%0 Journal Article %1 citeulike:780928 %A Radi, A. E. %A Sánchez, J. L. Acero %A Baldrich, E. %A O'Sullivan, C. K. %C Nanobiotechnology and Bioanalysis Group, Department of Chemical Engineering, Universitat Rovira i Virgili, Tarragona, Spain. abd.radi@urv.net %D 2006 %J J Am Chem Soc %K aptamer surface electrochemistry %N 1 %P 117--124 %R 10.1021/ja053121d %T Reagentless, reusable, ultrasensitive electrochemical molecular beacon aptasensor. %U http://dx.doi.org/10.1021/ja053121d %V 128 %X A bifunctional derivative of the thrombin-binding aptamer with a redox-active Fc moiety and a thiol group at the termini of the aptamer strand was synthesized. The ferrocene-labeled aptamer thiol was self-assembled through S-Au bonding on a polycrystalline gold electrode surface and the surface was blocked with 2-mercaptoethanol to form a mixed monolayer. By use of a fluorescent molecular beacon, the effect of counterions on quadruplex formation was established. The aptamer-modified electrode was characterized electrochemically by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). The modified electrode showed a voltammetric signal due to a one-step redox reaction of the surface-confined ferrocenyl moiety of the aptamer immobilized on the electrode surface in 10 mM N-(2-hydroxyethyl)piperazine-N'-2-ethanesulfonic acid (HEPES) buffer of pH 8.0. An increase in the DPV current signal was evident after blocking with 2-mercaptoethanol, effectively removing aptamer nonspecifically absorbed rather than bound to electrode surface or due to the formation of the aptamer-thrombin affinity interaction. The impedance measurement, in agreement with the differential pulse voltammetry (DPV), showed decreased Faradaic resistances in the same sequence. The "signal-on" upon thrombin association could be attributed to a change in conformation from random coil-like configuration on the probe-modified film to the quadruplex structure. The DPV of the modified electrode showed a linear response of the Fc oxidation signal to the increase in the thrombin concentration in the range between 5.0 and 35.0 nM with a linear correlation of r = 0.9988 and a detection limit of 0.5 nM. The molecular beacon aptasensor was amenable to full regeneration by simply unfolding the aptamer in 1.0 M HCl, and could be regenerated 25 times with no loss in electrochemical signal upon subsequent thrombin binding.

@article{citeulike:780928, abstract = {A bifunctional derivative of the thrombin-binding aptamer with a redox-active Fc moiety and a thiol group at the termini of the aptamer strand was synthesized. The ferrocene-labeled aptamer thiol was self-assembled through S-Au bonding on a polycrystalline gold electrode surface and the surface was blocked with 2-mercaptoethanol to form a mixed monolayer. By use of a fluorescent molecular beacon, the effect of counterions on quadruplex formation was established. The aptamer-modified electrode was characterized electrochemically by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). The modified electrode showed a voltammetric signal due to a one-step redox reaction of the surface-confined ferrocenyl moiety of the aptamer immobilized on the electrode surface in 10 mM N-(2-hydroxyethyl)piperazine-N'-2-ethanesulfonic acid (HEPES) buffer of pH 8.0. An increase in the DPV current signal was evident after blocking with 2-mercaptoethanol, effectively removing aptamer nonspecifically absorbed rather than bound to electrode surface or due to the formation of the aptamer-thrombin affinity interaction. The impedance measurement, in agreement with the differential pulse voltammetry (DPV), showed decreased Faradaic resistances in the same sequence. The "signal-on" upon thrombin association could be attributed to a change in conformation from random coil-like configuration on the probe-modified film to the quadruplex structure. The DPV of the modified electrode showed a linear response of the Fc oxidation signal to the increase in the thrombin concentration in the range between 5.0 and 35.0 nM with a linear correlation of r = 0.9988 and a detection limit of 0.5 nM. The molecular beacon aptasensor was amenable to full regeneration by simply unfolding the aptamer in 1.0 M HCl, and could be regenerated 25 times with no loss in electrochemical signal upon subsequent thrombin binding.}, added-at = {2006-07-31T20:01:51.000+0200}, address = {Nanobiotechnology and Bioanalysis Group, Department of Chemical Engineering, Universitat Rovira i Virgili, Tarragona, Spain. abd.radi@urv.net}, author = {Radi, A. E. and Sánchez, J. L. Acero and Baldrich, E. and O'Sullivan, C. K.}, biburl = {https://www.bibsonomy.org/bibtex/231877889ce190ffba7dbd339c91b8441/biblio24}, citeulike-article-id = {780928}, comment = {abd.radi@urv.net}, doi = {10.1021/ja053121d}, interhash = {c420f194314544b9c63b43d7806f8555}, intrahash = {31877889ce190ffba7dbd339c91b8441}, issn = {0002-7863}, journal = {J Am Chem Soc}, keywords = {aptamer surface electrochemistry}, month = {January}, number = 1, pages = {117--124}, priority = {2}, timestamp = {2006-07-31T20:01:51.000+0200}, title = {Reagentless, reusable, ultrasensitive electrochemical molecular beacon aptasensor.}, url = {http://dx.doi.org/10.1021/ja053121d}, volume = 128, year = 2006 }