Fast assembly of non-thiolated DNA on gold surface at lower pH

•Fast adsorption of non-thiolated DNA onto gold electrode achieved at low pH.•A and C are more effective than T and G due to their protonation at low pH and higher affinity to gold surface.•Detailed reaction kinetics and mechanism characterization and analytical applications. In a typical protocol f...

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Bibliographic Details
Published in:Journal of colloid and interface science 2013-12, Vol.411, p.92-97
Main Authors: Jiang, Hui, Materon, Elsa M., Sotomayor, Maria Del Pilar Taboada, Liu, Juewen
Format: Article
Language:English
Subjects:
Adsorption
binding capacity
Biosensors
Chemistry
complementary DNA
DNA
DNA - chemistry
DNA assembly
electrodes
Exact sciences and technology
ferricyanides
General and physical chemistry
Gold
Gold - chemistry
Hydrogen-Ion Concentration
Immobilization
ionic strength
Nucleic Acid Hybridization
Sulfhydryl Compounds - chemistry
Surface physical chemistry
Surface Properties
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Summary:•Fast adsorption of non-thiolated DNA onto gold electrode achieved at low pH.•A and C are more effective than T and G due to their protonation at low pH and higher affinity to gold surface.•Detailed reaction kinetics and mechanism characterization and analytical applications. In a typical protocol for attaching DNA to a gold electrode, thiolated DNA is incubated with the electrode at neutral pH overnight. Here we report fast adsorption of non-thiolated DNA oligomers on gold electrodes at acidic pH (i.e., pH ∼3.0). The peak-to-peak potential difference and the redox peak currents in typical cyclic voltammetry of [Fe(CN)6]3− are investigated to monitor the attachment. Compared with incubation at neutral pH, the lower pH can significantly promote the adsorption processes, enabling efficient adsorption even in 30min. The adsorption rate is DNA concentration-dependent, while the ionic strength shows no influence. Moreover, the adsorption is base-discriminative, with a preferred order of A>C≫G, T, which is attributed to the protonation of A and C at low pH and their higher binding affinity to gold surface. The immobilized DNA is functional and can hybridize with its complementary DNA but not a random DNA. This work is promising to provide a useful time-saving strategy for DNA assembly on gold electrodes, allowing fast fabrication of DNA-based biosensors and devices.
ISSN:0021-9797
1095-7103
DOI:10.1016/j.jcis.2013.08.043