title: Detoxification of gold nanorods by conjugation with thiolated poly(ethylene glycol) and their assessment as SERS-active carriers of Raman tags.
abstract: We present an effective, low cost protocol to reduce the toxicity of gold nanorods induced by the presence of cetyltrimethylammonium bromide (CTAB) on their lateral surface as a result of the synthesis process. Here, we use thiolated methoxy-poly(ethylene) glycol (mPEG-SH) polymer to displace most of the CTAB bilayer cap from the particle surface. The detoxification process, chemical and structural stability of as-prepared mPEG-SH-conjugated gold nanorods were characterized using a number of techniques including localized surface plasmon resonance (LSPR), transmission electron microscopy (TEM) and surface-enhanced Raman spectroscopy (SERS). In view of future applications as near-infrared (NIR) nanoheaters in localized photothermal therapy of cancer, we investigated the thermal behaviour of mPEG-SH-conjugated gold nanorods above room temperature. We found a critical temperature at around 40 degrees C at which the adsorbed polymer layer is susceptible to undergo conformational changes. Additionally, we believe that such plasmonic nanoprobes could act as SERS-active carriers of Raman tags for application in cellular imaging. In this sense we successfully tested them as effective SERS substrates at 785 nm laser line with p-aminothiophenol (pATP) as a tag molecule.
authors.affiliation: Nanobiophotonics Center, Institute for Interdisciplinary Research in Nanobioscience, Babes-Bolyai University, Cluj-Napoca, Romania. sboca@phys.ubbcluj.ro
authors.forename: Sanda C
authors.initials: SC
authors.lastname: Boca
authors.forename: Simion
authors.initials: S
authors.lastname: Astilean
mesh_terms: D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000009:adverse effects / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D043942:Nanotubes / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013438:Sulfhydryl Compounds / Q000737:chemistry
chemical_list: D002593:Cetrimonium Compounds; D013438:Sulfhydryl Compounds; D011092:Polyethylene Glycols; D006046:Gold; D000077286:Cetrimonium