Organic Solvent and Surfactant Free Fluorescent Organic Nanoparticles by Laser Ablation of Aggregation-Induced Enhanced Emission Dyes

摘要

Less toxic and highly fluorescent nanoparticles are in high demand to imagernbiological events and early-stage disease. A strategy to fabricate highly fluorescentrnorganic nanoparticles by laser ablation of aggregation-induced enhancedrnemission (AIE) luminophores, which are free of any organic solvent and surfactant,rnis presented. As these dyes provide no concentration quenching, thernincreased number of photoluminescent molecules in a nanoparticle producesrnbright fluorescence even with their small size (<2 nm), making them highlyrnsuitable for intracellular uptake and imaging for a variety of biomedical applications.rnThe design and synthesis of a new AIE luminophore, DCEtDCS, arernreported and its photoluminescent quantum yield enhancement up to 58% inrnthe aggregated state is demonstrated. Extremely stable nanoparticles of thisrnluminophore with a narrow size distribution, by laser ablation in water arernreported and its superior optical properties that are comparable to quantumrndots are verified. The highly negative surface charge of these nanoparticlesrnimpedes cellular uptake, but when the surface is coated with chitosan, arncationic polymer, intracellular uptake in microglia is achieved. The strategyrnprovides a novel tool to produce in water, ultrasmall and surfactant-free highlyrnfluorescent organic nanoparticles suitable for biomedical applications.