Coating identification in spherical and anisotropic gold nanomaterials by SERS technique

Recently the use of nanomaterials for the diagnosis and detection of malignant diseases has increased due to the versatility and properties of these nanostructures. For this work 60 nm commercial gold nanoparticles (TED PELLA inc.) and Nanostars manufactured by chemical synthesis (precursor reagent: HAuCl4, cationic surfactant: CTAB) of 117 nm were used for coating. Malachite green Isotyocianate (MGITC), mPEG-SH and ortho-pyridyldisulfide-polyethylene glycol-N-succinimidyl propionate (OPSS-PEG-NHS) was used. A SERS active nanoparticle complex was obtained by addition of a solution of MGITC to the gold nanoparticles colloidal solution in a 1:6 ratio. Later, an mPEG-SH solution was added to the mix. The nanoparticle-MGITC-mPEG-SH complex stability was revised using a UV-Vis spectrophotometer and a JEOL JEM 1000 transmission electron microscope. The SERS spectra were registered with a Raman Thermoscientific DXR microscopy system. Amplified bands associated with OPSS-PEG-NHS were identified in 389, 622, 859, 929, 1080, 1283, 1360, 1443, 1490 and 1450 cm^-1. The results indicate that through this methodology it is possible to identify gold nanomaterials coated with polymer through the Raman technique. In addition, greater amplification is observed with the use of nanostars compared to gold spheres. Finally, these nanomaterials are available for the marking of specific membrane for the study of different types of cancer by the SERS technique.