NMR Studies of Lys-2His Peptide Dendrimers Complexes with C60 and C70 Fullerenes

The use of dendrimers as nanocontainers for delivering poorly soluble drugs or bioactive molecules represents one of the most promising areas of their application in biomedicine. Peptide dendrimers are considered potential candidates due to their low cytotoxicity and biodegradability. In this study, we investigated complexes of peptide dendrimers containing double histidine amino acid residues (Lys‑2His) and hydrophobic fullerenes C₆₀ and C₇₀ in aqueous solution experimentally by NMR methods. NMR spectroscopy and relaxation data provide evidence for the encapsulation of fullerene by the dendrimer in the Lys‑2His + C₇₀ complex. This is due to interaction between the imidazole rings of histidine residues in the Lys-2His dendrimer and the C₇₀ fullerene. Notably, this effect was not observed in the Lys‑2His + C₆₀ complex. The obtained results are in good agreement with the data from atomistic molecular dynamics simulations obtained previously. These results are expected to be applicable not only for C₇₀ fullerenes but also to various poorly water-soluble C₇₀ derivatives, which may exhibit cytotoxic properties and biological activity. NMR spectroscopy has proven to be a powerful tool for investigating the formation and structural characteristics of complexes involving Lys‑2His dendrimers.