title: Au-NPs enhanced SPR biosensor based on hairpin DNA without the effect of nonspecific adsorption.
abstract: Gold nanoparticles (Au-NPs) are usually used to amplify surface plasmon resonance (SPR) signals, however, the serious nonspecific adsorption has largely limited their practical applications. Here, we developed a novel Au-NPs enhanced biosensor without the effect of nonspecific adsorption: cutting Au-NPs off from the biosensor surface by RsaI endonuclease. In order to further improve the sensitivity, the probe DNA was designed specially. After the cleavage reaction, the residual probe DNA formed hairpin structure, which also resulted in a great change in SPR dip shift. Then, with the coaction of Au-NPs and conformation change of probe DNA, the SPR signal was amplified greatly. Using this method, we monitored the process of DNA cleavage in real-time and achieved a detection level of 5×10(-8) M. Moreover, the result of X-ray photoelectron spectroscopy (XPS) experiment further confirmed that large nonspecific adsorption existed. However, because SPR recorded a process in which the Au-NPs were cut off, the serious nonspecific adsorption did not affect the experimental result.
authors.affiliation: College of Chemistry and Chemical Engineering, Graduate University of Chinese Academy of Sciences, Beijing 100049, PR China.
authors.forename: Qingfen
authors.initials: Q
authors.lastname: Luan
authors.forename: Kebin
authors.initials: K
authors.lastname: Zhou
authors.forename: Haina
authors.initials: H
authors.lastname: Tan
authors.forename: Dan
authors.initials: D
authors.lastname: Yang
authors.forename: Xin
authors.initials: X
authors.lastname: Yao
mesh_terms: D000327:Adsorption; D015374:Biosensing Techniques / Q000295:instrumentation*; D004247:DNA / Q000737:chemistry* / Q000235:genetics*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006046:Gold / Q000737:chemistry*; D017403:In Situ Hybridization / Q000295:instrumentation*; D055029:Inverted Repeat Sequences; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D020349:Surface Plasmon Resonance / Q000295:instrumentation*
chemical_list: D006046:Gold; D004247:DNA