Droplet microfluidics has proved efficiency in simple manipulating of small volumes of liquid samples, especially in combination with electrochemical means of detection e.g., field-effect transistors, amperometric sensors, impedimetric sensors, and etc. The abovementioned combination has grown in a lab on a chip approach for the detection of various substances. However, the problem of precise droplet manipulation and long-term recirculation over individual sensors still present. Here we present a microfluidic design and the way of liquid control that enables recirculation real-time monitoring of hundreds of droplets with nanowire-based impedimetric sensors. The long-term recirculation of droplets over the nanowire area can be used for monitoring biochemical reactions whose real-time analysis of the kinetics can be advantageous for a more precise analysis. The combination of circular microfluidics and nanosensors allows long term recirculation of droplets over the sensor which can be used for monitoring of bio-chemical reactions within solutions or cell/bacteria cultures. The generation of hundreds of droplet reactors provides high reliability and throughput of the result due to statistical reasons, precise flow-rate manipulation allows viability of the assay and impedimetric way of monitoring provides an immersive analysis of the embedded compounds.

Several three-terminal organic bioelectronic structures have been proposed so far to address the needs for a variety of biosensing applications. The most popular ones utlized organic field-effect transistors immobilizing a layer of bio-recognition elements that are operated in an electrolyte that enables one to selectively detect both proteins and genomic analytes. These features along with the foreseen low-cost for their production, make them very appealing for point-of-care biomedical applications. However, organic bioelectronic transistors do not always exhibit a performance level beyond state-of-the-art electrochemical sensors, which have been dominating the field since decades. This review offers a perspective view, based on a systematic comparison between the potentiometric and amperometric electrochemical sensors and their organic bioelectronic transistors counterparts. The key-relevant aspects of the sensing mechanisms are reviewed for both, and when actually in place, the amplification factors are reported as the ratio between the response of a rationally designed transistor and that of a homologous electrochemical sensor. The functional dependence of the bioelectronic sensors responses on the concentration of the species to be detected enabling their correct analytical quantification, is also addressed.

After the pioneering work of Wulff and Mosbach in the development of MIPs by chemical polymerization, in the 1980s synthesis of MIPs by electropolymerization has been successfully introduced. Electrosynthesis of MIPs can be performed in aqueous solutions, where protein molecules preserve their natural conformation. The layer thickness can be precisely tuned by controlling the amount of charge passed. A frequently applied indirect method for the characterization of MIPs exploits voltammetry and impedance spectroscopy of ferricyanide. The changes of the current signals are caused by the removal or binding of the target, but also by “nonspecific” pores. Furthermore, target binding brings about minute decreases of the big current signal. Nevertheless, several papers describing MIPs for both low and high molecular weight substances claim measuring ranges over several orders of magnitude with subnanomolar lower limits of detection. On the other hand, evaluation of the enzymatic activity or of direct electron transfer gives a direct quantification of the target bound to the MIP. MIPs can be synthesized from only one monomer and exhibit measuring ranges from micromolar up to the subnanomolar concentration range. On the other hand, many basic and technological problems have not yet been adequately tackled. We describe in the present talk the electrosynthesis of MIPs and the analytical performance of the electrochemical MIP-sensors for the following proteins: Acetylcholinesterase, Butyrylcholinesterase, Cytochrome P450, Laccase, Tyrosinase, Ferritin, Transferrin, Hemoglobin, and Serum Albumin.

Real-time monitoring of physiological parameters is essential for point-of-care testing. While nowadays routine tests are done through ex vivo analysis on frequently extracted blood, placing implantable sensors monitoring key blood parameters such as lactate, glucose, ions, and oxygen would suppose a giant step forward in the care of critically ill patients, improving the response time in emergencies and diminishing the invasiveness of the measurements. The recent advances in microelectronics and nanotechnology is a promising technology enabling moving in that direction. The goal of our work is to develop arrays of electrochemical sensors with selective and hemocompatible coatings, allowing future implementation of such measurements in patients. We perform the analysis of blood parameters in a label-free and electrochemical manner which is compatible with the inevitable miniaturization in a real application. The tuneable composition of the layer will allow to pursue further applications in the future by modification of the receptor molecules and their concentrations.

This paper describes the development of a biosensor designed to enzymatic detection of short-chain alcohols. The biorecognition element, alcohol dehydrogenase, was immobilized on self-assembled monolayers deposited on top of silicon nitride microcantilevers. The self-assembly process was performed by surface activation using 3-aminopropyltriethoxysilane, followed by glutaraldehyde and biomolecule binding. X-ray photoelectron spectroscopy and atomic force microscopy were used. The biosensor showed a lower response time, a sensibility from 0.03 to 1.2 mL/L. Its selectivity was analyzed through exposure to pure and mixed volatile solvents. Sensor sensibility was higher in the presence of short-chain alcohols family and practically null involving others polar or nonpolar solvents.

