鲎Reagents Guided Reading--A Guide to Bacterial Endotoxin Testing

鲎 reagent

The sputum reagent is a biological reagent obtained by extracting deformed cell lysate from the blue blood of the arthropod "鲎" which is born in the sea, and is freeze-dried at a low temperature, and is dedicated to detection of bacterial endotoxin and β-glucan.

鲎Reagents are based on source of raw materials:
There are currently four species of cockroaches in the world. Among them, only Tachypleus tridentatus Leach and Limulus polyphemus Linnaeus can produce sputum reagents. The corresponding sputum reagents are Tachypleus Amebocyte Lysate. , TAL) and Limulus Amebocyte Lysate (LAL), TAL has the same efficacy as LAL.

鲎 reagents are divided according to method:

Gel method

Dynamic turbidity method

End point turbidity method

Dynamic chromogenic reagent

End point chromogenic reagent

The gel method is a method for qualitatively detecting or semi-quantifying endotoxin by the principle of agglutination reaction between a sputum reagent and endotoxin. The common method of gel method 鲎 reagent is 0.1ml / support or 0.5ml / support or larger, when used, should be added after the reconstitution of pyrogen water (bacterial endotoxin test water). The gel method is to observe the presence or absence of gel formation as the end point of the reaction. This method is relatively simple and economical, does not require special measuring equipment, and can be qualitatively or semi-quantitatively determined.

The specific sputum reagent , ie the G factor 鲎 reagent, is the first product in China. It reacts exclusively to endotoxin, avoids the interference of G-factor bypass, makes the test result more reliable, and is not suitable for drug testing and clinical testing. The ideal test reagent is missing.

Dynamic turbidity method 鲎 reagent, endpoint turbidity method 鲎 reagent, dynamic chromogenic reagent 、 reagent, endpoint chromogenic reagent , reagent , these four methods are quantitative detection of endotoxin.

According to the detection principle, both the endpoint turbidity method and the dynamic turbidity method belong to the turbidity method. The turbidity method is a method for determining endotoxin content by detecting a change in turbidity during the reaction of a guanidine reagent with endotoxin. No commercial products were found at the end point turbidity method. The dynamic haze method (also known as dynamic turbidimetry) is a method for detecting the reaction time required for the turbidity of the reaction mixture to rise by a predetermined absorbance or for detecting the increase rate of the turbidity.

Both the endpoint chromogenic method and the dynamic chromogenic method belong to the chromogenic substrate method. The chromogenic matrix method is a method for determining the endotoxin content by using the coagulase produced by the reaction of the guanidine reagent and the endotoxin to determine the amount of chromophore released by the specific substrate color, and determining the endotoxin concentration according to the color of the product. For colorimetry. In 2005, Xiamen Radon Reagent Factory launched the 鲎 kit with 鲎tetrapeptide as the chromogenic substrate, which has strong anti-interference ability, sensitivity up to 0.005EU/ml, and the quality has reached the international leading level. At present, more than 500 units have used the kit, and some units have published corresponding literature. There are a small number of foreign products in China, but the price is much higher than domestic reagents, and the arrival period is long.

If you only need to test the endotoxin limit of the sample, you can choose the gel method , reagent, determine the endotoxin limit and the maximum effective dilution factor, and do the interference test of the sample to determine the sensitivity of the sputum reagent used.

If you need to quantify the endotoxin content in your sample, you should choose the chromogenic matrix 鲎 kit or the dynamic turbidity 鲎 reagent.

Dynamic turbidity and dynamic chromogenic methods require dynamic photometric instruments and supporting software with incubation systems, such as the microplate tester ELx808 and the software TALgent or Gen5. The dynamic turbidity method and the dynamic color rendering method are simple and convenient, one-step, and wide in linear range.

End point chromogenic method requires a matching microplate reader or a visible spectrophotometer for detection. A microplate reader with an incubation system, such as the microplate tester ELx808, can reduce the amount of reagents.