1. Basic nature
The application of acridine compounds in chemiluminescence detection has the following advantages:
Low background luminescence and high signal-to-noise ratio;
Less interference factors in luminescence reaction;
The light release is fast and concentrated, the luminous efficiency is high, and the luminous intensity is large;
It is easy to link with protein and the photon yield does not decrease after linking;
The markers are stable (storable for several months at 2-8°C), they have good solubility in water, are stable and are not easily hydrolyzed.
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 reaches the maximum in 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 labeling 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 widely used acridinium ester AE-NHS, the luminescence intensity of the acridinium ester DMAE-NHS or NSP-DMAE-NHS and antibody (Ab) conjugates is higher, and the luminescence dynamics of the two are very similar. Both are flash-type luminescence and both reach the highest at 0.4s, but the thermal stability of DMAE-NHS or NSP-DMAE-NHS is significantly higher than that of AE-NHS. AE-NHS is only stable in acidic solutions, when pH>6.3 It is easy to hydrolyze later, but DMAE-NHS or NSP-DMAE-NHS is not. For example, 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 luminescent markers for chemiluminescence immunoassays, these compounds also have other advantages, such as rapid concentration of light release, high luminous efficiency, high luminous intensity, easy to link with proteins, and the photon yield after linking does not decrease, 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.