCT applications.

The future of xPOCT devices will be driven by novel biotechnologies (e.g., aptamers) or targets (e.g., circulating RNAs or tumor cells, exosomes, and miRNAs), as well as applications like personalized medicine, homecare monitoring, and wearables.

Microfluidics-based point-of-care test for serodiagnosis of Lyme Disease

Currently, diagnostic testing for Lyme disease is done by determination of the serologic responses to Borrelia burgdorferi antigens, with the exception of the early localized phase of disease where diagnosis must be done clinically. Here, we describe the use of microfluidics technology to develop a multiplexed rapid lab-on-a-chip point of care (POC) assay for the serologic diagnosis of human Lyme disease. Following ELISA screening of 12 candidate antigens, we tested 8 on a microfluidic diagnostic system, called mChip-Ld, using a set of 60 serological samples. The mChip-Ld test, which can be performed in 15 minutes at the point of care, showed promising performance for detection of antibodies to B. burgdorferi using the PPO triplex test (rP100 + PepVF + rOspC-K, AUC of 0.844) compared to a gold-standard reference of culture confirmed clinical samples. The performance is comparable to the commonly used C6 peptide by lab-based ELISA. In addition, the mChip-Ld test showed promising performance for early-stage diagnosis of the disease using the antigen OspC-K (sensitivity and specificity of 84% and 92%, respectively; AUC of 0.877). Overall, this study underscores the potential of using microfluidics to aid the diagnosis of Lyme disease at the point of care.

Cell Phone-Based and Adherence Device Technologies for HIV Care and Treatment in Resource-Limited Settings: Recent Advances

Numerous cell phone-based and adherence monitoring technologies have been developed to address barriers to effective HIV prevention, testing, and treatment. Because most people living with HIV and AIDS reside in resource-limited settings (RLS), it is important to understand the development and use of these technologies in RLS. Recent research on cell phone-based technologies has focused on HIV education, linkage to and retention in care, disease tracking, and antiretroviral therapy adherence reminders. Advances in adherence devices have focused on real-time adherence monitors, which have been used for both antiretroviral therapy and pre-exposure prophylaxis. Real-time monitoring has recently been combined with cell phone-based technologies to create real-time adherence interventions using short message service (SMS). New developments in adherence technologies are exploring ingestion monitoring and metabolite detection to confirm adherence. This article provides an overview of recent advances in these two families of technologies and includes research on their acceptability and cost-effectiveness when available. It additionally outlines key challenges and needed research as use of these technologies continues to expand and evolve.

Opportunities and challenges for the application of microfluidic technologies in point-of-care veterinary diagnostics

There is a growing need for low-cost, rapid and reliable diagnostic results in veterinary medicine. Point-of-care (POC) tests have tremendous advantages over existing laboratory-based tests, due to their intrinsic low-cost and rapidity. A considerable number of POC tests are presently available, mostly in dipstick or lateral flow formats, allowing cost-effective and decentralised diagnosis of a wide range of infectious diseases and public health related threats. Although, extremely useful, these tests come with some limitations. Recent advances in the field of microfluidics have brought about new and exciting opportunities for human health diagnostics, and there is now great potential for these new technologies to be applied in the field of veterinary diagnostics. This review appraises currently available POC tests in veterinary medicine, taking into consideration their usefulness and limitations, whilst exploring possible applications for new and emerging technologies, in order to widen and improve the range of POC tests available.

Towards Improving Point-of-Care Diagnosis of Non-malaria Febrile Illness: A Metabolomics Approach

Introduction

Non-malaria febrile illnesses such as bacterial bloodstream infections (BSI) are a leading cause of disease and mortality in the tropics. However, there are no reliable, simple diagnostic tests for identifying BSI or other severe non-malaria febrile illnesses. We hypothesized that different infectious agents responsible for severe febrile illness would impact on the host metabololome in different ways, and investigated the potential of plasma metabolites for diagnosis of non-malaria febrile illness.

Methodology

We conducted a comprehensive mass-spectrometry based metabolomics analysis of the plasma of 61 children with severe febrile illness from a malaria-endemic rural African setting. Metabolite features characteristic for non-malaria febrile illness, BSI, severe anemia and poor clinical outcome were identified by receiver operating curve analysis.

