As one of the newly emerged nanomaterials, graphene quantum dots (GQDs) have shown great application potential as tracking probes and drug carriers in biological areas. The GQDs synthesized via the nitric acid reflux method in this study turned out to quench the fluorescence of human serum albumin (HSA) and gamma globulin (γ-globulin) in two different functional ways. The fluorescence quenching effect of GQDs on HSA is a static pattern and the predominant interaction forces are hydrogen bonds and van der Waals forces. Distinct from HSA, the interaction between GQDs and γ-globulins belongs to dynamic quenching and is driven by electrostatic forces. Ultraviolet–visible (UV–vis) differential spectrometry and transient state fluorescence spectrometry were also utilized to further confirm their quenching types. Also, thermodynamics parameters, the enthalpy change (Δ H ) and entropy change (Δ S ) of reaction between GQDs and proteins were obtained through a series of calculations from the van’t Hoff equation. Furthermore, the effect of GQDs on the conformational structure of proteins was characterized by synchronous fluorescence spectra (SFS), three-dimensional (3D) fluorescence and circular dichroism (CD) spectra. In addition, the binding mechanism of GQDs with HSA and γ-globulins were proposed based on the obtained experimental results. The research on the reaction between GQDs with HSA and γ-globulins offers promising insight for the further application of nanomaterials in biomedical fields.

中文翻译：

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石墨烯量子点与人血清白蛋白和γ-球蛋白相互作用的热力学

作为新兴的纳米材料之一，石墨烯量子点（GQDs）在生物领域作为追踪探针和药物载体显示出巨大的应用潜力。本研究中通过硝酸回流法合成的 GQDs 以两种不同的功能方式淬灭人血清白蛋白 (HSA) 和伽马球蛋白 (γ-球蛋白) 的荧光。GQDs 对 HSA 的荧光猝灭效应是一种静态模式，主要的相互作用力是氢键和范德华力。与 HSA 不同，GQDs 和 γ-球蛋白之间的相互作用属于动态猝灭，由静电力驱动。紫外-可见（UV-vis）差示光谱法和瞬态荧光光谱法也被用来进一步确认它们的淬灭类型。此外，热力学参数，GQDs与蛋白质反应的焓变(Δ H )和熵变(Δ S )是通过范特霍夫方程的一系列计算得到的。此外，GQDs 对蛋白质构象结构的影响通过同步荧光光谱 (SFS)、三维 (3D) 荧光和圆二色性 (CD) 光谱表征。此外，基于获得的实验结果提出了GQDs与HSA和γ-球蛋白的结合机制。GQDs与HSA和γ-球蛋白之间反应的研究为纳米材料在生物医学领域的进一步应用提供了有希望的见解。GQDs 对蛋白质构象结构的影响通过同步荧光光谱 (SFS)、三维 (3D) 荧光和圆二色性 (CD) 光谱表征。此外，基于获得的实验结果提出了GQDs与HSA和γ-球蛋白的结合机制。GQDs与HSA和γ-球蛋白之间反应的研究为纳米材料在生物医学领域的进一步应用提供了有希望的见解。GQDs 对蛋白质构象结构的影响通过同步荧光光谱 (SFS)、三维 (3D) 荧光和圆二色性 (CD) 光谱表征。此外，基于获得的实验结果提出了GQDs与HSA和γ-球蛋白的结合机制。GQDs与HSA和γ-球蛋白之间反应的研究为纳米材料在生物医学领域的进一步应用提供了有希望的见解。