Synthesis, functionalization, and characterization of rod-shaped gold nanoparticles as potential optical contrast agents

R.G. Rayavarapu, Wilhelmina Petersen, C. Ungureanu, Severine le Gac, Ton van Leeuwen, Srirang Manohar

    Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

    2 Citations (Scopus)


    Gold nanoparticles exhibit intense and narrow optical extinction bands due to the phenomenon of plasmon resonance making them useful as contrast agents for light-based imaging techniques. Localized heating results from the absorbed light energy, which shows potential for these particles in photothermal therapy as well. The bioconjugation of gold nanoparticles to appropriate antibodies targeted to tumors in vivo, could make highly selective detection and therapy of tumors possible. We have synthesised gold nanorods based on seed mediated protocols using two methods. The first method is based on using a mono-surfactant silver assisted method which produces gold nanorods having plasmon peaks between 670-850 nm within the "optical imaging and therapeutic window". These nanorods have aspect ratios between 2.3 - 3.7. A second method is a silver assisted bi-surfactant method which produce nanorods with peaks in the range of 850-1100 nm having aspect ratios between 5-11. Typical concentrations of these particles in aqueous dispersions are in the range of 1×1010 - 1×1011 particles per mL. We have bioconjugated these gold nanorods with anti-HER2/neu mouse monoclonal antibodies (MAb). Since the as-prepared CTAB-stabilized nanorods were found to be toxic to SKBR3 cells, we decided to coat the gold nanorods with polyethylene glycol (PEG). Characterization and size estimation of the nanoparticles were performed using electron microscopies, optical spectroscopy and confocal microscopy. We present these results and implications for use of these nanoparticles for in vivo biomedical applications.

    Original languageEnglish
    Title of host publicationMolecular Imaging
    EditorsKai Licha, Vasilis Ntziachristos
    Place of PublicationMunich
    Number of pages10
    ISBN (Print)0819467707, 9780819467706
    Publication statusPublished - 11 Jul 2007
    EventEuropean Conferences on Biomedical Optics, ECBO 2007 - ICM—International Conference Centre Munich, Munich, Germany
    Duration: 17 Jun 200721 Jun 2007

    Publication series

    NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
    ISSN (Print)1605-7422


    ConferenceEuropean Conferences on Biomedical Optics, ECBO 2007
    Abbreviated titleECBO


    • Bi-surfactant gold nanorods
    • Bioconjugation
    • Cytotoxicity of gold nanorods
    • Gold nanoparticles
    • Gold nanorods
    • Molecular imaging
    • PEGylation
    • Photothermal therapy
    • Plasmonic particles
    • Seed-mediated synthesis


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