Design of the nanointerface for detection, recovery, and regeneration of abnormal proteins

聚合物纳米微粒作为一种药物载体已引起人们的关注。要求载体是惰性的、无毒的，不会在体内积聚或降解。因此，我们选择了可降解的多肽--多L赖氨酸作为纳米粒子的骨架。由于PLL具有随pH和温度变化的无规、螺旋和β-Sheet之间的结构变化，因此我们期待药物从纳米颗粒中对刺激敏感地释放。PLL可以与聚乙二醇反应，以提高分散稳定性和延长在血液中的寿命(mpeg-pll聚合物)。然后，将mpeg-pll聚合物与作为疏水中心的磷脂酸(PA)偶联，得到mpeg-pll-PA纳米粒子。得到的聚合物通过PA部分之间的疏水缔合自发聚集成纳米颗粒形状。而mpeg-pll聚合物在较高的pH值和高温下形成β片状结构后组装成纳米颗粒(mpeg-pll纳米颗粒)。两种纳米粒子的大小均为10-80 nm，且均有正向变化。FITC标记的纳米颗粒被内化到A431细胞中。阿霉素(ADR)是一种抗癌药物，由于PA具有很强的疏水性，其在mPG-PLL-PA纳米粒中的包封率高于mPEG-PLL纳米粒。然而，药物释放呈现出相反的趋势。在pH值为4的条件下，阿霉素在mGFP-PLL纳米粒中的释药速度快于mEg-PLL-PA纳米粒。因此，负载阿霉素的mpeg-pll纳米粒子处理A431细胞后，细胞存活率下降。我们应用mpeg-pll聚合物的β-Sheet缔合来抑制蛋白质聚集。随着pH和温度的升高，PLL倾向于通过β-Sheet缔合方式聚集。这种聚集可以通过添加mpeg-pll聚合物来抑制。这表明，mpeg-pll聚合物能够抑制导致构象疾病的异常蛋白质的聚集。

Polymeric nanoparicles have been paid to attention as a drug carrier. It is required that carriers are inert and non-toxic and are not accumulated or are degradable in the body. Therefore we selected poly-L-lysine (PLL) that is degradable polypeptide for a backbone of a nanoparticle. Because PLL exhibits structural changes among random, helix, and β-sheet by pH and temperature, we expect the stimuli-sensitive release of drugs from nanoparticles.PLL was allowed to react with poly (ethylene glycol) (PEG) to improve the dispersion-stability and to prolong the lifetime in blood (mPEG-PLL polymer). Then, mPEG-PLL polymer was coupled with phosphatidic acid (PA) that acts as a hydrophobic site (mPEG-PLL-PA nanoparticle). The obtained polymers spontaneously aggregated into a nanoparticulate shape by the hydrophobic association among PA moieties. Whilst mPEG-PLL polymers were assembled to nanoparticles upon the formation of β-sheet structure in high pHs and high temperatures (mPEG-PLL nanoparticle). Both nanoparticles were 10-80nm in size and possessed the positive change. FITC-labeled nanoparticles were internalized into A431 cells. Adriamycin (ADR) that is an anticancer drug was incorporated into mPEG-PLL-PA nanoparticle more than mPEG-PLL nanoparticle because of PA's great hydrophobicity. However, drug release showed an opposite tendency. In pH4, release rate of ADR from mPEG-PLL nanoparticles was faster than that from mPEG-PLL-PA nanoparticles. Thereby survival rate of A431 cells decreased when they were treated with ADR-loaded mPEG-PLL nanoparticles.We applied β-sheet association of the mPEG-PLL polymer to inhibition of protein aggregation. PLL tends to aggregate through β-sheet association by raising pH and temperature. This aggregation could be inhibited by adding the mPEG-PLL polymer. This suggests that the mPEG-PLL polymer is capable of inhibiting aggregation of abnormal proteins that cause conformational diseases.