We present the development and implementation the Point-of-Care devices for the rapid identification of Streptococcus pyogenes and Streptococcus pneumoniae with simultaneous identification of antibiotic resistance genes. These bacteria are the main etiological factor of acute pharyngitis, palatine tonsils, scarlet fever, pneumonia, meningitis and development of sepsis, with high mortality and dangerous complications. In cases of alleged streptococci infection, antibiotics are used, and only in the absence of positive treatment results an antibiogram is requested and results are available after a few days. During this time, untreated infection can lead to significant deterioration of a patient’s health. The main advantage of the developed test will be fast identification of the bacteria from the throat swab with simultaneous analysis of the antibiotic resistance profile. As a result, the initial treatment will use antibiotics to which the strains are not resistant, leading to fast patient recovery. Results will be available after up to 30 min during the medical appointment. The innovation of the developed test will concern both the polymerase used for amplification of DNA and the approach to resistance testing. Innovation of the concept of drug resistance testing involves the study of not only the resistance genes within the detected bacteria but also the examination of the patient's natural bacterial flora. The presence of β-lactamase-encoding genes that will protect streptococci against antibiotics from the ampicillin group widely used in the treatment of this type of infection will be also identified

A mass casualty incident may result to tenths or hundreds of victims. The triage, being the procedure of classification of victims according to their medical emergency, and the unique identification of victims are procedures equally crucial for effectively managing the crisis in respect to personnel (emergency medical services and non-medical civil protection practitioners) and assets (ambulances, medical equipment, hospital beds etc.). The solution developed in this work aims at reducing the time needed for triage and identification procedures and at the same time enhancing the situation awareness of crisis managers. Our system consists of a) electronic wearable triage tags, aiming at replacing the legacy paper tags, supporting enhanced actuating and connectivity functionalities, visually presenting the status of medical emergency of the victims and uniquely identifying them, b) a mobile application, connected in real-time with a cloud-based data aggregation node, enabling the emergency personnel to control the wearable device and to record the personal and medical emergency information of the victims, c) an interoperability layer, supporting different connectivity options and capable of secure and reliable distribution of the collected data to multiple systems, such as Command and Control (C2s) systems of civil protection agencies, d) a web application, graphically presenting the victims’ medical emergency and their personal information in aggregated and in detail views, intended to be utilized by crisis managers in tactical and strategic level of command. The efficiency of our system has been demonstrated in multiple civil protection full scale exercises across Europe.

Many gas-phase biosensors have been developed for human volatiles (acetone, methyl mercaptan, trimethylamine, ethanol, isopropanol, etc.) and for residential harmful VOCs (formaldehyde, toluene, nicotine) causing some diseases. A novel gas imaging system by biofluorometry with enzyme immobilized mesh has been investigated to demonstrate a spatiotemporal gas-imaging for human volatiles (i.e. ethanol and acetaldehyde after drinking). A biofluorometric technique was applied to improve the performance (sensitivity, calibration range, gas-selectivity, etc.) of the gas-imaging system. The biofluorometric sniff-cam for ethanol was fabricated with ADH (alcohol dehydrogenase) immobilized mesh and an NADH fluorescent-visualization unit (UV-LED sheet array & highly sensitive camera), thus showing the two-dimensional real-time imaging of ethanol vapor distribution (0.5-200 ppm). The system showed rapid and accurate responses and a visible measurement of ethanol in the gas phase. The intensity of fluorescence was linearly related to the concentration of ethanol vapor. The high sensitivity fluorescent imaging of ethanol vapor allows to successfully visualize gaseous ethanol from the human body (exhaled air and skin gas) after drinking. The sniff-cam system would be useful for conventional detecting and imaging the volatile biomarkers.

Self-detachable sensors in body cavities such as a contact lens type and a mouthguard are attracted the attention on the preventive medicine. In this paper, a soft contact lens (SCL) sensor for tear sugar monitoring and the mouthguard (MG) sensor with biocompatible materials integrated with Bluetooth wireless module are introduced. The SCL biosensor for tear glucose was fabricated using biocompatible 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer and polydimethyl siloxane (PDMS) as the biosensor material. The biosensor consisted of a flexible Pt working electrode and an Ag/AgCl reference/counter electrode. Glucose oxidase (GOD) was immobilized on the sensing region. The SCL sensor allowed to monitor a rabbit tear glucose (normal concentration: 0.11mM). Also, the change of tear glucose induced by the change of blood sugar level was assessed by the oral glucose tolerance test. As another body cavity sensor, the MG thermistor with BLE wireless module was developed using a thermoplastic dental material. The MG sensor has succeeded in telemetry of oral temperature on a smart-watch monitoring display. In the future, the self-detachable body cavity sensors are expected to improve the quality of life.

Coming from natural and anthropogenic sources, hydrogen sulfide gas (H₂S) is a smelly hazardous substance at sub-ppm level which can lead to poisoning deaths at higher concentration. New sensors with high metrological properties (detection limit lower than 1ppm) and good stability are still needed to monitor and control the risk associated to this gas. The properties of a high-performance hydrogen sulfide gas sensor based on tin oxide and conductive polymers (polyaniline and poly(3,4-ethylenedioxythiophene):polystyrene sulfonate, PEDOT:PSS) are investigated. The principle of detection of this resistive sensor consists in a two steps reaction. H₂S reacts with tin oxide producing hydrochloride acid which dopes polyaniline leading to the increase of its conductivity. Those systems present high repeatability and reproducibility with sensitivities around 10%/ppm and a limit of detection closed to 30 ppb. Moreover, the effect of interfering species such as humidity and oxidative gases (ammonia) is addressed. Those species have a limited impact, corrigible by data treatment. Finally, the sensors present an increase of sensitivity with time, apparently due to the modification of the interface between the electrodes and the sensitive materials.