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Enhancing electrochemical detection on graphene oxide-CNT nanostructured electrodes using magneto-nanobioprobes.

Sharma P, Bhalla V, Dravid V, Shekhawat G - Sci Rep (2012)

Bottom Line: Sensitive detection was achieved by precisely designing the nanohybrid and correlating the available metal ions with analyte concentration.We confirmed the ultrahigh sensitivity of this method for a new generation herbicide diuron and its analogues up to sub-picomolar concentration in standard water samples.The novel immune-detection platform showed the excellent potential applicability in rapid and sensitive screening of environmental pollutants or toxins in samples.

View Article: PubMed Central - PubMed

Affiliation: Institute of Microbial Technology (CSIR), Sector 39-A, Chandigarh 160036, India.

ABSTRACT
Graphene and related materials have come to the forefront of research in electrochemical sensors during recent years due to the promising properties of these nanomaterials. Further applications of these nanomaterials have been hampered by insufficient sensitivity offered by these nanohybrids for the type of molecules requiring lower detection ranges. Here, we report a signal amplification strategy based on magneto-electrochemical immunoassay which combines the advantages of carbon nanotube and reduced graphene oxide together with electrochemical bursting of magnetic nanoparticles into a large number of metal ions. Sensitive detection was achieved by precisely designing the nanohybrid and correlating the available metal ions with analyte concentration. We confirmed the ultrahigh sensitivity of this method for a new generation herbicide diuron and its analogues up to sub-picomolar concentration in standard water samples. The novel immune-detection platform showed the excellent potential applicability in rapid and sensitive screening of environmental pollutants or toxins in samples.

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Schematic illustration of the two nanohybrid systems i.e. Au/Fe nanobioprobes on the microtitre plate and the subsequent metal ion sensing on rGO/CNT nanostructured electrodes.
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f1: Schematic illustration of the two nanohybrid systems i.e. Au/Fe nanobioprobes on the microtitre plate and the subsequent metal ion sensing on rGO/CNT nanostructured electrodes.

Mentions: Nanometer-sized magnetic particles of iron are potential candidates in catalysis, magnetic separation and biomedical applications12. However, pure iron nanoparticles are chemically unstable and easily oxidize, which limits their utility in biosensing and other applications. These particles are therefore coated with another inert layer such as metal-oxide (iron oxide), inorganic material (SiO2), and noble metals (gold and silver), thereby making core–shell nano-structures showing favorable magnetic properties of metal iron while preventing them from oxidation13. Gold has been one of the potential coating materials owing to its chemical inertness, biocompatibility, non-toxic, and diverse cluster geometries14. Very recently, inorganic or semiconductor nanoparticles tagged with receptor molecules has generated good interest for electrochemical detection of analyte1516. Anodic stripping voltammetry (ASV) has proved to be a very sensitive method for trace determination of metal ions liberated from nanoparticles. Recently, Liu developed multi-QDs functionalized silica nanoparticles based electrochemical amplification platform which dramatically enhanced the intensity of the signal and led to ultrasensitive detection17. Our previous study reported the use of gold nanoparticles mediated ASV technique based upon oxidative gold nanoparticles dissolution in an acidic solution. The consequent release of large amount of gold (Au) metal ions after dissolution lead to the development of sensitive stripping voltammetry based immunoassay18. However, it suffers from the use of strongly corrosive and hazardous agents such as HBr/Br2 for the oxidation of gold nanoparticles, which minimizes it's usage in common lab practices. Although great achievement has been obtained in this field, the finding of more sensitive, environment friendly convenient assay still attracts increasing interest for improving the sensitivity of bioassays. The present work demonstrates the development of metal ion derivatized electrochemical immunoassay based on gold-iron (Au/Fe) nanobioprobes for the detection of commonly used phenylurea herbicide diuron on reduced graphene oxide-carbon nanotubes (rGO/CNT) modified biosensing platform using specific anti-diuron antibodies (Figure 1). The use of core magnetic nanoparticles offers rapid immunocomplex formation on magneto-microtitre plates and their further electrochemical bursting into a large number of Fe2+ ions presented ultra-high sensitivity for diuron detection on SPE. The novel immune-detection platform demonstrated excellent potential applicability in rapid and sensitive screening of environmental pollutants or toxins in samples.


