Effect of surfactants on the chemiluminescence of acridinium dimethylphenyl ester labels and their conjugates
作者:Anand Natrajan、David Sharpe、David Wen
DOI:10.1039/c1ob05543g
日期:——
Chemiluminescent acridinium dimethylphenyl esters, containing two methyl groups flanking the phenolic ester bond, display excellent chemiluminescence stability and are used as labels in automated immunoassays for clinical diagnostics. Light emission from these labels is triggered with alkaline peroxide in the presence of the cationic surfactant cetyltrimethylammonium chloride. Under these conditions, light emission is rapid and is complete in <5 s. In the present study we examined the effect of various surfactants on light emission from acridinium dimethylphenyl ester labels and their conjugates containing hydrophilic linkers derived either from hexa(ethylene)glycol or a sulfobetaine zwitterion. Sulfobetaine zwitterions are very polar and incorporation of these functional groups in acridinium dimethyphenyl esters and their conjugates represents a new approach to improving the aqueous solubility of these chemiluminescent labels. Our results indicate that in general, surfactants affect light emission from these labels and their conjugates by two discrete mechanisms. Cationic surfactants, but not anionic or non-ionic surfactants, accelerate overall light emission kinetics and a more modest effect is observed with zwitterionic surfactants. Surfactants also enhance total light output and the magnitude of this enhancement is maximal for cationic surfactants and a sulfobetaine zwitterionic surfactant. These observations are the first to clearly delineate the role of the surfactant on the chemiluminescence reaction pathway of acridinium esters and can be rationalized based on known effects of surfactant aggregates on bimolecular and unimolecular reactions.
化学发光吖啶鎓二甲基苯基酯在酚酯键两侧含有两个甲基,具有极佳的化学发光稳定性,可用作临床诊断中自动免疫测定的标签。在阳离子表面活性剂十六烷基三甲基氯化铵的存在下,碱性过氧化物可触发这些标签发光。在本研究中,我们研究了各种表面活性剂对吖啶二甲苯基酯标签及其共轭物发光的影响,这些共轭物含有亲水性连接体,这些连接体可以来自六(乙烯)甘醇或磺基甜菜碱齐聚物。磺基甜菜碱齐聚物具有很强的极性,在吖啶鎓二甲基苯基酯及其共轭物中加入这些官能团是提高这些化学发光标签水溶性的一种新方法。我们的研究结果表明,一般来说,表面活性剂会通过两种不同的机制影响这些标签及其共轭物的发光。阳离子表面活性剂(而非阴离子或非离子表面活性剂)会加速整体光发射动力学,而齐聚物表面活性剂的影响则较为温和。表面活性剂还能提高总光输出,阳离子表面活性剂和硫代甜菜碱齐聚物表面活性剂的提高幅度最大。这些观察结果首次明确界定了表面活性剂在吖啶鎓酯化学发光反应途径中的作用,并可根据已知的表面活性剂聚集体对双分子和单分子反应的影响进行合理解释。