Novel Sweat-Based Wearable Device for Advanced Monitoring of Athletic Physiological Biometrics.

Blood testing has traditionally been the gold standard for the physiological analysis and monitoring of professional athletes. In recent years, blood testing has moved out of the laboratory thanks to portable handheld devices, such as lactate meters. However, despite its usefulness and widespread use, blood testing has several drawbacks and limitations, such as the need for the athlete to stop exercising for blood extraction and the inability to have data continuously collected. In this scenario, sweat has become an alternative to blood testing because of its rich content of electrolytes and metabolites, as well as small quantities of sugars, proteins, and ions. Nevertheless, there are few devices capable of analyzing this biofluid and providing useful information to users. In this paper, an electronic system designed for the autonomous analysis of sweat electrolytes and metabolites along with heart rate dynamics is presented. This system is part of a novel wearable device tailored for athletes that offers to the user a real-time assessment of their physiological status and performance.

High-efficient energy harvesting architecture for self-powered thermal-monitoring wireless sensor node based on a single thermoelectric generator.

In recent years, research on transducers and system architectures for self-powered devices has gained attention for their direct impact on the Internet of Things in terms of cost, power consumption, and environmental impact. The concept of a wireless sensor node that uses a single thermoelectric generator as a power source and as a temperature gradient sensor in an efficient and controlled manner is investigated. The purpose of the device is to collect temperature gradient data in data centres to enable the application of thermal-aware server load management algorithms. By using a maximum power point tracking algorithm, the operating point of the thermoelectric generator is kept under control while using its power-temperature transfer function to measure the temperature gradient. In this way, a more accurate measurement of the temperature gradient is achieved while harvesting energy with maximum efficiency. The results show the operation of the system through its different phases as well as demonstrate its ability to efficiently harvest energy from a temperature gradient while measuring it. With this system architecture, temperature gradients can be measured with a maximum error of 0.14 [Formula: see text]C and an efficiency of over 92% for values above 13 [Formula: see text]C and a single transducer.

Self-Powered Point-of-Care Device for Galvanic Cell-Based Sample Concentration Measurement.

A novel self-powered point-of-care low-power electronics approach for galvanic cell-based sample concentration measurement is presented. The electronic system harvests and senses at the same time from the single cell. The system implements a solution that is suitable in those scenarios where extreme low power is generated from the fuel cell. The proposed approach implements a capacitive-based method to perform a non-linear sweep voltammetry to the cell, but without the need to implement a potentiostat amplifier for that purpose. It provides a digital-user readable result without the need for external non-self-powered devices or instruments compared with other solutions. The system conception was validated for a particular case. The scenario consisted of the measurement of a NaCl solution as the electrolyte, which was related to the conductivity of the sample. The electronic reader continuously measured the current with a transfer function gain of 1.012 V mA-1. The overall system exhibited a maximum coefficient of variation of 6.1%, which was an improvement compared with the state-of-the-art. The proof of concept of this electronics system was validated with a maximum power consumption of 5.8 µW using commercial-off-the-self parts.

Competitive USB-Powered Hand-Held Potentiostat for POC Applications: An HRP Detection Case.

Considerable efforts are made to develop Point-of-Care (POC) diagnostic tests. POC devices have the potential to match or surpass conventional systems regarding time, accuracy, and cost, and they are significantly easier to operate by or close to the patient. This strongly depends on the availability of miniaturized measurement equipment able to provide a fast and sensitive response. This paper presents a low-cost, portable, miniaturized USB-powered potentiostat for electrochemical analysis, which has been designed, fabricated, characterized, and tested against three forms of high-cost commercial equipment. The portable platform has a final size of 10.5 × 5.8 × 2.5 cm, a weight of 41 g, and an approximate manufacturing cost of $85 USD. It includes three main components: the power module which generates a stable voltage and a negative supply, the front-end module that comprises a dual-supply potentiostat, and the back-end module, composed of a microcontroller unit and a LabVIEW-based graphic user interface, granting plug-and-play and easy-to-use operation on any computer. The performance of this prototype was evaluated by detecting chronoamperometrically horseradish peroxidase (HRP), the enzymatic label most widely used in electrochemical biosensors. As will be shown, the miniaturized platform detected HRP at concentrations ranging from 0.01 ng·mL-1 to 1 µg·mL-1, with results comparable to those obtained with the three commercial electrochemical systems.

Self-Powered Portable Electronic Reader for Point-of-Care Amperometric Measurements.

In this work, we present a self-powered electronic reader (e-reader) for point-of-care diagnostics based on the use of a fuel cell (FC) which works as a power source and as a sensor. The self-powered e-reader extracts the energy from the FC to supply the electronic components concomitantly, while performing the detection of the fuel concentration. The designed electronics rely on straightforward standards for low power consumption, resulting in a robust and low power device without needing an external power source. Besides, the custom electronic instrumentation platform can process and display fuel concentration without requiring any type of laboratory equipment. In this study, we present the electronics system in detail and describe all modules that make up the system. Furthermore, we validate the device's operation with different emulated FCs and sensors presented in the literature. The e-reader can be adjusted to numerous current ranges up to 3 mA, with a 13 nA resolution and an uncertainty of 1.8%. Besides, it only consumes 900 µW in the low power mode of operation, and it can operate with a minimum voltage of 330 mV. This concept can be extended to a wide range of fields, from biomedical to environmental applications.

'Plug-and-Power' Point-of-Care diagnostics: A novel approach for self-powered electronic reader-based portable analytical devices.

This paper presents an innovative approach in the portable Point-of-Care diagnostics field, the Plug-and-Power concept. In this new disposable sensor and plug-and-play reader paradigm, the energy required to perform a measurement is always available within the disposable test component. The reader unit contains all the required electronic modules to run the test, process data and display the result, but does not include any battery or power source. Instead, the disposable part acts as both the sensor and the power source. Additionally, this approach provides environmental benefits related to battery usage and disposal, as the paper-based power source has non-toxic redox chemistry that makes it eco-friendly and safe to follow the same waste stream as disposable test strips. The feasibility of this Plug-and-Power approach is demonstrated in this work with the development of a self-powered portable glucometer consisting of two parts: a test strip including a paper-based power source and a paper-based biofuel cell as a glucose sensor; and an application-specific battery-less electronic reader designed to extract the energy from the test strip, process the signal provided and show the glucose concentration on a display. The device was tested with human serum samples with glucose concentrations between 5 and 30 mM, providing quantitative results in good agreement with commercial measuring instruments. The advantages of the present approach can be extended to any kind of biosensors measuring different analytes and biological matrices, and in this way, strengthen the goals of Point-of-Care diagnostics towards laboratory decentralization, personalized medicine and improving patient compliance.