乳铁蛋白与纳米脂质体的相互作用及对磷脂膜结构的影响

The Interaction between Lactoferrin and Nanoliposomes and Its Influence on the Structure of Phospholipid Membrane

为探明纳米脂质体(N-lip)与食品蛋白的相互作用,采用薄膜分散法制备N-lip。以乳铁蛋白(Lf)为模型蛋白,评价不同蛋白浓度和滴加方式下形成的纳米脂质体/乳铁蛋白(N-lip/Lf)复合物的粒径、Zeta-电位和多分散系数,并用隐形率(Fs)来估计N-lip与Lf的结合程度。利用透射电子显微镜比较乳铁蛋白作用前、后的形貌变化,采用光谱法和X射线衍射分析Lf与N-lip的相互作用。结果表明:在磷脂质量浓度为10.0 mg/mL、磷脂与胆固醇质量比为10∶1、磷脂与Tween-80的质量比为4∶1、蛋白质量浓度为0.1 mg/mL时,形成的N-lip/Lf复合物平均粒径为(100.80±0.141)nm,电位为(-54.9±2.276)mV,具有较好的分散度。透射电子显微镜观察可见,Lf在N-lip边缘形成浅色包裹层。Lf与N-lip的相互作用促进了Lf中色氨酸和酪氨酸残基所处环境的疏水性增强,Lf的α-螺旋结构含量增加;Lf可以通过氢键、范德华力和疏水作用与N-lip磷脂双分子层膜发生相互作用,吸附到磷脂膜表面。研究结果可为脂质体与食品蛋白的互作及脂质体在食品工业中的潜在应用提供理论依据。

In order to explore the interaction between nano-liposome(N-lip)and food protein,N-lip was prepared by the thin film dispersion method.Lactoferrin(Lf)was used as the model protein to evaluate the effects of the nanoliposome/lactoferrin(N-lip/Lf)complex formation under different protein concentrations and dripping methods on the particle size,Zeta-potential and polydispersity coefficient,and the stealth rate(Fs)was used to estimate the degree of binding of N-lip and Lf.The transmission electron microscope was used to compare the morphological changes before and after the action of lactoferrin,and the interaction between Lf and N-lip was analyzed by spectroscopy and X-ray diffraction.The results showed that:when the phospholipid mass concentration was 10.0 mg/m L,the mass ratio of phospholipid to cholesterol was 10∶1,the mass ratio of phospholipid to Tween-80 was 4∶1,and the protein mass concentration was 0.1mg/m L,the average particle size and the zeta potential of the N-lip/Lf complex formed were(100.80±0.141)nm and(-54.9±2.276)m V,respectivlely,with favourable dispersion.Transmission electron microscope observation showed that Lf formed a light-colored wrapper around the edge of N-lip.The interaction between Lf and N-lip promoted the hydrophobicity of the environment where tryptophan and tyrosine residues in Lf were located,and the content of the alpha-helical structure of Lf increased;Lf could interact with the N-lip phospholipid bilayer membrane through hydrogen bonding,van der Waals force and hydrophobic interaction,adsorb to the surface of the phospholipid membrane and change the polar environment of the N-lip membrane.The research results can provide a theoretical basis for the interaction between liposomes and food proteins and the potential application of the former in the food industry.