Principal Findings

The plasma metabolome profile of malaria and non-malaria patients revealed fundamental differences in host response, including a differential activation of the hypothalamic-pituitary-adrenal axis. A simple corticosteroid signature was a good classifier of severe malaria and non-malaria febrile patients (AUC 0.82, 95% CI: 0.70–0.93). Patients with BSI were characterized by upregulated plasma bile metabolites; a signature of two bile metabolites was estimated to have a sensitivity of 98.1% (95% CI: 80.2–100) and a specificity of 82.9% (95% CI: 54.7–99.9) to detect BSI in children younger than 5 years. This BSI signature demonstrates that host metabolites can have a superior diagnostic sensitivity compared to pathogen-detecting tests to identify infections characterized by low pathogen load such as BSI.

Conclusions

This study demonstrates the potential use of plasma metabolites to identify causality in children with severe febrile illness in malaria-endemic settings.

In the tropics, malaria is commonly attributed to be the cause of most childhood fevers, while in fact this condition is more commonly caused by other pathogens that are clinically indistinguishable from malaria. These so-called non-malaria febrile illnesses include bacterial bloodstream infections, which are associated with a higher mortality than malaria. Most health care facilities in the tropics have malaria diagnostic tests available, but tests for non-malarial febrile illnesses are extremely limited. There is the critical need for new tests that can address the question ‘if a febrile patient is not suffering from malaria, then what is it and what treatment will be effective?’ Using metabolomics, we have comprehensively screened the biochemical profile of patients with severe febrile illness for biological markers of non-malaria febrile illness. The results show that severe malaria and non-malaria febrile illness trigger a distinct metabolic response in the host. We demonstrate that this pathophysiological difference can be exploited for differential diagnosis of severe febrile illness and identification of patients with bacterial bloodstream infections.

Development of a novel smartphone-based application for accurate and sensitive on-field hemoglobin measurement

A smartphone-based app for the accurate and sensitive measurement of hemoglobin was developed.

Programmable bio-nano-chip system: a flexible point-of-care platform for bioscience and clinical measurements

The development of integrated instrumentation for universal bioassay systems serves as a key goal for the lab-on-a-chip community. The programmable bio-nano-chip (p-BNC) system is a versatile multiplexed and multiclass chemical- and bio-sensing system for bioscience and clinical measurements. The system is comprised of two main components, a disposable cartridge and a portable analyzer. The customizable single-use plastic cartridges, which now can be manufactured in high volumes using injection molding, are designed for analytical performance, ease of use, reproducibility, and low cost. These labcard devices implement high surface area nano-structured biomarker capture elements that enable high performance signaling and are index-matched to real-world biological specimens. This detection modality, along with the convenience of on-chip fluid storage in blisters and self-contained waste, represents a standard process to digitize biological signatures at the point-of-care. A companion portable analyzer prototype has been developed to integrate fluid motivation, optical detection, and automated data analysis, and it serves as the human interface for complete assay automation. In this report, we provide a systems-level perspective of the p-BNC universal biosensing platform with an emphasis on flow control, device integration, and automation. To demonstrate the flexibility of the p-BNC, we distinguish diseased and non-case patients across three significant disease applications: prostate cancer, ovarian cancer, and acute myocardial infarction. Progress towards developing a rapid 7 minute myoglobin assay is presented using the fully automated p-BNC system.

Design, Synthesis, and Characterization of Small-Molecule Reagents That Cooperatively Provide Dual Readouts for Triaging and, When Necessary, Quantifying Point-of-Need Enzyme Assays

A newly designed small molecule reagent provides both qualitative and quantitative readouts in assays that detect enzyme biomarkers. The qualitative readout enables rapid triaging of samples so that only samples that contain relevant concentrations of the target analyte must be quantified. The reagent is accessible in essentially three steps and 34% overall yield, is stable as a solid when heated to 44 °C for >1 month, and does not produce background signal when used in an assay. This paper describes the design and synthesis of the reagent, characterizes its response properties, and establishes the scope of its reactivity.

