1. Basic nature
The application of acridine compounds in chemiluminescence detection has the following advantages:
① The background luminescence is low and the signal-to-noise ratio is high;
② Few interference factors in the luminescence reaction;
③ Rapid concentration of light release, high luminous efficiency, and high luminous intensity;
④ It is easy to connect with protein and the photon yield does not decrease after the connection;
⑤ The marker is stable (it can be stored for several months at 2-8°C).
The chemiluminescence of acridine compounds does not require a catalyst and can emit light in a dilute alkaline solution containing H2O2. The luminescence of the compound is flash type. After adding the luminescence starter, the emitted light intensity generally reaches the maximum about 0.5s, and the half-life is about 1s.
Acridine compounds are used in chemiluminescence immunoassay (CLIA). That is, the antibody or antigen is labeled with acridine salt, and HNO3+H2O2 and NaOH are used as the luminescence priming reagent. Some add Triton X-100, CTAC, Tween-20 and other surfactants to the luminescence priming reagent to enhance luminescence.
Acridine compounds are commonly used in environmental analysis, immunoassay, enzyme activity analysis and labeled oligonucleotide fragments, etc., and are used clinically to determine bacteria, viruses or other disease markers.
2. Acridine ester DMAE-NHS or NSP-DMAE-NHS
Acridine ester DMAE-NHS or NSP-DMAE-NHS is an ideal chemiluminescence immunoassay labeling substance with good luminescence performance. Compared with the currently widely used acridinium ester AE-NHS, the acridinium ester DMAE-NHS or NSP-DMAE-NHS and antibody (Ab) conjugates have higher luminescence intensity, the acridinium ester DMAE-NHS or NSP-DMAE -NHS is 1.03´107cps/ng, and AE-NHS is 1.0´105cps/ng Ab. The luminescence kinetic properties of the two are very similar. Both are flash-type luminescence and both reach a high level at 0.4s, but DMAE- The thermal stability of NHS or NSP-DMAE-NHS is significantly higher than that of AE-NHS. AE-NHS is only stable in acidic solutions and is easily hydrolyzed when pH>6.3, while DMAE-NHS or NSP-DMAE-NHS is not. At room temperature, it is very stable in a PB buffer with a pH of 7.0. After 16 days, the luminescence activity is only reduced by 3.6%. Their luminescence thermal stability with protein conjugates is similar to this.
The acridinium ester DMAE-NHS or NSP-DMAE-NHS is easy to label biomolecules and the luminescent activity and biological activity of the labeled compound are stable. The synthesized luminescent label is applied to chemiluminescence immunoassay with high sensitivity and other ideals. For example, the minimum detection limit of TSH is 0.007 mIμ/L. Therefore, the acridinium ester DMAE-NHS or NSP-DMAE-NHS has good application value for the research of chemiluminescence analysis and chemiluminescence immunoassay.
3. Acridine Sulfonamide NSP-SA-NHS
Acridine sulfonamide NSP-SA-NHS is a very effective chemiluminescence immunoassay labeling substance. It has the properties of large steric hindrance, good hydrolytic stability, thermal stability and high signal-to-noise ratio. Its light quantum yield is also better than that of acridinium ester AE-NHS. It has many advantages when applied to direct chemiluminescence analysis and chemiluminescence immunoassay.
Acridine sulfonamide NSP-SA-NHS chemiluminescence does not require a catalyst. It can emit light in a dilute alkaline solution with H2O2. It has many advantages, especially it does not require a catalytic process or an enhancer, thereby reducing the background Luminous, improved signal-to-noise ratio, less interference. As a luminescent marker for chemiluminescence immunoassay, this kind of compound also has other advantages, such as rapid concentration of light release, high luminous efficiency, high luminous intensity, easy to connect with protein, and the photon yield after the connection is not reduced, and the label is stable. , It can be stored for more than half a year at 2-8°C.
The stability of acridine sulfonamide NSP-SA-NHS is higher than that of acridine esters such as AE-NHS. The reason is that the C-N bond and the C-O bond have different bond levels, and the C-N bond is larger than the C-O bond. The ability of acridine amide compounds to resist hydrolysis is also stronger than that of acridine ester compounds.