A Preventive Medicine Framework for Wearable Abiotic Glucose Detection System

In this work, we present a novel abiotic glucose fuel cell with battery-less remote access. In the presence of a glucose analyte, we characterized the power generation and biosensing capabilities. This system is developed on a flexible substrate in bacterial nanocellulose with gold nanoparticles used as a conductive ink for piezoelectric deposition based printing. The abiotic glucose fuel cell is constructed using colloidal platinum on gold (Au-co-Pt) and a composite of silver oxide nanoparticles and carbon nanotubes as the anodic and cathodic materials. At a concentration of 20 mM glucose, the glucose fuel cell produced a maximum open circuit voltage of 0.57 V and supplied a maximum short circuit current density of 0.581 mA/cm2 with a peak power density of 0.087 mW/cm2 . The system was characterized by testing its performance using electrochemical techniques like linear sweep voltammetry, cyclic voltammetry, chronoamperometry in the presence of various glucose level at the physiological temperatures. An open circuit voltage (Voc) of 0.43 V, short circuit current density (Isc) of 0.405 mA/cm2 , and maximum power density (Pmax) of 0.055 mW/cm2 at 0.23 V were achieved in the presence of 5 mM physiologic glucose. The results indicate that glucose fuel cells can be employed for the development of a self-powered glucose sensor. The glucose monitoring device demonstrated sensitivity of 1.87 uA/mMcm2 and a linear dynamic range of 1 mM to 45 mM with a correlation coefficient of 0.989 when utilized as a self-powered glucose sensor. For wireless communication, the incoming voltage from the abiotic fuel cell was fed to a low power microcontroller that enables battery less communication using NFC technology. The voltage translates to the NFC module as the digital signals, which are displayed on a custom-built android application. The digital signals are converted to respective glucose concentration using a correlation algorithm that allows data to be processed and recorded for further analysis. The android application is designed to record the time, date stamp, and other independent features (e.g. age, height, weight) with the glucose measurement to allow the end-user to keep track of their glucose levels regularly. Analytics based on in-vitro testing were conducted to build a machine learning model that enables future glucose prediction for 15, 30 or 60 minutes

Smartphone-Enabled Personalized Diagnostics: Current Status and Future Prospects

Biosensors; Mètodes moleculars; Diagnòstics basat en telèfons intel·ligentsBiosensores; Métodos moleculares; Diagnósticos basados en teléfonos inteligentesBiosensors; Molecular methods; Smarthphone-based diagnosticsSmartphones are becoming increasingly versatile thanks to the wide variety of sensor and actuator systems packed in them. Mobile devices today go well beyond their original purpose as communication devices, and this enables important new applications, ranging from augmented reality to the Internet of Things. Personalized diagnostics is one of the areas where mobile devices can have the greatest impact. Hitherto, the camera and communication abilities of these devices have been barely exploited for point of care (POC) purposes. This short review covers the recent evolution of mobile devices in the area of POC diagnostics and puts forward some ideas that may facilitate the development of more advanced applications and devices in the area of personalized diagnostics. With this purpose, the potential exploitation of wireless power and actuation of sensors and biosensors using near field communication (NFC), the use of the screen as a light source for actuation and spectroscopic analysis, using the haptic module to enhance mass transport in micro volumes, and the use of magnetic sensors are discussed.Financial support from the Basque Government under the ELKARTEK program is also acknowledged. EB is funded by Instituto de Salud Carlos III, cofinanced by the European Regional Development Fund (grant CPII18/00025)

NFC Sensors Based on Energy Harvesting for IoT Applications

The availability of low-cost near-field communication (NFC) devices, the incorporation of NFC readers into most current mobile phones, and the inclusion of energy-harvesting (EH) capabilities in NFC chips make NFC a key technology for the development of green Internet of Things (IoT) applications. In this chapter, an overview of recent advances in the field of battery-less NFC sensors at 13.56 MHz is provided, and a comparison to other short-range RFID technologies is given. After reviewing power transfer in NFC, recommendations for the practical design of NFC-based sensor tags and NFC readers are made. A list of commercial NFC integrated circuits with energy-harvesting capabilities is also provided. A survey of recent battery-less NFC sensors developed by the group including soil moisture, water content, pH, color, and implanted NFC sensors is done

Wearable, low-power CMOS ISFETs and compensation circuits for on-body sweat analysis

