A Label-Free Deoxyribozymes Resonance Rayleigh Scattering Assay for Trace Lead(II) Based on Nanogold Catalysis of Chloroauric Acid-Vitamin C Particle Reaction

摘要

In pH 7.2 Tris-HCl buffer solution, the substrate strand DNA (SDNA) was hybridized to the enzyme strand DNA (EDNA) forming a double strand DNA (dsDNA). The SDNA in dsDNA could be cleaved by lead(II) to release a cleavaged single-stranded (ssDNA) that prevented the gold nanoparticles (AuNPs) from forming a stable AuNPs-ssDNA conjugate. The unconjugated AuNPs were aggregated to form AuNP aggregation (AuNPsA) that appeared as a resonance Rayleigh scattering (RS) peak at 532? nm. When the lead(II) concentration increased, the AuNPs-ssDNA increased, the AuNPsA decreased, the color changed from blue to red, and the RS intensity at 532? nm decreased. The decreased RS intensity ??I _{532? nm} was linear to the lead(II) concentration in the range of 0.67-60? nmol/L, with a detection limit of 0.3? nmol/L. The AuNPs-ssDNA exhibited a strong catalytic effect on the reaction between chloroauric acid and vitamin C (VC) that can be detected by an RS method at 620? nm. When the lead(II) concentration increased, the intensity at 620? nm increased, and the increased intensity ??I _{620? nm} was linear to the lead(II) concentration in the range of 1.33-120? pmol/L, with a detection limit of 0.5? pmol/L. The proposed method was applied to detect lead(II) in water samples, with satisfactory results.View full textDownload full textKeywordsDeoxyribozymes cleavage, Label-free, Lead(II), Nanogold catalysis, Resonance scattering assayRelated var addthis_config = { ui_cobrand: "Taylor & Francis Online", services_compact: "citeulike,netvibes,twitter,technorati,delicious,linkedin,facebook,stumbleupon,digg,google,more", pubid: "ra-4dff56cd6bb1830b" }; var addthis_config = {"data_track_addressbar":true,"ui_click":true}; Add to shortlist Link Permalink http://dx.doi.org/10.1080/00032719.2012.702174