Photoactivated Bacteriorhodopsin/SiNx Nanopore-Based Biological Nanofluidic Generator with Single-Protein Sensitivity

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 similar to 3.51 pA/per bR trimer, corresponding to charge density of 815 mu C/cm(2) generated by each bR monomer, which far exceeded the previously reported value of 1.4 mu C/cm(2). This finding and method would promote the development of artificial biological and hybrid nanofluidic devices in biosensing and energy conversion applications.

Automated summary

This study reports a method for probing the bioactivity of functional proteins using a biological nanofluidic device, achieving detection at the single-molecule level. The method enables higher charge density, suggesting potential applications in biosensing and energy conversion.