Disposable platform for bacterial lysis and nucleic acid amplification based on a single USB-powered printed circuit board.

Recent advances in electronics and microfluidics have enabled several research groups to develop fully integrated, sample-to-result isothermal nucleic acid amplification test (NAAT) platforms for the point of care. However, high component counts and costs have limited translation of these platforms beyond the clinic to low-resource settings-including homes. Many NAATs include complex, multi-component heater electronics based on flex circuits or multiple printed circuit boards (PCBs) to support essential NAAT steps such as lysis, sample deactivation, and nucleic acid amplification.

Near-digital amplification in paper improves sensitivity and speed in biplexed reactions.

The simplest point-of-care assays are usually paper and plastic devices that detect proteins or nucleic acids at low cost and minimal user steps, albeit with poor limits of detection. Digital assays improve limits of detection and analyte quantification by splitting a sample across many wells (or droplets), preventing diffusion, and performing analyte amplification and detection in multiple small wells. However, truly digital nucleic acid amplification tests (NAATs) require costly consumable cartridges that are precisely manufactured, aligned, and operated to enable low detection limits.

Isothermal Amplification with a Target-Mimicking Internal Control and Quantitative Lateral Flow Readout for Rapid HIV Viral Load Testing in Low-Resource Settings.

Point-of-care diagnostics often use isothermal nucleic acid amplification for qualitative detection of pathogens in low-resource healthcare settings but lack sufficient precision for quantitative applications such as HIV viral load monitoring. Although viral load (VL) monitoring is an essential component of HIV treatment, commercially available tests rely on relatively high-resource chemistries like real-time polymerase chain reaction and are thus used on an infrequent basis for millions of people living with HIV in low-income countries. To address the constraints of low-resource settings on nucleic acid quantification, we describe a recombinase polymerase amplification and lateral flow detection approach that quantifies HIV-1 DNA or RNA by comparison to a competitive internal amplification control (IAC) of a known copy number, which may be set to any useful threshold (in our case, a clinically relevant threshold for HIV treatment failure).

Two-Fluorophore Mobile Phone Imaging of Biplexed Real-Time NAATs Overcomes Optical Artifacts in Highly Scattering Porous Media.

Nucleic acid amplification tests (NAATs) are common in laboratory and clinical settings because of their low time to result and exquisite sensitivity and specificity. Laboratory NAATs include onboard positive controls to reduce false negatives and specialized hardware to enable real-time fluorescence detection. Recent efforts to translate NAATs into at-home tests sacrifice one or more of the benefits of laboratory NAATs, such as sensitivity, internal amplification controls (IACs), or time to result.

Mobile Phone Ratiometric Imaging Enables Highly Sensitive Fluorescence Lateral Flow Immunoassays without External Optical Filters.

Paper-based diagnostic tests based on the lateral flow immunoassay concept promise low-cost, point-of-care detection of infectious diseases, but such assays suffer from poor limits of detection. One factor that contributes to poor analytical performance is a reliance on low-contrast chromophoric optical labels such as gold nanoparticles. Previous attempts to improve the sensitivity of paper-based diagnostics include replacing chromophoric labels with enzymes, fluorophores, or phosphors at the expense of increased fluidic complexity or the need for device readers with costly optoelectronics.

Wavelengths and Lifetimes of Paper Autofluorescence: A Simple Substrate Screening Process to Enhance the Sensitivity of Fluorescence-Based Assays in Paper.

Porous media made of nitrocellulose and glass fiber are common "paper" substrates for lateral flow assays, microfluidic paper analytical devices and other point-of-care diagnostic assays. Such assays commonly use optical labels such as gold nanoparticles, latex beads, or fluorescent nanoparticles to visualize the presence of analytes. Fluorescent labels are commonly used in bioassays to enhance sensitivity, but autoluminescence of the paper substrate worsens signal-to-noise ratios of fluorescence-based assays.

Sensitive Protein Detection and Quantification in Paper-Based Microfluidics for the Point of Care.

The design of appropriate diagnostic assays for the point of care requires development of suitable biosensors, detection methods, and diagnostic platforms for sensitive, quantitative detection of biological analytes. Protein targets in particular are especially challenging to detect quantitatively and sensitively due to the lack of amplification strategies akin to nucleic acid amplification. However, recent advances in transducer and biosensor design, new detection labels, and paper-based microfluidics may realize the goal of sensitive, fast, portable, and low-cost protein detection.

Design of a New Type of Compact Chemical Heater for Isothermal Nucleic Acid Amplification.

Previous chemical heater designs for isothermal nucleic acid amplification have been based on solid-liquid phase transition, but using this approach, developers have identified design challenges en route to developing a low-cost, disposable device. Here, we demonstrate the feasibility of a new heater configuration suitable for isothermal amplification in which one reactant of an exothermic reaction is a liquid-gas phase-change material, thereby eliminating the need for a separate phase-change compartment. This design offers potentially enhanced performance and energy density compared to other chemical and electric heaters.

Novel open-source electronic medical records system for palliative care in low-resource settings.

Background: The need for palliative care in sub-Saharan Africa is staggering: this region shoulders over 67% of the global burden of HIV/AIDS and cancer. However, provisions for these essential services remain limited and poorly integrated with national health systems in most nations. Moreover, the evidence base for palliative care in the region remains scarce.