Bioactive magnetic near Infra-Red fluorescent core-shell iron oxide/human serum albumin nanoparticles for controlled release of growth factors for augmentation of human mesenchymal stem cell growth and differentiation

Abstract

Background: Iron oxide (IO) nanoparticles (NPs) of sizes less than 50 nm are considered to be non-toxic, biodegradable and superparamagnetic. We have previously described the generation of IO NPs coated with Human Serum Albumin (HSA). HSA coating onto the IO NPs enables conjugation of the IO/HSA NPs to various biomolecules including proteins. Here we describe the preparation and characterization of narrow size distribution core-shell NIR fluorescent IO/HSA magnetic NPs conjugated covalently to Fibroblast Growth Factor 2 (FGF2) for biomedical applications. We examined the biological activity of the conjugated FGF2 on human bone marrow mesenchymal stem cells (hBM-MSCs). These multipotent cells can differentiate into bone, cartilage, hepatic, endothelial and neuronal cells and are being studied in clinical trials for treatment of various diseases. FGF2 enhances the proliferation of hBM-MSCs and promotes their differentiation toward neuronal, adipogenic and osteogenic lineages in vitro. Results: The NPs were characterized by transmission electron microscopy, dynamic light scattering, ultraviolet-visible spectroscopy and fluorescence spectroscopy. Covalent conjugation of the FGF2 to the IO/HSA NPs significantly stabilized this growth factor against various enzymes and inhibitors existing in serum and in tissue cultures. IO/HSA NPs conjugated to FGF2 were internalized into hBM-MSCs via endocytosis as confirmed by flow cytometry analysis and Prussian Blue staining. Conjugated FGF2 enhanced the proliferation and clonal expansion capacity of hBM-MSCs, as well as their adipogenic and osteogenic differentiation to a higher extent compared with the free growth factor. Free and conjugated FGF2 promoted the expression of neuronal marker Microtubule-Associated Protein 2 (MAP2) to a similar extent, but conjugated FGF2 was more effective than free FGF2 in promoting the expression of astrocyte marker Glial Fibrillary Acidic Protein (GFAP) in these cells. Conclusions: These results indicate that stabilization of FGF2 by conjugating the IO/HSA NPs can enhance the biological efficacy of FGF2 and its ability to promote hBM-MSC cell proliferation and trilineage differentiation. This new system may benefit future therapeutic use of hBM-MSCs.

A minimally invasive adjustable‐depth blunt injector for delivery of pharmaceuticals into the posterior pole

“…The iron oxide enables easy detection of the nanoparticles in the target tissue using Prussian blue staining (Levy et al. ). Two hundred and fifty microlitres of IONP solution was injected into rabbit eyes.…”

“…; Levy et al. ). Rabbits were anesthetized with an intramuscular injection of ketamine (35 mg/kg) and xylazine (5 mg/kg).…”

Long-Term Safety of Transplanting Human Bone Marrow Stromal Cells into the Extravascular Spaces of the Choroid of Rabbits

“…In previous studies, we demonstrated that IONP-delivery of FGF2 can enhance hBMSC growth and differentiation in vitro [34]. In future studies, we will examine the possibility of prolonging graft survival in the EVSC by coinjection with IONPs loaded with growth factors that promote hBMSC survival.…”

Monitoring/Imaging and Regenerative Agents for Enhancing Tissue Engineering Characterization and Therapies

“…10,164,166 Studies show MSC labeling does not negatively affect cell viability 51 or ability to differentiate, regenerate tissue, and self-renew. 11,104,163 IONPs can also be used to transport SCs and other therapeutic agents. Their transport and location has been monitored in the brain, 26 heart, 68 vasculature, 149 muscle, 3,167 and joints.…”

“…137 Another strategy is conjugating IONPs with ligands to enhance receptor-mediated endocytosis and increase treatment efficacy. 104 Mechanical and thermal stimulation with different magnetic field regimens would be an interesting area to study as it can affect MSC fate 54,59 and has not been thoroughly explored.…”