纳米尺寸的金属有机框架材料兼具传统框架材料的规整孔隙、高比表面积, 和纳米材料在活体中的高渗透和长滞留效应, 被广泛应用于药物递送领域. 然而, 单纯递送化疗药物对肿瘤的治疗效果有限, 通常需要联合其他治疗方式以提高治疗效果. 本工作开发了一种普适的合成方案, 用于共轭聚合物-沸石咪唑酯骨架-8(ZIF-8)复合纳米立方体的制备. 借助表面活性剂十六烷基三甲基溴化铵, 将疏水共轭聚合物聚[2,6-(4,4-双-(2-乙基己基)-4H-环戊二烯并[2,1-b;3,4-b']二噻吩)-alt-4,7(2,1,3-苯并噻二唑)](PCPDTBT)包裹在ZIF-8中, 得到大小约60 nm的纳米立方体. 接着, 通过两亲性嵌段共聚物F127的修饰实现其在水溶液中的高分散性和胶体稳定性. 该复合材料能够高效负载抗肿瘤药物阿霉素并实现酸响应的药物释放, 有助于肿瘤的化疗. 同时, ZIF-8的包裹也将PCPDTBT的光热转换效率大幅提升至42.5%, 可用于高效的光热治疗. 动物实验表明, 通过化疗和光热治疗的联合, 载药后的复合纳米立方体能够在激光照射下显著抑制肿瘤的生长且不会对正常组织造成明显损伤, 是一种高效的抗肿瘤试剂.

Nano-sized metal-organic frameworks possess uniform pores and high specific surface area of traditional frameworks, and enhanced permeability and retention effect of the nanomaterials, can be used as a new class of drug carriers. Recently, these materials have been heavily explored in the fields of drug delivery and tumor theranostics. However, chemotherapy using these nanoparticles as drug delivery vehicles alone cannot lead to high tumor inhibition efficiency. Other therapeutic modalities should be combined to improve the therapeutic effect. In this work, a general approach for the synthesis of conjugated polymer (CP)-zeolitic imidazolate framework-8 (ZIF-8) nanocubes was developed. With the assistance of cetyl trimethyl ammonium bromide, hydrophobic conjugated polymer poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4- b']dithiophene)-alt-4,7(2,1,3-benzothiadiazole)] (PCPDTBT) was transferred into aqueous solution through microemulsion method. After mixing with zinc ions and 2-methylimidazole, PCPDTBT can be encapsulated within ZIF-8, forming nanocubes with an average size of around 60 nm. After surface modification with amphiphilic block copolymer F127, the obtained nanocubes exhibited high dispersity and colloidal stability in aqueous solutions. The hydrodynamic diameter of the F127 coated nanocubes was around 62 nm, and did not change obviously after storing for 7 d. The nanocomposites exhibited high drug loading capacity, and can release drug in an acidic responsive manner, which was beneficial for chemotherapy. Due to the strong absorption of PCPDTBT in the near infrared region, the nanocubes can be used for photothermal therapy with a 730 nm laser. ZIF-8 coating also improved the photothermal conversion efficiency of PCPDTBT to around 42.5%, which can be useful for efficient photothermal therapy. Animal experiments were performed to demonstrate the antitumor ability of the nanocubes. With the combination of chemotherapy and photothermal therapy, the drug loaded nanocubes can inhibit the tumor growth in vivo efficiently under laser irradiation, and meanwhile, do not cause obvious damage to normal organs. Therefore, the obtained nanocubes can be effective antitumor agents.