Filamentous virus-based membrane prepared by chemical cross-linking at liquid/liquid interface for a tailored molecular separation system

Abstract

Membranes with selective separation capability are desirable for use in energy-efficient processes. However, precise control of target selectivity for separation is still challenging due to difficulty in controlling porous membrane structures and interactions between membrane components and target molecules. In this study, we report a filamentous virus (M13 phage)-based membrane prepared by chemical cross-linking at liquid/liquid interfaces for selective molecular separation. The M13 phage membrane composed of oriented M13 phage assemblies showed a molecularly porous structure, enabling the size-selective separation of small organic compounds. Furthermore, the pore structure was controlled by the initial concentration of M13 phage solution, enabling broad size selectivity. The rejection rates of positively charged molecules tend to be greater than those of negatively charged molecules with similar molecular weights, possibly due to the negatively charged M13 phage membrane, indicating certain electrostatic interactions. Membrane preparation using M13 phage modified by peptides with a specific affinity for neodymium ions (Nd3+) was performed to realize the selective separation of small Nd3+. The membrane preferentially adsorbed Nd3+ over iron ions, demonstrating that the molecular recognition capability of the peptide clearly remained even after the chemical cross-linking reaction. This broad-spectrum separation membrane has potential applicability in various fields, such as wastewater treatment, the food industry, and the life sciences.