Potential of Magnetic Nanofiber Scaffolds with Mechanical and Biological Properties Applicable for Bone Regeneration

Abstract

Magnetic nanofibrous scaffolds of poly(caprolactone) (PCL) incorporating magnetic nanoparticles (MNP) were produced, and their effects on physico-chemical, mechanical and biological properties were extensively addressed to find efficacy for bone regeneration purpose. MNPs 12 nm in diameter were citrated and evenly distributed in PCL solutions up to 20% and then were electrospun into nonwoven nanofibrous webs. Incorporation of MNPs greatly improved the hydrophilicity of the nanofibers. Tensile mechanical properties of the nanofibers (tensile strength, yield strength, elastic modulus and elongation) were significantly enhanced with the addition of MNPs up to 15%. In particular, the tensile strength increase was as high as ∼25 MPa at 15% MNPs vs. ∼10 MPa in pure PCL. PCL-MNP nanofibers exhibited magnetic behaviors, with a high saturation point and hysteresis loop area, which increased gradually with MNP content. The incorporation of MNPs substantially increased the degradation of the nanofibers, with a weight loss of ∼20% in pure PCL, ∼45% in 10% MNPs and ∼60% in 20% MNPs. Apatite forming ability of the nanofibers tested in vitro in simulated body fluid confirmed the substantial improvement gained by the addition of MNPs. Osteoblastic cells favored the MNPs-incorporated nanofibers with significantly improved initial cell adhesion and subsequent penetration through the nanofibers, compared to pure PCL. Alkaline phosphatase activity and expression of genes associated with bone (collagen I, osteopontin and bone sialoprotein) were significantly up-regulated in cells cultured on PCL-MNP nanofibers than those on pure PCL. PCL-MNP nanofibers subcutaneously implanted in rats exhibited minimal adverse tissue reactions, while inducing substantial neoblood vessel formation, which however, greatly limited in pure PCL. In vivo study in radial segmental defects also signified the bone regeneration ability of the PCL-MNP nanofibrous scaffolds. The magnetic, bone-bioactive, mechanical, cellular and tissue attributes of MNP-incorporated PCL nanofibers make them promising candidate scaffolds for bone regeneration.

Harnessing magnetic-mechano actuation in regenerative medicine and tissue engineering

“…However, such concerns have been dissipated by a number of in vivo tests demonstrating that magnetic nanofibrous scaffolds of PCL implanted subcutaneously [93] and magnetic hydroxyapatite/collagen scaffolds implanted in rabbit distal femoral epiphysis and tibial mid-diaphysis did not appear to cause inflammation [94]. Furthermore, magnetic hydroxyapatite, prepared with different ratios of magnetic particles, when implanted in rabbit bone critical size defects produced in the condyle region, had similar biocompatibility to hydroxyapatite alone [95].…”

Proliferation and differentiation of mesenchymal stem cells on scaffolds containing chitosan, calcium polyphosphate and pigeonite for bone tissue engineering

“…[11][12][13][14] Nanophase ceramics have gained increasing attention because of their superior bioactivity as well as structural and compositional similarity to bone extracellular matrix.…”

Magnetoactive electrospun nanofibers in tissue engineering applications

“…Recent studies in this field have demonstrated that the use of polymer-based magnetoactive electrospun fibres leads to an enhancement in cell growth, proliferation and differentiation in comparison to their pristine fibrous polymer analogues. The exact mechanism by which magnetic scaffolds promote cell proliferation is still under investigation [132,133,137] and the area of magnetically-triggered tissue engineering is wide open for further development in the near future.…”

“…Singh et al (2014) have reported on magnetic electrospun nanofibrous scaffolds, based on PCL and iron oxide MNPs, with mechanical and biological properties applicable for bone regeneration. Among others, the authors demonstrated that the presence of MNPs within the non-woven fibrous mats results in an enhancement of their mechanical performance.…”

“…Among others, the authors demonstrated that the presence of MNPs within the non-woven fibrous mats results in an enhancement of their mechanical performance. Moreover, it was shown that osteoblastic cells favoured the MNPs-incorporated nanofibres, providing excellent cellular interactions compared to the pristine PCL [137].…”