Methods of femtosecond laser ablation in deionized water were used to fabricate ultrasmall (< 2 nm), bare (ligand-free) organic luminophore DCEtDCS nanoparticles, which exhibit aggregation enhanced emission in the green range (533 nm) with the quantum yield exceeding 58% and provide no concentration quenching. In contrast to chemically synthesized counterparts, laser-synthesized DCEtDCS nanoparticles do not contain any organic impurities due to their preparation in aqueous medium and do not require surfactants to stabilize colloidal solutions, which makes them highly suitable for intracellular uptake and bioimaging. The highly negative surface charge of these nanoparticles impeded their cellular uptake, but when the surface was coated with chitosan, a cationic polymer, intracellular uptake in microglia was achieved. Using in vitro model, we finally demonstrate the efficient employment of ultrasmall and surfactant free fluorescent organic nanoparticles prepared by laser ablation as markers in bioimaging.

Date Published: 4 March 2019
PDF
Proc. SPIE 10907, Synthesis and Photonics of Nanoscale Materials XVI, 109070U (4 March 2019); doi: 10.1117/12.2513821

Published in SPIE Proceedings Vol. 10907:
Synthesis and Photonics of Nanoscale Materials XVI
Andrei V. Kabashin; Jan J. Dubowski; David B. Geohegan, Editor(s)