(肝素/壳寡糖/Pluronic^(█))静电组装多层膜的构建

以壳寡糖/Pluronic聚合物纳米聚集体(COPNs)、肝素为组装基元构建仿(肝素/壳聚糖)多层膜,验证多层膜负载疏水药物的可行性.PluronicP123与1,3-丙烷磺内酯反应合成末端磺酸化的Pluronic聚合物,其与PluronicF127在水溶液中自组装形成表面带负电荷的混合胶束.利用壳寡糖与混合胶束的静电作用,获得COPNs,粒径与表面电位分析、透射电镜表征COPNs为直径(27.61±2.46)nm、表面zeta电位(6.12±1.82)m V、稳定的球形结构.石英晶体微天平(QCM)跟踪检测证明COPNs与肝素可在基材表面实现交替沉积;原子力显微镜(AFM)表征多层膜表面拓扑形貌,证明COPNs在表面沉积过程中稳定.将疏水的荧光探针芘载入COPNs参与多层膜的构建,荧光光谱实验结果表明多层膜可成功包载芘,且多层膜内芘的载入量与组装层数相关.以葛根素为模型药物,载药量测定与体外释药实验结果表明多层膜具有包载和缓释疏水药物的能力.

Interaction of ultrasonic wave with void-containing layer in solid

Using a general mode for sound reflection from multilayered media, we present in this paper the expressions for sound reflection and transmission coefficients on void-containing interface layer in solid and derive the characteristic equation for symmetric and antisymmetric modes of the interface waves along the layer. The method for evaluating the effective elastic moduli of void-containing solid is also introduced. The numerical calculation given in this paper shows the influences of the void volume concentration and layer thickness on the sound reflection coefficients and interface wave velocity, providing a theoretical basis for inverse of the mechanical properties of void-containing layer based on the ultrasonic measurement.