Patent Publication Number: US-2005115831-A1

Title: Eletrochemical sensing device

Description:
FIELD OF THE INVENTION  
      The present invention relates to an electrochemical sensing device, and more particular to an electrochemical sensor having a detachable testing holder.  
     BACKGROUND OF THE INVENTION  
      In recent decades, the principle of electrochemical sensing has been developed and applied in the field of detecting kinds of fluid ingredients. An electrochemical sensing device may be assembled with different equipments in different application fields. Nevertheless, an electrochemical sensing device in a general laboratory is generally different from that in a professional checking room. A basic framework of an electrochemical sensing device includes the following components:  
      1. A container, which is applied to contain a fluid sample and is a region for measuring an electrochemical reaction;  
      2. A chemical reagent, which is used for chemically reacting with an analyte contained in the fluid sample and generating an output signal with an electric parameter accordingly, wherein the electric parameter is corresponding to an ingredient of the analyte contained in the fluid sample;  
      3. Plural testing electrodes, which are selected from a group consisting of a counter electrode, a working electrode, a reference electrode, and a detecting electrode; and  
      4. A measuring device, such as an electrochemical meter, which provides the essential working voltage (or current) needed by the electrochemical reaction and measures the electric parameter (output voltage or current) produced by the electrochemical reaction to be recorded for processing the numerical analysis and displaying the testing result thereon.  
      In recent years, the electrochemical sensing device including a disposable electrochemical sensing strip and a main testing body is widely used for measuring an electrochemical reaction and the strength thereof. In general, the disposable sensing strip includes a reaction concavity, an electrochemical reaction layer, some electrode devices and so on. The main testing body provides the essential working voltage (or current) needed by the electrochemical reaction and measures the electric parameter (output voltage or current) produced by the electrochemical reaction to be recorded for processing the numerical analysis and displaying the testing result thereon. Nowadays, most of the health measuring devices, such as blood glucose meter, the uric acid meter, and the cholesterol meter, are the electrochemical sensing devices used in daily life.  
      Since the raw materials and the detailed manufacturing environments for the different batches of the electrochemical sensing strips still cannot be controlled very well at present, identical reactions between each electrochemical sensing strip and the target analyte can not be obtained. However, since the electrochemical sensing strips within the same batch are made of the same raw materials under the extremely similar manufacturing environments, their reactivities to a target analyte would be almost the same. Therefore, some electrochemical sensing strips within the same batch would be taken as samples for testing the relationship between the electrochemical sensing strips and the target analyte, and the testing results would be programmed into a program and the program would be stored in a storage device for being the correcting foundation during the practical applications. During the practical application, the storage device would be installed into a testing device first for correcting the testing device according to the program, and then the electrochemical sensing strip corresponding to the program is installed into the testing device for analyzing a sample.  
      As above-mentioned, it should have been noted that once the electrochemical sensing strips in the batch regarding the program in the storage device are exhausted, the storage device would become useless and should be renewed.  
      Please refer to  FIG. 1 , which shows the schematic view of the electrochemical sensing device according to the prior art. As shown in  FIG. 1 , the electrochemical sensing device  1  includes the testing body  11 , the storage device  12  having the storage chip  121 , and the electrochemical sensing strip  13 . The testing body  11  includes the connecting slots  111  and  112  for respectively connecting with the storage device  12  and the electrochemical sensing strip  13 . The storage chip  121  includes the information about the correction information of the electrochemical sensing strip  13 . In addition to holding the electrochemical sensing strip  13 , the connecting slot  112  also receives the signals of the electrochemical sensing strip  13  via the electrodes  1121 . Nevertheless, in general, the testing result of an electrochemical reaction is determined by the measuring time, that is to say that the testing results of different measuring time for the same reaction would be different. Therefore, the normal representative result for an electrochemical reaction is generally defined as the testing result obtained immediately after the happening of the reaction, nowadays. For example, taking the current blood glucose meter as an example, in order to obtain the testing result as soon as possible, the electrochemical sensing strip  13  is installed into the connecting slot  112  first, and then the user drops some blood onto the electrochemical sensing strip for being analyzed. However, some parts of the blood glucose meter are easily contaminated during the dropping process since it is difficult to completely control the quantity of the blood and some users have their own personal problems, such as vision problems and the equilibrant problems. In addition, the contamination not only causes some testing errors, affects the appearance of the meter, but also endangers the users (since the contamination might be infectious). In addition, since the connecting devices of the conventional electrochemical sensing device (such as the connecting slots and the relevant connecting components, for example, the metal strips) are always parts of the electrochemical sensing device and cannot be replaced by the user, it is always necessary to replace the whole electrochemical sensing device when the connecting devices are defected due to that the elasticity of the relevant connecting component is decreased and the poor contact resulting from being used for hundred times of strip insertions. In fact, almost the operating life of the conventional electrochemical sensing device is dependent on the operating life of the connecting slot for the sensing strip.  
