Limits...
Graphene and other nanomaterial-based electrochemical aptasensors.

Hernandez FJ, Ozalp VC - Biosensors (Basel) (2012)

Bottom Line: Due to their stability, easy chemical modifications and proneness to nanostructured device construction, aptamer-based sensors have been incorporated in a variety of applications including electrochemical sensing devices.In recent years, the performance of aptasensors has been augmented by incorporating novel nanomaterials in the preparation of better electrochemical sensors.In this review, we summarize the recent trends in the use of nanomaterials for developing electrochemical aptasensors.

View Article: PubMed Central - PubMed

Affiliation: Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, 375 Newton Rd, Iowa City, IA 52242, USA. frank-hernandez@uiowa.edu.

ABSTRACT
Electrochemical aptasensors, which are based on the specificity of aptamer-target recognition, with electrochemical transduction for analytical purposes have received particular attention due to their high sensitivity and selectivity, simple instrumentation, as well as low production cost. Aptamers are functional nucleic acids with specific and high affinity to their targets, similar to antibodies. However, they are completely selected in vitro in contrast to antibodies. Due to their stability, easy chemical modifications and proneness to nanostructured device construction, aptamer-based sensors have been incorporated in a variety of applications including electrochemical sensing devices. In recent years, the performance of aptasensors has been augmented by incorporating novel nanomaterials in the preparation of better electrochemical sensors. In this review, we summarize the recent trends in the use of nanomaterials for developing electrochemical aptasensors.

No MeSH data available.


Typical aptasensor strategies for: (a) amperometric, (b) potentiometric or (c) impedimetric measurements. In panel (a), ATP binding aptamer labeled with methylene blue (MB) at one end was immobilized on gold surface at the other end. Specific interaction between aptamer sequence and ATP induces a conformational change, which significantly changes the electron transfer distance between MB and the gold surface. In panel (b), a primary thrombin binding aptamer is immobilized on gold surface via a sulfhydryl bond (i). In the presence of thrombin (ii), the secondary thrombin aptamer (CdS-modified) binds the complex (iii). After addition of H2O2 (iv), the Cd2+ ions are detected by the ion-selected electrode (ISE). In panel (c), thrombin binding aptamer (PDB: 1QDF) is immobilized on gold surface as in (b) and the interaction between aptamer and thrombin (PDB: 1HAO) can be monitored by impedimetric measurements in the presence of ferricyanide.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4263542&req=5

biosensors-02-00001-f001: Typical aptasensor strategies for: (a) amperometric, (b) potentiometric or (c) impedimetric measurements. In panel (a), ATP binding aptamer labeled with methylene blue (MB) at one end was immobilized on gold surface at the other end. Specific interaction between aptamer sequence and ATP induces a conformational change, which significantly changes the electron transfer distance between MB and the gold surface. In panel (b), a primary thrombin binding aptamer is immobilized on gold surface via a sulfhydryl bond (i). In the presence of thrombin (ii), the secondary thrombin aptamer (CdS-modified) binds the complex (iii). After addition of H2O2 (iv), the Cd2+ ions are detected by the ion-selected electrode (ISE). In panel (c), thrombin binding aptamer (PDB: 1QDF) is immobilized on gold surface as in (b) and the interaction between aptamer and thrombin (PDB: 1HAO) can be monitored by impedimetric measurements in the presence of ferricyanide.

Mentions: Amperometric sensors determine the presence of target by detecting the changes in current resulting from the electrochemical oxidation or reduction of an electroactive species. It is usually performed by maintaining a constant potential at working electrode with respect to a reference electrode. The resulting current is directly correlated to the bulk concentration of the electroactive compound. This signal-transduction mechanism is frequently used for enzymatic and catalytic biosensors. The main advantage of this class of transducer is the low cost, therefore disposable electrodes are often used with this technique. The high degree of reproducibility that is possible for these (one time use) electrodes eliminates the cumbersome requirement for repeated calibration. The type of instrument used for these measurements is also very easy to obtain and can be inexpensive and compact, this allowing for the possibility of in situ measurements. Limitations for this signal transduction mechanism include the potential interferences to the response, if several electroactive compounds generate false current values. These effects have been eliminated for clinical applications through the use of selective membranes, which carefully control the molecular weight or the charge of compounds that have access to the electrode. Figure 1(a) shows a scheme of an amperometric aptasensor for the detection of ATP.


