Authors: D.C. Rambaldi, A. Zattoni, P. Reschiglian, M. Melucci, M. Zambianchi, G. Barbarella, S. Bonacchi, M. Montalti, E. Rampazzo
Affilation: University of Bologna, Italy
Pages: 183 - 186
Keywords: asymmetrical flow field flow fractionation, multi-angle light scattering, fluorescence detection, structured nanoparticles, nanoparticle size characterization
We present results indicating that Asymmetrical Flow Field-Flow Fractionation (AF4) on-line coupled with Multi-Angle Light Scattering (MALS) and Fluorescence (FD) detection can become the unparallel methodology for morphological and optical characterization of new, structured, fluorescent nanomaterials. AF4 is a flow-assisted technique ideally suited to size-separate dispersed samples over a broad size range (1 nm-1 μm) according to their hydrodynamic radius (rh). The “gentle” separation mechanism makes AF4 particularly suited for nanoparticle (NP) characterization in native, liquid dispersion conditions. On-line coupling of AF4 with detection techniques such as MALS and FD then appears to be an ideal, integrated approach for the simultaneous size and optical characterization of purified NPs. In this work silica NPs (SiO2NPs) doped with oligothiophene (TF) dyes were analyzed by AF4-MALS-FD. When applied to TF-SiO2NPs, AF4-MALS-FD provided fundamental information on two major aspects to be considered in the optimization of NP synthesis: a) NP aggregation, which may affect NP diffusivity and, then, the ability of NPs to permeate cell membranes; b) actual inclusion and self-organization of the dyes inside the NPs, which determine the spectroscopic properties.