Smartphone-based food diagnostic technologies: A review

A new generation of mobile sensing approaches offers significant advantages over traditional platforms in terms of test speed, control, low cost, ease-of-operation, and data management, and requires minimal equipment and user involvement. The marriage of novel sensing technologies with cellphones enables the development of powerful lab-on-smartphone platforms for many important applications including medical diagnosis, environmental monitoring, and food safety analysis. This paper reviews the recent advancements and developments in the field of smartphone-based food diagnostic technologies, with an emphasis on custom modules to enhance smartphone sensing capabilities. These devices typically comprise multiple components such as detectors, sample processors, disposable chips, batteries and software, which are integrated with a commercial smartphone. One of the most important aspects of developing these systems is the integration of these components onto a compact and lightweight platform that requires minimal power. To date, researchers have demonstrated several promising approaches employing various sensing techniques and device configurations. We aim to provide a systematic classification according to the detection strategy, providing a critical discussion of strengths and weaknesses. We have also extended the analysis to the food scanning devices that are increasingly populating the Internet of Things (IoT) market, demonstrating how this field is indeed promising, as the research outputs are quickly capitalized on new start-up companies

Electrochemical Plug-and-Power e-readers for Point-of-Care Applications

Point-of-Care diagnostic tests enable monitor health conditions and obtain fast results close to the patient, reducing medical costs, and allowing the control of infectious outbreaks. The interest in developing Point-of-Care devices is increasing due to they are suitable for a wide variety of applications. This doctoral thesis focuses on the development of Plug-and-Power electronic readers (e- readers) for electrochemical detections and the demonstration of their possibilities as Point-of-Care diagnostic testing. The solutions proposed in this study make it possible to improve Point-of-Care tests whose premises are laboratory decentralization, personalized medicine, rapid diagnosis, and improvement of patient care. Developed electronic readers can be powered from a conventional system, such as a USB port or a lithium battery, or can be defined as self-powered systems, capable of extracting energy from alternative energy sources, such as fuel cells, defining Plug-and-Power systems. The designed electrochemical detection devices in this thesis are based on low-power consumption electronic instrumentation circuits. These circuits are capable of controlling the sensing element, measuring its response, and representing the result quantitatively. The implemented devices can work with both electrochemical sensors and fuel cells. Furthermore, it is possible to adapt its measurement range, enabling its use in a wide variety of applications. Thanks to their reduced energy consumption, some of these developments can be defined as self-powered platforms able to operate only with the energy extracted from the biological sample, which in turn is monitored. These devices are easy-to-use and plug-and-play, enabling those unskilled individuals to carry out tests after prior training. Moreover, thanks to their user-friendly interface, results are clear and easy to understand. This doctoral dissertation is presented as an article compendium and composed of three publications detailed in chronological order of publication. The first contribution describes an innovative portable Point-of-Care device able to provide a quantitative result of the glucose concentration of a sample. The proposed system combines an e-reader and a disposable device based on two elements: a glucose paper-based power source, and a glucose fuel cell-based sensor. The battery-less e-reader extracts the energy from the disposable unit, acquires the signal, processes it, and shows the glucose concentration on a numerical display. Due to low-power consumption of the e-reader, the whole electronic system can operate only with the energy extracted from the disposable element. Furthermore, the proposed system minimizes the user interaction, which only must deposit the sample on the strip and wait a few seconds to see the test result. The second publication validates the e-reader in other scenarios following two approaches: using fuel cells as a power element, and as a dual powering and sensing element. The device was tested with glucose, urine, methanol, and ethanol fuel cells and electrochemical sensors in order to show the adaptability of this versatile concept to a wide variety of fields beyond clinical diagnostics, such as veterinary or environmental fields. The third study presents a low-cost, miniaturized, and customizable electronic reader for amperometric detections. The USB-powered portable device is composed of a full- custom electronic board for signal acquisition, and software, which controls the systems, represents and saves the results. In this study, the performance of the device was compared against three commercial potentiostats, showing comparable results to those obtained using three commercial systems, which were significantly more expensive. As proof of concept, the system was validated by detecting horseradish peroxidase samples. However, it could be easily extended its scope and measure other types of analytes or biological matrices since it can be easily adapted to detect currents a wide range of currents.Las pruebas de diagnostico Point-of-Care permiten monitorizar las condiciones de salud y obtener resultados rápidos cerca del paciente, reduciendo los costes médicos y permitiendo controlar brotes infecciosos. El interés por desarrollar dispositivos de Point- of-Care está aumentando debido a que son aplicables a una amplia variedad de aplicaciones. Esta tesis doctoral se centra en el desarrollo de lectores electrónicos (e-readers) Plug-and- Power para detecciones electroquímicas y la demostración de sus posibilidades como pruebas de diagnóstico de punto de atención (Point-of-Care). Las soluciones propuestas en este trabajo permiten mejorar las pruebas Point-of-Care, cuyas premisas son la descentralización de laboratorio, la medicina personalizada, el diagnóstico rápido y la mejora de la atención al paciente. Los lectores electrónicos desarrollados pueden ser alimentados desde un sistema convencional, como puede ser un puerto USB o una batería de litio, o definirse como sistemas autoalimentados, capaces de extraen energía de fuentes alternativas de energía, como celdas de combustible (fuel cells), definiendo así sistemas Plug-and-Power. Los dispositivos de detección electroquímica diseñados se basan en circuitos de instrumentación electrónica de bajo consumo. Estos circuitos son capaces controlar el elemento de sensado, medir su respuesta y representar el resultado de forma cuantitativa. Los dispositivos implementados pueden trabajar tanto con sensores electroquímicos como con fuel cells. Además, es posible adaptar su rango de medida, permitiendo su utilización en una amplia variedad de aplicaciones. Gracias a su reducido consumo de energía, algunos de estos desarrollos pueden definirse como plataformas autoalimentadas capaces de operar solo con la energía extraída de la muestra biológica, que a su vez es monitorizada. Estas plataformas electrónicas son fáciles de usar y Plug-and-Play, permitiendo que personas no cualificadas puedan utilizarlas después de un previo entrenamiento. Además, gracias a su interfaz fácil de usar, los resultados son claros y fáciles de interpretar

