SPECIFIC BEHAVIOUR OF THE BLOOD SEDIMENTATION PROCESSES EXAMINED BY THE ELECTROCHEMICAL IMPEDANCE MICROSENSOR

Electrochemical impedance microsensor for the fast monitoring of the blood sedimentation has been developed. Planar microsensor consisted of the interdigital array of electrodes (IDAE - finger/gap widths of different values from 5/5 μm to 400/400 μm) based on Au or Pt thin films sputtered on Si/SiO2 or ceramic alumina substrates. IDAE microsensor allows time measurements of electrical impedance changes - impedance rates - (at frequencies of order 0.1 kHz and 10 kHz) of small blood drop applied on it. The determination of the impedance rate during sedimentation and the impedance spectrometry at a low-frequency range of order of 1 kHz seems to be very helpful for a quick diagnostics of the health state. In the IDAE microsensor erythrocyte aggregation/rapid settling/packing periods associated with dryperiod are overlapping due to the planar arrangement of dimensions in order of 1-100 μm. The time monitoring of the blood sedimentation (in the range of 10-900 seconds) by the impedance method can distinguish between healthy and cancer state of blood and could serve for the simple long-term diagnostics after the surgical operation or as a screening procedure for early diagnoses

NOVEL APPROACH IN RATIOMETRIC TECHNIQUE OF SENSING

A novel method of ratio and relation measurement is introduced. On the basis of this principle, asymmetric ratio resistance and conductance microsensors have been developed which are set to an arbitrary relation temperature or electrochemical concentration. The combined resistance temperature sensor allows both to adjust its sensitivity to the defined value by trimming the asymmetry resistor resistances and to increase the accuracy 10 times in comparison with the classical ratiometric arrangement. The electrochemical conductance micro-sensor is able to monitor the concentration changes in µmol/L range with constant sensitivity adjustable by the frequency of the supply voltage. K e y w o r d s: ratiometric technique, relation measuring systems, resistance sensors, temperature, electrochemical conductanc

GOLD NANOSTRUCTURES SPUTTERED ON ZINC OXIDE THIN FILM AND CORNING GLASS SUBSTRATES

Forming of Au nanostructures on Corning glass substrates and transparent conductive oxide ZnO:Al thin films by the RF diode sequential sputtering is presented. The morphology of Au structures was analysed by scanning electron microscopy (SEM) with the free ImageJ software, the optical properties were evaluated by UV-Vis spectrometry and micro-Raman spectroscopy. The sputtering power density (deposition rate) and nominal Au thickness caused changes in the sizes (10 – 1000 nm2) and nearest neighbour NN distances (4 – 40 nm) of Au nanostructures. The morphology of nanostructures exhibited the LogNormal distribution of the size of nanostructures. The lowest sputtering power density/deposition rate (9 mW/mm2/0.12 nm s–1) was optimal to get both the high optical transparency and a superior activity surface-enhanced Raman scattering of 11-mercaptoundecanoic acid adsorbed on the Au/ZnO:Al film

Design of sensor systems for long time electrodermal activity monitoring

This article describes successive development of electrodermal activity monitoring sensor system. Our aim is to improve existing systems to be more practical and suitable for long-term monitoring. Therefore, compared to conventional devices, our system must be easily wearable, without limiting the examined person in ordinary life, with low power consumption, battery operated and reducing the impact of negative artefacts. Specifically, we describe here three devices. The first is serving mainly to familiarize with the methodology, extensive testing and optimization of measurement parameters. Based on the obtained result, we constructed second system in form of small ring - "EDA ring". Last sensor system is developed with the effort to integrate the monitoring of electrodermal activity in e-health and smart clothes

Elektro – optický monitoring citrátu sodného aplikovatelného v hemodialýze

V této práci se popisují naše počáteční experimenty ve vývoji „on-line“ senzoru na monitoring koncentrace citrátu sodného (Na3C6H2O7) v mimo mozkovém proudění krve v průběhu hemodialýzy. Přesný a rychlý monitoring by umožnil regulaci koncentrace citrátu a návrat do krevního řečiště těla v jeho původních hodnotách, tím pacienta významně méně zatíženého než v přítomnosti. Nedávno jsme se soustředili na stanovení koncentrace měřením elektrické impedance a odrazivosti ve zkoumané krvi. Našim cílem je zkoumat trendy vlivu těchto signálů na koncentraci a vyvinout vhodnou metodiku, která může být použita později v senzorech. Částečně začínáme pracovat také na citlivosti metodiky, přičemž bychom rádi výpočtem dosáhli ekvivalentní elektrický model řešení. To je založeno na elektrochemickém dvouvrstvém modelu a korespondenci s Cole-Cole grafyIn this paper, we describe our initial steps in the development of online sensor to monitor the tri-sodium citrate concentration in extra-cerebral blood flow during haemodialysis. Accurate and fast monitoring would allow the regulation of the concentration of citrate returning to the human bloodstream to its original values, thereby, making the patient significantly less burdened than at present. In the early stages, we focused on the determination of concentration by measuring of electrical impedance and reflection in the collected blood. Our aim is to study the trends of influencing these signals by concentration and to develop a suitable methodology that can be used later in the sensor. In part, we begin working on the selectivity of the methodology that we would like to achieve by calculating the equivalent electrical model of the solution. It is based on the electrochemical double layer model and the corresponding Cole-Cole graphs