Enhancing electrochemical DNA biosensing with active sensitisers

Pedro Estrela, Lai Chun Caleb Wong, Ed Regan, A.J. Hallett, S.J.A. Pope, N.J. Buurma

Research output: Contribution to conferencePaper

Abstract

Biosensors for DNA (genosensors) are of significant interest because they address the need for rapid diagnosis of, e.g., genetic disorders and infections by pathogens. Electrochemical genosensors are of particular interest because they are miniaturised more readily than optical sensors, typically require small sample volumes, little sample pre-treatment, and are suitable for use with portable instrumentation by minimally trained clinical personnel.
We here present the combination of two strategies towards sequence-selective DNA detection, viz. intrinsically sequence-selective electrochemical detection of DNA hybridisation and detection of double-stranded DNA by electronically active molecules. A capture strand, either DNA or PNA (peptide nucleic acid) is immobilised on an electrode, using immobilisation procedures which have previously been optimised for DNA detection using electrochemically impedance spectroscopy. Following hybridisation, an electronically active molecule binds to the duplex DNA on the electrode, establishing a detectable electronic contact, thus acting as “sensitisers” for the electrochemical detection.
Electrochemical impedance spectroscopy and cyclic voltammetry measurements were carried out using two types of sensitisers: a Co aqphen complex binding to dsDNA through intercalation and a cationic quaterthiophene binding through the minor groove.
The intercalation of a cobalt(II) complex containing mixed-ligands of 12,17-dihydronaphtho-2,3-hdipyrido-3,2-a:2',3'-c-phenazine-12,17-dione (aqphen) and glycolic acid (GA), [Co(GA)2(aqphen)] with DNA was investigated by electronic absorption spectroscopy. The corresponding phen complex, with an oxidation potential of 0.12 V vs Ag/AgCl, had previously shown weak intercalation. Increasing the conjugation with an anthraquinone increased significantly the binding affinity of the complex.
The use of an optoelectronically active cationic quaterthiophene as a sensitiser was also explored. This water-soluble quaterthiophene interacts with dsDNA with an affinity of 10^5 M-1 and has an oxidation potential of 1.0 V vs Ag/AgCl.
Both sensitisers show promising enhancement of electrochemical DNA detection and highlight structural features favouring selectivity in sensing, paving the way towards a new generation of point-of-care electrochemical biosensors for genotyping.

Conference

ConferenceElectrochem 2012
CountryIreland
CityDublin
Period2/09/124/09/12

Fingerprint

DNA
glycolic acid
Intercalation
Biosensors
Peptide Nucleic Acids
Anthraquinones
Oxidation
Electrodes
Molecules
Optical sensors
Pathogens
Cobalt
Electrochemical impedance spectroscopy
Absorption spectroscopy
Cyclic voltammetry
Spectroscopy
Personnel
Ligands
Water

Cite this

Estrela, P., Wong, L. C. C., Regan, E., Hallett, A. J., Pope, S. J. A., & Buurma, N. J. (2012). Enhancing electrochemical DNA biosensing with active sensitisers. Paper presented at Electrochem 2012, Dublin, Ireland.

Enhancing electrochemical DNA biosensing with active sensitisers. / Estrela, Pedro; Wong, Lai Chun Caleb; Regan, Ed; Hallett, A.J.; Pope, S.J.A.; Buurma, N.J.

2012. Paper presented at Electrochem 2012, Dublin, Ireland.

Research output: Contribution to conferencePaper

Estrela, P, Wong, LCC, Regan, E, Hallett, AJ, Pope, SJA & Buurma, NJ 2012, 'Enhancing electrochemical DNA biosensing with active sensitisers' Paper presented at Electrochem 2012, Dublin, Ireland, 2/09/12 - 4/09/12, .
Estrela P, Wong LCC, Regan E, Hallett AJ, Pope SJA, Buurma NJ. Enhancing electrochemical DNA biosensing with active sensitisers. 2012. Paper presented at Electrochem 2012, Dublin, Ireland.
Estrela, Pedro ; Wong, Lai Chun Caleb ; Regan, Ed ; Hallett, A.J. ; Pope, S.J.A. ; Buurma, N.J. / Enhancing electrochemical DNA biosensing with active sensitisers. Paper presented at Electrochem 2012, Dublin, Ireland.
@conference{d1f6dffa633e4a379192e95c1f85e47a,
title = "Enhancing electrochemical DNA biosensing with active sensitisers",
abstract = "Biosensors for DNA (genosensors) are of significant interest because they address the need for rapid diagnosis of, e.g., genetic disorders and infections by pathogens. Electrochemical genosensors are of particular interest because they are miniaturised more readily than optical sensors, typically require small sample volumes, little sample pre-treatment, and are suitable for use with portable instrumentation by minimally trained clinical personnel. We here present the combination of two strategies towards sequence-selective DNA detection, viz. intrinsically sequence-selective electrochemical detection of DNA hybridisation and detection of double-stranded DNA by electronically active molecules. A capture strand, either DNA or PNA (peptide nucleic acid) is immobilised on an electrode, using immobilisation procedures which have previously been optimised for DNA detection using electrochemically impedance spectroscopy. Following hybridisation, an electronically active molecule binds to the duplex DNA on the electrode, establishing a detectable electronic contact, thus acting as “sensitisers” for the electrochemical detection. Electrochemical impedance spectroscopy and cyclic voltammetry measurements were carried out using two types of sensitisers: a Co aqphen complex binding to dsDNA through intercalation and a cationic quaterthiophene binding through the minor groove. The intercalation of a cobalt(II) complex containing mixed-ligands of 12,17-dihydronaphtho-2,3-hdipyrido-3,2-a:2',3'-c-phenazine-12,17-dione (aqphen) and glycolic acid (GA), [Co(GA)2(aqphen)] with DNA was investigated by electronic absorption spectroscopy. The corresponding phen complex, with an oxidation potential of 0.12 V vs Ag/AgCl, had previously shown weak intercalation. Increasing the conjugation with an anthraquinone increased significantly the binding affinity of the complex. The use of an optoelectronically active cationic quaterthiophene as a sensitiser was also explored. This water-soluble quaterthiophene interacts with dsDNA with an affinity of 10^5 M-1 and has an oxidation potential of 1.0 V vs Ag/AgCl. Both sensitisers show promising enhancement of electrochemical DNA detection and highlight structural features favouring selectivity in sensing, paving the way towards a new generation of point-of-care electrochemical biosensors for genotyping.",
author = "Pedro Estrela and Wong, {Lai Chun Caleb} and Ed Regan and A.J. Hallett and S.J.A. Pope and N.J. Buurma",
year = "2012",
language = "English",
note = "Electrochem 2012 ; Conference date: 02-09-2012 Through 04-09-2012",

