Limits...
A reusable impedimetric aptasensor for detection of thrombin employing a graphite-epoxy composite electrode.

Ocaña C, Pacios M, del Valle M - Sensors (Basel) (2012)

Bottom Line: The aptasensor showed a linear response for thrombin in the range of 7.5 pM to 75 pM and a detection limit of 4.5 pM.The aptasensor was regenerated by breaking the complex formed between the aptamer and thrombin using 2.0 M NaCl solution at 42 °C, showing its operation for different cycles.The interference response caused by main proteins in serum has been characterized.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Universitat Autònoma de Barcelona, Bellaterra 08193, Spain. cristina.ocana@uab.es

ABSTRACT
Here, we report the application of a label-free electrochemical aptasensor based on a graphite-epoxy composite electrode for the detection of thrombin; in this work, aptamers were immobilized onto the electrodes surface using wet physical adsorption. The detection principle is based on the changes of the interfacial properties of the electrode; these were probed in the presence of the reversible redox couple [Fe(CN)(6)](3-)/[Fe(CN)(6)](4-) using impedance measurements. The electrode surface was partially blocked due to formation of aptamer-thrombin complex, resulting in an increase of the interfacial electron-transfer resistance detected by Electrochemical Impedance Spectroscopy (EIS). The aptasensor showed a linear response for thrombin in the range of 7.5 pM to 75 pM and a detection limit of 4.5 pM. The aptasensor was regenerated by breaking the complex formed between the aptamer and thrombin using 2.0 M NaCl solution at 42 °C, showing its operation for different cycles. The interference response caused by main proteins in serum has been characterized.

Show MeSH

Related in: MedlinePlus

Response to proteins evaluated: IgG (•), Fbr (○) and Thr (▾).
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3376577&req=5

f8-sensors-12-03037: Response to proteins evaluated: IgG (•), Fbr (○) and Thr (▾).

Mentions: To evaluate the sensitivity of the aptasensor we compared the calibration plots for the different proteins. Table 1 summarizes the parameters of the calibration curve of each protein and thrombin, as well as their respectives slopes and detection limits. The aptasensor showed the highest sensitivity for its target molecule, thrombin, with its slope being 6 orders of magnitude greater than the slope for IgG and five orders of magnitude more than the one for fibrinogen, as shown in Figure 8. Therefore, it was demostrated that the aptasensor showed a much higher sensitivity to Thr, regarding potential interfering proteins, which displayed this effect due to the high level of concentration in which they are present.


A reusable impedimetric aptasensor for detection of thrombin employing a graphite-epoxy composite electrode.

Ocaña C, Pacios M, del Valle M - Sensors (Basel) (2012)

Response to proteins evaluated: IgG (•), Fbr (○) and Thr (▾).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3376577&req=5

f8-sensors-12-03037: Response to proteins evaluated: IgG (•), Fbr (○) and Thr (▾).
Mentions: To evaluate the sensitivity of the aptasensor we compared the calibration plots for the different proteins. Table 1 summarizes the parameters of the calibration curve of each protein and thrombin, as well as their respectives slopes and detection limits. The aptasensor showed the highest sensitivity for its target molecule, thrombin, with its slope being 6 orders of magnitude greater than the slope for IgG and five orders of magnitude more than the one for fibrinogen, as shown in Figure 8. Therefore, it was demostrated that the aptasensor showed a much higher sensitivity to Thr, regarding potential interfering proteins, which displayed this effect due to the high level of concentration in which they are present.

Bottom Line: The aptasensor showed a linear response for thrombin in the range of 7.5 pM to 75 pM and a detection limit of 4.5 pM.The aptasensor was regenerated by breaking the complex formed between the aptamer and thrombin using 2.0 M NaCl solution at 42 °C, showing its operation for different cycles.The interference response caused by main proteins in serum has been characterized.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, Universitat Autònoma de Barcelona, Bellaterra 08193, Spain. cristina.ocana@uab.es

ABSTRACT
Here, we report the application of a label-free electrochemical aptasensor based on a graphite-epoxy composite electrode for the detection of thrombin; in this work, aptamers were immobilized onto the electrodes surface using wet physical adsorption. The detection principle is based on the changes of the interfacial properties of the electrode; these were probed in the presence of the reversible redox couple [Fe(CN)(6)](3-)/[Fe(CN)(6)](4-) using impedance measurements. The electrode surface was partially blocked due to formation of aptamer-thrombin complex, resulting in an increase of the interfacial electron-transfer resistance detected by Electrochemical Impedance Spectroscopy (EIS). The aptasensor showed a linear response for thrombin in the range of 7.5 pM to 75 pM and a detection limit of 4.5 pM. The aptasensor was regenerated by breaking the complex formed between the aptamer and thrombin using 2.0 M NaCl solution at 42 °C, showing its operation for different cycles. The interference response caused by main proteins in serum has been characterized.

Show MeSH
Related in: MedlinePlus