Chiral Carbon Dots Synthesized on Cellulose Nanocrystals

Abstract Hybrid nanoparticles composed of cellulose nanocrystals (CNCs) and carbon‐dots (C‐dots) have promising applications in chemistry, biology, and nanomedicine, owing to the photoluminescence, sensory properties, and cytocompatibility of C‐dots, and chirality, cytobiocompatibility, and high cellular uptake of CNCs. The possibility of circularly polarized luminescence in such nanoparticles is particularly attractive. Herein, scalable and straightforward hydrothermal synthesis of nitrogen‐doped fluorescent C‐dots under reflux condition by using CNCs as a carbon source and chiral substrate is reported. Under ultraviolet irradiation, hybrid C‐dot/CNC nanoparticles exhibit stronger emission of left‐handed, than right‐handed, circularly polarized light, with high dissymmetry factor up to 0.2. The nanoparticles are biocompatible: the normalized proliferation index above 100% is determined for MCF 7 cells cultured in the suspension of C‐dot/CNC nanoparticles. These hybrid nanoparticles can find applications as biotags for labeling, sensing, and therapeutics and as building blocks of photoluminescent cholesteric CNC films with photonic applications.