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

Real time monitoring of glucose in whole blood by smartphone

A combined thread-paper microfluidic device (μTPAD) is presented for the determination of glucose in blood. The device is designed to include all the analytical operations needed: red blood cell separation, conditioning, enzymatic recognition, and colorimetric transduction. The signal is captured with a smartphone or tablet working in video mode and processed by custom Android-based software in real-time. The automatic detection of the region of interest on the thread allows for the use of either initial rate or equilibrium signal as analytical parameters. The time needed for analysis is 12 s using initial rate, and 100 s using the equilibrium measurement with a LOD of 48 μM and 12 μM, respectively, and a precision around 7%. The μTPAD allows a rapid de- termination of glucose in real samples using only 3 μL of whole blood.This study was supported by the CTQ2016-78754-C2-1-R project from the Spanish MINEC

Flexible Passive NFC Tag for Multi-Gas Sensing

In this work we present a full-passive flexible multigas sensing tag for the determination of oxygen, carbon dioxide, ammonia, and relative humidity readable by a smartphone. This tag is based on near field communication (NFC) technology for energy harvesting and data transmission to a smartphone. The gas sensors show an optic response that is read through high-resolution digital color detectors. A white LED is used as the common optical excitation source for all the sensors. Only a reduced electronics with very low power consumption is required for the reading of the optical responses and data transmission to a remote user. An application for the Android operating system has been developed for the power supplying and data reception from the tag. The responses of the sensors have been calibrated and fitted to simple functions, allowing a fast prediction of the gases concentration. Cross-sensitivity has also been evaluated, finding that in most of the cases it is negligible or easily correctable using the rest of the readings. The election of the target gases has been due to their importance in the monitoring of modified atmosphere packaging. The resolutions and limits of detection measured are suitable for such kinds of applications.This work was supported by project CTQ2013-44545-R from the Ministry of Economy and Competitiveness (Spain) and Junta de Andalucía (Proyecto de Excelencia P10- FQM-5974). These projects were partially supported by European Regional Development Funds (ERDF). P. Escobedo wants to thank the Spanish Ministry of Education, Culture and Sport (MECD) for a pre-doctoral grant (FPU13/05032)

Microfluidic thread based device for the determination of glucose on whole blood

Gracias al alto poder de procesamiento de los teléfonos inteligentes junto con su capacidad para digitalizar objetos utilizando un detector de imagen integrado, se ha logrado desarrollar diferentes sensores que pueden utilizarse in-situ, y así obtener el parámetro analítico y concentración de analito mediante el uso de una aplicación desarrollada para ello. Actualmente, algunos de los sensores más utilizados con smartphones son los microfluídicos, debido al bajo volumen de muestra necesario para que funcionen y la posibilidad de integrar diferentes operaciones analíticas que permitan al usuario aplicar directamente la muestra al sensor sin ningún tratamiento previo. En este estudio, hemos desarrollado un dispositivo analítico microfluídico basado en hilo (μTAD) [2] para la determinación de glucosa directamente en una muestra de sangre total sin ningún tratamiento previo de la muestra. El dispositivo analítico se basa en el método colorimétrico utilizado para la determinación de glucosa en plasma utilizando glucosa oxidasa y peroxidasa de rábano, con la aparición de un color azul que se relaciona con la concentración de glucosa. Con el fin de utilizar sangre total directamente, el μTAD separa las células sanguíneas del plasma gracias a una membrana de separación incluida en el diseño del sensor, después de lo cual el plasma se tampona a 7.4 pH y se genera la coloración azul debido a la presencia de glucosa, en pocos segundos. El cambio de color del μTAD lo registra el Smartphone en un archivo de video que se analiza en tiempo real, de modo que cuando la relación R/B de las coordenadas del espacio de color RGB alcanza su máximo, guarda el valor y lo interpola en la función de calibración, obteniendo la concentración de glucosa de la muestra de sangre en pantalla.MINECO con los proyectos CTQ2013-44545-R y CTQ2016-78754-C2-1-R