表面羧基化对聚合物微气泡性能的影响

Influence of Carboxyl Modification on the Surface of Polymer Microbubbles

目的:探讨左旋聚乳酸(PLLA)及聚乙烯醇(PVA)为膜材的聚合物微气泡表面羧基化,对其形貌、粒径、稳定性及超声成像性能的影响。方法:首先对PVA膜材进行了羧基化修饰,通过红外光谱进行羧基化程度的表征。然后用羧基化前、后的PVA为原料分别制备了聚合物微气泡,光学显微镜及扫描电子显微镜(SEM)观察微气泡形貌,Zeta电位检测微气泡表面电荷特性,并对羧基化前后的微气泡进行体外超声成像实验。结果:羧基化不会显著影响微气泡的粒径,但会改变其表面结构,形成诸多凹陷;Zeta电位检测表明,羧基的引入使微气泡的表面电荷向负电性移动,微气泡羧基化之后能够显著增强超声成像效果,延长超声成像时间。结论:羧基的引入既由于静电斥力提高了微气泡的稳定性,又可赋予其耦联其他活性物质的能力,并可显著增强其超声成像效果。本研究为微气泡的生物医学应用打下了良好的基础。

Objective：To explore the influence of carboxylation on the surface of polymer MBs which made up of poly l-lactic acid and polyvinyl alcohol（PVA）on the morphology,size,stability and ultrasound imaging.Method：Firstly,the PVA was modified by carboxyl and the degree of PVA carboxylation was characterized by infrared spectroscopy.The polymer MBs were prepared by using PVA before and after carboxylation.The morphology of MBs were observed by optical microscope and scanning electron microscope.The unique electric charge characteristics of MBs surface were detected by Zeta potential detection.Finally,the ultrasound imaging experiments in vitro with MBs were performed before and after carboxyl.Result：Carboxylation didn＇t affect particle size but affect morphology signally and changed the structure on the surface such as the formulation of hollows.Zeta potential detection indicated carboxylation made the surface charge of MBs move to electronegative place.Carboxylation could signally enhance the effect and extend the time of ultrasonic imaging after carboxyl.Conclusion：The introduction of carboxyl give MBs the ability of coupling other active substances as well as enhancing the stability of MBs because of electrostatic repulsion.It can also signally enhance the effect of ultrasonic imaging.This study lay a good foundation for the biomedical application of MBs.