Activation of Schwann cells in vitro by magnetic nanocomposites via applied magnetic field

Abstract

Schwann cells (SCs) are attractive seed cells in neural tissue engineering, but their application is limited by attenuated biological activities and impaired functions with aging. Therefore, it is important to explore an approach to enhance the viability and biological properties of SCs. In the present study, a magnetic composite made of magnetically responsive magnetic nanoparticles (MNPs) and a biodegradable chitosan–glycerophosphate polymer were prepared and characterized. It was further explored whether such magnetic nanocomposites via applied magnetic fields would regulate SC biological activities. The magnetization of the magnetic nanocomposite was measured by a vibrating sample magnetometer. The compositional characterization of the magnetic nanocomposite was examined by Fourier-transform infrared and X-ray diffraction. The tolerance of SCs to the magnetic fields was tested by flow-cytometry assay. The proliferation of cells was examined by a 5-ethynyl-2-deoxyuridine-labeling assay, a PrestoBlue assay, and a Live/Dead assay. Messenger ribonucleic acid of BDNF, GDNF, NT-3, and VEGF in SCs was assayed by quantitative real-time polymerase chain reaction. The amount of BDNF, GDNF, NT-3, and VEGF secreted from SCs was determined by enzyme-linked immunosorbent assay. It was found that magnetic nanocomposites containing 10% MNPs showed a cross-section diameter of 32.33±1.81 µm, porosity of 80.41%±0.72%, and magnetization of 5.691 emu/g at 8 kOe. The 10% MNP magnetic nanocomposites were able to support cell adhesion and spreading and further promote proliferation of SCs under magnetic field exposure. Interestingly, a magnetic field applied through the 10% MNP magnetic scaffold significantly increased the gene expression and protein secretion of BDNF, GDNF, NT-3, and VEGF. This work is the first stage in our understanding of how to precisely regulate the viability and biological properties of SCs in tissue-engineering grafts, which combined with additional molecular factors may lead to the development of new nerve grafts.

Superparamagnetic Iron Oxide Nanoparticle-Mediated Forces Enhance the Migration of Schwann Cells Across the Astrocyte-Schwann Cell Boundary In vitro

“…SPIONs were synthesized using methodology described previously (Liu et al, 2015). In brief, 0.486 g NaOH (Sigma-Aldrich, USA) and 1.364 g KNO 3 (Acros Organics, Belgium) were dissolved in 135 ml deionized water and bubbled with N 2 .…”

“…SPIONs show strong magnetization in the presence of a magnetic field (MF), and retain no permanent magnetization upon removal of the field (Liu et al, 2015). This unique feature of SPIONs has led to several successful applications, including biological separation, drug delivery and stem cell labeling (Yang et al, 2004; Zhang et al, 2009; Eamegdool et al, 2014).…”

A magnetically responsive nanocomposite scaffold combined with Schwann cells promotes sciatic nerve regeneration upon exposure to magnetic field

“…22 Briefly, 200 mg of chitosan (molecular weight .310 kDa, SigmaAldrich) and 10 mL of a 0.1 M acetic acid solution were intermixed together to form a chitosan-acetic acid solution. The β-glycerophosphate salt solution, which was formed by intermixing 2 mL of PBS and 1,000 mg of β-glycerophosphate salt (Sigma-Aldrich), was added dropwise to the chitosan-acetic acid solution in an ice bath.…”

“…22 However, the degradation of the magnetic scaffold (MG) is unclear, which is the essential factor required by all tissue engineering biomaterials for in vivo application. 23 The variation of magnetization during the degradation time is unknown, which is a key element for the transplantation of the MG under exposure to MF in vivo.…”

The use of electric, magnetic, and electromagnetic field for directed cell migration and adhesion in regenerative medicine

“…Liu et al . explored the possibility that a magnetic composite of nanoparticles (MNPs) stimulated with an MF could regulate Schwann cell (SC) activity . Cells were seeded onto a magnetic composite made of MNPs and a biodegradable chitosan‐glycerophosphate polymer.…”