A smartphone dongle for diagnosis of infectious diseases at the point of care

This work demonstrates that a full laboratory-quality immunoassay can be run on a smartphone accessory. This low-cost dongle replicates all mechanical, optical, and electronic functions of a laboratory-based enzyme-linked immunosorbent assay (ELISA) without requiring any stored energy; all necessary power is drawn from a smartphone. Rwandan health care workers used the dongle to test whole blood obtained via fingerprick from 96 patients enrolling into care at prevention of mother-to-child transmission clinics or voluntary counseling and testing centers. The dongle performed a triplexed immunoassay not currently available in a single test format: HIV antibody, treponemal-specific antibody for syphilis, and nontreponemal antibody for active syphilis infection. In a blinded experiment, health care workers obtained diagnostic results in 15 min from our triplex test that rivaled the gold standard of laboratory-based HIV ELISA and rapid plasma reagin (a screening test for syphilis), with sensitivity of 92 to 100% and specificity of 79 to 100%, consistent with needs of current clinical algorithms. Patient preference for the dongle was 97% compared to laboratory-based tests, with most pointing to the convenience of obtaining quick results with a single fingerprick. This work suggests that coupling microfluidics with recent advances in consumer electronics can make certain laboratory-based diagnostics accessible to almost any population with access to smartphones.

Detection of protein biomarker using a blood glucose meter

mHeath technologies are recognized to play important roles in the future of personal care and medicine. However, their full potentials have not been reached, as most of current technologies are restricted to monitoring physical and behavioral parameters, such as body temperature, heart rate, blood pressure, and physical movement, while direct monitoring of biomarkers in body fluids can provide much more accurate and useful information for medical diagnostics. A major barrier to realizing the full potential of mHealth is the high costs and long cycles of developing mHealth devices capable of monitoring biomarkers in body fluids. To lower the costs and shorten the developmental cycle, we have demonstrated the leveraging of the most successful portable medical monitoring device on the market, the blood glucose meter (BGM), with FDA-approved smartphone technologies that allow for wireless transmission and remote monitoring of a wide range of non-glucose targets. In this protocol, an aptamer-based assay for quantification of interferon-γ (IFN-γ) using an off-the-shelf BGM is described. In this assay, an aptamer-based target recognition system is employed. When IFN-γ binds to the aptamer, it triggers the release of a reporter enzyme, invertase, which can catalyze the conversion of sucrose (not detected by BGM) to glucose. The glucose being produced is then detected using a BGM. The system mimics a competitive enzyme-linked immunosorbent assay (ELISA), where the traditional immunoassay is replaced by an aptamer binding assay; the reporter protein is replaced by invertase, and finally the optical or fluorescence detector is replaced with widely available BGMs.

Smartphone dongle for simultaneous measurement of hemoglobin concentration and detection of HIV antibodies

It is traditionally difficult to incorporate two classes of diagnostic tests into a single platform. In this work, we demonstrate a microfluidic-based smartphone dongle that simultaneously measures concentration of hemoglobin and detects HIV antibodies. Specifically, we demonstrate how a previously published immunoassay device, which measured optical density of silver precipitation on gold colloids, can be expanded to quantitatively measure hemoglobin concentration via a colorimetric assay. By lysing whole blood components with CHAPS detergent, we achieved highly reproducible measurement of hemoglobin concentration with the device. We tested this dual test on 38 patient samples from Columbia University Medical Center. Compared with the Hemocue Hb 201+ analyzer, hemoglobin concentrations from our device were accurate within 1.2 g dL(-1), while the HIV immunoassay (in the presence of CHAPS detergent) showed 95% sensitivity and 95% specificity, comparable to our previous studies. This work demonstrates the feasibility of integrating two classes of diagnostic tests (a colorimetric-based quantitative measurement and an immunoassay based on silver precipitation on gold colloids) into a low-cost, fast, and low-power dongle that works with smartphones, and creates a novel dual panel with clinical utility for antenatal-care settings.

Surface Tension Triggered Wetting and Point of Care Sensor Design

Rapid, simple, and inexpensive point-of-care (POC) medical tests are of significant need around the world. The transition between nonwetting and wetted states is used to create instrument-free surface tension sensors for POC diagnosis, using a layered electrospun mesh with incorporated dye to change color upon wetting.

Research highlights: translating chips

Microfluidic and microfabricated systems are providing key functionalities in diagnostic and therapeutic scenarios, translating beyond the research laboratory to pre-clinical animal studies and clinical studies with patients. Here, we highlight a recent study making use of miniaturization and automation in the development of a smartphone-integrated point-of-care diagnostic to detect antibodies to infectious diseases in a global health setting. We also review an intraocular implanted diagnostic system for glaucoma that relies on imaging the location of a fluid meniscus in a microchannel to readout pressure within the eye. Developments in low-cost and highly functional consumer electronic systems (e.g. smartphones in both highlighted works) has led to a continuing trend to incorporate such technologies with microfluidic fluid handling capabilities to achieve complete diagnostic solutions. We conclude with another implanted microdevice that delivers drug locally to tumors through electroosmotic flow and electromigration of charged drug species, which allows high drug concentrations near a tumor or resected tumor site while preventing high systemic levels associated with significant side-effects. The maturity of microsystem components are now allowing integration into fully functional systems that are poised to reach the clinic in a variety of forms - diagnostic to therapeutic.

