生物传感器
纳米团簇
DNA
荧光
检出限
适体
化学
组合化学
生物物理学
生物化学
分子生物学
生物
色谱法
量子力学
物理
有机化学
作者
Si Yang,Chenxi Li,Yuewen Yu,Hongyan Zhan,Jia Zhai,Rong Liu,Wenliang Chen,Yingxue Zou,Kexin Xu
标识
DOI:10.1016/j.snb.2023.135216
摘要
Sensitive and accurate in antibiotic detection is crucial for food security, environmental conservation, public health, and environmental protection. In this study, we developed an enzyme-free and label-free ratiometric fluorescence biosensor for highly sensitive detection of tetracycline (TET). This biosensor utilized a combination of target-triggered catalytic hairpin assembly (CHA) and DNA-silver nanocluster (DNA-AgNCs) dual-color fluorescent signal probes. Upon TET binding to the aptamer, it initiated the leakage of CHA initiator, resulting in the formation of numerous double-stranded DNA complexes. This process exposed the foothold sequence of hairpin-structured DNA-AgNCs (H3-AgNCs) that exhibit yellow fluorescence. Subsequently, the conformational changes in H3-AgNCs significantly reduced the yellow fluorescence intensity (FI) and reveal the auxiliary DNA-AgNCs (a-DNA-AgNCs) linkage sequence. The binding of a-DNA-AgNCs brought two dark AgNCs close, forming nanocluster dimers emitting red fluorescence. The results demonstrate that the variation in ratiometric signal is linear with TET concentration between 0.1 and 50 ng/mL, with a detection limit as low as 0.086 ng/mL. Additionally, this approach exhibited good recovery results with spiked milk samples. This enzyme-free and label-free combined signal amplification method with proportional signal output based on DNA-AgNCs provides valuable empirical reference for creating low-cost, stable, and highly-sensitive biosensors.
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