Fabrication and preliminary evaluation of alginate hydrogel-based magnetic springs with actively targeted heating and drug release mechanisms for cancer therapy

Abstract

In this study, we developed calcium alginate hydrogel-based magnetic springs containing magnetically aligned Fe 2 O 3 magnetic nanoparticles (MNPs) to render them responsive toward magnetic fields. Under a low-frequency magnetic field, a torque was exerted on the springs propelling them along their long axis. In contrast, under a high-frequency alternating magnetic field (AMF) of 200 kHz, the temperature of the spring increased up to 45 °C, making them suitable for magnetic hyperthermia. Moreover, the heat caused thermal stresses, resulting in the spring's mechanical deformation (shrinkage) that accelerated the drug release. Based on the observation of CO 2 using mass spectra, we verified the boundary conditions prevailing during thermal deformation and thermal cracking. In the AMF condition, a spring temperature of 43 °C was attained, and the drug release was about 35% higher than that of physiological temperature (37 °C). In addition, the mechanical and thermal properties of the magnetic hydrogel were investigated based on the concentration and alignment of MNP, because these properties affect the locomotion the drug release mechanism of the hydrogel. Ultimately, the viability of the spring for active targeted heating and drug release was verified via various in-vitro tests.