The state of point-of-care testing: a European perspective

Point-of-care testing (POCT) refers to any diagnostic test administered outside the central laboratory at or near the location of the patient. By performing the sample collection and data analysis steps in the same location POCT cuts down on transport and processing delays, resulting in the rapid feedback of test results to medical decision-makers. Over the past decades the availability and use of POCT have steadily increased in Europe and throughout the international community. However, concerns about overall utility and the reliability of benefits to patient care have impeded the growth of POCT in some areas. While there is no agreed-upon standard for how success should be judged, the increases in speed and mobility provided by POCT can lead to substantial advantages over traditional laboratory testing. When properly utilized, POCT has been shown to yield measurable improvements in patient care, workflow efficiency, and even provide significant financial benefits. However, important organizational and quality assurance challenges must be addressed with the implementation of POCT in any health care environment. To ensure maximal benefits it may be necessary to evaluate critically and restructure existing clinical pathways to capitalize better on the rapid test turnaround times provided by POCT.

Mobile device for disease diagnosis and data tracking in resource-limited settings

Here we describe a low-cost mobile device that combines cell-phone and satellite communication technologies with fluid miniaturization techniques for performing all essential functions of enzyme-linked immunosorbent assay (ELISA). Disease-specific antigens are immobilized on the microfluidic surface, and disease specific antibodies are captured on the surface and visualized with silver-gold amplification. The diagnostic result is automatically determined by the device by measuring the absorbance through the silver-gold amplification in the microchannel. The results are displayed for the user and are synchronized to a remote patient record. The overall system aims to be portable, robust, low-power, and fully utilize the ability of mobile devices for bringing better health care to resource poor areas.

Digital microfluidic platform for the detection of rubella infection and immunity: a proof of concept

BACKGROUND

Whereas disease surveillance for infectious diseases such as rubella is important, it is critical to identify pregnant women at risk of passing rubella to their offspring, which can be fatal and can result in congenital rubella syndrome (CRS). The traditional centralized model for diagnosing rubella is cost-prohibitive in resource-limited settings, representing a major obstacle to the prevention of CRS. As a step toward decentralized diagnostic systems, we developed a proof-of-concept digital microfluidic (DMF) diagnostic platform that possesses the flexibility and performance of automated immunoassay platforms used in central facilities, but with a form factor the size of a shoebox.

METHODS

DMF immunoassays were developed with integrated sample preparation for the detection of rubella virus (RV) IgG and IgM. The performance (sensitivity and specificity) of the assays was evaluated with serum and plasma samples from a commercial antirubella mixed-titer performance panel.

RESULTS

The new platform performed the essential processing steps, including sample aliquoting for 4 parallel assays, sample dilution, and IgG blocking. Testing of performance panel samples yielded diagnostic sensitivity and specificity of 100% and 100% for both RV IgG and RV IgM. With 1.8 μL sample per assay, 4 parallel assays were performed in approximately 30 min with <10% mean CV.

CONCLUSIONS

This proof of concept establishes DMF-powered immunoassays as being potentially useful for the diagnosis of infectious disease.

Molecular oncology testing in resource-limited settings

Cancer prevalence and mortality are high in developing nations, where resources for cancer control are inadequate. Nearly one-quarter of cancers in resource-limited nations are infection related, and molecular assays can capitalize on this relationship by detecting pertinent pathogen genomes and human gene variants to identify those at highest risk for progression to cancer, to classify lesions, to predict effective therapy, and to monitor tumor burden over time. Prime examples are human papillomavirus in cervical neoplasia, Helicobacter pylori and Epstein-Barr virus in gastric adenocarcinoma and lymphoma, and hepatitis B or C virus in hepatocellular cancer. Research is underway to engineer devices that overcome social, economic, and technical barriers limiting effective laboratory support. Additional challenges include an educated workforce, infrastructure for quality metrics and record keeping, and funds to sustain molecular test services. The combination of well-designed interfaces, novel and robust electrochemical technology, and telemedicine tools will promote adoption by frontline providers. Fast turnaround is crucial for surmounting loss to follow-up, although increased use of cell phones, even in rural areas, enhances options for patient education and engagement. Links to a broadband network facilitate consultation and centralized storage of medical data. Molecular technology shows promise to address gaps in health care through rapid, user-friendly, and cost-effective devices reflecting clinical priorities in resource-poor areas.

