The effect of polymer nanostructure on diffusion of small molecules using tryptophan as a FRET probe

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Colleges, School and Institutes


The amino acid L-tryptophan has been converted into a polymerizable monomer which has been incorporated into a range of cross-linked polymeric nanogels prepared by emulsion polymerization. By using time-lapse fluorescence spectroscopy the diffusion time of a small molecule Forster resonance energy transfer (FRET) pair, dansyl amide, into the central nanogel domain has been monitored through the decreased emission of the L-tryptophan FRET donor. In this initial study it has been found that diffusion of the small molecule into the nanogels is affected by altering the synthetic parameters (cross-linking density and co-monomer hydrophobicity). When increasing the cross-linking density of the nanogels the uptake diffusion time increased, while increasing the hydrophobicity of the co-monomer (and consequently lowering the glass-transition temperature (Tg)) caused a decrease in the diffusion time.


Original languageEnglish
Pages (from-to)380-385
Number of pages6
JournalEuropean Polymer Journal
Early online date16 Jun 2014
Publication statusPublished - Jan 2015


  • Tryptophan, FRET, Nanogel, Fluorescence, Polymer, Diffusion