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在近中性介质中,阳离子表面活性剂(CS)和核酸本身的共振Rayleigh散射(RRS)十分微弱,但当两者反应形成结合产物时,则观察到RRS急剧增强.研究了5种CS,当它们与核酸反应时,具有相似的反应条件和RRS光谱特征,但灵敏度差异较大,其中含芳基且分子量大的氯化十六烷基苄铵(CDBAC)最灵敏,而不含芳基分子量又较小的溴化十六烷基三甲铵(CTAB)灵敏度最低,前者对于ctDNA和yRNA的检出限分别为6.6和29.4ng·mL-1,后者则为13.3和53.6ng·mL-1.方法对于核酸有较好的选择性,可用于微量核酸的测定.研究还发现RRS强度不仅与阳离子表面活性剂的结构和分子量有关,而且其强度变化还与核酸构象转变有密切联系,因此RRS法有望成为研究核酸构象的有用手段.
In nearly neutral medium, the resonance Rayleigh scattering (RRS) of cationic surfactant (CS) and nucleic acid itself is very weak, but when the two react to form a binding product, a sharp increase of RRS is observed. Five kinds of CS, When they react with nucleic acids, they have similar reaction conditions and RRS spectral characteristics, but differ greatly in their sensitivity, with aryl and high molecular weight cetylbenzylammonium chloride (CDBAC) most sensitive but without aryl CTAB with the lowest molecular weight had the lowest sensitivity. The detection limits of cTAB and yRNA were 6.6 and 29.4 ng · mL-1 for the former and 13.3 and 53.6 ng · mL- 1. The method has good selectivity for nucleic acids and can be used for the determination of trace nucleic acids.The study also found that RRS intensity is not only related to the structure and molecular weight of cationic surfactants but also its intensity change is closely related to the conformational transition of nucleic acids The RRS method is expected to be a useful tool for studying the conformation of nucleic acids.