Red fluorescent carbon dots (R-CDs) are special desirable for biochemical analysis due to good biological compatibility and deep penetration; however, they remain as bottlenecks due to difficulties in expanding the sp² domain, especially those are fused from rigid polycyclic conjugated molecules (RPCMs) with heteroatom substituents due to huge steric hindrance and heteroatom blockage toward graphic lattice. Here, an RPCM with heteroatom substituents, 1,5-diamino-4,8-dihydroxyanthraquinone (DDAQ), based self-doped R-CDs with PL emission at 635 nm is reported. Further investigations reveal that the expanding, hybrid sp² domain with indanthrone tannin structure from DDAQ is mainly responsible for the obtained red fluorescence of R-CDs. Taking advantage of optical properties, R-CDs are considered to construct a colorimetric/fluorescent dual mode sensing array for quantifying trace levels of Fe³⁺ and glyphosate based on the static quenching, and a biomarker for cell imaging. The CD-based sensors exhibit outstanding recovery, high selectivity, and sensitivity, also facilitated dual-mode detection with the naked-eye. The R-CDs have low cytotoxicity, good cell membrane penetration for rapid cell entry, and high resolution, demonstrating their potential for biolabeling and bioanalytic applications.

中文翻译：

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从刚性多环共轭分子合成红色荧光碳点：生化应用中的双模式传感和生物成像

红色荧光碳点（R-CDs）由于具有良好的生物相容性和深入的渗透性，特别适用于生化分析；然而，由于难以扩展 sp ²域，它们仍然是瓶颈，尤其是那些由具有杂原子取代基的刚性多环共轭分子 (RPCM) 融合而成的，由于巨大的空间位阻和杂原子对图形晶格的阻塞。在这里，报道了具有杂原子取代基的 RPCM，1,5-二氨基-4,8-​​二羟基蒽醌 (DDAQ)，基于自掺杂 R-CD，在 635 nm 处发射 PL。进一步的研究表明，扩展的混合 sp ²来自 DDAQ 的阴丹酮单宁结构域主要负责获得 R-CD 的红色荧光。利用光学特性，R-CD 被认为可以构建比色/荧光双模式传感阵列，用于基于静态淬灭量化痕量 Fe ³⁺和草甘膦，以及细胞成像的生物标志物。基于 CD 的传感器表现出出色的恢复、高选择性和灵敏度，也促进了肉眼双模式检测。R-CDs 具有低细胞毒性、良好的细胞膜渗透性以实现快速细胞进入和高分辨率，证明了它们在生物标记和生物分析应用中的潜力。