      Furthermore, since the current electrochemical sensing strip is usually disposable, the electrochemical sensing device always has two connecting slots, one is used for connecting with the storage device and the other is used for connecting with the electrochemical sensing strip. Nevertheless, in order to simplify the structure of the electrochemical sensing device, reduce the occurrence of the relevant contamination, and lower down the relevant cost, it is necessary to rearrange the components of the electrochemical sensing device.  
      According to the drawbacks described above, for reducing the structural complexity of the electrochemical sensing device and the operating-life problems of sensing device dependent on the connecting slot for the sensing strip and the relevant cost, the applicant has devoted himself to develop a new electrochemical sensing device with a detachable testing holder through a series of experiments, tests and researches.  
     SUMMARY OF THE INVENTION  
      In accordance with an aspect of the present invention, an electrochemical sensing device is provided. The electrochemical sensing device includes a main body having a connecting slot, a testing holder having a detachable connection to the connecting slot, and an electrochemical sensing strip detachably combined with the testing holder for analyzing a sample.  
      Preferably, the main body further includes a display and a control key.  
      Preferably, the testing holder is a disposable testing holder.  
      Preferably, the testing holder further includes a storage component storing a correction information.  
      Preferably, the connecting slot further includes a plurality of signal contacts.  
      Preferably, the correction information is transmitted to the main body via the plurality of signal contacts when the testing holder is combined with the connecting slot.  
      Preferably, the electrochemical sensing strip includes at least an insulating substrate having a reaction concavity and an opening located thereon, an electrochemical reaction layer located in the reaction concavity, and an electrode device located in the reaction concavity for transmitting a signal resulting from an electrochemical reaction performed in the electrochemical reaction layer.  
      Preferably, the reaction concavity includes at least a hole.  
      Preferably, the electrode device passes through the hole.  
      Preferably, the electrode device includes plural electrodes selected from a group consisting of a counter electrode, a working electrode, a reference electrode and a detecting electrode.  
      Preferably, the plural electrodes are connected to the signal contacts for transmitting the signal when the testing holder is combined with the connecting slot and the electrochemical sensing strip is combined with the testing holder.  
      Preferably, each of the plural electrodes includes a metal and a thin film.  
      Preferably, the metal is one selected from a group consisting of a copper, a titanium, a nickel, a gold, a platinum, a rhodium, a palladium, a ruthenium, a silver, a chromium, an iron, an aluminum, an iridium and an alloy thereof.  
      Preferably, the thin film is made of a material selected from a group consisting of a copper, a titanium, a nickel, a gold, a platinum, a rhodium, a palladium, a ruthenium, a silver, a chromium, an iron, an aluminum, an iridium and an alloy thereof.  
      Preferably, each of the plural electrodes includes a carbon body and a thin film.  
      Preferably, the electrochemical reaction layer further includes a chemical agent for reacting with an analyte of the sample to generate the signal.  
      Preferably, the sample is added into the reaction concavity via said opening.  
      In accordance with another aspect of the present application, an electrochemical sensor is also provided. The electrochemical sensor includes a main body having a detachable testing device, and an electrochemical sensing strip detachably combined with the detachable testing holder for analyzing a sample.  
      Preferably, the detachable testing device includes a base having plural signal contacts and a disposable testing holder.  
      Preferably, the detachable testing device is connected to a storage component storing a correction information.  
      Preferably, the correction information is transmitted to the main body via the plural signal contacts when the detachable testing device is combined with the main body.  
      Preferably, the electrochemical sensing strip includes at least an insulating substrate having a reaction concavity and an opening located thereon, an electrochemical reaction layer located in the reaction concavity, and an electrode device located in the reaction concavity for transmitting a signal resulting from an electrochemical reaction performed in the electrochemical reaction layer.  
      Preferably, the reaction concavity includes at least a hole.  
      Preferably, the electrode device passes through the hole.  
      Preferably, the electrode device includes plural electrodes selected from a group consisting of a counter electrode, a working electrode, a reference electrode and a detecting electrode.  
      Preferably, the plural electrodes are connected to the signal contacts for transmitting the signal when the detachable testing device is combined with the connecting slot and the electrochemical sensing strip is combined with the main body.  
