Original source: Materials Today
When it comes to bone regeneration, magnetic particles are not the first idea that surfaces in thought. However, magnetic nanoparticles have become an ever-increasing topic of interest for biomedical applications with promise in targeted drug delivery and possible uses in bioimaging. But they also show potential in contributing to the regenerative capabilities of bioscaffolds.
At present, a study by Zhao and colleagues in Prof. Jingdi Chen’s group featured the creation of magnetically functionalised nanocrystals in situ. Through pH control the authors were capable of crystallising hydroxyapatite nanocrystals with magnetic nanoparticles of Iron (III) Oxide. Crystallising the nanocrystals onto a collagen and chitosan hybrid scaffold resulted in a bone regeneration scaffold that exhibited promising performance in vitro and in vivo [Zhao et al., Colloids and Surfaces B: Biointerfaces (2019), doi.org/10.1016/j.colsurfb.2018.11.003]
The exact mechanism by which the presence of magnetic nanoparticles augments the bioactivity of the scaffolds is still unknown. The authors postulate that the magnetocaloric effect, a phenomenon where a changing magnetic field causes a change in temperature in a material, contributes to the processes during bone regeneration. The yet cryptic benefit magnetic nanoparticles in osteogenesis opens a gateway to new research in a more complex and multifaceted approaches to wound regeneration.
“Based on the in situ strategy for bone repair by facilitated endogenous tissue [Chen et al., Colloids and Surfaces B:Biointerfaces 135 (2015) 581–587,doi: 10.1016/j.colsurfb.2015.08.019]. It provides a solution that can avoid the ex vivo culture of autologous cells and initiate in situ reparative endogenous repair processes in vivo. By functionalised bioscaffold to mimic the extracellular matrix, progenitor cells provided by autologous bone marrow and surrounding tissues then differentiate to bone cells under the direction of the in situ scaffold.”Explains Professor Jingdi Chen Principal Investigator of the study
The effect of the magnetic nanoparticles was studied through characterisation of the scaffolds’ structure, porosity and mechanical properties. This included SEM-EDS and XPS for physiochemical characterisation. However, as with all materials intended for implantation in the body, the significance of the magnetic functionalisation lies in its effects on cells and in vivo. This was assessed in the study by imaging osteoblast proliferation and the regenerative capability was measured in the repair of defects in murine bone crania. The scaffolds were observed to have superior biomineralized properties when containing the magnetic nanoparticles.