Growth enhancing effect of LBL-assembled magnetic nanoparticles on primary bone marrow cells

Magnetic field has been considered to have positive effect on growth of bone. Because amagnetic nanoparticle can be regarded as one magnetic dipole, the macroscopic assemblies of magnetic nanoparticles may exhibit magnetic effect on local objects. This paper fabricated macroscopic film of gamma-Fe2O3 nanoparticles by layer-by-layer (LBL) assembly on poly-D, L-lactic acid (PLA) scaffold, and studied the magnetic effect of the assembled gamma-Fe2O3 nanoparticles film on primary bone marrow cells. The primary bone marrow cells were extracted from a mouse and cultured on the PLA substrate decorated by the film of gamma-Fe2O3 nanoparticles after purification. Quantitative PCR (q-PCR) was used to show the cellular effect quantitatively. A just-found magnetosensing protein was employed to verify the magnetic effect of assembled film of nanoparticles on primary cells. It was exhibited that the decoration of nanoparticles enhanced themechanical property of the interface. By acting as the adhesion sites, the LBL-assembled film of nanoparticles seemed beneficial to the cellular growth and differentiation. The expression of magneto-sensing protein indicated that there was magnetic effect on the cells which resulted from the assembly of magnetic nanoparticles, implying its potential as a promising interface on scaffold which can integrate the physical effect with good biocompatibility to enhance the growth and differentiation of stem cells. The LBL-assembled film of magnetic nanoparticles may boost the development of novel scaffold which can introduce the physical stimulus into local tissue in vivo.