Ruiyi Li, Huahua Zhang, Zaijun Li
School of Pharmaceutical Science, Jiangnan University, Wuxi 214122, China.
School of Pharmaceutical Science, Jiangnan University, Wuxi 214122, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2022 Jul 5;275:121028. doi: 10.1016/j.saa.2022.121028. Epub 2022 Feb 14.
Graphene quantum dots have been widely applied in biosensing, fluorescence imaging, biomedicine, energy storage and conversion and catalysis, but design and synthesis of polychromatic graphene quantum dot with high luminous efficiency still faces great challenges. The study reports synthesis of histidine, serine and pentaethylenehexamine-functionalized and boron-doped graphene quantum dot (HSPB-GQD) via one-step pyrolysis. The resulting HSPB-GQD consists of graphene sheets of 2-5 nm with carboxyl, hydroxyl, amino, imino and imidazole. Synergy of histidine, serine, pentaethylenehexamine and boron atoms improves the luminescence behavior. This realizes unique switchable two-color luminescence. UV excitation of 370 nm produces one strong blue fluorescence with the maximum emission wavelength of 455 nm and quantum yield of 72.34%. Vis. excitation of 480 nm produces one strong yellow fluorescence with the maximum emission wavelength of 560 nm and quantum yield of 72.59%. The multiple proton dissociation system constructed by nitrogen-containing and oxygen-containing groups makes yellow fluorescence sensitive to environmental pH value. The intensity linearly increases with increasing pH in the range of 4.5-10.0. Organic molecules and inorganic ions do not interfere pH detection. HSPB-GQD as a promising fluorescence probe with negligible effect on cell viability was successfully applied to pH detection in biological and environmental water samples and cell imaging.
石墨烯量子点已广泛应用于生物传感、荧光成像、生物医学、能量存储与转换以及催化等领域，但具有高发光效率的多色石墨烯量子点的设计与合成仍面临巨大挑战。该研究报道了通过一步热解合成组氨酸、丝氨酸和五乙烯六胺功能化且硼掺杂的石墨烯量子点（HSPB-GQD）。所得的HSPB-GQD由2-5纳米的石墨烯片组成，含有羧基、羟基、氨基、亚氨基和咪唑。组氨酸、丝氨酸、五乙烯六胺和硼原子的协同作用改善了发光行为。这实现了独特的可切换双色发光。370纳米的紫外激发产生一种强蓝色荧光，最大发射波长为455纳米，量子产率为72.34%。480纳米的可见光激发产生一种强黄色荧光，最大发射波长为560纳米，量子产率为72.59%。由含氮和含氧基团构建的多质子解离体系使黄色荧光对环境pH值敏感。在4.5-10.0范围内，强度随pH值升高呈线性增加。有机分子和无机离子不干扰pH检测。HSPB-GQD作为一种对细胞活力影响可忽略不计的有前景的荧光探针，已成功应用于生物和环境水样中的pH检测以及细胞成像。