      Preferably, each of the plural electrodes includes a metal and a thin film.  
      Preferably, the thin film is made of a material selected from a group consisting of a copper, a titanium, a nickel, a gold, a platinum, a rhodium, a palladium, a ruthenium, a silver, a chromium, an iron, an aluminum, an iridium and an alloy thereof.  
      Preferably, each of the plural electrodes includes a carbon body and a thin film.  
      Preferably, the electrochemical reaction layer further includes a chemical agent for reacting with an analyte of the sample to generate said signal.  
      Preferably, the sample is added into the reaction concavity via the opening.  
      In accordance with another aspect of the present application, a portable electrochemical sensing device is provided. The portable electrochemical sensing device includes a main body having a connecting slot, and a testing holder having a detachable connection to the connecting slot.  
      The above contents and advantages of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed descriptions and accompanying drawings, in which: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is the schematic view of the electrochemical sensing device in the prior art;  
       FIG. 2 (A) is the exploded view of the disposable electrochemical sensing strip according to the first embodiment of the present invention;  
       FIG. 2 (B) is the perspective view showing the electrochemical sensing strip according to the first embodiment of the present invention;  
       FIG. 2 (C) is the schematic view showing the appearance of the electrochemical sensing strip according to the first embodiment of the present invention;  
       FIG. 2 (D) is the back view of the disposable electrochemical sensing strip according to the first embodiment of the present invention;  
       FIG. 3 (A) is the exploded view of the disposable electrochemical sensing strip according to the second embodiment of the present invention;  
       FIG. 3 (B) is the perspective view showing the electrochemical sensing strip according to the second embodiment of the present invention;  
       FIG. 3 (C) is the back view of the disposable electrochemical sensing strip according to the second embodiment of the present invention;  
       FIG. 4 (A) is the schematic view showing the components of the electrochemical sensing device according to the first embodiment of the present invention;  
       FIG. 4 (B) is the schematic view showing the assembly of the components shown in  FIG. 4 (A);  
       FIG. 5 (A) is the schematic view showing the components of the electrochemical sensing device according to the second embodiment of the present invention;  
       FIG. 5 (B) is the back view showing the components of the electrochemical sensing device according to the second embodiment of the present invention;  
       FIG. 5 (C) is the schematic view showing the assembly of the components shown in  FIG. 5 (A); and  
       FIG. 5 (D) is the back view showing the assembly of the components shown in  FIG. 5 (A). 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
      The present invention will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments of this invention are presented herein for purpose of illustration and description only; it is not intended to be exhaustive or to be limited to the precise form disclosed.  
      Please refer to FIGS.  2 (A)- 2 (D), wherein  FIG. 2 (A) is the exploded view of the disposable electrochemical sensing strip according to the first embodiment of the present invention,  FIG. 2 (B) is the perspective view showing the electrochemical sensing strip according to the embodiment,  FIG. 2 (C) is the schematic view showing the appearance of the electrochemical sensing strip according to the first embodiment, and  FIG. 2 (D) is the back view of the disposable electrochemical sensing strip according to the embodiment. As shown in  FIG. 2 (A), the electrochemical sensing strip  13  includes the insulating substrate  131  with the reaction concavity  132  located thereon and the side  1311  located between the reaction concavity  132  and an edge of the insulating substrate  131 , the electrochemical reaction layer  133  located in the reaction concavity  132  for performing an electrochemical reaction, the cover  135  with the window  1351  and the ventilator  1352 , the opening  1321  and the plural electrodes  1341 ,  1342 , and  1343 . The plural electrodes  1341 ,  1342 , and  1343  respectively have two metal thin films on their end surfaces, which are the metal thin films  13411 ,  13412 ,  13421 ,  13422 ,  13431  and  13432 , for detecting and transmitting the signal resulting from the electrochemical reaction. In addition, there are plural holes  1322  located at the bottom of the reaction concavity  132 , and the plural electrodes  1341 ,  1342 , and  1343  respectively pass through the holes  1322 . Since the electrochemical sensing strip  13  has the side  1311 , the opening  1321  and the ventilator  1352 , a capillary channel will be formed in the zone between the opening  1321  and the ventilator  1352 . When a sample (not shown) enters the reaction concavity  132  through the opening  1321 , the sample will be able to be spread uniformly into the reaction concavity  132  due to the siphon phenomenon on the capillary channel, and then an electrochemical reaction will be performed between the sample and the chemical compositions contained in the electrochemical reaction layer  133 . During the electrochemical reaction, the ventilator  1352  is applied to exhaust the redundant air in the reaction concavity  132  so as to maintain the pressure balance between the inner air of the reaction concavity  132  and the outer air thereof. There is a transparent membrane mounted in the window  1351  for observing the movement of the sample and the electrochemical reaction in the reaction concavity  132 . The plural electrodes  1341 ,  1342 , and  1343  are the counter electrode  1341 , the working electrode  1342 , and the reference electrode  1343 . In addition, another electrode (such as a detecting electrode) is able to be installed in the electrochemical sensing strip  13 , if necessary. Furthermore, it should be noted that the electrochemical sensing strip  13  is able to work as long as it includes a counter electrode and a working electrode, or a reference electrode and a working electrode.  
