title: Silica-coated gold nanostars for combined surface-enhanced Raman scattering (SERS) detection and singlet-oxygen generation: a potential nanoplatform for theranostics.
abstract: This paper reports the synthesis and characterization of surface-enhanced Raman scattering (SERS) label-tagged gold nanostars, coated with a silica shell containing methylene blue photosensitizing drug for singlet-oxygen generation. To our knowledge, this is the first report of nanocomposites possessing a combined capability for SERS detection and singlet-oxygen generation for photodynamic therapy. The gold nanostars were tuned for maximal absorption in the near-infrared (NIR) spectral region and tagged with a NIR dye for surface-enhanced resonance Raman scattering (SERRS). Silica coating was used to encapsulate the photosensitizer methylene blue in a shell around the nanoparticles. Upon 785 nm excitation, SERS from the Raman dye is observed, while excitation at 633 nm shows fluorescence from methylene blue. Methylene-blue-encapsulated nanoparticles show a significant increase in singlet-oxygen generation as compared to nanoparticles synthesized without methylene blue. This increased singlet-oxygen generation shows a cytotoxic effect on BT549 breast cancer cells upon laser irradiation. The combination of SERS detection (diagnostic) and singlet-oxygen generation (therapeutic) into a single platform provides a potential theranostic agent.
authors.affiliation: Fitzpatrick Institute for Photonics, Duke University, Durham, North Carolina 27708, United States.|Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, United States.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Fales
authors.affiliation: Fitzpatrick Institute for Photonics, Duke University, Durham, North Carolina 27708, United States.|Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, United States.
authors.forename: Hsiangkuo
authors.initials: H
authors.lastname: Yuan
authors.affiliation: Fitzpatrick Institute for Photonics, Duke University, Durham, North Carolina 27708, United States.|Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708, United States.|Department of Chemistry, Duke University, Durham, North Carolina 27708, United States.
authors.forename: Tuan
authors.initials: T
authors.lastname: Vo-Dinh
mesh_terms: D045744:Cell Line, Tumor; D005456:Fluorescent Dyes / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D006801:Humans; D053768:Metal Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D010778:Photochemotherapy; D012822:Silicon Dioxide / Q000737:chemistry*; D026082:Singlet Oxygen / Q000737:chemistry*; D013059:Spectrum Analysis, Raman; D013499:Surface Properties
chemical_list: D005456:Fluorescent Dyes; D026082:Singlet Oxygen; D006046:Gold; D012822:Silicon Dioxide