Theranostic magnetoliposomes coated by carboxymethyl dextran with controlled release by low-frequency alternating magnetic field

• Synthesis of carboxymethyl dextran-coated magnetoliposomes.
• Good stability in serum and high drug loading ability for doxorubicin.
• Enhanced drug release under low-frequency alternating magnetic field.
• High relaxivity ratio of r2 to r1 as T2-weighted contrast agent in MR imaging.
• A potential carrier for targeting diagnostic-therapy for cancers.

The aim of this work was to construct carboxymethyl dextran (CMD)-coated magnetoliposomes (MLs), another stealth MLs alternative to PEGylated MLs, for theranostic application. Particularly, the on-demand release of CMD-MLs under low-frequency alternating magnetic field (LF-AMF) was studied. We found that as-prepared MLs exhibited good stability and high drug loading ability for doxorubicin (DOX). Cytotoxicity assay against human neuroblastoma SH-SY5Y cells showed that the DOX-loaded CMD-MLs were less toxic than free DOX due to the sustained release of DOX. However, the release of DOX-loaded CMD-MLs was enhanced by low-frequency alternating magnetic field without hyperthermia generation. The MLs also acted as an efficient T2-weighted contrast agent during in vitro MRI measurements. The above results provide useful information on in vivo diagnostic/therapeutic efficacy of DOX-loaded CMD-MLs for some cancers, such as brain cancers.