Radiopacity endowed magnetic nanocomposite with hyperthermia and in vitro mineralization potential: a combinatorial therapeutic system for osteosarcoma

Abstract

The development of clinically advanced multifaceted therapeutic materials for osteosarcoma is at the forefront of cancer research. Accordingly, this work presents the design of a multifunctional magnetic nanocomposite composed of maghemite, strontium doped hydroxyapatite and silica nanoparticles prospectively holding indispensable therapeutic features such as magnetic hyperthermia, in vitro biomineralization, sustained drug release and intrinsic radiopacity for the treatment of osteosarcoma. The optimal composition has been identified by sequentially modulating the ratio of precursors of the magnetic nanocomposite synthesized by sol–gel technique. Structural and morphological characterization by x-ray diffraction, fourier transform infrared spectrum, Brunauer–Emmet–Teller and transmission electron microscopy analyses followed by VSM, hyperthermia and micro-CT analyses essentially assisted in the selective configuration of biofunctional properties. Results exemplify that MSHSr1 has a saturation magnetization of 47.4 emu g−1 and attained hyperthermia temperature (42 °C) at a very low exposure time of 4 min. MSHSr1 is further unique with respect to its exceptional x-ray attenuation ability (contrast enhancement 154.5% in digital radiography; CT number 3100 HU), early biomimetic mineralization (in vitro) evident by the formation of spheroidal apatite layer (Ca/P ratio 1.33) harvested from FESEM–EDX analysis and controlled release of Doxorubicin, the clinically used chemotherapeutic drug: 87.7% at 120 h in tumour analogous pH (6.5) when compared to physiological pH (71.3% at 7.4). MTT assay complemented with cytoskeleton (F-actin) staining of human osteosarcoma (HOS) cells affirm biocompatibility of MSHSr1. In vitro biomineralization authenticated by Alizarin red S and von Kossa staining has been further corroborated by semi-quantitative calcium estimation of HOS cells cultured with MSHSr1 for two weeks. The results therefore validate the multifunctionality of MSHSr1, and hence could be proposed as a combinatorial therapeutic nanocomposite for osteosarcoma treatment.