Magnetic nanostructures (MNS) have attracted considerable attention as promising functional probes for diagnostic and therapeutic applications in biomedicine. The promise lies in their “theranostic” potential where the diagnostics leverages the ability of MNS to enhance localized contrast in magnetic resonance imaging (MRI) while therapy makes use of thermal activation MNS under external radio frequency (RF) field for thermal therapy or as an actuation for release of therapy cargo. Here we utilized the theranostic potential of the MNS by decorating them on a thermosensitive hydrogel, a platform that allows controlled loading and release of therapeutic cargo based on the solution temperature. Carboxylated poly-NIPAAm hydrogel of diameter 100 nm were functionalized with 8 nm MFe2O4 (M=Fe, Zn0.2Mn0.8) nanoparticles via covalent interactions. The porous structure of hydrogel allows high loading of chemotherapy drugs (doxorubicin). Drug release during RF field was found approximately two-fold higher compared to diffusion based release for similar time intervals. Taking this further, when drug loaded MNS decorated hydrogels were incubated with liver hepatocellular carcinoma (HepG2) cells, more than 80 % cell death was observed with RF field exposures, attributing to thermal activation of MNS under RF field. In addition to drug delivery, the nanoconstruct demonstrate better contrast enhancement due to assembly of MNS, resulting in 6 times higher MR contrast enhancement than commercially available T2 contrast agent Feridex®. The ability to enhance MR contrast and controlled drug release show the potential of the MNS decorated hydrogels as a next generation theranostic agent in biomedicine.

Magnetic nanostructures decorated hydrogels as a theranostic platform for biomedical applications

253rd National Meeting (2017)

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