Mengistu Lemma Solomon, Bossard Frédéric, Rinaudo Marguerite
Laboratoire Rhéologie et Procédés (LRP), University of Grenoble Alpes-CNRS, 38000 Grenoble, France.
Biomaterials Applications, 6 Rue Lesdiguières, 38000 Grenoble, France.
Int J Mol Sci. 2016 Oct 26;17(11):1790. doi: 10.3390/ijms17111790.
Electrospinning was employed to obtain chitosan nanofibers from blends of chitosans (CS) and poly(ethylene oxide) (PEO). Blends of chitosan ( (weight-average molecular weight) = 102 kg/mol) and PEO (M (molecular weight) = 1000 kg/mol) were selected to optimize the electrospinning process parameters. The PEO powder was solubilized into chitosan solution at different weight ratios in 0.5 M acetic acid. The physicochemical changes of the nanofibers were determined by scanning electron microscopy (SEM), swelling capacity, and nuclear magnetic resonance (NMR) spectroscopy. For stabilization, the produced nanofibers were neutralized with K₂CO₃ in water or 70% ethanol/30% water as solvent. Subsequently, repeated washings with pure water were performed to extract PEO, potassium acetate and carbonate salts formed in the course of chitosan nanofiber purification. The increase of PEO content in the blend from 20 to 40 w% exhibited bead-free fibers with average diameters 85 ± 19 and 147 ± 28 nm, respectively. Their NMR analysis proved that PEO and the salts were nearly completely removed from the nanostructure of chitosan, demonstrating that the adopted strategy is successful for producing pure chitosan nanofibers. In addition, the nanofibers obtained after neutralization in ethanol-aqueous solution has better structural stability, at least for six months in aqueous solutions (phosphate buffer (PBS) or water).
采用静电纺丝法从壳聚糖（CS）与聚环氧乙烷（PEO）的共混物中制备壳聚糖纳米纤维。选择壳聚糖（重均分子量 = 102 kg/mol）与PEO（分子量 = 1000 kg/mol）的共混物来优化静电纺丝工艺参数。将PEO粉末以不同重量比溶解于0.5 M乙酸中的壳聚糖溶液中。通过扫描电子显微镜（SEM）、溶胀能力和核磁共振（NMR）光谱法测定纳米纤维的物理化学变化。为了进行稳定化处理，将制备的纳米纤维用碳酸钾在水或70%乙醇/30%水作为溶剂中进行中和。随后，用纯水反复洗涤以提取壳聚糖纳米纤维纯化过程中形成的PEO、乙酸钾和碳酸盐。共混物中PEO含量从20%增加到40%（重量）时，得到了无珠纤维，其平均直径分别为85±19和147±28 nm。它们的NMR分析证明，PEO和盐几乎完全从壳聚糖的纳米结构中去除，表明所采用的策略成功制备了纯壳聚糖纳米纤维。此外，在乙醇 - 水溶液中中和后得到的纳米纤维具有更好的结构稳定性，在水溶液（磷酸盐缓冲液（PBS）或水）中至少可保持六个月。
