System for differential determination of a proteolytic enzyme level in a bodily fluid

• US 20070009982A1
• Filed: 07/07/2006
• Published: 01/11/2007
• Est. Priority Date: 07/07/2005
• Status: Active Grant

• Current Assignee: Asulab SA (The Swatch Group AG)
• Original Assignee: Asulab SA (The Swatch Group AG)
• Inventors: Thurlemann, Charles, Haeberli, Andre, Frenkel, Erik
• Granted Patent: US 8,465,635 B2
• Time in Patent Office: Days
• US Class Current: 435/23
• CPC Class Codes: G01N 2333/974 Thrombin
• CPC Class Codes: G01N 33/4905 Determining clotting time of blood by chemical methods G01N33/86, C12Q1/54

Abstract

The system includes an assortment (10) of sensors (10a, 10b, 10c), the working electrode (14a) of each sensor being covered with a specific reagent of a given proteolytic enzyme, including a substrate capable of releasing leaving groups (LG) via the action of said enzyme, a measuring apparatus (20) having an electronic circuit imposing a current, whose intensity or voltage may or may not be variable, between the electrodes, and for receiving in return a signal representative of the release of the LG, and an electronic apparatus (30) for processing the transmitted signal and displaying, on a display screen (32), an indication representative of the release of the LG as a function of time. Application to determination, in a plasma or whole blood sample, of the factors responsible for a coagulation anomaly.

Claims

1. A System for the electrochemical determination of the evolution of the concentration or activity of at least one proteolytic enzyme for detecting a deficiency or abnormal activity thereof in a small sample of bodily fluid, wherein it includes:

an assortment of electrochemical sensors each having the shape of a tongue of small dimensions carrying at least one reference electrode and one working electrode on which a specific reagent for a given proteolytic enzyme is immobilised, the composition of which includes at least one chemical substrate, an end link of which can be cut by said enzyme to release leaving groups;

a measuring apparatus including at least one connecting slot for receiving a sensor and whose electronic circuit, powered by an energy source, imposes, between the electrodes of the sensor, an electric current whose intensity or voltage may or may not be variable, and for receiving in return an electric signal representative of the release of the leaving groups, and

an electronic apparatus including software for processing the signal transmitted by the measuring apparatus to display on a display screen an indication representative of the release of the leaving groups as a function of time.

2. The system according to claim 1, wherein the electronic circuit of the measuring apparatus is arranged for carrying out a chrono-amperometric determination.

3. The system according to claim 1, wherein each assortment of sensors is made up of several sensors, each having a specific reagent for a given proteolytic enzyme, wherein the measuring apparatus can include as many connecting slots as there are sensors in an assortment and in that the electronic apparatus software can differentiate the sensors to display curves sequentially or in a mosaic.

4. The system according to claim 1, wherein each sensor of an assortment includes a material mark corresponding to the determination of a specific enzyme, said mark on the sensor being complementary to a material mark on the connection with the measuring apparatus.

5. The system according to claim 1, wherein the assortment of electrochemical sensors also includes a calibration sensor.

6. The system according to claim 1, wherein the measuring apparatus further includes a closing device for insulating the sensors inserted into said apparatus from the external medium, and a thermoregulation device for keeping the sensors at a determined constant temperature during the entire measurement.

7. The system according to claim 1, wherein the measuring apparatus further includes a thermal probe for measuring the ambient temperature and in that the electronic apparatus software enables the reference curve to be selected as a function of said ambient temperature.

8. The system according to claim 1, wherein the measuring apparatus further includes a secondary display screen for displaying an overall or instantaneous parameter of the measurement being carried out.

9. The system according to claim 8, wherein the displayed parameter is the prothrombin time or the activated partial thromboplastin time when the bodily fluid is plasma or whole blood.

10. The system according to claim 1, wherein the measuring apparatus and the electronic apparatus are united in a single operating unit.

11. The system according to claim 1, wherein the volume of the sample of bodily fluid taken is less than 10 μ

l.

12. The system according to claim 1, wherein it displays an indication of the measurement carried out on the display screen in graphic or other form.

13. The system according to claim 1, wherein the biological fluid is blood, particularly whole blood, in which the evolution of the concentration of coagulation factors or conversely coagulation inhibitors is determined to detect any deficiency, or conversely an excess, or abnormal activity.

14. The system according to claim 12, wherein the composition of the specific reagent includes at least one oligopeptide substrate, an end link of which can be separated by a coagulation factor to give a leaving group, a thromboplastin and a buffer medium.