      Nowadays, in general, the electrodes  1341 ,  1342 ,  1343  and the metal thin films  13411 ,  13412 ,  13421 ,  13422 ,  13431  and  13432  are made of one material selected from a group consisting of a copper, a titanium, a nickel, a gold, a platinum, a rhodium, a palladium, a ruthenium, a silver, a chromium, an iron, an aluminum, an iridium and an alloy thereof. In which, a brass, an oxygen-free copper, a bronze, a phosphorized copper, a nickel silver copper and a beryllium copper are the most commonly used materials. Because the end surfaces of the electrodes should have the high sensitivity and stability, and the requirements of the sensitivity and the stability of the other portions of the electrodes are not so strict, only the end surfaces of the electrodes are necessarily formed by the noble metal and the other portions could be formed by general metals or the carbon for reducing the relevant cost. In addition, since the insulating substrate  131  and the reaction concavity  132  are formed integrally by the plastic injection molding, the relevant costs are reduced.  
      Please refer to FIGS.  3 (A)- 3 (B), which are schematic views showing the electrochemical sensing strip according to the second embodiment of the present invention.  FIG. 3 (A) is the exploded view of the electrochemical sensing strip according to the second embodiment of the present invention,  FIG. 3 (B) is the schematic view showing the appearance of the electrochemical sensing strip according to the second embodiment, and  FIG. 3 (C) is the back view of the disposable electrochemical sensing strip according to the embodiment. As shown in  FIG. 3 (A), the electrochemical sensing strip  23  includes the insulating substrate  231  with the reaction concavity  232  located thereon, the electrochemical reaction layer  233  located in the reaction concavity  232  for performing an electrochemical reaction, the cover  235  with the window  2351  and the ventilator  2352 , the opening  2321  and the plural electrodes  2341  and  2342 . The plural electrodes  2341  and  2342  respectively have two metal thin films on their end surfaces, which are the metal thin films  23411 ,  23412 ,  23421  and  23422  for detecting and transmitting the signal resulting from the electrochemical reaction. In addition, there are plural holes  2322  located at the bottom of the reaction concavity  232 , and the plural electrodes  2341  and  2342  respectively pass through the holes  2322 . Since the electrochemical sensing strip  23  has the opening  2321  and the ventilator  2352 , a capillary channel will be formed in the zone between the opening  2321  and the ventilator  2352 . When a sample (not shown) enters the reaction concavity  232  through the opening  2321 , the sample will be able to be spread uniformly into the reaction concavity  232  due to the siphon phenomenon on the capillary channel, and then an electrochemical reaction will be performed between the sample and the chemical compositions contained in the electrochemical reaction layer  233 . During the electrochemical reaction, the ventilator  2352  is applied to exhaust the redundant air in the reaction concavity  232  so as to maintain the pressure balance between the inner air of the reaction concavity  232  and the outer air thereof. There is a transparent membrane mounted in the window  2351  for observing the movement of the sample and the electrochemical reaction in the reaction concavity  232 . The plural electrodes  2341 ,  2342 , and  2343  are the counter electrode  2341  and the working electrode  1342 . In addition, the counter electrode  2341  is able to be replaced by an reference electrode and another electrode (such as a detecting electrode) is able to be installed in the electrochemical sensing strip  23 , if necessary.  
      Nowadays, in general, the electrodes  2341 ,  2342  and the metal thin films  23411 ,  23412 ,  23421  and  23422  are made of one material selected from a group consisting of a copper, a titanium, a nickel, a gold, a platinum, a rhodium, a palladium, a ruthenium, a silver, a chromium, an iron, an aluminum, an iridium and an alloy thereof. In which, a brass, an oxygen-free copper, a bronze, a phosphorized copper, a nickel silver copper and a beryllium copper are the most commonly used materials. Because the end surfaces of the electrodes should have the high sensitivity and stability, and the requirements of the sensitivity and the stability of the other portions of the electrodes are not so strict, only the end surfaces of the electrodes are necessarily formed by the noble metal and the other portions could be formed by general metals or the carbon for reducing the relevant cost. In addition, since the insulating substrate  231  and the reaction concavity  232  are formed integrally by the plastic injection molding, the relevant costs are reduced.  
