As new 2D layered nanomaterials, Bi2 O2 Se nanoplates have unique semiconducting properties that can benefit biomedical applications. Herein, a facile top-down approach for the synthesis of Bi2 O2 Se quantum dots (QDs) in a solution is described. The Bi2 O2 Se QDs with a size of 3.8 nm and thickness of 1.9 nm exhibit a high photothermal conversion coefficient of 35.7% and good photothermal stability. In vitro and in vivo assessments demonstrate that the Bi2 O2 Se QDs possess excellent photoacoustic (PA) performance and photothermal therapy (PTT) efficiency. After systemic administration, the Bi2 O2 Se QDs accumulate passively in tumors enabling efficient PA imaging of the entire tumors to facilitate imaging-guided PTT without obvious toxicity. Furthermore, the Bi2 O2 Se QDs which exhibit degradability in aqueous media not only have sufficient stability during in vivo circulation to perform the designed therapeutic functions, but also can be discharged harmlessly from the body afterward. The results reveal the great potential of Bi2 O2 Se QDs as a biodegradable multifunctional agent in medical applications.

中文翻译：

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可生物降解的Bi2 O2 Se量子点，用于光声成像引导的癌症光热疗法。

作为新型2D层状纳米材料，Bi2 O2 Se纳米板具有独特的半导体特性，可以使生物医学应用受益。在此，描述了一种在溶液中合成Bi2 O2 Se量子点（QD）的简便的自上而下的方法。Bi2 O2 Se量子点尺寸为3.8 nm，厚度为1.9 nm，具有35.7％的高光热转换系数和良好的光热稳定性。体外和体内评估表明，Bi2 O2 Se量子点具有出色的光声（PA）性能和光热疗法（PTT）效率。全身给药后，Bi2 O2 Se量子点在肿瘤中被动蓄积，从而可以对整个肿瘤进行有效的PA显像，从而有利于影像引导的PTT，而没有明显的毒性。此外，在水性介质中表现出可降解性的Bi2 O2 Se QDs不仅在体内循环过程中具有足够的稳定性以执行设计的治疗功能，而且随后可以无害地从体内排出。结果表明，Bi2 O2 Se量子点在医学应用中具有可生物降解的多功能剂的巨大潜力。