文章合成了一种新型pH敏感的金纳米粒子(gold nanoparticles,Au NPs),通过表面修饰亲水链在酸性条件下的解离引发聚集提高金纳米粒子在近红外区的吸收能力.首先合成末端巯基的原酸酯亲水链,并修饰到原位还原合成的金纳米表面获得POE-Au NPs.透射电子显微镜(transmission electron microscope,TEM)观察到在中性条件下金纳米粒子呈平均粒径5 nm单分散状态,在模拟肿瘤微环境pH=5.5酸性条件下,其表面修饰的聚乙二醇(PEG)段从原酸酯处触发断裂而游离,使得金纳米粒子聚集形成几百纳米团簇.光热性能测试结果表明,pH响应性聚集可以使得POE-Au NPs的光热转换效率达到58.8％,明显高于传统的无pH响应性的PEG-Au NPs.此外,细胞实验结果表明,POE-Au NPs具有良好的生物安全性.
Preparation and photothermal properties of acid-triggered assembled gold nanoparticles
Here novel pH-sensitive gold nanoparticles(Au NPs)were synthesized,their adsorption ca-pacity in the near-infrared region was improved by self-aggregation via their surface decorated hydro-philic chain dissociated under acidic conditions.Firstly,the ortho ester molecule with the end of the S-H bond was prepared and then decorated onto gold nanoparticles(POE-Au NPs).POE-Au NPs exhib-ited monodispersity with average particle size of 5 nm in neutral pH aqueous solution under transmis-sion electron microscope(TEM),while under acidic conditions of pH 5.5 in simulated tumor microen-vironment,the ortho ester bond broke and the PEG chains were dissociated from the Au NPs,which induced the Au NPs to aggregate into clusters of hundred nanometers.The photothermal property test showed that the photothermal conversion efficiency of POE-Au NPs reached 58.8％in acidic condi-tions,which was much higher than that of the traditional PEG-Au NPs.Furthermore,the cell safety evaluation confirmed the good biosafety of POE-Au NPs.
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