包裹多肽二氧化硅纳米颗粒的制备和性能研究

Study on preparation and properties of silica nanoparticles encapsulating polypeptide

目的研究在不同钙离子存在条件下二氧化硅的性质和对蛋白包裹能力有无变化,来确定其是否有作为口服载体的性能。方法研究包裹多肽二氧化硅纳米颗粒的制备、包裹多肽二氧化硅纳米颗粒的体外释放实验、包裹不同多肽的二氧化硅纳米颗粒的表征、包裹含有不同量的氯化钙和不同结构的多肽二氧化硅纳米颗粒性能。结果以含有His标签的增强绿色荧光蛋白(enhance green fluorescent portein,EGFP;PI 5.99)为模型,采用反相微乳液体系中加入适量氯化钙,钙离子既和二氧化硅纳米粒子内部的氧原子形成离子键,又和His标签形成络合作用,这样就将蛋白质固定在二氧化硅纳米粒子内部,经过多次洗涤泄露较少。酶切、加热、尿素变性等试验均显示其具有良好的稳定性。结论通过在传统的反相微乳液体系中加入适量的钙离子,就可以达到良好的包裹效果,且其在酸性条件下不易释放,而在碱性条件则相对容易释放,符合用于口服药物载体的基本要求。

Objective To research properties of silica nanoparticles encapsulating polypeptide under different calcium ion concentration conditions and ability changes of encapsulating polypeptide,and determine whether it has properties as an oral carrier. Methods The preparation of silica nanoparticles encapsulating polypeptide,release experiment in vivo,characterization of silica nanoparticles with different polypeptide,and properties of silica nanoparticles encapsulating polypeptide with different concentrations of calcium chloride and different structure were studied. Results With His tagged EGFP(PI 5. 99) as a model,when calcium chloride was added into reverse microemulsion system,calcium ion could not only form ionic bonds with oxygen atoms inside the silica nanoparticles,but also form complexation with His tags. The protein was immobilized inside the silica nanoparticles,and leaked less after repeated washing. Experimental results of enzyme cutting,heating,urea denaturation showed a good stability. Conclusion By adding proper calcium ion into the traditional reverse microemulsion system,good encapsulating effect could be achieved,and it is not easy to be released in acidic conditions,while in alkaline condition is released relatively easy,which meets the basic requirements for oral drug carrier.