Enhancing electrochemical detection on graphene oxide-CNT nanostructured electrodes using magneto-nanobioprobes.

Sharma P, Bhalla V, Dravid V, Shekhawat G - Sci Rep (2012)

Schematic illustration of the two nanohybrid systems i.e. Au/Fe nanobioprobes on the microtitre plate and the subsequent metal ion sensing on rGO/CNT nanostructured electrodes.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3500845&req=5

f1: Schematic illustration of the two nanohybrid systems i.e. Au/Fe nanobioprobes on the microtitre plate and the subsequent metal ion sensing on rGO/CNT nanostructured electrodes.
Mentions: Nanometer-sized magnetic particles of iron are potential candidates in catalysis, magnetic separation and biomedical applications12. However, pure iron nanoparticles are chemically unstable and easily oxidize, which limits their utility in biosensing and other applications. These particles are therefore coated with another inert layer such as metal-oxide (iron oxide), inorganic material (SiO2), and noble metals (gold and silver), thereby making core–shell nano-structures showing favorable magnetic properties of metal iron while preventing them from oxidation13. Gold has been one of the potential coating materials owing to its chemical inertness, biocompatibility, non-toxic, and diverse cluster geometries14. Very recently, inorganic or semiconductor nanoparticles tagged with receptor molecules has generated good interest for electrochemical detection of analyte1516. Anodic stripping voltammetry (ASV) has proved to be a very sensitive method for trace determination of metal ions liberated from nanoparticles. Recently, Liu developed multi-QDs functionalized silica nanoparticles based electrochemical amplification platform which dramatically enhanced the intensity of the signal and led to ultrasensitive detection17. Our previous study reported the use of gold nanoparticles mediated ASV technique based upon oxidative gold nanoparticles dissolution in an acidic solution. The consequent release of large amount of gold (Au) metal ions after dissolution lead to the development of sensitive stripping voltammetry based immunoassay18. However, it suffers from the use of strongly corrosive and hazardous agents such as HBr/Br2 for the oxidation of gold nanoparticles, which minimizes it's usage in common lab practices. Although great achievement has been obtained in this field, the finding of more sensitive, environment friendly convenient assay still attracts increasing interest for improving the sensitivity of bioassays. The present work demonstrates the development of metal ion derivatized electrochemical immunoassay based on gold-iron (Au/Fe) nanobioprobes for the detection of commonly used phenylurea herbicide diuron on reduced graphene oxide-carbon nanotubes (rGO/CNT) modified biosensing platform using specific anti-diuron antibodies (Figure 1). The use of core magnetic nanoparticles offers rapid immunocomplex formation on magneto-microtitre plates and their further electrochemical bursting into a large number of Fe2+ ions presented ultra-high sensitivity for diuron detection on SPE. The novel immune-detection platform demonstrated excellent potential applicability in rapid and sensitive screening of environmental pollutants or toxins in samples.

Bottom Line: Sensitive detection was achieved by precisely designing the nanohybrid and correlating the available metal ions with analyte concentration.We confirmed the ultrahigh sensitivity of this method for a new generation herbicide diuron and its analogues up to sub-picomolar concentration in standard water samples.The novel immune-detection platform showed the excellent potential applicability in rapid and sensitive screening of environmental pollutants or toxins in samples.

View Article: PubMed Central - PubMed

Affiliation: Institute of Microbial Technology (CSIR), Sector 39-A, Chandigarh 160036, India.

ABSTRACT
Graphene and related materials have come to the forefront of research in electrochemical sensors during recent years due to the promising properties of these nanomaterials. Further applications of these nanomaterials have been hampered by insufficient sensitivity offered by these nanohybrids for the type of molecules requiring lower detection ranges. Here, we report a signal amplification strategy based on magneto-electrochemical immunoassay which combines the advantages of carbon nanotube and reduced graphene oxide together with electrochemical bursting of magnetic nanoparticles into a large number of metal ions. Sensitive detection was achieved by precisely designing the nanohybrid and correlating the available metal ions with analyte concentration. We confirmed the ultrahigh sensitivity of this method for a new generation herbicide diuron and its analogues up to sub-picomolar concentration in standard water samples. The novel immune-detection platform showed the excellent potential applicability in rapid and sensitive screening of environmental pollutants or toxins in samples.

Show MeSH