Jiangsu Engineering Laboratory of Smart Carbon-Rich Materials and Device, School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, China.
Key Laboratory of Environmental Medicine Engineering of Ministry of Education, School of Public Health, Southeast University, Nanjing, 210009, PR China.
Biosens Bioelectron. 2022 Oct 15;214:114529. doi: 10.1016/j.bios.2022.114529. Epub 2022 Jul 2.
Flap endonuclease 1 (FEN1) is a structure-specific nuclease, which catalyzes the removal of 5' overhanging DNA flap from a specific DNA structure. FEN1 has been considered as an important biomarker for cancer diagnosis since it is over-expressed in various types of human tumor cells and closely related to cancer development. Nanoprobes gradually become basic tools for analyzing biomarkers variations in vivo. Here, we utilized aminoated mesoporous silica nanoparticles (NH-MSNs) with a rich porous structure as the fluorescence nanoprobes to entrap the rhodamine 6G (Rh6G) molecules. Then gold nanoparticles linked specific single-stranded DNA (AuNPs-ssDNA) as a molecular gate was used to coat the NH-MSNs surface. The fluorescence signal was weak when the fluorescence molecules were blocked by the AuNPs-ssDNA. In the presence of FEN1, it recognized and cleaved the specific ssDNA to release the Rh6G from NH-MSNs, which resulted in recovered fluorescence signals. Thus, the sensitive detection of FEN1 activity was realized by controlled-release of Rh6G. The fluorescence signal showed a good linear relationship with the logarithm of FEN1 activity ranging from 0.05 to 1.75 U with a detection limit of 0.03 U. Moreover, confocal imaging demonstrated that the proposed biosensor could distinguish tumor cells from normal cells. Therefore, this technique contributes to clinical diagnostic and therapeutic monitoring.
核酸内切酶 1（FEN1）是一种结构特异性核酸内切酶，能够催化从特定 DNA 结构上切除 5'突出的 DNA 发夹。由于在各种类型的人类肿瘤细胞中过度表达，并且与癌症的发展密切相关，因此 FEN1 被认为是癌症诊断的重要生物标志物。纳米探针逐渐成为分析体内生物标志物变化的基本工具。在这里，我们利用具有丰富多孔结构的氨基化介孔硅纳米粒子（NH-MSNs）作为荧光纳米探针来捕获罗丹明 6G（Rh6G）分子。然后，将与特定单链 DNA（AuNPs-ssDNA）连接的金纳米粒子用作分子门，以覆盖 NH-MSNs 表面。当荧光分子被 AuNPs-ssDNA 阻断时，荧光信号很弱。当 FEN1 识别并切割特定的 ssDNA 以将 Rh6G 从 NH-MSNs 中释放出来时，荧光信号恢复，从而实现了对 FEN1 活性的灵敏检测。荧光信号与 FEN1 活性的对数呈良好的线性关系，在 0.05 至 1.75 U 的范围内，检测限为 0.03 U。此外，共聚焦成像表明，所提出的生物传感器能够区分肿瘤细胞和正常细胞。因此，这项技术有助于临床诊断和治疗监测。
