Department of Mechanical Engineering, University of Wisconsin in Milwaukee, Milwaukee, WI 53211, USA.
Biomaterials. 2010 Jun;31(18):4944-51. doi: 10.1016/j.biomaterials.2010.02.073. Epub 2010 Mar 25.
A pH-sensitive molecularly imprinted polymer (MIP) nanospheres/hydrogel composite exhibiting controlled release of dexamethasone-21 phosphate disodium (DXP) was developed as a potential coating for implantable biosensors to improve their biocompatibility. The molecularly imprinted pH-sensitive nanospheres were prepared by UV-initiated precipitation polymerization using DXP as the template molecule. The DXP loading and release experiments showed that the MIP nanospheres exhibited a higher loading level and slower release rate than non-imprinted polymer (NIP) nanospheres due to the interaction of DXP with the DXP-imprinted cavities within the MIP nanospheres. Furthermore, the MIP nanospheres exhibited a faster DXP release rate at a lower pH value within the pH range tested (i.e., 6.0-7.4), which is desirable for suppressing inflammation because inflammation induces an acidic microenvironment. In contrast, the NIP nanospheres did not show a notable pH-responsive DXP release behavior. The hydrogel poly(2-hydroxyethyl methacrylate (HEMA) -N-vinyl-2-pyrrolidinone (NVP) -2-methacryloyloxyethyl phosphorylcholine (MPC)) was prepared by UV polymerization. The MIP nanospheres were successfully incorporated into the hydrogel. The equilibrium water content and swelling kinetics of the MIP nanospheres/hydrogel composite were similar to those of pure hydrogel. The MIP nanospheres/hydrogel composite exhibited a much better controlled DXP release profile than the pure hydrogel. This pH-sensitive MIP nanospheres/hydrogel composite designed as a coating for implantable biosensors can potentially suppress the inflammation response of the implanted biosensors efficiently thereby effectively improving their lifetime.
一种 pH 敏感的分子印迹聚合物（MIP）纳米球/水凝胶复合材料，具有控制释放地塞米松-21 磷酸二钠盐（DXP）的功能，被开发为一种潜在的可植入生物传感器涂层，以提高其生物相容性。采用 DXP 作为模板分子，通过紫外光引发沉淀聚合制备了 pH 敏感的分子印迹纳米球。DXP 的负载和释放实验表明，由于 DXP 与 MIP 纳米球内的 DXP 印迹空穴相互作用，MIP 纳米球表现出更高的负载水平和更慢的释放速率，而非印迹聚合物（NIP）纳米球则没有。此外，MIP 纳米球在测试的 pH 范围内（即 6.0-7.4）表现出更快的 DXP 释放速率，这对于抑制炎症是理想的，因为炎症会引起酸性微环境。相比之下，NIP 纳米球没有表现出明显的 pH 响应性 DXP 释放行为。水凝胶聚（2-羟乙基甲基丙烯酸酯（HEMA）-N-乙烯基-2-吡咯烷酮（NVP）-2-甲基丙烯酰氧基乙基磷酸胆碱（MPC））是通过紫外光聚合制备的。MIP 纳米球成功地掺入到水凝胶中。MIP 纳米球/水凝胶复合材料的平衡水含量和溶胀动力学与纯水凝胶相似。MIP 纳米球/水凝胶复合材料表现出比纯水凝胶更好的控制 DXP 释放性能。这种设计为可植入生物传感器涂层的 pH 敏感 MIP 纳米球/水凝胶复合材料，有望有效抑制植入式生物传感器的炎症反应，从而有效延长其使用寿命。
