壳聚糖纳米粒子荧光探针的制备和表征

Preparation and Characterization of the Fluorescent Chitosan Nanoparticle Probe

通过低分子量的壳聚糖(LCS)聚阳离子与三聚磷酸钠(TPP)的静电作用制备纳米级壳聚糖微球,并利用壳聚糖链上丰富的氨基与荧光素异硫氰酸酯(FITC)反应从而制备纳米壳聚糖微球荧光探针(NFCS)。结果表明,当壳聚糖分子量为60000,LCS与TPP的质量比为6∶1时,可得到粒度均一的球形纳米粒子,平均粒径为40±3 nm。荧光倒置显微镜观察证实FITC结合到壳聚糖微球上。荧光光谱分析显示NFCS的最大激发波长、最大发射波长与游离态FITC无显著差异。光漂白实验证实NFCS的稳定性比游离态FITC有显著提高。

The chitosan （CS） nanoparticles were prepared by crosslinking of low molecular weight chitosan with polyanion sodium tripolyphosphate （TPP）. The fluorescent chitosan nanoparticles （NFCS） could be obtained by the reaction between the isothiocyanate group of fluorescein isothiocyanate（FITC） and the primary amine group of the D-glucosamine residue. Results showed that the molecular weight of chitosan as well as the mass ratio of CS to TPP have significant effects on the diameter of the nanoparticles. When the molecular weight of chitosan was controlled at around 50000, and the mass ratio of CS to TPP was at 6： 1, the spherical shape particles with average diameter of （40 ± 3 ） nm were obtained, which was detected by transmission elec- tron microscopy and dynamic light scattering. Fluorescent imaging proved that the FITC was attached on the chitosan nanoparticles. The maximal excitation and emission wavelength of NFCS was almost the same as the free FITC. In comparison with free FITC, the particle probes are more stable against photobleaching.