Polydopamine-functionalized superparamagnetic clusters as potential magnetic carriers for delivery of Platinum anticancer drugs

One of the major challenges of antitumor drugs delivery is the development of suitable carriers for therapeutic molecules. Superparamagnetic iron oxide nanoparticles (SPIONs) are promising magnetic drug carriers as they are biocompatible, biodegradable, readily tunable in size and shape, and controllable by external magnetic fields. We propose and demonstrate the possible synthesis of bioinspired polydopamine-functionalized superparamagnetic clusters (MNC@PDO) to be applied to the anticancer drug cisplatin [cis-dichloro-diammino-platinum(II), CDDP] loading and delivery processes. For these specific nanosystems the drug release capacity has been tested. In this context, the first synthetic step is based on an oil-phase evaporation-induced self-assembly strategy, to fabricate the magnetic nanocrystal clusters (MNC). We demonstrated that for the choice of the best size and volume of SPIONs, the adopted solvent and the surfactant concentration are very important parameters. With this strategy, we can produce nanoclusters with a high density of magnetic cores, a size comprised between 90 and 100 nm, and a multilayer structure. Secondly, the surface of the MNCs was functionalized with polydopamine (PDO) for improving their stability, moreover different concentrations of dopamine were assayed to determine the best compromise between stability of the clusters and loading capacity. Finally, the CDDP was grafted to the surface of stable MNC@PDO systems (MNC@PDO-CDDP), studying its release efficiency from these nanoparticles. The MNC@PDO systems reveal to be promising models for the uptake and specific tissue delivery of chemotherapeutic drugs, in antitumor therapy. Moreover, the MNC@PDO nanosytems show a pH-responsive behaviour of great significance in controlled drug delivery and targeting of specific sites.