米糠纳米纤维素的制备表征及其细胞毒性

Preparation and Characterization of Rice Bran Nanocellulose and Cytotoxicity Evaluation

以提取的米糠纤维素(纤维素质量分数90.22%)为原料,采用不同体积分数硫酸水解(60%、64%和68%)制备获得米糠纳米纤维素(Rice bran nanocellulose,RBNC),对其表面形貌、尺寸、电位、化学结构、热稳定性及晶体结构进行了表征,并进一步评价了其细胞毒性。透射电镜和原子力显微镜结果显示,制备得到的RBNC是长度在196.45~257.26 nm、直径为8.46~16.34 nm、长径比为17.06~24.34范围内的针状粒子;Zeta电位值在-32.9~-35.2 mV范围内;红外光谱和X-射线衍射分析表明得到的RBNC化学结构未发生变化,仍保留纤维素Ⅰ型晶体结构。体积分数为64%的硫酸水解得到的RBNC长径比最优(24.34±3.63)、结晶度最高(81.32%)、Zeta电位绝对值最大(-35.20±0.85)mV。进一步的细胞毒性评价表明,RBNC分别在≤2000μg/mL和≤500μg/mL质量浓度范围内,对Caco-2和HepG-2细胞无显著毒性,表现出良好的生物相容性。

The study was carried out to obtain rice bran nanocellulose(RBNC)from rice bran cellulose(cellulose mass:90.22%)using sulfuric acid hydrolysis with different volume fractions(60%,64%and 68%).The morphology,potential,size,structure,physicochemical properties and cytotoxicity of RBNC were investigated in the further study.The results of transmission electron microscopy(TEM)and atomic force microscopy(AFM)confirmed that the obtained RBNC were needle-like shape with lengths ranging from 196.45 to 257.26 nm,diameters from 8.46 to 16.34 nm,and aspect ratios from 17.06 to 24.34.Zeta potential values of NC suspensions ranged from-32.9 to-35.2 mV.Fourier transform infrared spectroscopy(FTIR)and X-ray diffraction(XRD)analysis indicated that the chemical structure of the obtained RBNC still retained the cellulose type I crystal structure.Moreover,the RBNC obtained by hydrolysis with 64%volume fraction of sulfuric acid had the best aspect ratio(24.34±3.63),the highest crystallinity(81.32%),and the highest absolute zeta potential(-35.20±0.85)mV.In addition,cytotoxicity evaluation revealed that RBNC did not decreased cell viability significantly to Caco-2 cells in the concentration range of≤2000μg/mL,and to HepG-2 cells in the concentration range of≤500μg/mL,indicating that RBNC had a good biocompatibility.