光谱法研究聚赖氨酸与纤维蛋白原的相互作用

聚赖氨酸是一种重要的聚阳离子，在生物医药领域具有广泛的应用前景。但是，目前其血液相容性的相关报道较少，特别是通过光谱法研究其与血液中重要蛋白的相互作用。因此，通过多种光谱法研究聚赖氨酸与纤维蛋白原的相互作用，进一步评价其血液相容性具有一定的创新性。本实验通过荧光、紫外和圆二色谱研究聚赖氨酸对纤维蛋白原结构的影响。其中，聚赖氨酸的正电性随着浓度增大而增大;复合实验显示，0.01 mg·mL-1的聚赖氨酸对纤维蛋白原的功能影响较小，随着浓度增大，相互作用增强;荧光光谱显示，纤维蛋白原在λ_em=341 nm处出现浓度依赖性的荧光猝灭;紫外光谱显示，聚赖氨酸对纤维蛋白原吸收强度(200～240和278 nm处)的影响在0.025 mg·mL-1时较小，并出现浓度依赖性的减少;圆二色光谱显示，随着聚赖氨酸浓度增大，纤维蛋白原的α-螺旋含量减少，β-折叠、β-转角和无规卷曲含量增加。结果表明，聚赖氨酸会与纤维蛋白原发生静电相互作用，对其结构造成浓度依赖性的影响。当浓度为0.01和0.025 mg·mL-1时，聚赖氨酸对纤维蛋白原结构的影响较小;而浓度过大时，影响较大，势必破坏纤维蛋白原的生理功能。因此，研发和应用聚赖氨酸时必须充分考虑浓度因素。本实验提供了一种简便而系统的方法来研究材料与蛋白的作用,有利于充分评价材料的血液相容性。此外，上述研究结果对聚赖氨酸的生物医学应用具有重要的指导意义。

Studies on the Interaction of Poly-L-lysine with Fibrinogen with Spectroscopic Methods

Poly-L-lysine is an important polycation which has great prospect in the biomedical application.However,there are few reports on the blood compatibility of poly-L-lysine at present,especially the interaction between poly-L-lysine and some im-portant proteins from the blood,which is studied with spectroscopic methods.Therefore,it is of certain innovation to further evaluate the blood compatibility of poly-L-lysine,which is studied by the interaction between poly-L-lysine and fibrinogen with many spectroscopic methods.In this study,the fluorescence,ultraviolet visible and circular dichroism spectroscopy were used to research the effects of poly-L-lysine on the structure of fibrinogen.Briefly,zeta potential experiment showed that positive poten-tial of poly-L-lysine increased with increasing concentration.Complexation experiment showed that 0.01 mg·mL-1 poly-L-ly-sine had little effect on the function of fibrinogen,and the interaction strengthened with concentration increasing.Fluorescence spectra showed that the fluorescence of fibrinogen was quenched in a concentration dependent way when the emission wavelength was 341 nm (λem=341 nm).Ultraviolet visible spectra showed that the absorption intensity of fibrinogen at 200~240 and 278 nm,which was less affected by 0.025 mg·mL-1 poly-L-lysine,reduced with the concentration of poly-L-lysine increasing.Cir-cular dichroism spectra showed when the concentration of poly-L-lysine increased,the effect of poly-L-lysine on the secondary structure of fibrinogen strengthened.Overall,as the concentration of poly-L-lysine increased,theα-helix content of fibrinogen decreased and theβ-fold,β-turn and random coil content of fibrinogen increased.These results showed that the electrostatic in-teraction was occurred between poly-L-lysine and fibrinogen,which influenced the structure of fibrinogen by concentration de-pendence.While the effect of poly-L-lysine (0.01 and 0.025 mg·mL-1 )on fibrinogen was little,poly-L-lysine of high concen-tration would damage the physiological function of fibrinogen.Therefore,it is necessary to consider the concentration factor in the development and application of poly-L-lysine.In this study,a simple,convenient and systematic method is utilized to study the interaction between materials and fibrinogen,which is helpful to evaluate the blood compatibility of materials sufficiently. Furthermore,the results of this study will provide important guiding information for the biomedical applications of poly-L-ly-sine.