Search results for "Senso"
showing 10 items of 4750 documents
SiPM as miniaturised optical biosensor for DNA-microarray applications
2015
A miniaturized optical biosensor for low-level fluorescence emitted by DNA strands labelled with CY5 is showed. Aim of this work is to demonstrate that a Si-based photodetector, having a low noise and a high sensitivity, can replace traditional detection systems in DNA-microarray applications. The photodetector used is a photomultiplier (SiPM), with 25 pixels. It exhibits a higher sensitivity than commercial optical readers and we experimentally found a detection limit for spotted dried samples of ∼1 nM. We measured the fluorescence signal in different operating conditions (angle of analysis, fluorophores concentrations, solution volumes and support). Once fixed the angle of analysis, for s…
Method and apparatus using selected superparamagnetic labels for rapid quantification of immunochromatographic tests
2009
Mika PA Laitinen1, Jari Salmela2, Leona Gilbert1, Risto Kaivola1, Topi Tikkala2, Christian Oker-Blom1, Jukka Pekola3, Matti Vuento11Department of Biological and Environmental Science; 2Department of Physics, University of Jyväskylä, Jyväskylä, Finland; 3Low Temperature Laboratory, Helsinki University of Technology, Helsinki, FinlandAbstract: A rapid method and instrumentation for quantification of immunochromatographic tests (ICT) are described. The principle and performance of the method was demonstrated by measuring the levels of human chorionic gonadotropin (hCG) present in urine. The test format was a sandwich assay using two distinct monoclonal antib…
Silver based sensors from CD for chloride ions detection
2021
This preliminary work shows a new and innovative way to produce silver based electrodes from compact discs and its application towards the detection of chloride ions. A complete sensor was obtained from the compact discs with working, reference and counter electrode made of silver. Chloride ions were detected by exploiting the high affinity of silver with this anion to produce silver chloride. This electrochemical oxidation of silver can be monitored by using an electrochemical technique such as linear scan voltammetry. Indeed, during linear scan voltammetry the oxidation of silver to silver chloride lead to a peak current that increases linearly with chloride concentration. Using this tech…
Indicator-free electrochemical DNA hybridization biosensor
1998
A new electrochemical hybridization biosensor protocol without an external indicator is described. The biosensor format involves the immobilization of inosine-substituted (guanine-free) probe onto the carbon paste transducer, and a direct chronopotentiometric detection of the duplex formation by the appearance of the guanine oxidation peak of the target. Such a use of the intrinsic DNA electrochemical response for monitoring hybridization events offers several advantages (over the common use of external indicators), including the appearance of a new peak, a flat background, or simplicity. A 4 min short hybridization period allows a detection limit around 120 ng/ml. Performance characteristi…
Electrochemical detection of uric acid and ascorbic acid using r-GO/NPs based sensors
2021
Abstract A sensitive and selective electrochemical sensor, based on reduced graphene oxide and gold nanoparticles obtained by simple co-electrodeposition, was developed for the detection of uric acid and ascorbic acid. Because of the electrochemical oxidation of both uric and ascorbic acid depending on the pH, the sensor performances were studied at different pH values. Excellent results were obtained for uric acid detection in a linear range from 10 to 500 µmol dm−3 with a sensitivity of 0.31 µA cm−2 µM−1. A limit of detection and quantification of 3.6 µM and 10.95 µmol dm−3, respectively, was calculated. Sensors showed good selectivity toward different interfering species present in the m…
Solid glucose biosensor integrated in a multi-well microplate coupled to a camera-based detector: Application to the multiple analysis of human serum…
2018
Abstract In the present work, a biosensor adapted in a 96-well microplate has been coupled with a smartphone-based photometer in order to develop a low-cost colorimetric multi-sample dispositive. The strength of this biosensing system is based on the integration of the biosensor into the 96-well microplate and the use of a smartphone and free image analysis software as a microplate reader. The performance of the proposed biosensor has been demonstrated to determine glucose in several human serum samples. This method is simple, cost-effective, sensitive and selective for the determination of glucose in serum, with detection limits of 1.8 mg/dL and a good linearity over the range 6–88 mg/dL. …
New Reusable Solid Biosensor with Covalent Immobilization of the Horseradish Peroxidase Enzyme: In Situ Liberation Studies of Hydrogen Peroxide by Po…
2019
Herein, we reported a chemiluminescent biosensor based on the covalent immobilization of the horseradish peroxidase (HRP) enzyme on a polydimethylsiloxane (PDMS) support to quantify in situ hydrogen peroxide (H2O2). The chemiluminescent reaction based on the use of luminol as an oxidizable substrate, with HRP as the catalyst, has been used in order to quantify H2O2 as the oxidizing agent. The performance of the proposed biosensor has been demonstrated to determine H2O2 liberated by cells in a culture medium and for evaluating the delivery of H2O2 from denture cleaner tablets, as examples of application. For both analyses, the results indicated that the biosensor is cost-effective, sensitive…
Experimental Investigation of Fused Biconical Fiber Couplers for Measuring Refractive Index Changes in Aqueous Solutions
2016
A detailed experimental study of a simple and compact fiber optic sensor based on a fused biconical fiber coupler is presented, in which the sensitivity is improved by operating the coupler beyond the first coupling cycle. The sensor is demonstrated to perform high sensitivity measurements of refractive index changes by means of variation of sugar concentration in water. The device is operated to achieve a linear transmission response, allowing a linear relation between the sugar concentration and the output signal. The initial sensitivity was measured as 0.03 units of normalized transmission per unit of sugar concentration (g/100 mL), with a noise detection limit of a sugar concentration o…
Electrochemical detection of chloride ions using Ag-based electrodes obtained from compact disc
2022
Abstract In this work electrochemical sensors fabricated from compact disc material (waste or new) are used to quantify chloride ions in different types of samples. All three electrodes, working, counter, and pseudo-reference electrodes, were fabricated from the compact disc and directly used. Different parameters were studied in order to demonstrate the possibility of using this waste material for efficient and low-cost electrochemical sensors. Chloride sensing performance was evaluated using linear scan voltammetry as the detection technique. A sensitivity of 0.174 mA mM−1 cm−2 with a limit of detection of 20 μM and excellent selectivity against many interferents was observed. Selectivity…
Sensory & consumer studies with special populations: children and elderly
2015
revue créée en 2015; The need to adapt the usual sensory methods to face the particularities of children and elderly has been emphasized since many years. A diversity of methods that could be used with children according to their developmental stage, and to a lesser extent with elderly depending on their cognitive status, have been described. This review aims at underlining limits but also possibilities for measuring, in children and elderly, sensory reactions, food acceptance and also for exploring cognitive aspects of food perception. The main points to conduct successfully sensory and consumer studies with these populations are highlighted.