Cellulose and Paper Department, National Research Centre, Dokki, Giza, Egypt; Univ. Grenoble Alpes, CNRS, Grenoble INP, LGP2, F-38000 Grenoble, France.
Univ. Grenoble Alpes, CNRS, Grenoble INP, LGP2, F-38000 Grenoble, France; University of Monastir, Faculty of Sciences, UR13 ES 63 - Research Unity of Applied Chemistry & Environment, 5000 Monastir, Tunisia; Higher Institute of Technological Studies of Ksar Hellal, Department of Textile, Tunisia.
Int J Biol Macromol. 2020 Oct 1;160:538-547. doi: 10.1016/j.ijbiomac.2020.05.181. Epub 2020 May 26.
This paper reports the manufacturing by 3D printing of scaffolds for in-situ mineralization of hydroxyapatite using aqueous suspensions of alginate and polyvinyl alcohol (PVA)-grafted cellulose nanofibers (CNF). Bifunctional CNF with carboxyl and aldehyde moieties were prepared from bleached bagasse pulp and crosslinked with PVA. Aqueous hydrogels for 3D printing were prepared by directly mixing PVA-grafted CNF with sodium alginate, with and without the addition of phosphate ions. A calcium chloride solution was sprayed during the printing process in order to partially crosslink alginate and to increase the dimensional stability of the printed gel. At the end of the printing process, the prepared scaffolds were dipped into a CaCl solution to: i) complete alginate crosslinking and ii) promote hydroxyapatite nucleation and growth by reaction with phosphate ions. In order to better understand the mechanisms governing manufacturing of scaffolds by 3D printing, the rheological behavior of alginate/PVA-grafted CNF and the mechanical properties of unit filaments obtained by direct hydrogel extrusion were investigated. The final scaffolds were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). This study shows that 3D printed sodium alginate/PVA-grafted CNF hydrogels are promising scaffold materials for bone tissue engineering.
本文报道了使用海藻酸钠和接枝纤维素纳米纤维（CNF）的聚乙烯醇（PVA）水悬浮液通过 3D 打印制造用于原位矿化羟基磷灰石的支架。从漂白蔗渣制备了具有羧基和醛基的双功能 CNF，并与 PVA 交联。通过直接混合 PVA 接枝 CNF 与海藻酸钠，在添加和不添加磷酸盐离子的情况下制备用于 3D 打印的水凝胶。在打印过程中喷入氯化钙溶液，以部分交联海藻酸钠并提高打印凝胶的尺寸稳定性。打印过程结束后，将制备好的支架浸入 CaCl 溶液中：i）完全交联海藻酸钠，ii）通过与磷酸盐离子反应促进羟基磷灰石成核和生长。为了更好地理解 3D 打印制造支架的机制，研究了海藻酸钠/PVA 接枝 CNF 的流变行为和通过直接水凝胶挤出获得的单丝的机械性能。最终的支架通过扫描电子显微镜（SEM）、傅里叶变换红外光谱（FTIR）和热重分析（TGA）进行了表征。本研究表明，3D 打印的海藻酸钠/PVA 接枝 CNF 水凝胶是骨组织工程有前途的支架材料。
