Photoactivated Bacteriorhodopsin/SiN<sub><i>x</i></sub> Nanopore-Based Biological Nanofluidic Generator with Single-Protein Sensitivity
Dandan Wang, Yong Wang, Haijuan Li, Yanchao Han, Ping Hu, Kongshuo Ma, Mordechai Sheves, Yongdong Jin
Abstract
Nanofluidics is an emerging hot field that explores the unusual behaviors of ions/molecules transporting through nanoscale channels, which possesses a broad application prospect. However, in situ probing bioactivity of functional proteins on a single-molecule level by a nanofluidic device has not been reported, and it is still a big challenge in the field. Herein, we reported a biological nanofluidic device with a single-protein sensitivity, based on natural proton-pumping protein, bacteriorhodopsin (bR), and a single SiNx nanopore. Nanofluidic single-molecule probing of bR proton-pumping activity and its light response were achieved under applied voltage of 0 V, by biologically self-powered steady-state ionic current nanopore sensing. Green-light irradiation of the device led to the monitoring of a steady-state proton current of ∼3.51 pA/per bR trimer, corresponding to charge density of 815 μC/cm2 generated by each bR monomer, which far exceeded the previously reported value of 1.4 μC/cm2. This finding and method would promote the development of artificial biological and hybrid nanofluidic devices in biosensing and energy conversion applications.