Electrochemical biosensor by screen printing and method of fabricating same
First Claim
1. An electrochemical biosensor, comprising:
- an insulating substrate;
a layer of electrically conductive wires disposed on said insulating substrate;
an electrode layer comprising a plurality of electrodes including a reference electrode and at least one electrode, and at least two contact ports adapted to connect to a measuring device, said electrode layer being disposed on said layer of electrically conductive wires except for said reference electrode;
a middle insulating layer disposed on said electrode layers without covering said electrodes and said contact ports, said middle insulating layer having a slot therein, above said electrodes;
an active reaction layer having substances of reactant, reaction catalyst, mediator and surfactant spread on the surface of said electrodes and defining an electrode reaction area; and
an upper cover adhered to said middle insulating layer,said upper cover having a closed chamber therein disposed at a rear end of said slot and extending above and in communication with said rear end of said slot, said slot defining a capillary inflow channel to enable a sample to be rapidly introduced into and fill said electrode reaction area by capillary action upon contact with a front tip of said capillary inflow channel and flow of said sample is stopped at a certain point along said capillary inflow channel due to said chamber.
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Accused Products
Abstract
An electrochemical biosensor formed by screen printing and method of fabricating such biosensor is disclosed in the present invention. The biosensor can quickly absorb a sample to be measured therein, effectively control volume of the sample fed and “fill-and-position” the sample therein. The biosensor includes an electrode layer (electrode area) comprising two or three electrodes, which are a working electrode, a reference electrode and an auxiliary electrode (tri-electrode) on an insulating substrate. An active reaction layer containing reactant, reaction catalyst, mediator, wetting agent and surfactant is spread on the surface of the electrode layer. A sample inflow area is formed above the electrode area by adding an upper cover on top of a middle insulating layer with a U-shaped opening formed therein. Sample solution with a minute amount about 0.8 to 1 μl can be rapidly introduced into the electrode area and the active reaction layer via the inflow area by siphon or capillary, where the ingredient of the sample can be analysed by measuring reaction between the sample, reaction catalyst and mediator in the reaction layer using electrochemical potentiometric or amperometric method. An upwardly extended closed space formed within the upper cover above the electrode area adjacent to the front of conductive wires can be effectively used to control sample volume and “fill-and-position” the sample.
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Citations
26 Claims
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1. An electrochemical biosensor, comprising:
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an insulating substrate; a layer of electrically conductive wires disposed on said insulating substrate; an electrode layer comprising a plurality of electrodes including a reference electrode and at least one electrode, and at least two contact ports adapted to connect to a measuring device, said electrode layer being disposed on said layer of electrically conductive wires except for said reference electrode; a middle insulating layer disposed on said electrode layers without covering said electrodes and said contact ports, said middle insulating layer having a slot therein, above said electrodes; an active reaction layer having substances of reactant, reaction catalyst, mediator and surfactant spread on the surface of said electrodes and defining an electrode reaction area; and an upper cover adhered to said middle insulating layer, said upper cover having a closed chamber therein disposed at a rear end of said slot and extending above and in communication with said rear end of said slot, said slot defining a capillary inflow channel to enable a sample to be rapidly introduced into and fill said electrode reaction area by capillary action upon contact with a front tip of said capillary inflow channel and flow of said sample is stopped at a certain point along said capillary inflow channel due to said chamber. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A method of fabricating an electrochemical biosensor, comprising the steps of:
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forming a layer of electrically conductive wires on a substrate by screen printing which then is dried between 40°
C. and 120°
C.;forming an electrode layer on top of said layer of electrically conductive wires by screen printing and drying said substrate between 40°
C. and 120°
C.;forming a middle insulating layer with a slot formed therein above said electrode layer, wherein a working electrode, a reference electrode and an auxiliary electrode are confined within said slot and the opposite ends of said electrodes are exposed to make contact with a measuring device; applying an active reaction layer on said slot; adhering an upper cover formed with an opening therein above said middle insulating layer, wherein said opening is positioned at a rear end of said slot; and applying a surface layer above said upper cover, wherein said opening defines a closed chamber within said upper cover above and in communication with said rear end of said slot, said slot defining a capillary inflow channel such that a sample of substance can be rapidly introduced into and fill said electrode layer by capillary action upon contact of the substance with a front tip of said capillary inflow channel, and flow of said sample in said slot is stopped at a certain point in said slot due to said chamber. - View Dependent Claims (24, 25, 26)
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Specification