In this work, a new selective and simple fluorescence probe based on polyethylenimine(PEI) functionalized carbon dots (PEI-CDs) for fast determination of 6-thioguanine (6-TG) was developed. We successfully prepared the highly fluorescent PEI-CDs by hydrothermal method, and completed the synthesis and modification processes in one step. The fluorescence quantum yield (QY) of the as-synthesized CDs was 38% and higher than that of most previous reports (5–30%). The fluorescence intensity of PEI-CDs decreased obviously with gradually increased concentration of 6-TG. The interference substances caused a negligible effect on the fluorescence intensity of the (PEI-CDs)-6-TG reaction system with the interference ratios all below 2.8%. Under optimum conditions, a great linear relationship between fluorescence intensity function log(F₀/F) and concentration of 6-TG in a wide range from 4 μM to 800 μM with a detection limit (S/N = 3) of 1.33 μM was obtained. And this proposed approach was successfully applied for the determination of 6-TG in human serum and urine samples. Furthermore, the PEI-CDs fluorescence probe has superior potential in practical application of detecting 6-TG due to its inexpensive precursors, simple operation, low toxicity and excellent biocompatibility.

在这项工作中，开发了一种基于聚乙烯亚胺（PEI）功能化碳点（PEI-CD）的新型选择性简单荧光探针，用于快速测定6-硫代鸟嘌呤（6-TG）。我们通过水热法成功制备了高荧光性的PEI-CD，并一步一步完成了合成和修饰过程。合成后的CD的荧光量子产率（QY）为38％，高于大多数以前的报告（5-30％）。随着6-TG浓度的逐渐升高，PEI-CD的荧光强度明显降低。干扰物质对（PEI-CDs）-6-TG反应系统的荧光强度的影响可忽略不计，所有干扰比率均低于2.8％。在最佳条件下，荧光强度函数log（F ₀ / F）和6-TG的浓度范围从4μM到800μM，检测极限（S / N = 3）为1.33μM。并将该方法成功应用于人血清和尿液中6-TG的测定。此外，PEI-CDs荧光探针因其廉价的前体，简单的操作，低毒性和出色的生物相容性而在检测6-TG的实际应用中具有巨大的潜力。