Aqueous synthesis of glutathione (GSH) coated Ag₂S quantum dots (QD) with strong emission in the medical imaging window (700–900 nm) was performed from AgNO₃. Variations in temperature, time, pH and sulfur source (Na₂S and thioacetamide) were studied to tune the emission wavelength and intensity of the QDs. The optimum synthesis conditions to produce the smallest QDs (ca. 7 nm) with the highest quantum yield (70%) and excellent stability were determined as 50 °C and pH 10 where Na₂S was used in 2 h reactions. The cytotoxicity was evaluated with MTT assay on the HT29 and MCF7 cancer cell lines and indicated no significant toxicity of the QDs up to 200 μg mL⁻¹. The Photothermal Therapy (PTT) potential was first investigated using a 795 nm, continuous-wave fiber coupled diode laser using aqueous solutions of QDs and then on HT29 and MCF7 cells. QD (150 μg mL⁻¹) treated MCF7 cells almost quantitatively died after 10 min irradiation at 795 nm (700 mW, 1.82 W cm⁻²) and the viability of HT29 cells dropped to 40%. Most cell death was late apoptotic/necrotic. This study indicates that such a laser irradiation procedure and the QDs are safe, yet their combination provides dramatic cell death upon short laser treatment. PTT coupled with strong intracellular optical signal promotes Ag₂S-GSH QDs as potential theranostic nanoparticles.

中文翻译：

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用于近红外图像引导光热疗法的Ag2S-谷胱甘肽量子点

从AgNO ₃进行水合合成的谷胱甘肽（GSH）涂层的Ag ₂ S量子点（QD）在医学成像窗口（700-900 nm）中具有强发射。研究了温度，时间，pH和硫源（Na ₂ S和硫代乙酰胺）的变化，以调节量子点的发射波长和强度。在50°C和pH 10的条件下（其中Na ₂ S用于2 h反应），确定了以最小的量子点（约7 nm）具有最高的量子产率（70％）和优异的稳定性的最佳合成条件。通过MTT分析对HT29和MCF7癌细胞系进行了细胞毒性评估，结果表明，至200μgmL ^-1的QD均无明显毒性。首先使用795 nm连续波光纤耦合二极管激光器，使用QD水溶液研究HT29和MCF7细胞上的光热疗法（PTT）电势。经QD（150μgmL ^-1）处理的MCF7细胞在795 nm（700 mW，1.82 W cm ^-2）照射10分钟后几乎定量死亡，并且HT29细胞的活力降至40％。大多数细胞死亡是晚期凋亡/坏死。这项研究表明，这种激光辐照程序和量子点是安全的，但是它们的组合在短时间的激光治疗后会导致严重的细胞死亡。PTT结合强大的细胞内光信号促进Ag ₂ S-GSH QDs作为潜在的治疗纳米颗粒。