摘要
发现碳点对鲁米诺电化学发光体系有明显的抑制作用,并且由于碳点对单双链DNA的吸附性差异,与单双链结合的碳点对鲁米诺电化学发光体系的抑制程度不同,基于此实现了对DNA的快速、简便、灵敏的检测.考察了碳点粒径、浓度对鲁米诺电化学发光体系的抑制行为的影响.优化了溶液pH值,鲁米诺浓度等电化学发光条件.在优化的最佳实验条件下,该方法检测DNA的线性范围为1.0×10-10～7.5×10-9mol/L,检出限为5.2×10-11mol/L.
In this paper,the microwave synthesis method was adopted to prepare carbon quantum dots(CDots),in which glucose acted as carbon source,water as solvent and polyethylene glycol(PEG-200) as passivation agent.With the different heating time,CDots with different size were gotten.Then,it was found that Cdots had an obvious inhibition effect on luminol electrochemiluminescence(ECL) system.The possible mechanism of inhibition effect of CDots on luminol ECL was discussed,it may be due to the electron transfer between CDots and the excited luminol.It was also reported that single-stranded DNA(ssDNA) could be adsorbed on the CDots’s surface via π-π stacking interactions,while double-stranded DNA(dsDNA) did not possess this feature.In this work,it was found that the inhibited luminol ECL signal by CDots was further decreased at ssDNA modified gold electrode.This result could be attributed to the adsorption reaction between ssDNA and Cdots.That is to say,CDots in solution approached toward the electrode surface by adsorption of ssDNA and the ECL signal of luminol was inhibited greatly.However,with the addition of complementary DNA,the hybridization reaction took place and the electrostatic repulsion between dsDNA and CDots made CDots keep away from the surface of electrode,which resulted in the increase of the inhibited luminol ECL signal.So,there were different ECL signals between ssDNA and dsDNA because of the different adsorption ability of CDots to ssDNA and dsDNA.Based on those findings,a simple,rapidly and sensitive detection method for DNA was developed.The influence of the size of CDots and their concentration on the inhibited ECL behaviors was further investigated.Then,the ECL reaction conditions,including pH and luminol concentration have also been optimized.Under the optimal experimental conditions,the linear range of the proposed method for determination of DNA is 1.0×10-10～7.5×10-9mol/L and the detection limits is 5.2×10-11mol/L.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2013年第4期644-648,共5页
Acta Chimica Sinica
基金
国家自然科学基金(No.20905044)
陕西省自然科学基金(No.2012JQ2006)资助~~
关键词
鲁米诺
电化学发光
抑制作用
碳点
DNA检测
luminol
electrochemiluminescence
inhibiting effect
carbon quantum dots(CDots)
DNA determination
