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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.


Approaches for preparing graphene-based electrochemical sensing platforms. An impedimetric sensor with (a) covalent and (b) non-covalent aptamer immobilization, (c) graphene quantum dots, (d) magnetic nanoparticles-graphene bioelectronics.
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biosensors-02-00001-f002: Approaches for preparing graphene-based electrochemical sensing platforms. An impedimetric sensor with (a) covalent and (b) non-covalent aptamer immobilization, (c) graphene quantum dots, (d) magnetic nanoparticles-graphene bioelectronics.

Mentions: Aptamers can be immobilized on graphene nanocomposites via covalent bonds for developing reusable sensors or via physical adsorption of aptamers on graphene to obtain one time use sensors. Both strategies have been demonstrated to be useful in aptasensor development. 3,4,9,10-perylene tetracarboxylic acid (PTCA) is an archetypal π-stacking organic perylene dye with favorable photo and chemical stability. PTCA strongly adsorbs on graphene through π-π stacking and thus prevents graphene aggregation. Another advantage of PTCA composites is the added carboxyl groups which can be exploited for covalent attachment of aptamers. Graphene-promoted PTCA (GPD) nanocomposites has been synthesized as redox probe for developing an electrochemical thrombin aptasensor [48]. The authors reported a novel redox sensor by achieving a well-defined cathodic peak which was not observed previously with graphene. A detection range of 0.001 nM to 40 nM with limit of detection at 200 fM was obtained for thrombin detection (Figure 2(a)). In a similar application of PTCA-graphene nanocomposite, an electrochemical aptasensor was developed for detection of cancer cells by using nucleolin binding (AS1411) aptamer [49]. Nucleolin is a marker protein for cancer cells which is overexpressed on the tumor cell membranes. EIS measurements were employed to detect binding of cancer cells on the electrode surface with a detection limit of 794 cells/mL. The reported detection limit and dynamic range were better compared to a chemiluminescent sensor [50] and a nanofiber based electrochemical sensor [51] with the same aptamer sequence. Detection limit of this graphene based sensor was comparable to those of previously reported single-walled carbon nanotube (SWCNT) based aptasensor (620 cells/mL) [52]. However, graphene based cytosensor can be considered an improvement due to a lower production cost. The constructed graphene nanocomposite sensor surface was also tested with MTT (Methylthiazolyldiphenyl-tetrazolium bromide) assay for cytotoxicity and found to be non-toxic.


Graphene and other nanomaterial-based electrochemical aptasensors.

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

Approaches for preparing graphene-based electrochemical sensing platforms. An impedimetric sensor with (a) covalent and (b) non-covalent aptamer immobilization, (c) graphene quantum dots, (d) magnetic nanoparticles-graphene bioelectronics.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

biosensors-02-00001-f002: Approaches for preparing graphene-based electrochemical sensing platforms. An impedimetric sensor with (a) covalent and (b) non-covalent aptamer immobilization, (c) graphene quantum dots, (d) magnetic nanoparticles-graphene bioelectronics.
Mentions: Aptamers can be immobilized on graphene nanocomposites via covalent bonds for developing reusable sensors or via physical adsorption of aptamers on graphene to obtain one time use sensors. Both strategies have been demonstrated to be useful in aptasensor development. 3,4,9,10-perylene tetracarboxylic acid (PTCA) is an archetypal π-stacking organic perylene dye with favorable photo and chemical stability. PTCA strongly adsorbs on graphene through π-π stacking and thus prevents graphene aggregation. Another advantage of PTCA composites is the added carboxyl groups which can be exploited for covalent attachment of aptamers. Graphene-promoted PTCA (GPD) nanocomposites has been synthesized as redox probe for developing an electrochemical thrombin aptasensor [48]. The authors reported a novel redox sensor by achieving a well-defined cathodic peak which was not observed previously with graphene. A detection range of 0.001 nM to 40 nM with limit of detection at 200 fM was obtained for thrombin detection (Figure 2(a)). In a similar application of PTCA-graphene nanocomposite, an electrochemical aptasensor was developed for detection of cancer cells by using nucleolin binding (AS1411) aptamer [49]. Nucleolin is a marker protein for cancer cells which is overexpressed on the tumor cell membranes. EIS measurements were employed to detect binding of cancer cells on the electrode surface with a detection limit of 794 cells/mL. The reported detection limit and dynamic range were better compared to a chemiluminescent sensor [50] and a nanofiber based electrochemical sensor [51] with the same aptamer sequence. Detection limit of this graphene based sensor was comparable to those of previously reported single-walled carbon nanotube (SWCNT) based aptasensor (620 cells/mL) [52]. However, graphene based cytosensor can be considered an improvement due to a lower production cost. The constructed graphene nanocomposite sensor surface was also tested with MTT (Methylthiazolyldiphenyl-tetrazolium bromide) assay for cytotoxicity and found to be non-toxic.

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.