Composite magnetic 3D-printing filament fabrication protocol opens new perspectives in magnetic hyperthermia

Three-dimensional (3D) printing technology has emerged as a promising tool for meticulously fabricated scaffolds with high precision and accuracy, resulting in intricately detailed biomimetic 3D structures. Producing magnetic scaffolds with the aid of additive processes, known as 3D printing, reveals multitude and state-of-the-art areas of application such as tissue engineering, bone repair and regeneration, drug delivery and magnetic hyperthermia. A crucial first step is the development of innovative polymeric composite magnetic materials. The current work presents a fabrication protocol of 3D printed polymer-bonded magnets using the Fused Deposition Modeling 3D printing method. Polymer-bonded magnets are defined as composites with permanent-magnet powder embedded in a polymer binder matrix. By using a low-cost mixing extruder, four (4) different filament types of 1.75 mm were fabricated using commercial magnetite magnetic nanoparticles mixed with a pure polylactic acid powder (PLA) and a ferromagnetic PLA (Iron particles included) filaments. The powder mixture of the basic filaments was compounded mixed with the nanoparticles (NPs), and extruded to fabricate the 3D printing filament, which is subsequently characterized structurally and magnetically before the printing process. Magnetic polymer scaffolds are finally printed using composite filaments of different concentration in magnetite. Our results demonstrate that the heating efficiency (expressed in W g −1 ) of the 3D printed magnetic polymer scaffolds (ranging from 2 to 5.5 W g −1 at magnetic field intensity of 30 mT and field frequency of 365 kHz) can be tuned by choosing either a magnetic or a non-magnetic filament mixed with an amount of magnetite NPs in different concentrations of 10 or 20 wt%. Our work opens up new perspectives for future research, such as the fabrication of complex structures with suitable ferromagnetic custom-made filaments adjusting the mixing of different filaments for the construction of scaffolds aimed at improving the accuracy of magnetic hyperthermia treatment.