Laboratoire Matière et Systèmes Complexes, UMR 7075, CNRS and Université Paris Diderot, 10 Rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13, France.
Nanoscale. 2019 Feb 14;11(7):3344-3359. doi: 10.1039/c8nr09849b.
Gold nanoparticles have been thoroughly used in designing thermal ablative therapies and in photoacoustic imaging in cancer treatment owing to their unique and tunable plasmonic properties. While the plasmonic properties highly depend on the size and structure, controllable aggregation of gold nanoparticles can trigger a plasmonic coupling of adjacent electronic clouds, henceforth leading to an increase of light absorption within the near-infrared (NIR) window. Polymer-engraftment of gold nanoparticles has been investigated to achieve the plasmonic coupling phenomenon, but complex chemical steps are often needed to accomplish a biomedically relevant product. An appealing and controllable manner of achieving polymer-based plasmon coupling is a template-assisted Au+3 reduction that ensures in situ gold reduction and coalescence. Among the polymers exploited as reducing agents are polyethyleneimines (PEI). In this study, we addressed the PEI-assisted synthesis of gold nanoparticles and their further aggregation to obtain fractal NIR-absorbent plasmonic nanoaggregates for photothermal therapy and photoacoustic imaging of colorectal cancer. PEI-assisted Au+3 reduction was followed up by UV-visible light absorption, small-angle X-ray scattering (SAXS), and photo-thermal conversion. The reaction kinetics, stability, and the photothermal plasmonic properties of the as-synthesized nanocomposites tightly depended on the PEI : Au ratio. We defined a PEI-Au ratio range (2.5-5) for the one-pot synthesis of gold nanoparticles that self-arrange into fractal nanoaggregates with demonstrated photo-thermal therapeutic and imaging efficiency both in vitro and in vivo in a colorectal carcinoma (CRC) animal model.
金纳米颗粒由于其独特且可调谐的等离子体特性，已被广泛应用于设计热消融疗法和癌症治疗的光声成像。虽然等离子体特性高度依赖于尺寸和结构，但金纳米颗粒的可控聚集可以引发相邻电子云的等离子体耦合，从而导致近红外（NIR）窗口内的光吸收增加。已经研究了金纳米颗粒的聚合物接枝来实现等离子体耦合现象，但通常需要复杂的化学步骤来完成具有生物医学相关性的产品。实现基于聚合物的等离子体耦合的一种吸引人且可控的方法是模板辅助的 Au+3 还原，该方法可确保原位金还原和聚合并行。在用作还原剂的聚合物中，有聚乙烯亚胺（PEI）。在这项研究中，我们解决了 PEI 辅助合成金纳米颗粒及其进一步聚集以获得分形 NIR 吸收等离子体纳米聚集体，用于结直肠癌的光热治疗和光声成像。通过紫外-可见光吸收、小角 X 射线散射（SAXS）和光热转换来跟踪 PEI 辅助的 Au+3 还原。反应动力学、稳定性和所合成的纳米复合材料的光热等离子体特性严格依赖于 PEI：Au 比。我们定义了一个 PEI-Au 比范围（2.5-5），用于一锅法合成自组装成分形纳米聚集体的金纳米颗粒，在结直肠癌细胞（CRC）动物模型中证明了体外和体内的光热治疗和成像效率。