Assessing the impact of mHealth interventions in low- and middle-income countries--what has been shown to work?

BACKGROUND

Low-cost mobile devices, such as mobile phones, tablets, and personal digital assistants, which can access voice and data services, have revolutionised access to information and communication technology worldwide. These devices have a major impact on many aspects of people's lives, from business and education to health. This paper reviews the current evidence on the specific impacts of mobile technologies on tangible health outcomes (mHealth) in low- and middle-income countries (LMICs), from the perspectives of various stakeholders.

DESIGN

Comprehensive literature searches were undertaken using key medical subject heading search terms on PubMed, Google Scholar, and grey literature sources. Analysis of 676 publications retrieved from the search was undertaken based on key inclusion criteria, resulting in a set of 76 papers for detailed review. The impacts of mHealth interventions reported in these papers were categorised into common mHealth applications.

RESULTS

There is a growing evidence base for the efficacy of mHealth interventions in LMICs, particularly in improving treatment adherence, appointment compliance, data gathering, and developing support networks for health workers. However, the quantity and quality of the evidence is still limited in many respects.

CONCLUSIONS

Over all application areas, there remains a need to take small pilot studies to full scale, enabling more rigorous experimental and quasi-experimental studies to be undertaken in order to strengthen the evidence base.

Mobile phones to support adherence to antiretroviral therapy: what would it cost the Indian National AIDS Control Programme?

INTRODUCTION

Adherence to antiretroviral treatment (ART) is critical to maintaining health and good clinical outcomes in people living with HIV/AIDS. To address poor treatment adherence, low-cost interventions using mobile communication technology are being studied. While there are some studies that show an effect of mobile phone reminders on adherence to ART, none has reported on the costs of such reminders for national AIDS programmes. This paper aims to study the costs of mobile phone reminder strategies (mHealth interventions) to support adherence in the context of India's National AIDS Control Program (NACP).

METHODS

The study was undertaken at two tertiary level teaching hospitals that implement the NACP in Karnataka state, South India. Costs for a mobile phone reminder application to support adherence, implemented at these sites (i.e. weekly calls, messages or both) were studied. Costs were collected based on the concept of avoidable costs specific to the application. The costs that were assessed were one-time costs and recurrent costs that included fixed and variable costs. A sequential procedure for costing was used. Costs were calculated at national-programme level, individual ART-centre level and individual patient level from the NACP's perspective. The assessed costs were pooled to obtain an annual cost per patient. The type of application, number of ART centres and number of patients on ART were varied in a sensitivity analysis of costs.

RESULTS

The Indian NACP would incur a cost of between 79 and 110 INR (USD 1.27-1.77) per patient per year, based on the type of reminder, the number of patients on ART and the number of functioning ART centres. The total programme costs for a scale-up of the mHealth intervention to reach the one million patients expected to be on treatment by 2017 is estimated to be 0.36% of the total five-year national-programme budget.

CONCLUSIONS

The cost of the mHealth intervention for ART-adherence support in the context of the Indian NACP is low and is facilitated by the low cost of mobile communication in the country. Extending the use of mobile communication applications beyond adherence support under the national programme could be done relatively inexpensively.

Clinical laboratory data: acquire, analyze, communicate, liberate

The availability of portable healthcare devices, which can acquire and transmit medical data to remote experts would dramatically affect healthcare in areas with poor infrastructure. Smartphones, which feature touchscreen computer capabilities and sophisticated cameras, have become widely available with over billion units shipped in 2013. In the clinical laboratory, smartphones have recently brought the capabilities of key instruments such as spectrophotometers, fluorescence analyzers and microscopes into the palm of the hand. Several research groups have developed sensitive and low-cost smartphone-based diagnostic assay prototypes for testing cholesterol, albumin, vitamin D, tumor markers, and the detection of infectious agents. This review covers the use of smartphones to acquire, analyze, communicate, and liberate clinical laboratory data. Smartphones promise to dramatically improve the quality and quantity of healthcare offered in resource-limited areas.

