Dendritic magnetite nanocarriers for drug delivery applications

Abstract

A novel arginine-based dendritic block is grown on the surface of APTS-coated Fe₃O₄ nanoparticles by conventional growth approach of Michael addition/amidation reactions. The thus-obtained dendritic magnetite nanocarriers (DMNCs) were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), atomic force microscopy (AFM), vibrating sample magnetometry(VSM), dynamic light scattering (DLS) and thermogravimetric (TGA) analysis. The functionalization of MNPs with the dendritic block was evident from FTIR and TGA analyses. The nanocarriers had an average size of 10 nm and exhibited superparamagnetism with high magnetization values at room temperature. The aqueous colloidal suspension of DMNCs (10 mg ml⁻¹ of Fe) showed a temperature rise up to 43 °C in 5 min and yielded a moderate specific absorption rate (SAR) value of 30 W g⁻¹ of magnetite under the influence of AC magnetic field of 10 kA m⁻¹ and 425 kHz frequency. Biocompatibility of the developed nanocarriers was evaluated in vitro by assessing their cytotoxicity on human cervical cancer cells (HeLA cells) using a sulforhodamine B (SRB) assay. Encapsulation and release of the anticancer drug doxorubicin (DOX) was investigated. The change in surface charge, as evident from zeta potential analyzer and quenching of fluorescence intensity, strongly suggests the interaction of DOX with the DMNCs. The nanocarriers showed good capacity to encapsulate DOX, with loading as high as 65% (w/w) and a pH-responsive sustained release of 54% at pH 5.0. Also, the release of DOX from the nanocarriers increased up to 80% on application of an AC magnetic field.