肿瘤来源的外泌体可作为早期诊断癌症的有前途的生物标志物。本文基于通过滚环扩增（RCA）将载有3,3',5,5'-四甲基联苯二胺（TMB）的石墨烯量子点纳米酶（TMB-GQDzymes）被封装入DNA花朵（DFs），开发了一种色度学/光热双模式外泌体感测平台，用于检测人类乳腺癌细胞（MCF-7）的外泌体。为了实现特异性的检测，EpCAM适配体被固定在孔板上，而另一种CD63适配体的互补序列被设计到循环模板中以获得丰富的捕获探针。受益于双适配体识别策略，形成了EpCAM适配体/外泌体/TMB-GQDzymes@ DFs的三明治结构，其中GQDzymes可以在存在H2O2的情况下催化TMB的氧化。 TMB氧化的产物（oxTMB）不仅可以引起吸收变化，还可以产生近红外激光驱动的光热效应，实现外泌体的双模式检测，检测限为每微升1027个颗粒（色度法）和2170个颗粒（光热检测）。此外，该感测平台在血清样本分析中已经表现出优秀的性能，可以很好地区分乳腺癌患者和健康人群。总的来说，所提出的双读出生物传感器为外泌体检测在生物学研究和临床应用中开辟了有前途的前景。版权所有©2023 Elsevier B.V. 发布。

Tumor-derived exosomes can be served as a kind of promising biomarkers for early diagnosis of cancers. Herein, a colorimetric/photothermal dual-mode exosomes sensing platform is developed for human breast cancer cell (MCF-7)-derived exosomes based on encapsulation of 3,3',5,5'-tetramethylbenzidine-loaded graphene quantum dot nanozymes (TMB-GQDzymes) into DNA flowers (DFs) via rolling circle amplification (RCA). To achieve specific detection, EpCAM aptamer for MCF-7 cell-derived exosomes is immobilized on the well plate, while the complementary sequence of another CD63 aptamer is designed into the circular template to obtain abundant capture probes. Benefitting from the dual-aptamer recognition strategy, a sandwich structure of EpCAM aptamer/exosomes/TMB-GQDzymes@DFs is formed, in which the GQDzymes can catalyze the oxidation of TMB in the presence of H2O2. The resulting products of TMB oxidation (oxTMB) can induce not only the absorption changes but also a near-infrared (NIR) laser-driven photothermal effect, achieving dual-mode detection of exosomes with the limit of detection (LOD) of 1027 particles/μL (colorimetry) and 2170 particles/μL (photothermal detection), respectively. In addition, this sensing platform has demonstrated excellent performance to well distinguish breast cancer patients from healthy individuals in serum samples analysis. Overall, the proposed dual-readout biosensor opens promising prospects for exosome detection in biological study and clinical applications.Copyright © 2023. Published by Elsevier B.V.