目的 构建尺寸可变纳米递送系统PAMAM/DOX-pep并进行表征,检测其理化性质并评价其体外抗肿瘤效果与靶向性。方法 将阿霉素（DOX）物理包埋在阳离子聚合物PAMAM的疏水空腔内,以4-（N-马来酰亚胺基甲基）环己烷羧酸N-羟基琥珀酰亚胺酯（SMCC）作为交联剂,采用金属基质蛋白酶（MMP-2）敏感的多肽pep（CPLGVRGC）串联小粒径纳米颗粒形成大尺寸纳米递送系统（PAMAM/DOX-pep）,对各纳米颗粒的粒径、电位、理化性质以及对小鼠乳腺癌细胞（4T1）的抑制作用、细胞摄取效果和核靶向作用进行检测。结果 PAMAM/DOX粒径约为10 nm,载药率为23%,多肽pep交联后形成的PAMAM/DOX-pep粒径约为200 nm,可在低pH下缓释DOX,7天内体外保持稳定且溶血率低、安全无毒,其与MMP-2共孵育后细胞摄取量与核靶向性显著增加。结论 尺寸可变纳米颗粒有助于克服尺寸所引发的递送障碍,将药物靶向递送至乳腺癌细胞核内并发挥作用,为纳米递送系统的设计提供了新策略。

Objective To construct and characterize the size-variable nano-delivery system PAMAM/DOX-pep,examine its physicochemical properties and evaluate its antitumor and targeting effects in vitro. Methods Small particle size PAMAM/DOX was obtained by physically encapsulating DOX within the hydrophobic cavity of the cationic polymer PAMAM. The large size nano-delivery system(PAMAM/DOX-pep)was formed by tandem linking small size nanoparticles by MMP-2 sensitive peptide pep(CPLGVRGC)using SMCC as a cross-linker. The particle size,potential,physical and chemical properties,inhibitory effect,cell uptake and nuclear targeting effect of each nanoparticle on mouse breast cancer cells(4T1)were detected. Results The particle size of PAMAM/DOX was about 10 nm,and the drug loading rate was 23%. PAMAMAM/DOX-pep,formed after cross-linking of peptide,had a particle size of about 200 nm,which could release DOX slowly at low pH,and remained stable,safe and non-toxic in vitro for 7 days with low hemolysis rate,and its cellular uptake amount and nuclear targeting rate increased significantly after co-incubation with MMP. Conclusions Size-variable nanoparticles overcome size-induced delivery barriers to target and deliver drugs to the 4T1 nucleus,providing a new strategy for the design of nano delivery systems.