Ultra-Bright Fluorescent Organic Nanoparticles Based on Small-Molecule Ionic Isolation Lattices

18 January 2021, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


Ultra-bright fluorescent nanoparticles hold great promise for demanding bioimaging applications. Recently, extremely bright molecular crystals of cationic fluorophores were obtained by hierarchical co-assembly with cyanostar anion-receptor complexes of associated counterions. These small-molecule ionic isolation lattices (SMILES) ensure spatial and electronic isolation to prohibit dye aggregation quenching. We report a simple, one-step supramolecular approach to formulate SMILES materials into nanoparticles. Rhodamine-based SMILES nanoparticles stabilized by glycol amphiphiles show high fluorescence quantum yield (30%) and brightness per volume (5000 M–1 cm–1 / nm3) with 400 dyes packed into 16-nm particles, corresponding to an absorption coefficient of 4 × 107 M–1 cm–1. UV excitation of the cyanostar component leads to highest brightness (>6000 M–1 cm–1 / nm3) by energy transfer to rhodamine emitters. Coated nanoparticles stain cells and are thus promising for bioimaging.


fluorescent nanoparticles
aggregation-caused quenching
fluorescent dyes
Fluorescence imaging
Molecular Self-assembly

Supplementary materials



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