Investigation of hollow mesoporous NiFe2O4 nanospheres fabricated via a template-free solvothermal route as pH-responsive drug delivery system for potential anticancer application

Abstract A novel magnetic-targeted pH-responsive intelligent drug carrier based on hollow mesoporous structured NiFe2O4 nanospheres was designed and developed for potential anticancer treatment in the present study. The hollow mesoporous NiFe2O4 nanospheres were fabricated through a template-free solvothermal approach and the possible formation mechanism of this structure was proposed. The products were investigated comprehensively for their morphology, microstructure, composition and magnetic properties using a wide series of characterization methods. The NiFe2O4 nanospheres were demonstrated to possess a well-defined spherical morphology, homogeneous particle size distribution, large hollow cavities and abundant mesopores, unique superparamagnetic behavior, high saturation magnetization as well as good biocompatibility. Due to these desirable physicochemical properties, the hollow mesoporous NiFe2O4 nanospheres were expected to be employed as a potential vehicle for loading and delivering anticancer drug of doxorubicin hydrochloride (DOX). Drug release behavior was evidenced to be controllable and pH-responsive with effective DOX release of 73.1% and 58.8% in acidic conditions (pH 4.0 and 5.5), whereas insufficient drug release of 44.7% at a neutral atmosphere (pH 7.4) within 48 h. More importantly, the DOX-loaded NiFe2O4 nanospheres displayed significant anti-proliferation and apoptosis effects on human breast cancer cells (MCF-7), which further indicated the promising potential application of constructed drug delivery nanocarriers in the field of cancer therapy.