Wonderful sharing of Shanghai Aopu Bio R&D Director
The initial stage of POCT product development is due to the influence of technology and low penetration rate. It is a qualitative product and needs to be judged by the user's naked eye, such as morphological observation and tester's experience. Due to the different experience of different inspectors, there is a gap in the judgment results, so that the results of the tests are not so accurate. However, with the development of technology, the sensitivity of POCT can reach the level of Peak per milliliter, the detection speed is within 20 minutes, and some results are even available in 2 to 5 minutes. Nowadays, some products combined with some supporting testing instruments can not only obtain accurate quantification, but also get a multiple detection. The future direction of POCT development is gradually moving towards intelligence. The following is a brief introduction to the labeling substances used in POCT products, including luminescent or fluorescent labels, radionuclides, enzymes, chemiluminescent substances, color markers, etc., among which more used in POCT products is luminescence or fluorescence. Markers and color markers.
The technology of colloidal gold has been developed for decades. It is widely used in POCT products because of its high maturity. After so many years of development, the cost has dropped to a very low level. Many manufacturers can produce cost-effective. Very high product, but there are some disadvantages, its color is very single, and it is limited by application, because the sensitivity is relatively low. With the development of technology, some manufacturers still use color latex instead of traditional colloids, because color latex can carry out various chemical modification, cross-linking can be used to cross-link antibodies and antigens with colored latex, color can do To a variety of rainbow colors. But there are also disadvantages such as high cost. The emerging fluorescent labeling technology is gradually replacing color markers. It is a big development trend. Fluorescent markers can achieve good batch-to-batch variation. Various chemical modifications can be made on fluorescent microspheres to achieve covalent Cross-linking, stability is very good, the difference between batches is very good, the sensitivity can be increased by at least one order of magnitude compared with the previous products, and some can be more than two to three orders of magnitude, and can be quantified with the corresponding instruments. However, due to the necessity of supporting instruments, the development cycle and cost are higher than those of the previous products.
Here are a few fluorescent markers. First look at fluorescein, which is a kind of radiant in various luminescent materials. The illuminating range covers the area from infrared to ultraviolet. Some companies have a product line of fluorescein, covering from 400 nm to 800 nm. There are nearly 20 kinds of fluorescein to choose from, which is very rich. Some antibodies or proteins can be fluorescently labeled by modification. There are many commercial fluorescent dyes to choose from, but the traditional fluorescein has its own defects. For example, its Stokes displacement is very narrow, the detection equipment is very susceptible to the excitation light infection signal, the sensitivity is poor, and its other The fluorescence lifetime is very short, basically only about 5 to 100 nanoseconds. These all limit the performance of fluorescein stability. The second one is widely used in rare earth elements. The amount of luminescence is weaker than that of traditional fluorescein, but it has a large Stokes shift, which can effectively remove the interference signals of emitted light and excitation light, and the decay time of fluorescent substances is relatively short. The fluorescence lifetime is longer.
Another fast-growing development is quantum dot marking, which consists of nanoscale fluorescent and semiconducting materials. It is not affected by photobleaching. It can achieve rainbow effect. The wavelength of the excitation source is wider, multiple markers are applied, and the fluorescence lifetime is longer. . Finally, it is "upward luminescence". Unlike fluorescence, fluorescence is a process in which high-energy energy is converted into a low-energy state, and up-conversion luminescence is an opposite process. Generally, two or more low-energy photons are absorbed to generate a high-energy sub-transformation. This is a process of high energy state. Some domestic manufacturers are doing the ups and downs, which were first used by the US military and later transferred to civilian use. Domestic Aopu Biotechnology has developed a technology platform based on fluorescent microspheres and time resolution. On the platform, the company has developed two major tests, firstly the detection of some markers, as well as the most widely used PCT, PCT in emergency or ICU applications. It is itself a particularly good indicator of the sensitivity and specificity of identifying bacterial infections. The physical operation is relatively simple. The first step is to take a certain amount of sample, add it to the fluorescent liquid, and then add it to the reading plate. Wait for fifteen minutes to read it. The original design concept of this platform is to adhere to the concept of doing quality products, to achieve the ultimate product, so in the clinical trials, it is also in Shanghai (such as Zhongshan Hospital, etc.) for clinical. This is the result of some serum or plasma tests performed by Aopu. It can be seen that the correlation coefficient R^2 can reach above 0.99, and the consistency with Roche's system is very good. The result of the plasma test is followed by the sample of the interfering substance. It can be seen that the interfering substance has little interference with the detection result of the Aopu product.
In the future, there will be two development directions for POCT, one is familyization and the other is precision and accuracy. The latter direction may be more widely used in ICU, emergency department or some community terminals. In the latter demand, I feel that there are some liquid phase, fluorescent or chemiluminescence technologies that can be used in this area. Aopu currently develops some products based on this concept and may be listed after 2017.
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