Quantum tunnelling-integrated optoplasmonic nanotrap enables conductance visualisation of individual proteins

Biao-Feng Zeng; Zian Wang; Yuxin Yang; Xufei Ma; Liang Xu; Yi Shen; Long Yi; Yizheng Fang; Ye Tian; Zhenrong Zheng; Yudong Cui; Ji Cao; Ge Bai; Weixiang Ye; Pan Wang; Cuifang Kuang; Joshua B. Edel; Aleksandar P. Ivanov; Xu Liu; Longhua Tang

arXiv · 2601.01560

Quantum tunnelling-integrated optoplasmonic nanotrap enables conductance visualisation of individual proteins

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Abstract

Biological electron transfer (ET) relies on quantum mechanical tunnelling through a dynamically folded protein. Yet, the spatiotemporal coupling between structural fluctuations and electron flux remains poorly understood, largely due to limitations in existing experimental techniques, such as ensemble averaging and non-physiological operating conditions. Here, we introduce a quantum tunnelling-integrated optoplasmonic nanotrap (QTOP-trap), an optoelectronic platform that combines plasmonic optical trapping with real-time quantum tunnelling measurements. This label-free approach enables single-molecule resolution of protein conductance in physiological electrolytes, achieving sub-3 nm spatial precision and 10-μs temporal resolution. By synchronising optoelectronic measurements, QTOP-trap resolves protein-specific conductance signatures and directly correlates tertiary structure dynamics with conductance using a "protein switch" strategy. This methodology establishes a universal framework for dissecting non-equilibrium ET mechanisms in individual conformational-active proteins, with broad implications for bioenergetics research and biomimetic quantum device design.

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Biao-Feng Zeng, Zian Wang, Yuxin Yang, Xufei Ma, Liang Xu, Yi Shen, Long Yi, Yizheng Fang, Ye Tian, Zhenrong Zheng, Yudong Cui, Ji Cao, Ge Bai, Weixiang Ye, Pan Wang, Cuifang Kuang, Joshua B. Edel, Aleksandar P. Ivanov, Xu Liu, Longhua Tang. 2026-01-04. Quantum tunnelling-integrated optoplasmonic nanotrap enables conductance visualisation of individual proteins. https://arxiv.org/abs/2601.01560

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