title: In situ growth of positively-charged gold nanoparticles on single-walled carbon nanotubes as a highly active peroxidase mimetic and its application in biosensing.
abstract: We prepared a new positively-charged gold nanoparticle ((+)AuNPs)-single-walled carbon nanotubes (SWNTs) nanohybrids. The results showed that small (+)AuNPs dispersed uniformly on the surface of SWNTs. Importantly the resulting nanohybrids exhibited fascinating peroxidase-like activity, which can catalyze oxidation of the peroxidase substrate 3,3,5,5-tetramethylbenzidine (TMB) by H2O2 to develop a blue color in aqueous solution. Furthermore, single-stranded DNA (ss-DNA) can resist salt-induced (+)AuNPs-SWNTs nanohybrids aggregation, whereas double-stranded DNA (ds-DNA) can not inhibit salt-induced nanohybrids aggregation. Based on these unique properties of the (+)AuNPs-SWNTs nanohybrids, we developed a label-free colorimetric method for DNA hybridization detection. The response to target DNA concentration was linear in the range of 0.025-0.5μM with a detection limit of 2nM (3σ). Based on the specific recognition of aptamer, the method can be extended to detect non-nucleic acid targets such as cocaine. The present limit of detection for cocaine is 2nM. The method offers the advantages of simple, cheap, rapid and sensitive.
authors: Key laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Shaanxi Normal University, Xi'an 710062, China.
authors: Yuanfu
authors: Y
authors: Zhang
authors: Chunli
authors: C
authors: Xu
authors: Baoxin
authors: B
authors: Li
authors: Yanbin
authors: Y
authors: Li
mesh_terms: D040761:Biomimetic Materials / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation*; D003042:Cocaine / Q000032:analysis*; D003217:Conductometry / Q000295:instrumentation; D003460:Crystallization / Q000379:methods; D004247:DNA / Q000737:chemistry*; D004789:Enzyme Activation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry; D037742:Nanotubes, Carbon / Q000737:chemistry*; D009195:Peroxidase / Q000737:chemistry*; D055672:Static Electricity
chemical_list: D037742:Nanotubes, Carbon; D006046:Gold; D004247:DNA; D009195:Peroxidase; D003042:Cocaine