目的 为了实现光热化疗联合治疗，提高抗肿瘤效果，将具有抗肿瘤作用的β-榄香烯（β-elemene，Ele）装载于聚乳酸羟基乙酸共聚物［poly(D,L-lactide-co-glycolic acid)，PLGA］纳米粒（Ele-PLGA NPs）中，并在载药纳米粒表面进一步包覆了聚单宁酸（poly-tannic acid，pTA），制得Ele-PLGA-pTA纳米粒（Ele-PLGA-pTA NPs）。方法 首先利用O/W乳化法制备Ele-PLGANPs，然后加入单宁酸与Fe³⁺发生络合反应，形成pTA分子层附着在Ele-PLGA NPs表面，最终形成Ele-PLGA-pTA NPs，通过马尔文激光粒度仪和透射电子显微镜对该系统的粒径、ζ电位、稳定性以及粒子形态进行考察；分别利用HPLC法和BCA试剂盒对β-榄香烯的载药量和单宁酸的包覆率进行测定；通过红外热成像仪评价PLGA-pTA NPs的光热升温效率和光热稳定性；通过MTT法考察载药纳米粒对Lewis肺癌细胞（Lewis lung cancer cell，LLC）的细胞毒性；通过建立小鼠LLC皮下肿瘤模型对Ele-PLGA-pTA NPs的体内光热-化疗联合抗肿瘤效果进行探究。结果 经测定，Ele-PLGA-pTA NPs对β-榄香烯的载药量和单宁酸的包覆率分别为（6.6±0.1）%、（5.4±0.1）%。其形态呈球形，粒径为（202.9±2.7）nm，ζ电位为（-37.5±0.2）mV，分散性良好。体外光热性能考察结果表明，在近红外激光（NIR laser）的照射下，PLGA-pTA NPs表现出良好的光热转换能力和光热稳定性。体外细胞实验结果表明，空白载体组（PLGA-pTANPs）基本没有细胞毒性，与单一化疗组（Ele-PLGA-pTANPs）相比，光热-化疗联合组（Ele-PLGA-pTANPs＋Laser）具有更强的细胞毒性。体内实验结果表明，与单纯光热治疗组（PLGA-pTA NPs＋Laser）和单一化疗组（Ele-PLGA-pTANPs）对照组相比，光热-化疗联合组（Ele-PLGA-pTANPs＋Laser）对小鼠肿瘤生长的抑制效果最为显著（P＜0.001）。结论 所制备的Ele-PLGA-pTANPs能够实现光热-化疗联合治疗，显著提高抗肿瘤效果。

Objective To achieve combined chemo-photothermal therapy for improved anti-tumor efficacy, β-elemene (Ele) with antitumor effect was encapsulated into poly(D,L-lactide-co-glycolic acid) nanoparticles (Ele-PLGA NPs) and coated with a poly-tannic acid (pTA) layer to obtain Ele-PLGA-pTA NPs.Methods Firstly, Ele-PLGA NPs were prepared by an O/W emulsification method, then the following added with tannic acid and Fe³⁺ could coordinate with each other and form a steady pTA layer on the surface of ElePLGA NPs to obtain Ele-PLGA-pTA NPs. The prepared Ele-PLGA-pTA NPs were characterized in particle size, ζ potential, stability and morphology through DLS and TEM. The drug loading efficiency of β-elemene and the coating rate of tannic acid were quantified by HPLC and the BCA kit, respectively. In addition, the photothermal effect and photothermal stability of PLGA-pTA NPs were evaluated by an IR camera and analyzed by the FLIR software. The cytotoxicity of Ele-PLGA-pTA NPs on Lewis lung cancer cell (LLC) was investigated by MTT assay. And the in vivo anti-tumor efficacy was explored on LLC tumor bearing mice.Results For the prepared Ele-PLGA-pTA NPs, the drug loading efficiency of β-elemene and the coating rate of tannic acid were (6.6 ±0.1)% and (5.4 ±0.1)%, respectively. Ele-PLGA-pTA NPs were spherical in shape, the ζ potential was (-37.5 ±0.2) mV and the particle size was (202.9 ±2.7) nm with good dispersibility. PLGA-pTA NPs exhibited high photothermal conversion effficiency and photothermal stability. Compared to single chemotherapy (Ele-PLGA-pTA NPs), the combined chemo-photothermal therapy (Ele-PLGA-pTA NPs + Laser) showed significantly enhanced cytotoxicity, while blank control (PLGA-pTA NPs) almost had no cytotoxicity. Also, the tumor inhibition rate for the combined chemo-photothermal therapy (Ele-PLGA-pTA NPs + Laser) was much higherthan that for single chemotherapy (Ele-PLGA-pTA NPs) or photothermal therapy (PLGA-pTA NPs + Laser) (P<0.001).Conclusion Ele-PLGA-pTA NPs prepared could achieve combined chemo-photothermal therapy and improve the overall antitumor efficacy.

R283.6

国家自然科学基金项目(81803737)