Ultrasensitive Nanofluidic Detection of 17β-Estradiol in Natural Water by DNA Circuit-Mediated Hyperbranched DNA Nanowire Dual-Signal Amplification
Na Li, Zhoujian Pan, Zihan Hao, Qun Ma, Yan Yan, Xin Sui, Yingqi Li, Yijing Liao, Xi Mai, Zhong Feng Gao, Fan Xia
Abstract
The pervasive detection of trace 17β-estradiol (E2) in aquatic ecosystems necessitates innovative analytical platforms capable of ultrahigh sensitivity and field applicability. Herein, we report a nanofluidic biosensor integrating polydopamine-functionalized graphene oxide (PDA/GO) membranes with an entropy-driven DNA circuit and hyperbranched DNA nanowires (HDW) for femtomolar-level E2 quantification. Leveraging E2-specific aptamer recognition, the system triggers an entropy-driven DNA circuit and subsequent hierarchical assembly of guanine quadruplex (G4)-enriched HDW nanostructures on nanochannel surfaces, amplifying interfacial electronegativity through phosphate backbone accumulation. This charge amplification synergizes with subnanometer-confined ion transport modulation, achieving an 8.19-fold current enhancement upon E2 binding. The optimized biosensor exhibited a linear dynamic range spanning five orders (1 fM to 100 pM) with a detection limit of 0.39 fM, comparable to conventional LC-MS/MS for the analysis of E2. Rigorous specificity testing demonstrated high anti-interference against structural analogs and endocrine disruptors. Practical validation in real water samples (Yellow River, Heihu Spring, Qian Lake, and an aquaculture pond) demonstrated recovery rates of 91.2-109%, supported by robust stability and environmental resilience. This work establishes nucleic acid nanotechnology-enhanced nanofluidics, addressing critical gaps in on-site endocrine disruptor monitoring through synergistic molecular recognition and interfacial charge engineering.