Universal mobile electrochemical detector designed for use in resource-limited applications

This paper describes an inexpensive, handheld device that couples the most common forms of electrochemical analysis directly to "the cloud" using any mobile phone, for use in resource-limited settings. The device is designed to operate with a wide range of electrode formats, performs on-board mixing of samples by vibration, and transmits data over voice using audio--an approach that guarantees broad compatibility with any available mobile phone (from low-end phones to smartphones) or cellular network (second, third, and fourth generation). The electrochemical methods that we demonstrate enable quantitative, broadly applicable, and inexpensive sensing with flexibility based on a wide variety of important electroanalytical techniques (chronoamperometry, cyclic voltammetry, differential pulse voltammetry, square wave voltammetry, and potentiometry), each with different uses. Four applications demonstrate the analytical performance of the device: these involve the detection of (i) glucose in the blood for personal health, (ii) trace heavy metals (lead, cadmium, and zinc) in water for in-field environmental monitoring, (iii) sodium in urine for clinical analysis, and (iv) a malarial antigen (Plasmodium falciparum histidine-rich protein 2) for clinical research. The combination of these electrochemical capabilities in an affordable, handheld format that is compatible with any mobile phone or network worldwide guarantees that sophisticated diagnostic testing can be performed by users with a broad spectrum of needs, resources, and levels of technical expertise.

Systematic review on what works, what does not work and why of implementation of mobile health (mHealth) projects in Africa

BACKGROUND

Access to mobile phone technology has rapidly expanded in developing countries. In Africa, mHealth is a relatively new concept and questions arise regarding reliability of the technology used for health outcomes. This review documents strengths, weaknesses, opportunities, and threats (SWOT) of mHealth projects in Africa.

METHODS

A systematic review of peer-reviewed literature on mHealth projects in Africa, between 2003 and 2013, was carried out using PubMed and OvidSP. Data was synthesized using a SWOT analysis methodology. Results were grouped to assess specific aspects of project implementation in terms of sustainability and mid/long-term results, integration to the health system, management process, scale-up and replication, and legal issues, regulations and standards.

RESULTS

Forty-four studies on mHealth projects in Africa were included and classified as: "patient follow-up and medication adherence" (n = 19), "staff training, support and motivation" (n = 2), "staff evaluation, monitoring and guidelines compliance" (n = 4), "drug supply-chain and stock management" (n = 2), "patient education and awareness" (n = 1), "disease surveillance and intervention monitoring" (n = 4), "data collection/transfer and reporting" (n = 10) and "overview of mHealth projects" (n = 2). In general, mHealth projects demonstrate positive health-related outcomes and their success is based on the accessibility, acceptance and low-cost of the technology, effective adaptation to local contexts, strong stakeholder collaboration, and government involvement. Threats such as dependency on funding, unclear healthcare system responsibilities, unreliable infrastructure and lack of evidence on cost-effectiveness challenge their implementation. mHealth projects can potentially be scaled-up to help tackle problems faced by healthcare systems like poor management of drug stocks, weak surveillance and reporting systems or lack of resources.

CONCLUSIONS

mHealth in Africa is an innovative approach to delivering health services. In this fast-growing technological field, research opportunities include assessing implications of scaling-up mHealth projects, evaluating cost-effectiveness and impacts on the overall health system.

Democratizing molecular diagnostics for the developing world

OBJECTIVES

Infectious diseases that are largely treatable continue to pose a tremendous burden on the developing world despite the availability of highly potent drugs. The high mortality and morbidity rates of these diseases are largely due to a lack of affordable diagnostics that are accessible to resource-limited areas and that can deliver high-quality results. In fact, modified molecular diagnostics for infectious diseases were rated as the top biotechnology to improve health in developing countries.

METHODS

In this review, we describe the characteristics of accessible molecular diagnostic tools and discuss the challenges associated with implementing such tools at low infrastructure sites.

RESULTS

We highlight our experience as part of the "Grand Challenge" project supported by the Gates Foundation for addressing global health inequities and describe issues and solutions associated with developing adequate technologies or molecular assays needed for broad access in the developing world.

CONCLUSIONS

We believe that sharing this knowledge will facilitate the development of new molecular technologies that are extremely valuable for improving global health.

Shared learning in an interconnected world: innovations to advance global health equity

The notion of "reverse innovation"--that some insights from low-income countries might offer transferable lessons for wealthier contexts--is increasingly common in the global health and business strategy literature. Yet the perspectives of researchers and policymakers in settings where these innovations are developed have been largely absent from the discussion to date. In this Commentary, we present examples of programmatic, technological, and research-based innovations from Rwanda, and offer reflections on how the global health community might leverage innovative partnerships for shared learning and improved health outcomes in all countries.