Surface functionalization of halloysite nanotubes with supermagnetic iron oxide, chitosan and 2-D calcium-phosphate nanoflakes for synergistic osteoconduction enhancement of human adipose tissue-derived mesenchymal stem cells

Abstract

Halloysite nanotubes (HNTs) are known to be the highly emerging materials in nano-medicinal applications. However, comprehensive exploitation of HNTs for the regenerative medicinal applications is still necessary to be done. Therefore, towards enhancing the osteogenic potential of human adipose tissue-derived mesenchymal stem cells (hADMSCs), this study synthesized a novel and multifunctional nanoscaffold of chitosan (CTs) functionalized supermagnetic halloysite nanotubes (M-HNTs) decorated with the calcium phosphate 2-D nanoflakes (CaP) (termed as; M-HNTs-CTs-CaP). Stepwise modified nanoscaffolds were characterized by FE-SEM, FE-SEM-EDS, FE-HR-TEM, XPS, FT-IR and VSM analyses. The hADMSCs osteogenic potential was confirmed by calcification (Alizarin Red S staining), phosphate quantification and immunocytochemistry. Nanoscaffolds; CaP, M-HNTs-CaP and M-HNTs-CTs-CaP were significantly enhanced and up-regulated osteogenic potential compared to the HNTs, M-HNTs, M-HNTs-CTs. Among the nanoscaffolds studied, M-HNTs-CTs-CaP exhibited highest osteogenesis, due to the enhanced CaP distribution on M-HNTs-CTs surface, and synergistic osteoconduction contributed from Fe₃O₄, chitosan and CaP. Moreover, immunocytochemistry analysis and morphologically observation showed well differentiated osteoblast on the M-HNTs-CTs-CaP surface. Therefore, M-HNTs-CTs-CaP found to have a strong osteogenic potential of hADMSCs, and might be serve as highly applicable, next generation nanoscaffold for bone tissue engineering application.

Keywords: Bone tissue engineering; Calcium phosphate nanoflakes; Halloysite nanotubes; Multifunctional nanoscaffolds; Osteoconduction; hADMSCs.