It is very difficult to prepare red/near-infrared emission carbon dots (CDs) for bio-imaging applications which are needed because of their deep tissue penetration, minimal auto-fluorescence, and low emission light damage to bio-tissues. Near-infrared emitting CDs (NIR-CDs) were synthesized from sulfonated tetraphenylporphyrin using a solvothermal method. They have excitation-independent properties with a maximum emission at 692 nm. Studies showed that this unique near-infrared emission mainly originated from the aggregated molecular states of the CDs. The NIR-CDs showed good water solubility, exceptional biocompatibility, low toxicity, and superior cellular labelling ability. This work could significantly advance the structural design and preparation of NIR-CDs and corresponding bio-imaging applications.

制备用于生物成像应用的红色/近红外发射碳点 (CD) 非常困难，因为它们具有深层组织穿透性、最小的自发荧光和对生物组织的低发射光损伤。使用溶剂热法从磺化四苯基卟啉合成近红外发射 CDs (NIR-CDs)。它们具有与激发无关的特性，最大发射波长为 692 nm。研究表明，这种独特的近红外发射主要源于 CD 的聚合分子状态。NIR-CDs 表现出良好的水溶性、卓越的生物相容性、低毒性和卓越的细胞标记能力。这项工作可以显着推进 NIR-CD 的结构设计和制备以及相应的生物成像应用。