Modulating the Morphology of Gold Graphitic Nanocapsules for Plasmon Resonance-Enhanced Multimodal Imaging

Anal Chem. 2016 May 17;88(10):5385-91. doi: 10.1021/acs.analchem.6b00714. Epub 2016 Apr 27.

Abstract

With their unique optical properties and distinct Raman signatures, graphitic nanomaterials can serve as substrates for surface-enhanced Raman spectroscopy (SERS) or provide signal amplification for bioanalysis and detection. However, a relatively weak Raman signal has limited further biomedical applications. This has been addressed by encapsulating gold nanorods (AuNRs) in a thin graphitic shell to form gold graphitic nanocapsules. This step improves plasmon resonance, which enhances Raman intensity, and has the potential for integrating two-photon luminescence (TPL) imaging capability. However, changing the morphology of gold graphitic nanocapsules such that high quality and stability are achieved remains a challenge. To address this task, we herein report a confinement chemical vapor deposition (CVD) method to prepare the construction of AuNR-encapsulated graphitic nanocapsules with these properties. Specifically, through morphological modulation, we (1) achieved higher plasmon resonance with near-IR incident light, thus achieving greater Raman intensity, and (2) successfully integrated two-photon luminescence dual-modal (Raman/TPL) bioimaging capabilities. Cancer-cell-specific aptamers were further modified on the AuNR@G graphitic surface through simple, but strong, π-π interactions to achieve imaging selectivity through differential cancer cell recognition.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aptamers, Nucleotide / chemistry
  • Cell Survival / drug effects
  • Gold / chemistry*
  • Graphite / chemistry*
  • Humans
  • MCF-7 Cells
  • Microscopy, Confocal
  • Multimodal Imaging / methods*
  • Nanocapsules / chemistry*
  • Nanocapsules / toxicity
  • Nanotubes / chemistry
  • Spectrum Analysis, Raman
  • Surface Plasmon Resonance

Substances

  • Aptamers, Nucleotide
  • Nanocapsules
  • Gold
  • Graphite