Ultrasensitive Label-free Electrochemical Immunosensor based on Multifunctionalized Graphene Nanocomposites for the Detection of Alpha Fetoprotein

Yaoguang Wang,Qin Wei,Dawei Fan,Hongmin Ma,Dan Wu,Yong Zhang,Xuehui Pang,Bin Du

doi:10.1038/srep42361

Yaoguang Wang, Qin Wei + Show 6 more

Open Access

https://doi.org/10.1038/srep42361

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Journal: Scientific Reports	Publication Date: Feb 10, 2017
Citations: 53	License type: open-access

Affiliation: University of Jinan

Abstract

In this work, a novel label-free electrochemical immunosensor was developed for the quantitative detection of alpha fetoprotein (AFP). Multifunctionalized graphene nanocomposites (TB-Au-Fe3O4-rGO) were applied to modify the electrode to achieve the amplification of electrochemical signal. TB-Au-Fe3O4-rGO includes the advantages of graphene, ferroferric oxide nanoparticles (Fe3O4 NPs), gold nanoparticles (Au NPs) and toluidine blue (TB). As a kind of redox probe, TB can produce the electrochemical signal. Graphene owns large specific surface area, high electrical conductivity and good adsorption property to load a large number of TB. Fe3O4 NPs have good electrocatalytic performance towards the redox of TB. Au NPs have good biocompatibility to capture the antibodies. Due to the good electrochemical performance of TB-Au-Fe3O4-rGO, the effective and sensitive detection of AFP was achieved by the designed electrochemical immunosensor. Under optimal conditions, the designed immunosensor exhibited a wide linear range from 1.0 × 10−5 ng/mL to 10.0 ng/mL with a low detection limit of 2.7 fg/mL for AFP. It also displayed good electrochemical performance including good reproducibility, selectivity and stability, which would provide potential applications in the clinical diagnosis of other tumor markers.

Highlights

As a star among two-dimensional nanomaterials, graphene has attracted tremendous research interest in the field of electrochemistry due to their intrinsic properties, including the electronic, optical, and mechanical properties associated with their planar structure[14,15]
It can be observed that the reduced graphene oxide (rGO) of Au-Fe3O4-rGO is thin and wrinkled, which resembles crumpled silk veil waves
The Fe3O4 NPs are loaded on the surface of rGO with an average diameter about 200 nm

Summary

Electrochemical Immunosensor based on Multifunctionalized

Graphene Nanocomposites for the received:21October2016 accepted: 08 January 2017. Yaoguang Wang, Yong Zhang, Dan Wu, Hongmin Ma, Xuehui Pang, Dawei Fan, Qin Wei & Bin Du. Due to the good electrochemical performance of TB-Au-Fe3O4-rGO, the effective and sensitive detection of AFP was achieved by the designed electrochemical immunosensor. According to our previous reports[21,22,23,24], reduced graphene oxide functionalized with ferroferric oxide (Fe3O4-rGO) can be used in adsorbing a variety of heavy metals In this case, a label-free electrochemical immunosensor based on multifunctionalized graphene nanocomposites (TB-Au-Fe3O4-rGO) was designed for the quantitative detection of AFP. 43, anti-AFP can be conjugated on the surface of TB-Au-Fe3O4-rGO due to the bonding between amino groups of antibodies and Au NPs. After incubated at 4 °C for 1 h and washed, BSA solution (10 mg/mL, 3 μL) was added onto the electrode to eliminate nonspecific binding sites.

Results and Discussion

Conclusion

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