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  • br Comparison with the alternative

    2020-08-12


    3.6. Comparison with the alternative PSA immunosensors
    In Table 2, the analytical characteristics of some recently reported methods for the electrochemical immunosensing of PSA are compared with those of our proposed immunosensor
    Response characteristics of the different electrochemical immunosensors based on the nanomaterials for determination of PSA tumor marker.
    Type of affinity assay Real sample LOD DLR References
    LOD: Limit of detection; DLR: Dynamic linear range; GRP: Graphene nanoplatelets; GCE: Glassy carbon electrode; SPE: Screen-printed electrode; Ab: Antibody; Nb: Nanobody; g-C3 N4 : Graphitic carbon nitride; GQD: Graphene quantum dot; AuNR: gold nanorod; [email protected]: Luminol functionalized platinum nanoparticles loaded on graphene nanosheets; PEDOT: Poly(3,4-ethylenedioxythiophene); [email protected]: Mesoporous core-shell [email protected] nanoparticle; NH2 -GS: Amino group functionalized graphene
    nanosheets; SA-HRP: Streptavidin-horseradish peroxidase; rGO: Reduced graphene oxide; MWCNT: Multiwalled carbon nanotube.
    [17–19,22,24–30]. As is obvious, although the immunosensors reported in the literature could effectively achieve the PSA detection, there was a scope for improvement in the current biosensor. The immobilization of high conductive MWCNT/His-rGO on the electrode surface was resulted in a significant ampli-fication on the detection signal. In addition, the presence of carboxyl and amine functional groups on the His-rGO can pro-vide the ability of covalently attaching thionine and anti-PSA antibody to the modified electrode surface. In fact, the hybrid nanomaterials offer task-specific functional properties besides the individual properties of their constituent materials. Herein, the His-rGO hybrid nanomaterial was synthesized to integrate the properties of both amino Apomorphine and graphene nanosheets. Importantly, the remarkable electrical conductivity of graphene improves the electrode performance, whereas covalently grafted amino acid facilitates the stable binding of redox indicator and bioreceptor on the modified electrode surface. Further, the MWCNT/His-rGO nanofilm offers a remarkably improved electrical conductivity compared to that of the corresponding GO. L-histidine functionalized rGO nanosheets are nontoxic and biocompatible, enabling sensing of biomolecules with high degree of physiological safety.
    As a result, important features of the described immunosens-ing strategy such as low detection limit, wide linear range, high accuracy, good repeatability and reproducibility introduce this biosensor as a powerful tool for detection of Apomorphine prostate cancer through determination of PSA concentration in human serum.
    4. Conclusions
    Prostate specific antigen is a well-established tumor marker that aids the diagnosis and staging of prostate cancer. Despite impressive developments in the PSA sensing, the simple, sensitive, selective and poin-of-care determination of this tumor marker has remained a key challenge in early detection of prostate cancer. In this study, an ultrasensitive electrochemical immunosensor was designed for the quantitative detection of PSA by a voltammet-ric method. The MWCNT/His-rGO was used as a signal amplified nanoplatform to immobilize both of antibody and thionine and accelerate the electron transfer on the electrode interface. The designed immunosensor showed a linear concentration range from 10 fg mL−1 to 20 ng mL−1, with a low detection limit of 2.8 fg mL−1 for PSA. Such a strategy provides impressive advantages that include the reagentless nature of the platform, the adaptability to point-of-care approaches, and the possibility to use it with complex real samples. Despite these advantages, the proposed biosensing method is time and cost-consuming.
    Acknowledgements
    We greatly appreciate the support of this work by Research Council of Razi University.
    References
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