      Please refer to FIGS.  4 (A)- 4 (B).  FIG. 4 (A) is the schematic view showing the components of the electrochemical sensing device according to the first embodiment of the present invention, and  FIG. 4 (B) is the schematic view showing the assembly of the components shown in FIG.  4 (A). As shown in  FIG. 4 (A), the electrochemical sensing device  1  includes the testing body  11 , the electrochemical sensing strip  13 , the display  113 , and the control key  114 . The testing body  11  includes the connecting slot  111 , a testing holder  14  detachably connected to the connecting slot  111 , a storage component  141 , and the signal contacts  1411 . The electrochemical sensing strip  13  includes the electrodes  134  and is able to be connected to the testing holder  14 . In which, the testing holder  14  includes plural connecting holes  142 .  
      As shown in FIGS.  4 (A)-(B), since the reactions between the electrochemical sensing strip within different batches and the target analyte are not exactly identical, it is necessary to find out the correction information for the individual batch of electrochemical sensing strips. However, the correction information is what stored in the storage component  141 . During the practical application, the stored correction information in the storage component  141  would be transmitted to the testing body  11  via the signal contact  1111  on the connecting slot  111  when the testing holder  14  is connected to the connecting slot  111 . Since the testing holder  14  has a detachable connection to the connecting slot  111  and is specific to the electrochemical sensing strips  13  within the particular batch, the testing holder  14  would become useless and should be exchanged when the electrochemical sensing strips  13  within the relevant batch are used out. In addition, the signal contacts  1112  would be connected to the electrodes  134  via the connecting holes  142  for transmitting the signal resulting from the electrochemical reaction into the testing body  11  when the electrochemical sensing strip  13  is connected to the testing holder  14  and the testing holder  14  is connected to the connecting slot  111 .  
      Please refer to FIGS.  5 (A)- 5 (D).  FIG. 5 (A) is the schematic view showing the components of the electrochemical sensing device according to the second embodiment of the present invention,  FIG. 5 (B) is the back view showing the components of the electrochemical sensing device according to the embodiment in  FIG. 5 (A),  FIG. 5 (C) is the schematic view showing the assembly of the components shown in  FIG. 5 (A), and  FIG. 5 (D) is the back view showing the assembly of the components shown in  FIG. 5 (A). As shown in FIGS.  5 (A)- 5 (B), the electrochemical sensing device  2  includes the testing body  21 , the electrochemical sensing strip  23 , the testing holder  24 , the display  213  and the control key  214 . The testing body  21  includes the connecting slot  211 . The testing holder  24  is detachably connected to the connecting slot  211  and includes the signal contacts  241  and the transmitting component  242 . The electrochemical sensing strip  23  includes the electrodes  2341  and  2342  ( FIG. 5 (B)), the opening  2321  and the ventilator  2352 , and is detachably connected to the testing holder  24 . The electrodes  2341  and  2342  would be connected to the signal contacts  241  when the electrochemical sensing strip  23  is connected to the testing holder  24 . The transmitting component  242  is applied to transmit the signals received by the signal contacts  241  to the testing body  21 .  
      Since the reactions between the electrochemical sensing strips within different batches and the target analyte are not exactly identical, a storage component (not shown) containing the correction information for the individual batches of electrochemical sensing strips is able to be installed into the testing holder  24  for providing the testing body  21  the relevant correction information, if necessary. On the contrary, it is also possible to buy the electrochemical sensing strips meeting the relevant built-in correction limitations of the testing body for convenience. However, since the testing holder  24  of the present invention is a detachable testing holder, it is possible to exchange the testing holder  24  when it is contaminated.  
      In view of the aforesaid, the present invention provides a novel electrochemical sensing device having the detachable component composed of the storage element and the testing holder. The detachable component is able to be replaced when the relevant electrochemical sensing strips are exhausted. In addition, since the structure of the electrochemical sensing device of the present invention is more compact and the occurrences of the relevant contaminations are reduced, the relevant cost is saved and the safeties of the users are improved. Therefore, the present invention is extremely suitable for being used in the industrial production.  
      While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.