}

TY - CONF

T1 - Enhancing electrochemical DNA biosensing with active sensitisers

AU - Estrela, Pedro

AU - Wong, Lai Chun Caleb

AU - Regan, Ed

AU - Hallett, A.J.

AU - Pope, S.J.A.

AU - Buurma, N.J.

PY - 2012

Y1 - 2012

N2 - Biosensors for DNA (genosensors) are of significant interest because they address the need for rapid diagnosis of, e.g., genetic disorders and infections by pathogens. Electrochemical genosensors are of particular interest because they are miniaturised more readily than optical sensors, typically require small sample volumes, little sample pre-treatment, and are suitable for use with portable instrumentation by minimally trained clinical personnel. We here present the combination of two strategies towards sequence-selective DNA detection, viz. intrinsically sequence-selective electrochemical detection of DNA hybridisation and detection of double-stranded DNA by electronically active molecules. A capture strand, either DNA or PNA (peptide nucleic acid) is immobilised on an electrode, using immobilisation procedures which have previously been optimised for DNA detection using electrochemically impedance spectroscopy. Following hybridisation, an electronically active molecule binds to the duplex DNA on the electrode, establishing a detectable electronic contact, thus acting as “sensitisers” for the electrochemical detection. Electrochemical impedance spectroscopy and cyclic voltammetry measurements were carried out using two types of sensitisers: a Co aqphen complex binding to dsDNA through intercalation and a cationic quaterthiophene binding through the minor groove. The intercalation of a cobalt(II) complex containing mixed-ligands of 12,17-dihydronaphtho-2,3-hdipyrido-3,2-a:2',3'-c-phenazine-12,17-dione (aqphen) and glycolic acid (GA), [Co(GA)2(aqphen)] with DNA was investigated by electronic absorption spectroscopy. The corresponding phen complex, with an oxidation potential of 0.12 V vs Ag/AgCl, had previously shown weak intercalation. Increasing the conjugation with an anthraquinone increased significantly the binding affinity of the complex. The use of an optoelectronically active cationic quaterthiophene as a sensitiser was also explored. This water-soluble quaterthiophene interacts with dsDNA with an affinity of 10^5 M-1 and has an oxidation potential of 1.0 V vs Ag/AgCl. Both sensitisers show promising enhancement of electrochemical DNA detection and highlight structural features favouring selectivity in sensing, paving the way towards a new generation of point-of-care electrochemical biosensors for genotyping.

AB - Biosensors for DNA (genosensors) are of significant interest because they address the need for rapid diagnosis of, e.g., genetic disorders and infections by pathogens. Electrochemical genosensors are of particular interest because they are miniaturised more readily than optical sensors, typically require small sample volumes, little sample pre-treatment, and are suitable for use with portable instrumentation by minimally trained clinical personnel. We here present the combination of two strategies towards sequence-selective DNA detection, viz. intrinsically sequence-selective electrochemical detection of DNA hybridisation and detection of double-stranded DNA by electronically active molecules. A capture strand, either DNA or PNA (peptide nucleic acid) is immobilised on an electrode, using immobilisation procedures which have previously been optimised for DNA detection using electrochemically impedance spectroscopy. Following hybridisation, an electronically active molecule binds to the duplex DNA on the electrode, establishing a detectable electronic contact, thus acting as “sensitisers” for the electrochemical detection. Electrochemical impedance spectroscopy and cyclic voltammetry measurements were carried out using two types of sensitisers: a Co aqphen complex binding to dsDNA through intercalation and a cationic quaterthiophene binding through the minor groove. The intercalation of a cobalt(II) complex containing mixed-ligands of 12,17-dihydronaphtho-2,3-hdipyrido-3,2-a:2',3'-c-phenazine-12,17-dione (aqphen) and glycolic acid (GA), [Co(GA)2(aqphen)] with DNA was investigated by electronic absorption spectroscopy. The corresponding phen complex, with an oxidation potential of 0.12 V vs Ag/AgCl, had previously shown weak intercalation. Increasing the conjugation with an anthraquinone increased significantly the binding affinity of the complex. The use of an optoelectronically active cationic quaterthiophene as a sensitiser was also explored. This water-soluble quaterthiophene interacts with dsDNA with an affinity of 10^5 M-1 and has an oxidation potential of 1.0 V vs Ag/AgCl. Both sensitisers show promising enhancement of electrochemical DNA detection and highlight structural features favouring selectivity in sensing, paving the way towards a new generation of point-of-care electrochemical biosensors for genotyping.

M3 - Paper

ER -