Graphene and other nanomaterial-based electrochemical aptasensors.

Hernandez FJ, Ozalp VC - Biosensors (Basel) (2012)

Typical aptasensor strategies for: (a) amperometric, (b) potentiometric or (c) impedimetric measurements. In panel (a), ATP binding aptamer labeled with methylene blue (MB) at one end was immobilized on gold surface at the other end. Specific interaction between aptamer sequence and ATP induces a conformational change, which significantly changes the electron transfer distance between MB and the gold surface. In panel (b), a primary thrombin binding aptamer is immobilized on gold surface via a sulfhydryl bond (i). In the presence of thrombin (ii), the secondary thrombin aptamer (CdS-modified) binds the complex (iii). After addition of H2O2 (iv), the Cd2+ ions are detected by the ion-selected electrode (ISE). In panel (c), thrombin binding aptamer (PDB: 1QDF) is immobilized on gold surface as in (b) and the interaction between aptamer and thrombin (PDB: 1HAO) can be monitored by impedimetric measurements in the presence of ferricyanide.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263542&req=5

biosensors-02-00001-f001: Typical aptasensor strategies for: (a) amperometric, (b) potentiometric or (c) impedimetric measurements. In panel (a), ATP binding aptamer labeled with methylene blue (MB) at one end was immobilized on gold surface at the other end. Specific interaction between aptamer sequence and ATP induces a conformational change, which significantly changes the electron transfer distance between MB and the gold surface. In panel (b), a primary thrombin binding aptamer is immobilized on gold surface via a sulfhydryl bond (i). In the presence of thrombin (ii), the secondary thrombin aptamer (CdS-modified) binds the complex (iii). After addition of H2O2 (iv), the Cd2+ ions are detected by the ion-selected electrode (ISE). In panel (c), thrombin binding aptamer (PDB: 1QDF) is immobilized on gold surface as in (b) and the interaction between aptamer and thrombin (PDB: 1HAO) can be monitored by impedimetric measurements in the presence of ferricyanide.
Mentions: Amperometric sensors determine the presence of target by detecting the changes in current resulting from the electrochemical oxidation or reduction of an electroactive species. It is usually performed by maintaining a constant potential at working electrode with respect to a reference electrode. The resulting current is directly correlated to the bulk concentration of the electroactive compound. This signal-transduction mechanism is frequently used for enzymatic and catalytic biosensors. The main advantage of this class of transducer is the low cost, therefore disposable electrodes are often used with this technique. The high degree of reproducibility that is possible for these (one time use) electrodes eliminates the cumbersome requirement for repeated calibration. The type of instrument used for these measurements is also very easy to obtain and can be inexpensive and compact, this allowing for the possibility of in situ measurements. Limitations for this signal transduction mechanism include the potential interferences to the response, if several electroactive compounds generate false current values. These effects have been eliminated for clinical applications through the use of selective membranes, which carefully control the molecular weight or the charge of compounds that have access to the electrode. Figure 1(a) shows a scheme of an amperometric aptasensor for the detection of ATP.

Bottom Line: Due to their stability, easy chemical modifications and proneness to nanostructured device construction, aptamer-based sensors have been incorporated in a variety of applications including electrochemical sensing devices.In recent years, the performance of aptasensors has been augmented by incorporating novel nanomaterials in the preparation of better electrochemical sensors.In this review, we summarize the recent trends in the use of nanomaterials for developing electrochemical aptasensors.

View Article: PubMed Central - PubMed

Affiliation: Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, 375 Newton Rd, Iowa City, IA 52242, USA. frank-hernandez@uiowa.edu.

ABSTRACT
Electrochemical aptasensors, which are based on the specificity of aptamer-target recognition, with electrochemical transduction for analytical purposes have received particular attention due to their high sensitivity and selectivity, simple instrumentation, as well as low production cost. Aptamers are functional nucleic acids with specific and high affinity to their targets, similar to antibodies. However, they are completely selected in vitro in contrast to antibodies. Due to their stability, easy chemical modifications and proneness to nanostructured device construction, aptamer-based sensors have been incorporated in a variety of applications including electrochemical sensing devices. In recent years, the performance of aptasensors has been augmented by incorporating novel nanomaterials in the preparation of better electrochemical sensors. In this review, we summarize the recent trends in the use of nanomaterials for developing electrochemical aptasensors.

No MeSH data available.