3D Biomimetic Magnetic Structures for Static Magnetic Field Stimulation of Osteogenesis

Abstract

We designed, fabricated and optimized 3D biomimetic magnetic structures that stimulate the osteogenesis in static magnetic fields. The structures were fabricated by direct laser writing via two-photon polymerization of IP-L780 photopolymer and were based on ellipsoidal, hexagonal units organized in a multilayered architecture. The magnetic activity of the structures was assured by coating with a thin layer of collagen-chitosan-hydroxyapatite-magnetic nanoparticles composite. In vitro experiments using MG-63 osteoblast-like cells for 3D structures with gradients of pore size helped us to find an optimum pore size between 20–40 µm. Starting from optimized 3D structures, we evaluated both qualitatively and quantitatively the effects of static magnetic fields of up to 250 mT on cell proliferation and differentiation, by ALP (alkaline phosphatase) production, Alizarin Red and osteocalcin secretion measurements. We demonstrated that the synergic effect of 3D structure optimization and static magnetic stimulation enhances the bone regeneration by a factor greater than 2 as compared with the same structure in the absence of a magnetic field.

Bioactive chitosan‐based scaffolds with improved properties induced by dextran‐grafted nano‐maghemite and l‐arginine amino acid

“…MNPs‐incorporating biomaterials have been shown to have high potential in activating cells involved in osteogenic processes, being responsive to external magnetic fields, which affect the cellular microenvironment . The static or alternating magnetic stimulation has been highlighted to promote the implant integration and increase the newly developed bone density, thus promoting a rapid and better healing of the injury . Static magnetic fields (1 mT to 1 T) have shown to accelerate the proliferation, migration, orientation and differentiation of osteoblast‐like cells .…”

“…17 The static or alternating magnetic stimulation has been highlighted to promote the implant integration and increase the newly developed bone density, thus promoting a rapid and better healing of the injury. 18,19 Static magnetic fields (1 mT to 1 T) have shown to accelerate the proliferation, migration, orientation and differentiation of osteoblastlike cells. [20][21][22] Moreover, it has been proven to induce the osteogenic differentiation in bone marrow-derived mesenchymal stem cells 23 as a consequence of diamagnetic properties of cell membranes and extracellular matrices, 24 which modify their fluxes, and structures according to static magnetic stimuli.…”

Collagen/Chitosan Functionalization of Complex 3D Structures Fabricated by Laser Direct Writing via Two-Photon Polymerization for Enhanced Osteogenesis

“…In our case, the optical inspection provided by the detailed SEM analysis provide evidence on the degree of uniformity of the coating and of other particular aspects regarding the role of Col/CT blending ratio on the uniformity of the coating of the 3D structures and that were discussed in this section. The 3D structures were fabricated by two-photon polymerization, where the size of the volume pixel (voxel) is 2 µm width and 4 µm height [14]. However, neighboring lines were not as tall as the voxel itself, as we imposed a 2 µm overlap to provide good structural integrity and polymerization degree.…”

Magnetic Materials in Promoting Bone Regeneration

“…In 2017, Aliramaji et al synthesized iron-oxide MNPs using reverse co-precipitation, and investigated the effects of chitosan-based magnetic scaffolds with MNPs (0, 0.5, 1, and 2%) on the cellular activity of bone tissue (Aliramaji et al, 2017). In 2018, an MNP composite layer containing collagen, chitosan, and hydroxyapatite was fabricated by Paun et al to ensure the magnetic properties of three-dimensional biomimetic materials that could accelerate osteogenesis in SMFs (Paun et al, 2018).…”