纳米金颗粒增强信号的表面等离子体共振生物传感器用于甲氧檗因高灵敏检测的研究

报道了一种基于表面等离子体共振(SPR)生物传感器的高灵敏检测抗癌药物甲氧檗因的新方法. 分别在纳米金颗粒和金膜表面修饰富含腺嘌呤(A)的DNA链, 当存在甲氧檗因时, 由于一个甲氧檗因分子可与4个A碱基相结合, 从而使得修饰在纳米金颗粒和金膜表面的DNA形成稳定的双链结构, 进而将功能化纳米金颗粒捕获在金膜表面. 由于纳米金颗粒与金膜之间的电场耦合效应可增强SPR信号, 从而可实现对小分子甲氧檗因的高灵敏、特异性检测. 本方法的检测下限低至0.07 pmol/L, 相对比色法和荧光法而言, 降低了约5～6个数量级. 以4种药物(盐酸小檗碱、青霉素G、硫酸庆大霉素、5-氟尿嘧啶)作为对照考察了该传感器的选择性, 结果表明该传感器具有较好的选择性.

High Sensitive Coralyne Detection by Using of Au Nanoparticles-Enhanced Surface Plasmon Resonance Biosensor

Coralyne,a kind of planar alkaloid,has more pronounced antitumor activity compared to other protoberberine alkaloids.It was found that coralyne could induce the adenine(A)-rich DNA oligonucleotides to form a double strand DNA,with a stoichiometry of one coralyne per four adenine bases.In this paper,a high sensitive approach for the detection of anticancer drug coralyne based on surface plasmon resonance(SPR) and the high selectivity and sensitivity recognition process of coralyne with the A-rich DNA oligonucleotides was established.Generally,it was difficult to detect small molecules directly using conventional SPR biosensors since the changes of refractive index,which was resulted by binding small molecules,were usually small.Here,the Au nanoparticles was introduced for enhancing the sensitivity.The A-rich DNA strands were modified on Au nanoparticles and on Au film respectively.In the presence of coralyne and the functional Au nanoparticles,the A-rich DNA strands could form the duplex through the specific coordination between coralyne and adenine,and then the functional Au nanoparticles were captured on the Au film.SPR signal was enhanced by the electronic coupling between the localized plasmon of Au nanoparticles and the surface plasmon wave associated with Au film.If only coralyne or the functional Au nanoparticles was present,the resonance wavelength was almost unchanged.It meant that there was no A-coralyne-A complex formed.Thus,this method could be used to detect coralyne,and the background was low.The results showed that the SPR sensor was highly sensitive,and the limit of detection was ca.0.07 pmol/L(S/N=3).It was about 5—6 orders of magnitude lower than those of fluorescent and colorimetric methods.Moreover,four kinds of small molecule drugs(berberine hydrochloride,penicillin,gentamicin sulfate,and 5-fluorouracil) were used as control to investigate the selectivity of this SPR biosensor.For penicillin,gentamicin sulfate,and 5-fluorouracil,all of the resonance wavelength shifts were lower than 0.4 nm.For high concentration of berberine hydrochloride,the resonance wavelength shifts were ca.0.5—0.6 nm.The results showed that this SPR biosensor has good selectivity.This work may extend the application of SPR biosensors in drug discovery and development.