Fluorescent probes with superior two-photon fluorescence are highly attractive in the field of bioimaging. Herein, we report a one-pot hydrothermal route to synthesis amine, sulfo cofunctionalized graphene quantum dots (GQDs), which acts as efficient one-photon and two-photon fluorescent probes for cellular imaging. As synthesized GQDs exhibit ultrastability due to the edge-site functionalization of amine and sulfo groups. In addition, GQDs display attractive two-photon fluorescence properties. The two-photon absorption cross section of GQDs reaches up to 31,000 GM, which substantially exceeds that of the majority of traditional fluorescent materials. Furthermore, the noncytotoxicity GQDs exhibit a negligible photothermal effect under 808 nm femtosecond laser irradiation, which is suitable for long-term two-photon imaging and observation. These findings open new possibilities for using two-photon fluorescent GQDs in various biological applications.

中文翻译：

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具有高双光子荧光的超稳定胺，磺基共官能化石墨烯量子点用于细胞成像

具有卓越的双光子荧光的荧光探针在生物成像领域具有很高的吸引力。在这里，我们报告一锅法热合成胺，磺基共官能化石墨烯量子点（GQDs）的热液路线，其作为有效的单光子和双光子荧光探针的细胞成像。作为合成的GQD由于胺和磺基的边缘位官能化而显示出超稳定性。另外，GQD显示出有吸引力的两光子荧光特性。GQD的双光子吸收截面高达31,000 GM，大大超过了大多数传统荧光材料的截面积。此外，非细胞毒性GQD在808 nm飞秒激光照射下表现出的光热效应可忽略不计，这适合于长期的双光子成像和观察。