Authors: J.L. Chavez, J.L. Wong and R.S. Duran
Affilation: University of Florida, United States
Pages: 275 - 278
Keywords: nanoparticles, core-shell, fluorescence, encapsulation, fluorescent dyes
Novel core-shell nanoparticles were prepared as encapsulating agents for fluorescent organic dyes. These particles protect the dyes from polar solvents, allowing their use in aqueous environments, such as biological systems. The nanoparticles were synthesized using a ternary surfactant system containing the dyes as templates, using octadecyltrimethoxysilane (OTMS) as a reactive surfactant. Silanol groups were formed by the hydrolysis and condensation of the OTMS methoxy groups, to act as anchoring points for the growth of a siloxane shell. The dyes used in this study are polarity and rigidity sensitive; as a consequence, the dyes’ emission was studied by steady state fluorescence (SSF) and fluorescent lifetime measurements. The data obtained showed the effects of the isolation of the dyes from the solvent. An increase in the viscosity, together with a decrease in the polarity of the encapsulation volume, produced changes in the emission maxima of the dyes, demonstrating that the dyes were effectively encapsulated within the interior of the nanoparticles. Changes in the lifetime of the excited probes after the shell growth were compared to the results from SSF measurements. Preliminary results showed that these core-shell particles can be modified with biologically relevant species enabling their use as biomarkers.