Complementary metal-oxide-semiconductor (CMOS) technology has been a key driver behind the trend of reduced power consumption and increased integration of electronics in consumer devices and sensors. In the late 1990s, the integration of ion-sensitive field-effect transistors (ISFETs) into unmodified CMOS helped to create advancements in lab-on-chip technology through highly parallelised and low-cost designs. Using CMOS techniques to reduce power and size in chemical sensing applications has already aided the realisation of portable, battery-powered analysis platforms, however the possibility of integrating these sensors into wearable devices has until recently remained unexplored. This thesis investigates the use of CMOS ISFETs as wearable electrochemical sensors, specifically for on-body sweat analysis. The investigation begins by evaluating the ISFET sensor for wearable applications, identifying the key advantages and challenges that arise in this pursuit. A key requirement for wearable devices is a low power consumption, to enable a suitable operational life and small form factor. From this perspective, ISFETs are investigated for low power operation, to determine the limitations when trying to push down the consumption of individual sensors. Batteryless ISFET operation is explored through the design and implementation of a 0.35 \si{\micro\metre} CMOS ISFET sensing array, operating in weak-inversion and consuming 6 \si{\micro\watt}. Using this application-specific integrated circuit (ASIC), the first ISFET array powered by body heat is demonstrated and the feasibility of using near-field communication (NFC) for wireless powering and data transfer is shown. The thesis also presents circuits and systems for combatting three key non-ideal effects experienced by CMOS ISFETs, namely temperature variation, threshold voltage offset and drift. An improvement in temperature sensitivity by a factor of three compared to an uncompensated design is shown through measured results, while adding less than 70 \si{\nano\watt} to the design. A method of automatically biasing the sensors is presented and an approach to using spatial separation of sensors in arrays in applications with flowing fluids is proposed for distinguishing between signal and sensor drift. A wearable device using the ISFET-based system is designed and tested with both artificial and natural sweat, identifying the remaining challenges that exist with both the sensors themselves and accompanying components such as microfluidics and reference electrode. A new ASIC is designed based on the discoveries of this work and aimed at detecting multiple analytes on a single chip. %Removed In the latter half of the thesis, Finally, the future directions of wearable electrochemical sensors is discussed with a look towards embedded machine learning to aid the interpretation of complex fluid with time-domain sensor arrays. The contributions of this thesis aim to form a foundation for the use of ISFETs in wearable devices to enable non-invasive physiological monitoring.Open Acces

General-purpose passive wireless point–of–care platform based on smartphone

A versatile, compact and low-cost analytical platform has been designed, tested and validated to be used in the point-of-care settings. This passive measurement system is powered and complemented by a standard smartphone including a programmed application for measurement configuration and data processing as well as wireless results sharing. Electrochemical and electrochemiluminescence analytical techniques can be configured and realized by this platform that employs standard screen-printed electrodes for the sample managing and off-the-shelf electronic components. The power, electrical and optical signal processing have been studied in depth. The system can harvest energy up to 22.5 mW, set up a voltage in the range of ±1.15 V, and measure potentials in a range of 600 mV with an uncertainty of 1 mV, and current from 2 μA to 0.75 mA with a resolution of 1.1 μA. Moreover, standard tests have been performed to the platform consisting of amperometric, potentiometric, cyclic voltammetry and electrochemiluminescent analytical techniques, showing excellent agreement with a reference instrument. Finally, our design has also been applied to glucose, pH and H2O2 determinations, providing the full analytical parameters which are in very good agreement with the reference instrument results. Ranges (0.065–0.75 M, 0.62–100 mM and 3–9 pH units for glucose, H2O2 and pH, respectively) and limits of detection (0.024 M and 0.03 mM for glucose and H2O2, respectively) make this low-cost platform (<US$8) suitable for analytical applications.This study was supported by projects from the Spanish MINECO (CTQ2016-78754-C2-1- R), European Regional Development Funds (ERDF). and Spanish Ministry of Education, Culture and Sport for a R&D predoctoral grant (FPU13/05032

Application prospects for wearable body surface microfluidic system in sports

The wearable body surface microfluidic system has great application potential in the field of sports. The use of the wearable body surface microfluidic system to monitor the physiological state of athletes can solve problems faced such as long inspection cycle in sports monitoring, difficulties in continuous monitoring, dependence on laboratory platforms, athlete resistance and other problems faced in technological integration to promote the development of the sports field. In recent years, the development of key technologies such as microfluidic chips and microneedle delivery provides an ideal solution for real-time monitoring and even immediate intervention of physiological states during exercise. This paper summarizes the latest research progress of wearable body surface microfluidic systems and focuses on eight wearable body surface microfluidic systems that may be applied in the field of sports, with their application prospects in sports analyzed and discussed. Finally, the application direction of the wearable body surface microfluidic system that may achieve breakthroughs is illustrated with the prospect demonstration of the future research and development direction of wearable sports equipment. This paper aims to focus on technical problems in the development of the sports field, provide multi-disciplinary solutions and advocate technology integration as well as provide scientific and technological assistance for the development of the sports field

Wearable electrochemical biosensors in North America

Tremendous research and commercialization efforts around the world are focused on developing novel wearable electrochemical biosensors that can noninvasively and continuously screen for biochemical markers in body fluids for the prognosis, diagnosis and management of diseases, as well as the monitoring of fitness. Researchers in North America are leading the development of innovative wearable platforms that can comfortably comply to the human body and efficiently sample fluids such as sweat, interstitial fluids, tear and saliva for the electrochemical detection of biomarkers through various sensing approaches such as potentiometric ion selective electrodes and amperometric enzymatic sensors. We start this review with a historical timeline overviewing the major milestones in the development of wearable electrochemical sensors by North American institutions. We then describe how such research efforts have led to pioneering developments and are driving the advancement and commercialization of wearable electrochemical sensors: from minimally invasive continuous glucose monitors for chronic disease management to non-invasive sweat electrolyte sensors for dehydration monitoring in fitness applications. While many countries across the globe have contributed significantly to this rapidly emerging field, their contributions are beyond the scope of this review. Furthermore, we share our perspective on the promising future of wearable electrochemical sensors in applications spanning from remote and personalized healthcare to wellness