title: A simple "clickable" biosensor for colorimetric detection of copper(II) ions based on unmodified gold nanoparticles.
abstract: A novel colorimetric copper(II) biosensor has been developed based on the high specificity of alkyne-azide click reaction to the catalysis of copper ions and unmodified gold nanoparticles (AuNPs) as the signal reporter. The clickable DNA probe consists of two parts: an azide group-modified double-stranded DNA (dsDNA) hybrid with an elongated tail and a short alkyne-modified single-stranded DNA (ssDNA). Because of low melting temperature of the short ssDNA, these two parts are separated in the absence of Cu(2+). Copper ion-induced azide-alkyne click ligation caused a structural change of probe from the separated form to entire dsDNA form. This structural change of probe can be monitored by the unmodified AuNPs via mediating their aggregation with a red-to-blue colorimetric read-out because of the differential ability of ssDNA and dsDNA to protect AuNPs against salt-induced aggregation. Under the optimum conditions, this biosensor can sensitively and specifically detect Cu(2+) with a low detection limit of 250 nM and a linear range of 0.5-10 μM. The method is simple and economic without dual-labeling DNA and AuNPs modification. It is also highly selective for Cu(2+) in the presence of high concentrations of other environmentally relevant metal ions because of the great specificity of the copper-caused alkyne-azide click reaction, which potentially meets the requirement of the detection in real samples.
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China.
authors.forename: Qinpeng
authors.initials: Q
authors.lastname: Shen
authors.forename: Wenhua
authors.initials: W
authors.lastname: Li
authors.forename: Shiyun
authors.initials: S
authors.lastname: Tang
authors.forename: Yufang
authors.initials: Y
authors.lastname: Hu
authors.forename: Zhou
authors.initials: Z
authors.lastname: Nie
authors.forename: Yan
authors.initials: Y
authors.lastname: Huang
authors.forename: Shouzhuo
authors.initials: S
authors.lastname: Yao
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D057930:Click Chemistry / Q000295:instrumentation*; D003124:Colorimetry / Q000295:instrumentation*; D003300:Copper / Q000032:analysis*; D004247:DNA / Q000737:chemistry*; D004784:Environmental Monitoring / Q000295:instrumentation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006046:Gold / Q000737:chemistry*; D007477:Ions; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000295:instrumentation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D007477:Ions; D014874:Water Pollutants, Chemical; D006046:Gold; D003300:Copper; D004247:DNA