Magneto-mechanical stimulation of bone growth in a bonded array of ferromagnetic fibres

Physical and Biological Characterization of Ferromagnetic Fiber Networks: Effect of Fibrin Deposition on Short-Term In Vitro Responses of Human Osteoblasts

“…However, theoretically the optimal region for transduction of strain to cells in vivo lies within interfiber spaces as depicted in Figure 1a. 2 In this study, it is proposed that the deposition of fibrin at early time points, either as the result of physiological processes or clinical application, would facilitate cell attachment in interfiber regions. This hypothesis was investigated using in vitro cultures of HObs.…”

“…1a). Figure 1b shows predictions for the peak strain 2 induced within in-growing bone tissue, as a function of the fiber segment aspect ratio, for two matrix stiffness levels, for a field strength of 1 T (typical of fields currently employed for diagnostic purposes). Since the stiffness of granulation tissue is around 0.001 GPa 12 and that of immature bone is in the range of 0.03 to 0.1 GPa 12 and strains of *1 millistrain 13,14 are known to be effective in stimulating bone growth, this plot suggests that beneficial therapeutic effects might be possible in the early stages of healing using fields no greater than those already employed for diagnostic purposes.…”

“…Porous magnetoactive layers, made of slender ferromagnetic fibers, bonded together at cross-over points, have been proposed for use as implant coatings due to their potential to impart mechanical strains in vivo to in-growing bone tissue. 1,2 Most ferromagnetic devices are contraindicated for medical resonance imaging due to risks related to movement and dislodgement 3 ; however, implant fixation using ferromagnetic materials is currently used in several dental systems for removable dental prostheses. 4 Ferritic stainless steel grades, such as 444 and 447J1, have been approved for these magnetic attachments.…”

Effective balance equations for elastic composites subject to inhomogeneous potentials

“…They have been experimentally investigated (see, e.g., the recent work [21]) and they can provide a basis for biomimetic applications such as artificial muscles [26]. Composite materials made of ferromagnetic or paramagnetic fibers and particles have been recently theoretical and experimentally investigated (see, e.g., [12,31], respectively), as the strains that develop as a consequence of an imposed magnetic field can be exploited for biomimetic applications and provide physiological benefits, for example in the context of bone growth (see, e.g., [25]). The electromagnetic force when both an electric and a magnetic field are applied also depends on the velocity of the material and therefore cannot be considered in our formulation.…”

“…and In the following section, we equate coefficients of l for l = 0, 1, ... in (22)(23)(24)(25) to obtain an effective system of PDEs for the zeroth order displacement field in the homogenized domain Ω H (see Figure 1). Since we aim at deriving a model that involves macroscale quantities only, it is convenient to define the following cell average operators…”