Non-covalent functionalization of carbon nano-onions with pyrene–BODIPY dyads for biological imaging

Abstract

We report a novel approach based on non-covalent interactions for the functionalization of carbon nano-onions (CNOs) with fluorophores. The assembly of pyrene-BODIPY conjugates on the CNO surface by means of pi-pi-stacking results in fluorescent carbon nanoparticles that are successfully uptaken by HeLa cancer cells with no cytotoxicity observed. The ability to functionalize carbon-based nanomaterials by using mild conditions will pave the way for future clinical application of these versatile nanomaterials

Carbon Nano‐Onions: A Review of Recent Progress in Synthesis and Applications

“…These composites showed long‐term stability and very high dispersion in polar solvents . In addition, it was reported that non‐covalent modification of the CNO surface using pyrene‐BODIPY, 1,4‐naphthoquinone or 9,10‐phenanthrenoquinone changes their hydrophobic properties . Composites containing CNOs and polyelectrolytes, such as poly(diallyldimethylammonium chloride) (PDDA) or chitosan (Chit), were also obtained ,.…”

“…The nuclei were stained with Hoechst 33342, while lysosomes were stained with Lysotracker red probe. Scale bar represents 10 μm . Reprinted from Refs.…”

“…Similar properties were observed for CNO‐pyrene‐BODIPY derivatives. An intense green fluorescence signal was observed in lysosomal vesicles and the cell cytoplasm (Figure H, I) . The CNOs may also be applied as a platform for targeting cancer cells or bioimaging ,…”

“…[160] CNOs modified with fluorophores were used as markers for biological materials in organisms such as zebrafish, [161] Hydra vulgaris [162] and mice. [163] CNOs functionalized with fluorophores showed high fluorescence intensity, which allowed for easy cell penetration and high-quality imaging, e. g., in human breast cancer MCF-7, [101,108] HeLa cells [107,109,117,164] and KB cells (Figure 6). [107,164] The combination of both light and electron microscopy for imaging HeLa cells treated with fluorescein-CNO derivatives (6) confirmed an endocytosis pathway for the uptake of 6.…”

“…An intense green fluorescence signal was observed in lysosomal vesicles and the cell cytoplasm ( Figure 6H, I). [117] The CNOs may also be applied as a platform for targeting cancer cells or bioimaging. [94,107] The low toxicity, high electrical conductivity and high thermal stability of CNOs leads to the use of these CNs as main components for constructing optical and electrochemical sensors for the detection of biologically important molecules, such as hormones or enzymes.…”