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Research On High Sensitivity Sensor Based On Interdigitated Array Microelectrode

Posted on:2021-03-16Degree:MasterType:Thesis
Country:ChinaCandidate:Q Y MengFull Text:PDF
GTID:2428330611980651Subject:Integrated circuit engineering
Abstract/Summary:PDF Full Text Request
The Interdigitated array microelectrode?IDAM?sensor is widely used in various kind of detection because its simple structure,easy mass production,small size with sensitive response,and it can quickly establish a stable signal in the detection.On the other hand,the sensitivity and selectivity of the sensor based on IDAM still need to be improved.In this paper,the structure of IDAM was optimized by analyzing its equivalent circuit,and the pulse electroplating was introduced to optimize the fabrication process which could improve its sensitivity.Furthermore,the measured object was pretreated according to its characteristics,and the IDAM was specially modified to improve its selectivity,so the high precision and repeatability detection of different measured objects was realized.The main work and achievements are as follows:?1?This work started with the analysis of equivalent circuit of the interdigital electrode to adjust the structure.The detection limit of standard solution for manganese ions is reduced to 1 nmol L-1 after optimized,and the electrode can be repeatedly cleaned and used for more than 100 times.?2?After the optimization the IDAM sensor,it was used to detect the Salmonella typhimurium bacteria.In order to carry out specific detection,the Salmonella typhimurium bacteria labeled in milk is extracted by means of magnetic bead enrichment and separation,which is converted into manganese ion concentration for detection.The detection limit is 2.0 CFU ml-1,which greatly improves the detection accuracy and shortens the detection time to 45 minutes.?3?Modified by carbon nanotubes and organic polymers a interdigital electrode based field effect transistor sensor?FET-sensor?was fabricated,which improved the sensitivity of the interdigital electrode while providing selectivity to specific detected of copper ions.Hafnium oxide,A high-k material was added between the substrate and the electrode to reduce the device's resistance and enhance the electron transport.Therefore,The former's LOD of the selective detection of copper reached 20 nmol L-1.The LOD of the one modified with hafnium oxide layer was as low as 200 pmol L-1which is 100 time more sensitive than without the sensitivity layer.?4?Finally,the manufacture of IDAM was optimized by pulse electroplating.Single crystal and polycrystalline gold electrodes were manufactured by controlling the conditions of pulse electroplating.It was further found through experiments that the impedance of the single crystal gold electrode was only 68%of the traditional one at the characteristic frequency.And the rough surface of the polycrystalline gold electrode was capable to coupling the chloramphenicol antibody,the quantity coupling by polycrystalline one was six times to the single crystal one at peak.This provides novel methods for the manufacture of micro interdigital electrode and the possibility of performance improvement.
Keywords/Search Tags:Interdigitated array microelectrode, Equivalent circuit analysis, FET, SWCNT, Pulse electrochemical deposition
PDF Full Text Request
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