Abstract：
In the present study, we have engineered a molecular logic gate system employing both Fe2+ ions and cholesterol as bioanalytes for innovative detection strategies. We utilized a green-synthesis method employing the mango leaves extract to create fluorescent graphene quantum dots termed \"mGQDs\". Through techniques like HR-TEM, i.e., high-resolution transmission electron microscopy, Raman spectroscopy, and XPS, i.e., X-ray photoelectron spectroscopy, the successful formation of mGQDs was confirmed. The photoluminescence (PL) characteristics of mGQDs were investigated for potential applications in metal ion detection, specifically Fe2+ traces in water, by using fluorescence techniques. Under 425 nm excitation, mGQDs exhibited emission bands at 495 and 677 nm in their PL spectrum. Fe2+-induced notable quenching of mGQDs\' PL intensity decreased by 97% with 2.5 μM Fe2+ ions; however, adding 20 mM cholesterol resulted in a 92% recovery. Detection limits were established through a linear Stern-Volmer (S-V) plot at room temperature, yielding values of 4.07 μM for Fe2+ ions and 1.8 mM for cholesterol. Moreover, mGQDs demonstrated biocompatibility, aqueous solubility, and nontoxicity, facilitating the creation of a rapid nonenzymatic cholesterol detection method. Selectivity and detection studies underscored mGQDs\' reliability in cholesterol level monitoring. Additionally, a molecular logic gate system employing Fe2+ metal ions and cholesterol as a bioanalyte was established for detection purposes. Overall, this research introduces an ecofriendly approach to craft mGQDs and highlights their effectiveness in detecting metal ions and cholesterol, suggesting their potential as versatile nanomaterials for diverse analytical and biomedical applications.
摘要：
在本研究中,我们设计了一种分子逻辑门系统，采用Fe2离子和胆固醇作为生物分析物，用于创新的检测策略。我们利用绿色合成方法，使用芒果叶提取物来创建称为“mGQDs”的荧光石墨烯量子点。通过像HR-TEM这样的技术,即，高分辨率透射电子显微镜，拉曼光谱,XPS,即，X射线光电子能谱,mGQDs的成功形成得到证实。研究了mGQDs的光致发光（PL）特性在金属离子检测中的潜在应用，特别是水中的Fe2+痕迹，通过使用荧光技术。在425nm激发下，mGQD在其PL光谱中在495和677nm处表现出发射带。用2.5μMFe2离子，Fe2引起的mGQDsPL强度的显着猝灭降低了97％；但是，添加20mM胆固醇导致92%的回收率。在室温下通过线性Stern-Volmer（S-V）图确定检测限，Fe2+离子的值为4.07μM，胆固醇的值为1.8mM。此外，mGQD证明了生物相容性，水溶性，和无毒性，促进快速非酶胆固醇检测方法的创建。选择性和检测研究强调了mGQDs在胆固醇水平监测中的可靠性。此外,为了检测目的,建立了采用Fe2+金属离子和胆固醇作为生物分析物的分子逻辑门系统。总的来说,这项研究介绍了一种生态友好的方法来制作MGQDs，并强调了它们在检测金属离子和胆固醇方面的有效性，表明它们作为多种分析和生物医学应用的多功能纳米材料的潜力。
