Ultralarge Single-Layer Porous Protein Nanosheet for Precise Nanosize Separation

Area of Science:

• Materials Science
• Biotechnology
• Chemical Engineering

Background:

• Developing highly permeable and size-selective membranes is crucial for energy-efficient chemical separations.
• Fabricating ultrathin selective layers with uniform nanopores (1-10 nm) remains a significant challenge.

Purpose of the Study:

• To design and fabricate a novel free-standing porous nanosheet membrane using proteins.
• To achieve precise separation of fine chemicals with high flux.

Main Methods:

• Utilized a tobacco mosaic virus mutant (TMVm) protein with a 4 nm inner pore.
• Cross-linked TMVm proteins in a 2D orientation via a copper(II)-catalyzed disulfide-bond reaction.
• Assembled ultralarge single-layer TMVm nanosheets and created a ~40 nm thick ultrafiltration membrane via vacuum filtration.

Main Results:

• Successfully developed ultralarge single-layer TMVm nanosheets with well-defined nanopores.
• The resulting membrane precisely separated substances of approximately 4 nm in size.
• Achieved a water permeance of ~7000 L m⁻² h⁻¹ bar⁻¹, an order of magnitude higher than conventional ultrafiltration membranes.

Conclusions:

• The protein-based nanosheet membrane offers a promising platform for energy-efficient and precise separation processes.
• This approach overcomes limitations in fabricating ultrathin, homogeneous nanoporous membranes.
• Demonstrated superior performance for ultrafiltration applications compared to existing technologies.