No abstract

Sweat analysis by means of minimally invasive wearable sensors is considered a potentially disruptive method for assessing clinical parameters, with exciting applications in early medical diagnostics and high-performance sports. Electrochemical sensors and biosensors are especially attractive because of the possibility of the electronic integration of wearable devices. In this article, we review several aspects regarding the potentialities and present limitations of electrochemical sweat (bio)sensors, including: the main target analytes and their relationships with clinical conditions; most usual electrochemical techniques of transduction used according to the nature of the target analytes; issues connected to the collection of representative sweat samples; aspects regarding the associated, miniaturized electronic instrumentation used for signal processing and communication; and signal processing by machine learning.

In this work, we present the development of a point-of-care platform for the serologic diagnosis of infectious diseases. The complete system consists of magnetic particles with immobilized antigens, disposable electrochemical cells, hardware and software. The main purpose of this paper is to present the last two components. The platform is powered by a rechargeable battery and can be controlled using mobile devices, allowing point-of-care diagnosis of diseases. The platform was successfully tested for the diagnosis of foot-and-mouth disease, human and bovine brucellosis, and Chagas disease.

The development of an inmunosensor for the point-of-care detection of the foot-and-mouth cattle disease is presented. The detector is based on an ELISA method with electrochemical detection. A non-structural protein, 3ABC, is used to selectively detect antibodies is used to selectively detect anti-3ABC antibodies produced after infection. The biological test is performed onto a screen printed electrodes. A dedicated small, portable potentiostat is employed for the control of the sensors, as well as data acquisition, processing, and storage.

Superparamagnetic iron oxide nanoparticles coated with natural polymers have found many applications in the field of biosensors as magnetic carriers due to the combination of two characteristics: the possibility of controlling the particles movement by applying external magnetic fields and attaching biomolecules to the particle through a chemical bond. The aim of this work was to prepare long-term stabilized particles with acid groups available to be used as magnetic carriers of biomolecules. In this study, we present the synthesis of maghemite nanoparticles coated with alginate, a natural polymer. Particles were characterized by electron microscopy. Magnetic properties were studied by vibrating sample magnetometry, which revealed the superparamagnetic behavior of maghemite nanoparticles. Horseradish peroxidase (HRP) was chemically bonded to the maghemite-alginate particles and the enzymatic activity of HRP was determined by a colorimetric technique. The maghemite-alginate particles were immobilized onto the surface of a gold electrode by means of a magnet and the HRP activity was followed electrochemically, showing that these particles can be successfully used in amperometric sensors. Furthermore, maghemite-alginate particles were also used for the diagnosis of the foot-and-mouth disease by means of an enzyme-linked immunoassay with electrochemical detection. 3ABC protein, a non-structural protein of the virus, was linked to the maghemite-alginate particles and used to selectively detect anti-3ABC antibodies in cattle sera.