Abstract Semiconductor quantum dots (QDs) are one of the most interesting photoluminescent nanomaterials with very promising applications in cancer nanomedicine. In this work, ZnS fluorescent quantum dots (ZnS-QDs) were synthesized and stabilized by carboxymethylcellulose (CMC) as a pH-sensitive biopolymer using a facile one-step green aqueous colloidal process at distinct pH conditions (acidic, neutral and alkaline) and chemical proportions of precursors (Zn2+, S2−). The optical properties of these nanoconjugates (ZnS@CMC) were characterized by UV–visible and photoluminescence spectroscopy. The morphological features and physicochemical properties were evaluated by TEM, FTIR spectroscopy, zeta potential, and dynamic light scattering (DLS) analyses. The cytocompatibility in vitro of ZnS@CMC was assessed by MTT assay using normal and malignant glioma cells. The UV–Vis results indicated that ZnS-QDs were effectively produced with different bandgap energies (from 4.5 to 3.8 eV) blue-shifted from bulk (Ebulk = 3.61 eV), and sizes (typically from 3.3 to 4.5 nm), dependent on the pH and concentration ratio of precursors during the synthesis. Analogously, the changes of synthesis parameters significantly altered the photoluminescence emission energies and intensities within the visible range of spectra (PL maxima from λ = 400–430 nm, at pH = 3.5, [Zn:S] ratio = 1:2). The cell viability results in vitro (>90%) demonstrated no cytotoxicity of ZnS@CMC nanohybrids towards both cell types. Importantly, these ZnS@CMC nanoconjugates behaved as active fluorescent nanoprobes for bioimaging malignant glioma cells proving the high potential for applications in cancer nanomedicine.

中文翻译：

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用于脑癌细胞生物成像的 ZnS 量子点/生物聚合物光致发光纳米探针的绿色合成

摘要 半导体量子点 (QD) 是最有趣的光致发光纳米材料之一，在癌症纳米医学中具有非常有前景的应用。在这项工作中，在不同的 pH 条件（酸性、中性和碱性）下，使用简便的一步绿色水性胶体工艺，合成并稳定了 ZnS 荧光量子点（ZnS-QD）作为 pH 敏感生物聚合物的羧甲基纤维素（CMC）和前体（Zn2+、S2-）的化学比例。这些纳米共轭物（ZnS@CMC）的光学性质通过紫外-可见光和光致发光光谱表征。通过 TEM、FTIR 光谱、zeta 电位和动态光散射 (DLS) 分析评估形态特征和理化性质。使用正常和恶性胶质瘤细胞通过 MTT 法评估 ZnS@CMC 的体外细胞相容性。UV-Vis 结果表明，ZnS-QD 可以有效地产生，具有不同的带隙能量（从 4.5 到 3.8 eV）蓝移从体（Ebulk = 3.61 eV）和尺寸（通常从 3.3 到 4.5 nm），这取决于合成过程中前体的 pH 值和浓度比。类似地，合成参数的变化显着改变了可见光谱范围内的光致发光发射能量和强度（PL 最大值从 λ = 400-430 nm，在 pH = 3.5，[Zn:S] 比率 = 1:2）。体外细胞活力结果 (>90%) 表明 ZnS@CMC 纳米杂化物对两种细胞类型都没有细胞毒性。重要的，