A new strategy for the fluorescent and colorimetric sensing of hydrogen peroxide (H2O2) and glucose based on the metal oxide - carbon-dot hybrid structure was investigated. The sensing system is related to the catalytic oxidation reaction of glucose-by-glucose oxidase (GOx) to H2O2. In this study, a metal oxide hybrid with nitrogen-doped carbon dots (MFNCDs) that showed intrinsic peroxidase-like activity was synthesized and used as a catalyst instead of GOx to oxidize 3,3',5,5'-tetramethylbenzidine (TMB) to blue-emitting oxidized TMB (oxTMB) in the presence of hydrogen peroxide (H2O2). The fluorescence of MFNCDs/TMB at 405 nm was quenched in the presence of H2O2 through the inner filter effect (IFE) and electron transfer within MFNCDs, oxTMB, and glucose system. Therefore, the fluorescence and absorbance intensity can be applied to the quantitative determination of the concentration of H2O2 and glucose with a wide linear range. The detection limit for H2O2 and glucose based on the colorimetric method were as low as 84 nM and 0.41 μM, respectively. In contrast, the detection limit for H2O2 and glucose based on the fluorescent method were as low as 97 nM and 0.85 μM, respectively. Furthermore, the colorimetric readout on the paper device based on the changing color of the solution could also be integrated with a smartphone platform to conduct the on-site analysis of glucose without the use of the spectrometer. In addition, this dual sensor can be applied to detect glucose in real serum with highly accurate results, making it a good candidate for biosensor applications.

中文翻译：

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使用 N 掺杂碳点和金属氧化物混合结构的简单纸基比色和荧光葡萄糖传感器

研究了一种基于金属氧化物-碳点混合结构的过氧化氢 (H2O2) 和葡萄糖的荧光和比色传感新策略。传感系统与葡萄糖-葡萄糖氧化酶 (GOx) 到 H2O2 的催化氧化反应有关。在这项研究中，合成了一种具有类似过氧化物酶活性的氮掺杂碳点 (MFNCD) 的金属氧化物杂化物，并将其用作催化剂代替 GOx 氧化 3,3',5,5'-四甲基联苯胺 (TMB)在过氧化氢 (H2O2) 存在下发射蓝光的氧化 TMB (oxTMB)。MFNCDs/TMB 在 405 nm 处的荧光在 H2O2 存在下通过内过滤效应 (IFE) 和 MFNCDs、oxTMB 和葡萄糖系统内的电子转移被淬灭。所以，荧光和吸光度强度可用于定量测定H2O2和葡萄糖的浓度，线性范围宽。基于比色法的 H2O2 和葡萄糖的检测限分别低至 84 nM 和 0.41 μM。相比之下，基于荧光法的 H2O2 和葡萄糖的检测限分别低至 97 nM 和 0.85 μM。此外，基于溶液颜色变化的纸质设备上的比色读数也可以与智能手机平台集成，在不使用光谱仪的情况下进行葡萄糖的现场分析。此外，这种双传感器可用于检测真实血清中的葡萄糖，结果高度准确，使其成为生物传感器应用的理想选择。