Structures of Nanodiamonds with Photoactive Modifiers

Abstract

For the first time, binary and ternary complexes of fullerenes and diphthalocyanines of europium with detonation nanodiamonds have been obtained, which can serve as platforms for the delivery of these hydrophobic molecules into aqueous biological media for the tasks to improve magnetic resonance imaging, photodynamic therapy, and diagnostics using luminescent labels. Detonation nanodiamonds (size ~4–5 nm) had a positive potential (30–70 mV) in an aqueous medium due to groups (CH, COH) grafted onto the surface as a result of heat treatment in a hydrogen atmosphere. During the interaction of positively charged diamonds with electronegative hydrated fullerenes in an aqueous medium, the initial aggregates of each of the components were destroyed, and their electrostatic bonding led to the formation of stable compact complexes ~20 nm in size according to the data of dynamic light scattering and small-angle neutron scattering in colloids under normal conditions (20°С). Binary complexes included, on average, two fullerene molecules per 30–40 diamond particles. The introduction of diphthalocyanine molecules into a binary colloid resulted in the formation of stable ternary structures. The obtained complexes of diamonds, fullerenes, and diphthalocyanine molecules are promising for biomedical applications due to the luminescent and magnetic properties of the components.