The ideal photothermal therapy agent should exhibit a high energy conversion capacity, but it should not induce any cytotoxic effects unless it is exposed to electromagnetic radiation. We present data on biocompatibility and photothermal conversion capacity of colloidal gold nanoparticle assemblies (NPAs), obtained by hydroxylamine hydrochloride reduction at room temperature. The cytotoxic profile of NPAs with a mean diameter of 20 and 120 nm, respectively, was assessed using 3-[4,5-dimethylthiazole-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay, demonstrating tolerable cytotoxic effect on A549 human lung adenocarcinoma cell line at gold concentrations up to 150 μg gold/mL. Insights regarding the oxidative stress were gained using peroxide-sensitive fluorescent probes, which showed no additional oxidative stress due to NPA exposure. Using infrared thermal imaging, the photothermal conversion was evidenced, the effect being more prominent for the 120-nm diameter NPAs irradiated with the 785-nm laser. The photothermal capabilities of NPAs were highlighted also by Raman imaging studies, showing intracellular carbon by-products due to the thermal damage. Intracellular carbon deposits overlapping with the nanoparticle-rich sites were identified. These results highlight that NPAs are a versatile platform with possible applications in nanoparticle-based photothermal therapy.

中文翻译：

---

通过羟胺还原获得的金纳米粒子组件的光热性能评估

理想的光热治疗剂应表现出高能量转换能力，但除非暴露于电磁辐射下，否则不应诱发任何细胞毒性作用。我们提供了在室温下通过盐酸羟胺还原获得的胶体金纳米颗粒组件 (NPA) 的生物相容性和光热转换能力的数据。使用 3-[4,5-二甲基噻唑-2-基]-2,5-二苯基溴化四唑 (MTT) 测定法评估了平均直径分别为 20 和 120 nm 的 NPA 的细胞毒性特征，证明对金浓度高达 150 μg/mL 的 A549 人肺腺癌细胞系。使用过氧化物敏感荧光探针获得了有关氧化应激的见解，该探针未显示由于 NPA 暴露而产生的额外氧化应激。使用红外热成像，证明了光热转换，用 785 nm 激光照射的 120 nm 直径 NPA 的效果更为突出。拉曼成像研究也强调了 NPA 的光热能力，显示由于热损伤导致细胞内碳副产物。鉴定出与富含纳米颗粒的位点重叠的细胞内碳沉积物。这些结果突出表明 NPA 是一种多功能平台，可能在基于纳米颗粒的光热疗法中得到应用。鉴定出与富含纳米颗粒的位点重叠的细胞内碳沉积物。这些结果突出表明 NPA 是一种多功能平台，可能在基于纳米颗粒的光热疗法中得到应用。鉴定出与富含纳米颗粒的位点重叠的细胞内碳沉积物。这些结果突出表明 NPA 是一种多功能平台，可能在基于纳米颗粒的光热疗法中得到应用。