Search results for "Biosensor"
showing 10 items of 236 documents
Luminometric Sub-nanoliter Droplet-to-droplet Arrays (LUMDA-chip) for Drug Screening on Phase I Metabolism Enzymes
2013
Here we show the fabrication of the Luminometric Sub-nanoliter Droplet-to-droplet Array (LUMDA chip) by inkjet printing. The chip is easy to be implemented and allows for amultiplexed multi-step biochemical assay in sub-nanoliter liquid spots. This concept is here applied to the integral membrane enzyme CYP3A4, i.e. themost relevant enzymatic target for phase I drug metabolism, and to some structurally-related inhibitors.
Micro and Nano patterns for Biosensing: from enzymatic assays to single cells interaction arrays
2012
In this thesis work, solution dispensing techniques have been employed for the realization of complex biological arrays. Inkjet printing techniques were employed for the generation of drug screening platforms. This approach was initially proved with a model enzyme system like Glucose Oxidase substrate covalently linked to a functionalized silicon oxide support. On this support an enzymatic substrate (D-glucose)/inhibitor (D-glucal) couple was accurately dispensed. A simple optical detection method was used to prove the screening capability of the microarray with the possibility to assay with high reproducibility at the single spot level. Afterwards, this methodology has been extended to CYP…
Formation Kinetics of Mixed Self-Assembled Monolayers of Alkanethiols on GaAs(100)
2017
International audience; We report on the formation kinetics of mixed self-assembled monolayers (SAMs) comprising 16-mercaptohexadecanoic acid (MHDA) and 11-mercapto-1-undecanol (MUDO) thiols on GaAs(100) substrates. These compounds were selected for their potential in constructing highly selective and efficient architectures for biosensing applications. The molecular composition and quality of one-compound and mixed SAMs were determined by the Fourier transform infrared absorption spectroscopy measurements. The formation of enhanced-quality mixed SAMs was investigated as a function of the molecular composition of the thiol mixture and the proportion of ethanol/water solvent used during thei…
BIO Bragg gratings on microfibers for label-free biosensing
2021
[EN] Discovering nanoscale phenomena to sense biorecognition events introduces new perspectives to exploit nano science and nanotechnology for bioanalytical purposes. Here we present Bio Bragg Gratings (BBGs), a novel biosensing approach that consists of diffractive structures of protein bioreceptors patterned on the surface of optical waveguides, and tailored to transduce the magnitude of biorecognition assays into the intensity of single peaks in the reflection spectrum. This work addresses the design, fabrication, and optimization of this system by both theoretical and experimental studies to explore the fundamental physicochemical parameters involved. Functional biomolecular gratings ar…
Bioanalytical system for detection of cancer cells with photoluminescent ZnO nanorods
2016
Using photoluminescent ZnO nanorods and carbohydrate marker SSEA-4, a novel cancer cell recognition system was developed. Immobilization of SSEA-4 antibodies (αSSEA-4) on ZnO nanorods was performed in buffer solution (pH = 7.1) over 2 h. The cancer cell line probes were fixed on the glass slide. One hundred microliters of ZnO-αSSEA-4 conjugates were deposited on the cell probe and exposed for 30 min. After washing photoluminescence spectra were recorded. Based on the developed methodology, ZnO-αSSEA-4 probes were tested on patient-derived breast and colorectal carcinoma cells. Our data clearly show that the carbohydrate SSEA-4 molecule is expressed on cancer cell lines and patient-derived c…
DNA nanofilm thickness measurement on microarray in air and in liquid using an atomic force microscope.
2005
International audience; The measurement of the thickness of DNA films on microarray as a function of the medium (liquid, air) is gaining importance for understanding the signal response of biosensors. Thiol group has been used to attach DNA strands to gold micropads deposited on silicon surface. Atomic force microscopy (AFM) was employed in its height mode to measure the change in the pad thickness and in its force mode to measure the indentation depth of the nanofilm. A good coherence between the height and force modes is observed for the film thickness in air. The adhesion force was found to be an alternative way to measure the surface coverage of the biolayer at nanoscopic scale. However…
Ultrathin and nanostructured ZnO-based films for fluorescence biosensing applications
2011
The fluorescence-based sensing capability of ultrathin ZnO-SiO(2) nanoplatforms, deposited by an integrated approach of colloidal lithography and metal organic chemical vapor deposition, has been investigated upon adsorption of fluorescein-labeled albumin, used as model analyte biomolecule. The protein immobilization process after spontaneous adsorption/desorption significantly enhances the green emission of the different ZnO-based films, as evidenced by scanning confocal microscopy, corresponding to a comparable protein coverage detected by X-ray photoelectron spectroscopy. Moreover, experiments of fluorescence recovery after photobleaching evidence that the protein lateral diffusion at th…
Nanosized hydrophobic gels: Advanced supramolecules for use in electrochemical bio- and immunosensing
2018
Abstract Nanosized hydrogels have emerging as versatile supramolecules materials with application in various electrochemical biosensing devices. This review reports a systematic study of the usefulness of nano-sized hydrogels in the different steps of the process of development of electrochemical biosensing systems. The advantages offered by nano-sized hydrogels in detection of analytes are illustrated with representative recent examples that highlight the scientific interest in widening the use of hydrogel nanoparticles in electrochemical biosensing methods. In this review, different types of hydrogel nanoparticles-based electrochemical biosensors, such as enzyme, protein, and nucleic acid…
Iris-Like Tunable Aperture Employing Liquid-Crystal Elastomers
2014
A liquid-crystal elastomer (LCE) iris inspired by the human eye is demonstrated. With integrated polyimide-based platinum heaters, the LCE material is thermally actuated. The radial contraction direction, similar to a mammalian iris, is imprinted to the LCE by a custom-designed magnetic field. Actuation of the device is reproducible over multiple cycles and controllable at intermediate contraction states.
Core-clad phosphate glass fibers for biosensing
2019
Recently, a phosphate glass with composition 20 CaO-20 SrO-10 Na2O-50 P2O5 (mol%) was found to have good potential as a biomaterial and to possess thermal properties suitable for fiber drawing. This study opened the path towards the development of fully bioresorbable fibers promising for biosensing. In the past, this phosphate glass with CeO2 was found to increase the refractive index and the glass stability. Therefore, a new SrO-containing glass was prepared with 1 mol% of CeO2 and core fibers were drawn from it. A core-clad fiber was also processed, where the core was a Ce-doped glass and the clad undoped, to allow for total internal reflection. The mechanical properties of the core and c…