Abstract: Using silk fibroin as raw material and 1,1,1,3,3,3-hexafluoro-2-propanol as solvent，the solution-enhanced dispersion by supercritical fluid (SEDS) process was used to prepare silk fibroin nanoparticles. The influences of pressure，solution concentration，solution velocity and CO2 velocity on particle size and particle size distribution of nanoparticles were investigated；the Zeta potential，Headspace gas chromatography (HS-GC)，Fourier transform infrared spectroscopy (FTIR)，X-ray diffraction (XRD) and Differential scanning calorimetry (DSC) were also used to characterize the resulting nanoparticles. The results of dynamic laser light scattering detection show that the particle size of silk fibroin nanoparticles increases with the increase of pressure，solution concentration and solution velocity；while the opposite phenomenon is observed for the CO2 velocity，and the minimum particles size is 298nm. The Zeta potential of silk nanoparticles is ?39mV. The results of HS-GC show the organic solvent residue of silk nanoparticles is 20μg/L. After SEDS process，the results of FTIR show that chemical structure and functional group of the silk fibroin do not change，however，the results of XRD and DSC indicate that the secondary structure shifts from random coil to β-sheet.

Key words: silk fibroin, solution-enhanced dispersion by supercritical fluid, nanoparticles, preparation, characterization

摘要： 以丝素蛋白为原料，以六氟异丙醇为溶剂，采用超临界流体强制分散溶液（SEDS）工艺制备了丝素纳米颗粒。单因素实验考察了压力、溶液浓度、溶液流速和CO2流速等因素对丝素纳米颗粒平均粒径分布的影响，并通过Zeta电位、HS-GC、FTIR、XRD和DSC等技术手段对制备的丝素纳米颗粒进行了表征。动态激光光散射仪检测结果表明：随压力、溶液浓度和流速的增大，丝素纳米颗粒平均粒径增大；随CO2流速的增大，丝素纳米颗粒平均粒径减小，最小达到298nm。丝素纳米颗粒Zeta电位为?39mV。HS-GC表明丝素纳米颗粒有机溶剂残留量为20μg/L。FTIR表明经SEDS工艺处理后丝素化学结构和官能团不会发生变化。XRD和DSC显示经SEDS工艺处理后丝素内部分子结构发生重排，由无规则卷曲向β折叠转换。

关键词: 丝素, 超临界流体强制分散溶液, 纳米颗粒, 制备, 表征