Search results for "SENSORS"
showing 10 items of 343 documents
Noninvasive monitoring of polymer curing reactions by dielectrometry
2011
A microwave sensor system for the noninvasive monitoring of the curing process of a thermoset material placed inside a metallic mold is described. The microwave sensor is designed as an open-ended coaxial resonator with a curved surface adapted to the mold inner shape. The analysis of the microwave resonator comprises a recently developed method for deembedding the effect of coupling network in overcoupled resonators, so the range of permitted measurements encompass both low and high dielectric losses of polymeric materials. Results show that noninvasive, continuous monitoring of the microwave dielectric properties of the thermoset material can be performed in real time, allowing one to che…
Dielectric characterization of biocompatible hydrogels for application to Epidermal RFID devices
2015
Functionalized skin-like membranes are currently under investigation for the design of a new class of Epidermal Electronics devices for sensing and healing applications. The dynamic response of epidermal antennas in presence of absorption and release of fluids is a key-point to design RFID radio-sensors and actuators. This paper addresses the characterization of the dielectric property of PVA-based biocompatible hydrogel membranes in the UHF RFID band by means of a modified ring resonator. Samples having different compositions are measured in the dry state as well as when exposed to a progressive release of body fluids emulating perspirations or wound exudates. It was found that the permitt…
Development and characterization of xyloglucan-poly(vinyl alcohol) hydrogel membrane for Wireless Smart wound dressings
2018
Abstract Hydrogel-based smart wound dressings that combine the traditional favourable properties of hydrogels as skin care materials with sensing functions of relevant biological parameters for the remote monitoring of wound healing are under development. In particular, lightweight, ultra-high frequency radiofrequency identification (UHF RFID) sensor are adjoined to xyloglucan-poly(vinyl alcohol) hydrogel films to battery-less monitor moisture level of the bandage in contact with the skin, as well as wireless transmit the measured data to an off-body reader. This study investigates the swelling behavior of the hydrogels in contact with simulated biological fluids, and the modification of th…
Photoelectrochemical Bisphenol S Sensor Based on ZnO‐Nanoroads Modified by Molecularly Imprinted Polypyrrole
2019
Molecularly imprinted polymers are important tools for the design of sensors and other molecular recognition based analytical systems. In this paper the development of a photoelectrochemical sensor for selective bisphenol determination is reported. The sensor is based on a glass/ZnO/MIP‐Ppy structure consisting of glass modified by a ZnO layer (glass/ZnO), which is functionalized by molecularly imprinted conducting polymer polypyrrole (MIP‐Ppy). The sensitivity of the sensor to bisphenol is in the range of 0.7–12.5 µm. Selectivity tests to other bisphenolic compounds are performed. Some aspects of a photoinduced response mechanism in glass/ZnO/MIP‐Ppy nanostructures are predicte…
Novel Immune TiO2 Photoluminescence Biosensors for Leucosis Detection
2012
Abstract Novel immune photoluminescent biosensor, based on TiO2 nanoparticles, for retroviral leucosis detection has been developed. The photoluminescence spectra were excited by solid state laser with wavelength 355 nm and measured in the range of 370-800 nm. Original photoluminescence spectrum of TiO2 nanoparticles showed wide maximum at 515 nm. The biosensitive layer was formed by immobilization of retroviral leucosis antigens on the surface of TiO2 nanoparticles. Immobilization of antigens on TiO2 surface led to UV-shift of photoluminescence spectrum and increase of PL intensity. The response to different concentrations of retroviral leucosis antibodies has been measured. The decrease o…
Application of Room Temperature Photoluminescence From ZnO Nanorods for Salmonella Detection
2014
ZnO nanorods grown by gaseous-disperse synthesis are confirmed by XRD analysis to have the wurtzite crystal structure. The obtained crystallites, as found from SEM studies, are 57 +/- 9 nm in diameter and 470 +/- 30 nm long on the average. Two emission bands of photoluminescence from ZnO nanorods observed at room temperature are centered at 376 and 520 nm. A biosensitive layer is prepared by immobilization of anti-Salmonella antibodies from liquid solutions on the ZnO surface. Immobilization of the biosensitive layer onto ZnO nanorods is found to increase the intensity of PL. After further reaction with Salmonella antigens (Ags), the PL intensity is found to decrease proportional to Ag conc…
Hypersensitive tunable Josephson escape sensor for gigahertz astronomy
2020
Sensitive photon detection in the gigahertz band constitutes the cornerstone to study different phenomena in astronomy, such as radio burst sources, galaxy formation, cosmic microwave background, axions, comets, gigahertz-peaked spectrum radio sources and supermassive black holes. Nowadays, state of the art detectors for astrophysics are mainly based on transition edge sensors and kinetic inductance detectors. Overall, most sensible nanobolometers so far are superconducting detectors showing a noise equivalent power (NEP) as low as 2x10-20 W/Hz1/2. Yet, fast thermometry at the nanoscale was demonstrated as well with Josephson junctions through switching current measurements. In general, det…
Real-time and low-cost sensing technique based on photonic bandgap structures
2011
[EN] A technique for the development of low-cost and high-sensitivity photonic biosensing devices is proposed and experimentally demonstrated. In this technique, a photonic bandgap structure is used as transducer, but its readout is performed by simply using a broadband source, an optical filter, and a power meter, without the need of obtaining the transmission spectrum of the structure; thus, a really low-cost system and real-time results are achieved. Experimental results show that it is possible to detect very low refractive index variations, achieving a detection limit below 2 x 10(-6) refractive index units using this low-cost measuring technique. (C) 2011 Optical Society of America[
Photoplethysmograhic sensors, potential and limitations: Is it time for regulation? A comprehensive review
2023
Healthcare is expected to increasingly shift care out of inpatient settings thanks to wearable monitoring systems. Photoplethysmography (PPG) is an optical technique already integrated into wrist-worn commercial products which presents significant advantages in terms of cost and dimensions. PPG-based devices, despite their ability to detect multiple cardiovascular parameters, are affected by several influencing conditions that depend both on technological or environmental variables, and on intra- and inter-subject variability that influences the whole measurement chain and reliability, hindering an objective characterization of PPG devices. Plus, the lack of standardization for data collect…
Quantum dots functionalised artificial peptides bioinspired to the D1 protein from the Photosystem II of Chlamydomonas reinhardtii for endocrine disr…
2021
Herein we describe the design and synthesis of novel artificial peptides mimicking the plastoquinone binding niche of the D1 protein from the green photosynthetic alga Chlamydomonas reinhardtii, also able to bind herbicides. In particular, molecular dynamics (MD) simulations were performed to model in silico the behaviour of three peptides, D1Pep70-H, D1Pep70-S264K and D1Pep70-S268C, as genetic variants with different affinity towards the photosynthetic herbicide atrazine. Then the photosynthetic peptides were functionalised with quantum dots for the development of a hybrid optosensor for the detection of atrazine, one of the most employed herbicides for weed control in agriculture as well …