Paper-Based Biosensors for Analysis of Water

The presence of contaminants in water generates a great concern worldwide. As contaminants, we can refer different classes of chemicals, such as pharmaceuticals, personal care products, heavy metals, and also microorganisms, such as waterborne pathogens. Some of the chemical compounds have the potential to bioaccumulate in the aquatic biota. Hence, the development of simple and portable methods for the detection of contaminants in the aquatic environment can improve their monitoring and, consequently, the study of their environmental impact. In this context, the development of paper-based analytical tools and also of biosensor devices has been exploited for quantitative and semiquantitative analysis of several contaminants in different water matrices. The association of these two analytical strategies can provide the implementation of low-cost, portable, and easily handled methods for detecting chemical and biological contaminations in water. In this chapter, we provide a review of the developed paper-based analytical biosensors, highlighting the features of the paper-based (paper substrate and fabrication procedures) and biosensor devices (transducers and biorecognition elements). Moreover, the application of the referred paper-based biosensors for the detection of different water contaminants (pathogens, pharmaceuticals, and heavy metals) in environmental and wastewater samples is discussed

Hybrid Nanocomposites of Plasmonic Metal Nanostructures and 2D Nanomaterials for Improved Colorimetric Detection

This research was supported by EU funds through the FEDER European Regional Development Fund project LISBOA-01-0145-FEDER-031311, by Portuguese national funds provided by FCT—Fundação para a Ciência e Tecnologia, through grant SFRH/BD/09347/2021, PTDC/NANOPT/31311/2017, PTDC/QUI-QIN/29778/2017 and UID/EEA/00066/2020 projects and Instituto Politécnico de Lisboa (IPL/2021/WASTE4CAT_ISEL and IPL/2021/MuMiAS-2D_ISEL).Plasmonic phenomena and materials have been extensively investigated for a long time and gained popularity in the last few years, finding in the design of the biosensors platforms promising applications offering devices with excellent performances. Hybrid systems composed of graphene, or other 2D materials, and plasmonic metal nanostructures present extraordinary optical properties originated from the synergic connection between plasmonic optical effects and the unusual physicochemical properties of 2D materials, thus improving their application in a broad range of fields. In this work, firstly, an overview of the structures and properties of 2D nanomaterials will be provided along with the physics of surface plasmon resonance and localized surface plasmon resonance. In the second part of the work, some examples of colorimetric biosensors exploiting the outstanding properties of hybrids nanocomposites will be presented. Finally, concluding perspectives on the actual status, challenges, and future directions in plasmonic sensing biosensing will be provided. Special emphasis will be given to how this technology can be used to support digitalization and virtualization in pandemic handling.publishersversionpublishe