Folate encapsulation in PEG-diamine grafted mesoporous Fe₃O₄ nanoparticles for hyperthermia and in vitro assessment

Effective and targeted delivery of the antitumour drugs towards the specific cancer spot is the major motive of drug delivery. In this direction, suitably functionalised magnetic iron oxide nanoparticles (NPs) have been utilised as a theranostic agent for imaging, hyperthermia and drug delivery applications. Herein, the authors reported the preparation of multifunctional polyethyleneglycol-diamine functionalised mesoporous superparamagnetic iron oxide NPs (SPION) prepared by a facile solvothermal method for biomedical applications. To endow targeting ability towards tumour site, folic acid (FA) is attached to the amine groups which are present on the NPs surface by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride/N-hydroxysuccinimide chemistry. FA attached SPION shows good colloidal stability and possesses high drug-loading efficiency of ∼ 96% owing to its mesoporous nature and the electrostatic attachment of daunosamine (NH₃⁺) group of doxorubicin (DOX) towards the negative surface charge of carboxyl and hydroxyl group. The NPs possess superior magnetic properties in result endowed with high hyperthermic ability under alternating magnetic field reaching the hyperthermic temperature of 43°C within 223 s at NP's concentration of 1 mg/ml. The functionalised NPs possess non-appreciable toxicity in breast cancer cells (MCF-7) which is triggered under DOX-loaded SPION.