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Due to the application of the new technologies, POCT (Point of Care Testing) has developed rapidly in recent years. The evolution of POCT devices has experienced four stages:1. qualitative detection(reagent strip, reagent paper). 2. semi-quantification(swatch card colorimetric or semi-quantitative instrument reading) 3. full quantitative system(manual operation)4.automatic and intelligent device
The basic principles of POCT technology can be roughly divided into four categories:
(1) Infiltrating the relevant liquid reagent in the conventional method into the water absorbing material of the filter paper and various microporous membranes, forming an integrated dry reagent block, and then fixing it on the hard matrix to become various forms of diagnostic reagents. article.
(2) Miniaturize traditional analytical instruments and simplify operation methods, making them portable and palm-type devices.
(3) Integrate the above two into a unified system.
(4) Apply biosensing technology to detect the analyte by using a biosensor.
The 7 main technologies
The dry chemical technique is to dry a plurality of reaction reagents on a paper sheet, and use the liquid present in the sample to be used as a reaction medium, and the measured components are directly reacted with a dry reagent solidified on the carrier. Add color test after the test specimen, and use eye-qualification or instrumental test (semi-quantitative). Suitable for all kinds of samples such as whole blood, serum, plasma, urine.
For example, semi-quantitative testing of procalcitonin (PCT) is the use of this method. General chemical tests such as urine protein and glucose are also included in this category.
2.Multi-layer coating technology
Multi-layer coating technology is transplanted from photographic film production technology. A plurality of reaction reagents were sequentially coated on a substrate to prepare a dry tablet. The dry film made by the multi-layer coating technology is evener than the dry chemical paper, and can be accurately quantified by instrument detection, such as the dry chemical analysis system currently used in clinical practice.
POCT strip technology can be used to determine proteins and enzymes, such as myocardial markers, hormones and various proteins, etc., mostly qualitative tests. The separation of the analyte in the matrix is accomplished by paper chromatography and the target analyte is captured by a specific antibody immobilized on the surface of the chromatography strip for qualitative analysis, which can be accomplished by observing the color.
4.Selective electrode technology
The ion-selective electrode combined with the sensor, including biosensor and chemical sensor technology, has been made into a portable instrument for rapid detection of blood gas (PH, PCO2, PO2, etc.) and electrolytes (K+, Na+, Cl-, etc.), which has been widely used in clinical practice.
5.Infrared and far infrared spectrophotometry
Commonly used in the production of transdermal testing equipment, can be used to detect blood hemoglobin, bilirubin, glucose and other components. This kind of testing instrument can continuously monitor the target components in the patient's blood without blood drawing, which can avoid cross-infection and blood specimen contamination caused by blood draw, reduce the cost of each test and shorten the reporting time. However, the accuracy of such transdermal test results needs to be improved.
A biosensor is coupled to a specific biodetector (such as an enzyme, antibody or nucleic acid probe) to a transducer for direct determination of the target analyte without separating it from the matrix
The biochip uses the concept of the iniaturized Total Analysis System (uTAS) based on the Micro Electro Mechanical System (MEMS) proposed at the end of the last century, combining all sample processing and measurement steps. Analysts can obtain chemical information expressed in the form of electrical signals in a short time and space interval. The Microfluidic Chip is currently the most active field and development frontier in uTAS. It centralizes the ideal of transferring analytical laboratory functions to the chip, the Lab-On-a-Chip. LOC)
At present, biochips can be divided into gene chips (DNA chips), protein chips, cell chips, and lab-on-a-Chip (LOC).
Contact Person: Mr. Bob Zhu