Applied Surface Science, Vol.450, 396-403, 2018
Fabrication and characterization of glycine-loaded PEG nanoparticles for drug delivering: A comprehensive SERS study
This study reports on the successful preparation and characterization of a biocompatible colloidal suspension comprising glycine (Gly) loaded into polyethylene glycol (PEG) nanoparticles (Gly@PEG/NPs) and suspended within PBS. The interaction between the Gly molecule and the PEG nanoparticles is herein investigated using normal Raman spectroscopy and surface-enhanced Raman spectroscopy (SERS), the latter employing silver substrate. Additionally, scanning and transmission electron microscopy (TEM), dynamic light scattering, zeta-potential, and Fourier transform infrared spectroscopy (FTIR) were employed to support our analyses. Morphological analyzes revealed that Gly@PEG/NPs have nonspherical shape with average diameter (polydispersion index) of 54.3 nm (0.16). Moreover, high-resolution TEM images demonstrated the coexistence of crystalline and amorphous phases in the Gly@PEG/NPs structure. The FTIR, normal Raman and SERS spectra strongly suggest that the protonated amino groups (NHthorn3) of the Gly molecules bind to the oxygen atoms of the PEG molecule by means of hydrogen bonds, leaving the carboxylate groups (COO similar to) facing outwards to the bulk aqueous-like medium. Finally, MTT assay demonstrated that Gly@PEG/NPs are very much biocompatible at Gly concentrations of up to 1.0 mol/L while free Gly shows toxicity in the same range. (C) 2018 Elsevier B.V. All rights reserved.