温度/pH/磁三元复合水凝胶的辐射制备及其对牛血清白蛋白吸附机制

Preparation of Temperature/pH/Magnetic Ternary Hydrogels by Radiation and Its Adsorption Mechanism on Bovine Serum Albumin

目的研究新型智能温度/pH/磁三元复合水凝胶(NIPAAm/HHPC/Fe3O4)给药系统的体外载药量及验证释药机理。方法在室温下,采用电子束辐射方法成功制备温度/pH/磁三元复合水凝胶。用牛血清白蛋白(BSA)作为模拟药物,利用荧光分光光度计等手段验证复合水凝胶对于药物的吸附机理。结果pH=9.0,水凝胶对BSA的饱和吸附量最小(0.34 mg/g)。当温度在20℃~42℃时,水凝胶对BSA饱和吸附量呈现明显的单调递减趋势。随着外加磁场强度的增加,水凝胶对BSA饱和吸附量逐渐减少。结论由于pH的不同,静电排斥力、疏水作用力等会引起水凝胶与BSA的相互作用机制不同。此外,温度的差异也会导致水凝胶骨架的伸展与收缩,引起水凝胶对BSA饱和吸附量的变化。当然,外加磁场强度越大,越不利于水凝胶对BSA的吸附。

Objective The loading capacity and adsorption mechanism of a new type of intelligent drug delivery system on magnetic/pH/temperature ternary composite hydrogel(NIPAAm/HHPC/Fe3O4:noted as NHF)was studied in vitro.Methods The NHF hydrogel was successfully prepared by electron beam radiation at room temperature,and the adsorption mechanism on bovine serum albumin(BSA)as a simulated drug in vitro was verified by means of Ultraviolet-Visible spectrophotometer and fluorescence spectrophotometer,etc.Results The saturated adsorption capacity of the NHF hydrogel to BSA is the smallest(0.34 mg/g)at pH=9.0.When the temperature range is 20℃~42℃,the saturated adsorption capacity of the NHF hydrogel to BSA illustrates a monotonously decreasing trend.Finally,the saturated adsorption capacity of the NHF hydrogel to BSA is gradually reduced with the increasing of the intensity magnetic field.Conclusion The possible adsorption mechanism of NHF hydrogel to BSA is proposed.Because different pH values were used,different interaction mechanisms between hydrogel and BSA by electrostatic repulsion and hydrophobic force would be caused.In addition,the expansion and contraction of the NHF hydrogel skeleton would also be changed and as a result the NHF hydrogel have different the saturated adsorption capacity to BSA at different temperatures.Obviously,the greater the intensity of outer magnetic field is,the more unfavorable effect BSA exerts on the adsorption of NHF hydrogel.