Regulating the fluorescence of carbon dots (CDs) is important but highly challenging. Here, carbon dots with tunable dual emissions were facilely fabricated via modulating the polymerization and carbonization processes of o-phenylenediamine (OPD) with lysine (Lys) as the co-precursor and modulator, respectively. The self-polymerization/carbonization of the OPD molecules contributed to the blue/green emission of the OPD-derived CDs. The introduction of Lys in the CD fabrication process efficiently suppressed the carbonization of the OPD polymer chains and enhanced the self-polymerization of the OPD molecules. Meanwhile, the formed OPD-Lys co-polymer chains endowed the final CD product with a new green emission center. The dual-emissive CDs were distinctly sensitive to polarity fluctuations, providing a ratiometric fluorescence response towards solution polarity. Due to their specific distribution in the endoplasmic reticulum (ER), the as-prepared dual-emissive CDs successfully distinguished the polarity variations in ER under stress, which offers a new approach for the early diagnosis of cell injury.

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具有可调双重发射的碳点：从机理到内质网极性的特殊成像

调节碳点（CD）的荧光很重要，但极具挑战性。在这里，通过调节o的聚合和碳化过程，可以轻松地制造出具有可调双重排放的碳点。-苯二胺（OPD）与赖氨酸（Lys）分别作为共前体和调节剂。OPD分子的自聚合/碳化导致OPD衍生的CD发出蓝/绿光。在CD制造过程中引入Lys可以有效抑制OPD聚合物链的碳化，并增强OPD分子的自聚合。同时，形成的OPD-Lys共聚物链为最终的CD产品赋予了新的绿色发射中心。双发射CD对极性波动非常敏感，提供了对溶液极性的比例荧光响应。由于它们在内质网（ER）中的特定分布，因此制备的双发射CD成功地区分了应力下ER中的极性变化，