Cabana-Montenegro Sonia, Barbosa Silvia, Taboada Pablo, Concheiro Angel, Alvarez-Lorenzo Carmen
Departamento de Farmacología, Farmacia y Tecnología Farmacéutica, R+D Pharma Group (GI-1645), Facultad de Farmacia and Health Research Institute of Santiago de Compostela (IDIS), Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
Área de Física de la Materia Condensada, Facultad de Física, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
Pharmaceutics. 2019 Jan 26;11(2):52. doi: 10.3390/pharmaceutics11020052.
Block copolymer dispersions that form gels at body temperature and that additionally are able to reduce a gold salt to nanoparticles (AuNPs) directly in the final formulation under mild conditions were designed as hybrid depots for photothermal therapy. The in situ gelling systems may retain AuNPs in the application zone for a long time so that localized elevations of temperature can be achieved each time the zone is irradiated. To carry out the work, dispersions were prepared covering a wide range of poloxamine Tetronic 1307:gold salt molar ratios in NaCl media (also varying from pure water to hypertonic solution). Even at copolymer concentrations well above the critical micelle concentration, the reducing power of the copolymer was maintained, and AuNPs were formed in few hours without extra additives. Varying the copolymer and NaCl concentrations allowed a fine tuning of nanoparticles' shape from spherical to triangular nanoplates, which determined that the surface plasmon resonance showed a maximum intensity at 540 nm or at 1000 nm, respectively. The information gathered on the effects of (i) the poloxamine concentration on AuNPs' size and shape under isotonic conditions, (ii) the AuNPs on the temperature-induced gelling transition, and (iii) the gel properties on the photothermal responsiveness of the AuNPs during successive irradiation cycles may help the rational design of one-pot gels with built-in temperature and light responsiveness.
设计了一种嵌段共聚物分散体，其在体温下形成凝胶，并且能够在温和条件下直接在最终制剂中将金盐还原为纳米颗粒（AuNP），用作光热疗法的混合储库。原位凝胶系统可使AuNP在应用区域长时间保留，从而每次照射该区域时都能实现局部温度升高。为开展这项工作，在NaCl介质（从纯水到高渗溶液不等）中制备了涵盖广泛泊洛沙明Tetronic 1307：金盐摩尔比的分散体。即使在共聚物浓度远高于临界胶束浓度时，共聚物的还原能力仍得以保持，且无需额外添加剂即可在数小时内形成AuNP。改变共聚物和NaCl浓度可对纳米颗粒的形状进行微调，从球形变为三角形纳米片，这决定了表面等离子体共振分别在540nm或1000nm处显示出最大强度。收集到的关于（i）等渗条件下泊洛沙明浓度对AuNP尺寸和形状的影响，（ii）AuNP对温度诱导的凝胶转变的影响，以及（iii）在连续照射循环期间凝胶性质对AuNP光热响应性的影响等信息，可能有助于合理设计具有内置温度和光响应性的一锅法凝胶。
