Phthalocyanine-Sensitized Graphene–CdS Nanocomposites: An Enhanced Photoelectrochemical Immunosensing Platform

Authors

  • Dr. Yong-Jie Li,

    1. State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (P.R. China), Fax: (+86) 25-83597204
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  • Meng-Jie Ma,

    1. State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (P.R. China), Fax: (+86) 25-83597204
    2. Institute of Petrochemical Technology, Changzhou University, Changzhou, 213164 (P.R. China)
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  • Dr. Gui Yin,

    1. State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (P.R. China), Fax: (+86) 25-83597204
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  • Dr. Yong Kong,

    Corresponding author
    1. State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (P.R. China), Fax: (+86) 25-83597204
    2. Institute of Petrochemical Technology, Changzhou University, Changzhou, 213164 (P.R. China)
    • State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (P.R. China), Fax: (+86) 25-83597204
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  • Prof. Jun-Jie Zhu

    Corresponding author
    1. State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (P.R. China), Fax: (+86) 25-83597204
    • State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (P.R. China), Fax: (+86) 25-83597204
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Abstract

A novel strategy is developed for the fabrication of graphene–CdS (G–CdS) nanocomposites by in situ growth of CdS nanoparticles onto simultaneously reduced graphite oxide, which is noncovalently functionalized by sodium 1-pyrene sulfonate through strong π–π stacking interactions. Subsequently, cobalt 2,9,16,23-tetraaminophthalocyanine (CoTAPc) is self-assembled on the G–CdS nanocomposites through electrostatic interactions to produce phthalocyanine-sensitized G–CdS nanocomposites. The photoactive superstructure enhances the photocurrent generation capability, and presents an efficient photoelectrochemical immunosensing platform for the ultrasensitive detection of the prostate-specific antigen (PSA). The quantitative measurement of PSA is based on the decrease in the photocurrent intensity of the phthalocyanine-sensitized G–CdS nanocomposites, which results from an increase in the steric hindrance due to the formation of the immunocomplex. A linear relationship between the photocurrent decrease and the PSA concentration is obtained in the wide range from 1 pg mL−1 to 5 μg mL−1 with a detection limit of 0.63 pg mL−1. The proposed sensor shows high sensitivity, stability, reproducibility, and can become a promising platform for other biomolecular detection.

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