A Smart Wristband Integrated with an IoT-Based Alarming System for Real-Time Sweat Alcohol Monitoring.

Breathalyzer is a common approach to measuring blood alcohol concentration (BAC) levels of individuals suspected of drunk driving. Nevertheless, this device is relatively high-cost, inconvenient for people with limited breathing capacity, and risky for COVID-19 exposure. Here, we designed and developed a smart wristband integrating a real-time noninvasive sweat alcohol metal oxide (MOX) gas sensor with a Drunk Mate, an Internet of Thing (IoT)-based alarming system. A MOX sensor acquired transdermal alcohol concentration (TAC) which was converted to BAC and sent via the IoT network to the Blynk application platform on a smartphone, triggering alarming messages on LINE Notify. A user would receive an immediate alarming message when his BAC level reached an illegal alcohol concentration limit (BAC 50 mg%; TAC 0.70 mg/mL). The sensor readings showed a high linear correlation with TAC (R2 = 0.9815; limit of detection = 0.045 mg/mL) in the range of 0.10−1.05 mg/mL alcohol concentration in artificial sweat, achieving an accuracy of 94.66%. The sensor readings of ethanol in water were not statistically significantly different (p > 0.05) from the measurements in artificial sweat and other sweat-related solutions, suggesting that the device responded specifically to ethanol and was not affected by other electrolytes in the artificial sweat. Moreover, the device could continuously monitor TAC levels simulated in real-time in an artificial sweat testing system. With the integration of an IoT-based alarming system, the smart wristband developed from a commercial gas sensor presented here offers a promising low-cost MOX gas sensor monitoring technology for noninvasive and real-time sweat alcohol measurement and monitoring.

Portable, smartphone-linked, and miniaturized photonic resonator absorption microscope (PRAM Mini) for point-of-care diagnostics.

We report the design, development, and characterization of a miniaturized version of the photonic resonator absorption microscope (PRAM Mini), whose cost, size, and functionality are compatible with point-of-care (POC) diagnostic assay applications. Compared to previously reported versions of the PRAM instrument, the PRAM Mini components are integrated within an optical framework comprised of an acrylic breadboard and plastic alignment fixtures. The instrument incorporates a Raspberry Pi microprocessor and Bluetooth communication circuit board for wireless control and data connection to a linked smartphone. PRAM takes advantage of enhanced optical absorption of ∼80 nm diameter gold nanoparticles (AuNP) whose localized surface plasmon resonance overlaps with the ∼625 nm resonant reflection wavelength of a photonic crystal (PC) surface. When illuminated with wide-field low-intensity collimated light from a ∼617 nm wavelength red LED, each AuNP linked to the PC surface results in locally reduced reflection intensity, which is visualized by observing dark spots in the PC-reflected image with an inexpensive CMOS image sensor. Each AuNP in the image field of view can be easily counted with digital resolution. We report upon the selection of optical/electronic components, image processing algorithm, and contrast achieved for single AuNP detection. The instrument is operated via a wireless connection to a linked mobile device using a custom-developed software application that runs on an Android smartphone. As a representative POC application, we used the PRAM Mini as the detection instrument for an assay that measures the presence of antibodies against SARS-CoV-2 infection in cat serum samples, where each dark spot in the image represents a complex between one immobilized viral antigen, one antibody molecule, and one AuNP tag. With dimensions of 23 × 21 × 10 cm3, the PRAM Mini offers a compact detection instrument for POC diagnostics.

Review of HIV Self Testing Technologies and Promising Approaches for the Next Generation.

The ability to self-test for HIV is vital to preventing transmission, particularly when used in concert with HIV biomedical prevention modalities, such as pre-exposure prophylaxis (PrEP). In this paper, we review recent developments in HIV self-testing and self-sampling methods, and the potential future impact of novel materials and methods that emerged through efforts to develop more effective point-of-care (POC) SARS-CoV-2 diagnostics. We address the gaps in existing HIV self-testing technologies, where improvements in test sensitivity, sample-to-answer time, simplicity, and cost are needed to enhance diagnostic accuracy and widespread accessibility. We discuss potential paths toward the next generation of HIV self-testing through sample collection materials, biosensing assay techniques, and miniaturized instrumentation. We discuss the implications for other applications, such as self-monitoring of HIV viral load and other infectious diseases.