Preparation and Characterization of Smart Poly (N-‎Isopropylacrylamide)‎ Nanoparticles Containing Vascular ‎Endothelial Growth Factor for Induction of Angiogenesis in ‎Human Bone Marrow-derived Mesenchymal Stem Cells

Aims: Growth factor (GFs) delivery with the certain concentration and release kinetic is one of the main challenges in tissue engineering. The aim of this study was the preparation and characterization of smart poly (N-isopropylacrylamide) nanoparticles containing vascular endothelial growth factor for induction of angiogenesis in human bone marrow-derived mesenchymal stem cells.
In this exprimental study, two different formulations of temperature-sensitive Poly (N-isopropylacrylamide) (PNIPAM) nanoparticles (NPs) were synthesized by free radical polymerization technique. Nanoprecipitation and diffusion methods were used to load the vascular endothelial growth factor (VEGF) in PNIPAM NPs. The effects of released VEGF on the differentiation of human bone marrow stem cells (hBMSCs) into endothelial cells in angiogenic, osteogenic, and 50% angiogenic-osteogenic culture medium were investigated, using flow cytometry and light microscope. Statistical analysis was performed, using the GraphPad Prism 6 software.
Findings: The nanoprecipitation process caused polymer degradation due to using the organic N, N-Dimethylacetamide solvent. The cumulative VEGF released after 72hours for 70%. A total of 10ng/ml VEGF released from PNIPAM nanoparticles, in 2D culture with cell density of 3×104 hBMSCs, after 7 days, leading to the endothelial differentiation, capillary-like tube formation, and expression of 20% vWF as angiogenic marker.
The PNIPAM NPs have the potential to load and release the angiogenic GFs for induction of angiogenesis in hBMSCs and in osteogenic medium.