Functionalization\nof Nanodiamond Surfaces with Metal\nβ‑Diketonato Complexes with Possible Application in Cancer\nTreatment

Nanodiamonds (NDs)\nare used more frequently as drug carriers\nthrough\nabsorption or chemical modification. In this report, we describe the\nchemical binding of metal β-diketonato complexes onto the ND\nsurface using an aminosilane linker. The metals used were iron(III)\nand copper(II), with β-diketones, acetylacetone, trifluoroacetylacetone,\nand the naturally occurring curcumin, which is known for its biological\nactivity. Improved cytotoxicity was observed with metal complexes\nbound to the drug carrier compared to the free metal complexes as\na result of increased stability when bound to a carrier. The curcumin-containing\ncopper(II) conjugate demonstrated an IC<sub>50</sub> of 1.85 μM\nagainst the HeLa cell line and showed no toxicity in a larval zebrafish\nbioassay.