CN2458626Y

CN2458626Y - Sensor for detecting pylorus helicobacterium

Info

Publication number: CN2458626Y
Application number: CN 00260523
Authority: CN
Inventors: 韩泾鸿; 张虹; 董蕾; 龚均
Original assignee: NO 2 HOSPITAL AFFILIATED TO XI; Institute of Electronics of CAS
Current assignee: NO 2 HOSPITAL AFFILIATED TO XI; Institute of Electronics of CAS
Priority date: 2000-11-23
Filing date: 2000-11-23
Publication date: 2001-11-07
Anticipated expiration: 2010-11-23

Abstract

The utility model relates to a sensor for detecting pylorus helicobacteria. A grid surface of an ion sensitive field effect is fixed with a urea sensitive layer. Compared with the general technology, the utility model uses an opposite method; the urea sensitive layer is formed on a SiN surface and can quickly detect urease and pylorus helicobacteria.

Description

Sensor for detecting helicobacter pylori

The utility model belongs to a sensor, especially detect the field effect sensor of urease.

Helicobacter pylori (helicobacter pylori) was discovered since 1983 by Warren and Marshallri, Hp), the research on Hp and the relationship between Hp and gastrointestinal diseases has been intensive over the last decade, forming a research hotspot. The second consensus in the national Association of H.pylori in Guangzhou and the Asian region of H.pylori in Singapore in 1997 8 in 1997 has made a preliminary consensus on the diagnosis of HP and evaluation of various methods. Research and clinical diagnostic standards for HP diagnosis are proposed by the guangzhou conference. The scientific research diagnosis standards comprise: (1) the bacteria are cultured positively; (2) negative for bacterial culture, but with a large number of typical bacteria stained in the tissue, or with a small number of typical or large number of atypical bacteria stained in the tissue, UBT (A), (B) and (C) are added¹³C or¹⁴C urea breath test), fast urease, PCR, serum any one of four; (3) UBT, fast urease, PCR and blood stain are positive in two items; (4) in-situ identification technology, tissue dyeing, fast urease, serology and PCR.

The clinical diagnosis criteria are: (1) the bacteria are cultured positively. (2) Tissue stains a large number of representative bacteria. Tissue staining, fast urease test, UBT and PCR. The Asia-Pacific consensus can consider that the rapid urease test is the first choice for performing intragastric microscopic examination, has high specificity, does not need tissue staining, and needs to take mucosal tissue for standby. The method can save dyeing cost and is worthy of consideration. Serological methods, which have high false positive and negative rates, are not suitable for clinical applications.

ThePCR method has high sensitivity, but is easy to generate false positive, and the best method is¹³C or¹⁴C Urea Breath Test (UBT),¹⁴the urease UBT C is radioactive,¹³the C-urease-UBT is safer, and the two methods need expensive instruments and equipment and a specific nuclide specimen processing method, and are not easy to perform by general medical units. In addition, any antibiotic and PPT produced false negatives within 4 weeks of discontinuation.

The urease test is based on the principle that helicobacter pylori can produce urease, trace urea (normal concentration is 3-4mM) in stomach is decomposed to produce ammonia and carbon dioxide, so that the pH value of local parts is increased, and gastric acid is neutralized to cause bacteria fixed value pathogenicity. This method involves formulating a reagent containing urea, a pH indicator (phenol red) and a preservative. The reagent generates ammonia after the urease of the Hp bacteria of the active tissue decomposes urea under the acidic condition (the pH value is less than 6.8, the reagent is yellow brown, the reagent is changed into alkaline (the pH value is more than 8.4), phenol red is changed into red purple red from yellow, and the color can be distinguished to determine whether the reagent is positive.

The utility model aims at providing a detect helicobacter pylori sensor. Based on the principle that the digestive tract is infected by helicobacter pylori and urease is generated on the gastric mucosa, a novel biological sensitive field effect tube is designed and is specially used for detecting the urease. The presence of urease indicates infection by H.pylori.

The utility model is mainly characterized in that a urea sensitive layer is fixed on the surface of the grid electrode with the ion sensitive field effect.

The utility model discloses a with the opposite thinking of conventional technology, form the sensitive layer of urea on the SiN surface, can the short-term test go out urease to detect out helicobacter pylori's existence.

FIG. 1 shows a schematic diagram of the structure of a sensor chip for detecting helicobacter pylori. In the figure 1, 1 is a reference electrode, 2 is sealant, 3 is a source electrode and a drain electrode lead, 4 is a passivation layer, and 5 is Si₃N₄ Film 6 is SiO ₂7 is P⁺Isolation region, 8 urea sensitive layers.

Fig. 2 is a diagram of a sensor package structure. In fig. 2, 21 is a sensor chip, 22 is a small hole of a plastic tube, 23 is a sensor electrode lead, 24 is a reference electrode liquid junction, 25 is a reference electrode lead, 26 is sealant, 27 is an Ag/AgCl wire, 28 is a reference electrode salt bridge, and 29 is a medical plastic tube.

General enzyme biographyThe sensor is prepared by immobilizing enzyme on Si₃N₄Surface, such as immobilized urease, measures urea. The novel sensor fixes urea and detects helicobacter pylori by recognizing the presence of urease. This is a processing technique that is the reverse of conventional enzyme biosensor techniques. The urea is selected as a sensitive material, a special embedding method using polyacrylamide or polyvinyl chloride (PVC) as a carrier is adopted, and urea is subjected to certain treatment before embedding due to strong water solubility of urea. The urea solution with a certain concentration is fixed on the surface of the grid electrode of the ion sensitive field effect transistor to form a film 8 sensitive to urease. When the sensor is exposed to urease, the following reactions occur:

when the sensor contacts urease, urea fixed on the surface of the grid electrode and water are hydrolyzed under the catalytic reaction of the urease to generate ammonia and carbamic acid, and the carbamic acid is naturally degraded into another molecule of ammonia and carbonic acid. This locally alkalifies the solution at the surface of the sensor gate region. Thereby changing the output characteristics of the ion sensitive field effect transistor. The concentration of the urease is detected by detecting the change of the output characteristic, and the concentration of helicobacter pylori is also quantitatively detected.

The sensor for detecting helicobacter pylori can be packaged into a structure shown in fig. 2 to form a catheter type helicobacter pylori sensor. Can be inserted into stomach to match with gastroscope, and can directly detect helicobacter pylori infection on stomach wall.

Claims

1. A sensor for detecting helicobacter pylori comprises a reference electrode, a sealant, a source electrode, a drain electrode lead, a passivation layer, and Si₃N₄Film, SiO₂、P⁺And the isolation region is characterized in that a urea sensitive layer is fixed on the surface of the grid electrode.

2. The sensor of claim 1, wherein said urea sensitive film is an organic film.