纤维素纳米晶荧光探针的制备及光学性能

Preparation and Optical Properties of Fluorescent Probes Based on Cellulose Nanocrystals

将羧基化纤维素纳米晶(C-CNC)与4-((2-氨基乙基)氨基)-9-甲基-1,8-萘二甲酰亚胺(AANI)染料共价键结合制得荧光纤维素纳米晶(F-CNC),并采用透射电子显微镜(TEM)、X射线衍射(XRD)和红外光谱(FT-IR)等对其进行了表征,进一步分析了F-CNC的光学性质和荧光标记成像性能。表征结果表明:AANI成功连接到了C-CNC表面,CNC基底提高了染料的亲水性,AANI在H_2O中的最大溶解度为0.8 mmol/L,而制备的F-CNC母液中染料浓度为1.2 mmol/L。F-CNC在水溶液中分散稳定,且呈现良好的亮黄色荧光发射性能;同时F-CNC保留了C-CNC的棒状形态、尺寸变化不大,结晶度及晶体结构也没有明显变化。C-CNC与F-CNC的结晶度分别为61.2%和67.7%。由于溶剂极性降低会压缩CNC双电层,造成CNC呈现一定程度聚集状态,这使F-CNC相较于AANI表现出对溶剂极性更高的荧光敏感性。荧光标记成像结果表明:当F-CNC质量浓度为0、3.375×10^(-4)和6.75×10^(-4)g/L时,孵育10 h后细胞的存活率分别为49.08%、44.21%和40.71%,同时F-CNC对Hela细胞具有良好的荧光标记成像性能,且对细胞毒性不大。

Multifunctional fluorescent cellulose nanocrystals(F-CNC)was prepared by the covalently bonded carboxylated cellulose nanocrystals(C-CNC)with 4-((2-aminoethyl)amino)-9-methyl-1,8-naphthalimide(AANI).Then,F-CNC was characterized by transmission electron microscopy(TEM),X-ray diffraction(XRD)and infrared spectroscopy(FT-IR),respectively.The optical properties and fluorescence-labeled imaging properties of F-CNC were further analyzed.The characterization results showed that AANI was successfully attached to the surface of C-CNC and the CNC substrate improved the hydrophilicity of the dye.The maximum solubility of AANI in H 2O was 0.8 mmol/L,while the concentration of dye in the prepared F-CNC mother liquor was 1.2 mmol/L.F-CNC was stable in aqueous solution and exhibited a good bright yellow fluorescence emission property.At the same time,F-CNC retained the rod shape of C-CNC and had little change in size.The crystallinity and crystal structure didn′t changed significantly.The crystallinities of C-CNC and F-CNC were 61.2% and 67.7%,respectively.The decrease of the solvent polarity compressed the double layer of the F-CNC and caused the aggregation of the F-CNC to some extent,resulting in higher fluorescence sensitivity of F-CNC to solvent polarity than that of AANI.The results of fluorescent labeling showed that when the mass concentrations of F-CNC were 0,3.375×10-4 and 6.75×10-4 g/L,the survival rates of cells after incubated for 10 h were 49.08%,44.21% and 40.71%,respectively.F-CNC had good fluorescent-labeled imaging performance for Hela cells,and had low toxicity to cells.