TY - JOUR
T1 - A label-free electrochemical DNA biosensor based on a Zr(IV)-coordinated DNA duplex immobilised on a carbon nanofibre|chitosan layer
AU - Wipawakarn, Patoommarn
AU - Ju, Huangxian
AU - Wong, Danny K Y
PY - 2012/3
Y1 - 2012/3
N2 - A label-free electrochemical biosensor for detecting DNA hybridisation was developed by monitoring the change in the voltammetric activity of ferrocenecarboxylic acid at the biosensor-solution interface. The biosensor was constructed by initially immobilising on a glassy carbon electrode an anchoring layer consisting of chitosan, carboxyl group functionalised carbon nanofibres and glutaraldehye. Chitosan acted as an adhering agent and carbon nanofibres were strategically used to provide a large surface area with binding points for DNA immobilisation, while glutaraldehye was a linker for DNA probes on the electrode surface. Based on a two-factorial design, cyclic voltammetry of [Fe(CN) 6] 3-/4- was performed to optimise the composition of the anchoring layer. Next, a 17-base pair DNA probe was attached to the anchoring layer, followed by its complementary target. Zr(IV) ion, known to exhibit affinity for oxygen-containing electroactive markers, for example, ferrocenecarboxylic acid, was then coordinated in the DNA duplex. In this way, ferrocenecarboxylic acid was attracted towards the biosensor for oxidation. A change in the voltammetric oxidation current of ferrocenecarboxylic acid pre- and post-hybridisation was used to provide an indication of hybridisation. A linear dynamic range between 0.5 and 40 nM and a detection limit of 88 pM of DNA target were then achieved. In addition, the biosensor exhibited good selectivity, repeatability and stability for the determination of DNA sequences.
AB - A label-free electrochemical biosensor for detecting DNA hybridisation was developed by monitoring the change in the voltammetric activity of ferrocenecarboxylic acid at the biosensor-solution interface. The biosensor was constructed by initially immobilising on a glassy carbon electrode an anchoring layer consisting of chitosan, carboxyl group functionalised carbon nanofibres and glutaraldehye. Chitosan acted as an adhering agent and carbon nanofibres were strategically used to provide a large surface area with binding points for DNA immobilisation, while glutaraldehye was a linker for DNA probes on the electrode surface. Based on a two-factorial design, cyclic voltammetry of [Fe(CN) 6] 3-/4- was performed to optimise the composition of the anchoring layer. Next, a 17-base pair DNA probe was attached to the anchoring layer, followed by its complementary target. Zr(IV) ion, known to exhibit affinity for oxygen-containing electroactive markers, for example, ferrocenecarboxylic acid, was then coordinated in the DNA duplex. In this way, ferrocenecarboxylic acid was attracted towards the biosensor for oxidation. A change in the voltammetric oxidation current of ferrocenecarboxylic acid pre- and post-hybridisation was used to provide an indication of hybridisation. A linear dynamic range between 0.5 and 40 nM and a detection limit of 88 pM of DNA target were then achieved. In addition, the biosensor exhibited good selectivity, repeatability and stability for the determination of DNA sequences.
UR - http://www.scopus.com/inward/record.url?scp=84858706678&partnerID=8YFLogxK
U2 - 10.1007/s00216-012-5733-0
DO - 10.1007/s00216-012-5733-0
M3 - Article
C2 - 22297858
AN - SCOPUS:84858706678
SN - 1618-2642
VL - 402
SP - 2817
EP - 2826
JO - Analytical and bioanalytical chemistry
JF - Analytical and bioanalytical chemistry
IS - 9
ER -