Uptake of magnetic nanoparticles for adipose-derived stem cells with multiple passage numbers

With the increasingly promising role of nanomaterials in tissue engineering and regenerative medicine, the interaction between stem cells and nanoparticles has become a critical focus. The entry of nanoparticles into cells has become a primary issue for effectively regulating the subsequent safety and performance of nanomaterials in vivo. Although the influence of nanomaterials on endocytosis has been extensively studied, reports on the influence of stem cells are rare.Moreover, the effect of nanomaterials on stem cells is also dependent upon the action mode. Unfortunately, the interaction between stem cells and assembled nanoparticles is often neglected. In this paper, we explore for the first time the uptake of γ-Fe2O3 nanoparticles by adipose-derived stem cells with different passage numbers. The results demonstrate that cellular viability decreases and cell senescence level increases with the extension of the passage number. We found the surface appearance of cellular membranes to become increasingly rough and uneven with increasing passage numbers. The iron content in the dissociative nanoparticles was also significantly reduced with increases in the passage number. However, we observed multiple-passaged stem cells cultured on assembled nanoparticles to have similarly low iron content levels. The mechanism may lie in the magnetic effect of γ-Fe2O3 nanoparticles resulting from the field-directed assembly. The results of this work will facilitate the understanding and translation of nanomaterials in the clinical application of stem cells.

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 a magnetic nanopartide 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 γ-Fe_2O_3 nanoparticles by layer-by-layer(LBL) assembly on poly-D,L-lactic acid(PLA) scaffold,and studied the magnetic effect of the assembled γ-Fe_2O_3 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 γ-Fe_2O_3 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 the mechanical 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 magnetosensing 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.