纳米团簇
G-四倍体
适体
荧光
半抗原
DNA
生物分析
生物物理学
组合化学
血红素
检出限
滚动圆复制
材料科学
化学
分子生物学
纳米技术
抗体
生物
生物化学
色谱法
物理
DNA复制
遗传学
量子力学
血红素
酶
作者
Siyu Zuo,Chunli Yang,Jiayang He,Yumeng Liao,Xin Shang,Jiaxi Gao,Ruo Yuan,Wenju Xu
标识
DOI:10.1016/j.snb.2022.131976
摘要
Immunosensors with many merits such as simplicity, high sensitivity and selectivity are intriguing for the detection of antibodies, especially bivalent antibody (e.g. anti-digoxin antibody, DigA). In this work, we report a sensitive immunosensor for DigA based on the switchable fluorescence of DNA-templated silver nanoclusters (AgNCs) modulated by hemin/G-quadruplex (hGq). To explore the fluorescing performance of one hGq-quenching dual-AgNCs (d-AgNCs), here we design a functional hosting DNA strand (HGH) encoding with one centered G-rich segment for forming hGq complex in the presence of hemin and K+, two terminated C-rich template sequences for the identical clustering of d-AgNCs, and two flanked symmetric domains for specific recognizing and linking. Because of the photoexcited electron transfer process to the stacked hGq, the originally presynthesized d-AgNCs colocalized in two ends are non-emissive, which are retainable after complementarily hybridizing with two recognizable single strands that are both tagged with a digoxigenin hapten, a Fab fragment. Upon introducing DigA, the steric strain associated with the affinity binding of two haptens results in the opening and stretch of hGq in a coil spacer, thereby lighting-up the d-AgNCs fluorescence. Based on one-step signal switch stimulated by targeting antibody, this label-free immunosensor strategy is of high specificity and sensitivity with low picomolar detection limit, as well as simplification, rapidness and cost-effectiveness.
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