One spiro to shift them all: tuning fluorescent organic nanoparticles emission via steric design

Abstract

Three quadrupolar fluorene-based dyes differing only by non-conjugated substituents form fluorescent organic nanoparticles (dFONs) with tunable emission from blue to yellow. A spirocyclic central substituent induces a marked red-shift via altered packing. When internalized into cells, dFONs evolve showing a characteristic blue-shift, enabling fluorescence-based monitoring of nanoparticle integrity and bioimaging performance.