【摘要】 DNA纳米技术在生物传感领域引起人们广泛的研究兴趣，现已构建多种二维和三维DNA功能纳米结构。滚环扩增（RCA）作为一种等温扩增技术，为DNA纳米材料的设计和自组装提供了新途径。该文通过RCA一锅法合成封装有辣根过氧化物酶（HRP）的DNA纳米花（HRP@DNFs），进一步基于双核酸适体识别构建光热生物传感器，用于肝细胞癌（HCCs）中循环肿瘤细胞（CTCs）的高灵敏、高特异性检测。当HRP包封到DNFs后，由于DNFs内部形成高度有序的氢键水环境，使得HRP的催化活性显著增强。为实现HCCs检测，在DNFs中设计了能够特异性识别HepG2 HCCs的核酸适体TLS11a作为信号放大标记物，同时制备了EpCAM核酸适体修饰的磁珠（EpCAM-MBs）作为载体捕捉HepG2细胞。当HepG2存在时，通过双核酸适体特异性识别形成MBs/HepG2/HRP@DNFs三明治结构。磁分离后，向体系中加入3,3’,5,5’-四甲基联苯胺（TMB）和H2O2,HRP@DNFs催化TMB发生氧化。在808 nm激光照射下，氧化态TMB产生强的光热转换效应，从而实现对HepG2细胞的高灵敏、高特异性光热检测。该方法所建立的一锅法自组装DNA纳米花封装酶分子策略在癌症等重大疾病早期诊断中具有极大的应用潜力。更多还原

【Abstract】 DNA nanotechnology has attracted a broad research interest in biosening field,in which various functional two-or three-dimensional DNA nanostructures have been constructed.Rolling circle amplification（RCA）as an isothermal amplification technique has provided a new way for the design and self-assembly of DNA nanomaterials.Herein, the horseradish peroxidase（HRP）-embedded DNA nanoflowers（HRP@DNFs）are one-pot synthesized by RCA,which are further applied to the fabrication of photothermal biosensor for highly sensitive and selective detection of circulating tumor cells（CTCs）in hepatocellular carcinomas（HCCs）based on dual-aptamer recognition. After encapsulation of HRP into DNFs,the catalytic activity of HRP is significantly enhanced due to the formation of highly ordered and hydrogen-bonded water environment.For HCCs detection,the aptamer TLS11a that can specifically recognize the HepG2 HCCs is designed in DNFs as the signal amplification labels,while the EpCAM aptamer-modified magnetic beads（EpCAM-MBs）are prepared as the carrieres to capture HepG2 cells.In the presence of HepG2,the sandwich structure of MBs/HepG2/HRP@DNFs is formed via specific dual-aptamer recognition. After magnetic separation and addition of 3,3’,5,5’-tetramethylbenzidine（TMB）and H₂O₂ into the system,the HRP@DNFs can catalyze the oxidation of TMB.Upon irradiated by 808 nm infrared laser,a strong photothermal conversion effect is produced by oxidized TMB,resulting in the photothermal detection of HepG2 cells with high sensitivity and specificity.Overall,the proposed strategy for one-pot self-assembly of enzyme-embedded DNA nanoflowers possesses a great potential in early diagnosis of diseases,especially cancers.更多还原