Department of Chemistry, National Taiwan University, Taipei, Taiwan.
Anal Chem. 2013 Mar 19;85(6):3263-70. doi: 10.1021/ac303613d. Epub 2013 Feb 26.
We have developed a sensitive and selective photoluminescence (PL) quenching assay for the detection of acetylcholine (ACh) that uses reduced graphene oxide decorated with carbon dots (C-dots@RGO). The highly stable C-dots@RGO synthesized from catechin and graphene oxide through a hydrothermal reaction displays excitation-wavelength dependence of PL. Acetylcholinesterase (AChE) converts ACh to choline, which in turn is oxidized by choline oxidase (ChOx) to produce betaine and H2O2 that generates the reactive oxygen species (ROS). The as-produced ROS induces PL quenching of the C-dots@RGO through an etching process. With respect to sensitivity, the optimal reaction/sensing temperature and pH are 37 °C and 9.0, respectively, using C-dots@RGO (0.4 mg·mL(-1)) and AChE and ChOx at the activities of 0.5 and 0.1 unit·mL(-1), respectively. The PL intensity (excitation/emission wavelengths 365/440 nm) of the C-dots@RGO is inversely proportional to the concentration of ACh over a range of 0.05-10 nM (r = 0.997), with a limit of detection (signal-to-noise ratio 3) of 30 pM. We have validated this assay by determination of concentrations of ACh in plasma and blood samples, with results of 2.6 ± 0.8 nM (n = 5) and 6.8 ± 0.4 nM (n = 5), respectively. Our study opens an avenue for the detection of various analytes by use of C-dots@RGO in conjunction with different enzymes, substrates, and/or inhibitors.
我们开发了一种灵敏且选择性的光致发光（PL）猝灭分析方法，用于检测乙酰胆碱（ACh），该方法使用还原氧化石墨烯修饰的碳点（C-dots@RGO）。通过水热反应从儿茶素和氧化石墨烯合成的高度稳定的 C-dots@RGO 显示出 PL 的激发波长依赖性。乙酰胆碱酯酶（AChE）将 ACh 转化为胆碱，胆碱随后被胆碱氧化酶（ChOx）氧化生成甜菜碱和 H2O2，产生活性氧（ROS）。产生的 ROS 通过蚀刻过程诱导 C-dots@RGO 的 PL 猝灭。就灵敏度而言，使用 C-dots@RGO（0.4 mg·mL(-1)) 和 AChE 和 ChOx 的活性分别为 0.5 和 0.1 单位·mL(-1)时，最佳反应/传感温度和 pH 值分别为 37°C 和 9.0。C-dots@RGO 的 PL 强度（激发/发射波长 365/440nm）与 ACh 的浓度呈反比，范围为 0.05-10 nM（r = 0.997），检测限（信噪比 3）为 30 pM。我们通过测定血浆和血液样本中的 ACh 浓度验证了该分析方法，结果分别为 2.6 ± 0.8 nM（n = 5）和 6.8 ± 0.4 nM（n = 5）。我们的研究为使用 C-dots@RGO 结合不同的酶、底物和/或抑制剂检测各种分析物开辟了一条途径。
