The ever-growing demand for fluorogenic dyes usable in the rapid construction of analyte-responsive fluorescent probes, has recently contributed to a revival of interest in the chemistry of diketopyrrolopyrrole (DPP) pigments. In this context, we have explored the potential of symmetrical and unsymmetrical DPP derivatives bearing two or one 4-pyridyl substituents acting as optically tunable group(s). The unique fluorogenic behavior of these molecules, closely linked to N-substitution/charge state of their pyridine unit (i.e., neutral pyridine or cationic pyridinium), has been used to design DPP-based fluorescent probes for detection of hypoxia-related redox enzymes and penicillin G acylase (PGA). In this paper, we describe synthesis, spectral characterization and bioanalytical validations of these probes. Dramatic differences in terms of aqueous stability and enzymatic fluorescence activation were observed. This systematic study enables to delineate the scope of application of pyridine-flanked DPP fluorophores in the field of enzyme biosensing.

在快速构建分析物响应型荧光探针中使用的荧光染料的需求不断增长，最近促使人们重新唤起对二酮吡咯并吡咯（DPP）颜料化学的关注。在这种情况下，我们已经探索了带有两个或一个4-吡啶基取代基作为光学可调基团的对称和不对称DPP衍生物的潜力。这些分子的独特荧光行为，与其吡啶单元的N-取代/电荷状态紧密相关（即（中性吡啶或阳离子吡啶鎓）已被用于设计基于DPP的荧光探针，用于检测缺氧相关的氧化还原酶和青霉素G酰基转移酶（PGA）。在本文中，我们描述了这些探针的合成，光谱表征和生物分析验证。观察到水稳定性和酶促荧光活化方面的显着差异。这项系统的研究使人们能够确定在酶生物传感领域中吡啶侧翼的DPP荧光团的应用范围。