Ultra‐Thin Self‐Assembled Protein‐Polymer Membranes: A New Pore Forming Strategy

Abstract

Self‐assembled membranes offer a promising alternative for conventional membrane fabrication, especially in the field of ultrafiltration. Here, a new pore‐making strategy is introduced involving stimuli responsive protein‐polymer conjugates self‐assembled across a large surface area using drying‐mediated interfacial self‐assembly. The membrane is flexible and assembled on porous supports. The protein used is the cage protein ferritin and resides within the polymer matrix. Upon denaturation of ferritin, a pore is formed which intrinsically is determined by the size of the protein and how it resides in the matrix. Due to the self‐assembly at interfaces, the membrane constitutes of only one layer resulting in a membrane thickness of 7 nm on average in the dry state. The membrane is stable up to at least 50 mbar transmembrane pressure, operating at a flux of about 21 000–25 000 L m−2 h−1 bar−1 and displayed a preferred size selectivity of particles below 20 nm. This approach diversifies membrane technology generating a platform for “smart” self‐assembled membranes.

Template-Assisted Preparation of Micrometric Suspended Membrane Lattices of Photoluminescent and Non-Photoluminescent Polymers by Capillarity-Driven Solvent Evaporation: Application to Microtagging

“…The formation of suspended polymer membranes also using templates featuring pass-through pipe arrays, which are fully-open at their bottom, allows possible effects of the silicon substrate underneath the pipes to be ruled out, at the same time extending the field of application of the proposed preparation method, e.g. to filtration and lighting 38 , 39 .…”

Ferritin: A Versatile Building Block for Bionanotechnology

“…Using protein structures in combination with synthetic as well as genetic alterations has proven to be highly interesting for the production of new materials. These materials may be applicable in electronic devices, sensors, medicine, or for biofunctionalization of surfaces. ,,,, Even though for all of these applications, the most often used is probably ferritin because the behavior and structural properties have been intensely studied as well as the ease of availability of various ferritins and ferritin-like structures, it is worth mentioning the potential of other protein cage structures as DPs and also virus like particles (CCMV, CPMV, M13, M2), which possess the ability of cell permeability. Moreover, the elucidation of new protein structures leads to a wide range of genetic and synthetic modifications of those blends with inorganic nanoparticles for future applications from electronic devices to in vivo delivery systems.…”

Protein‐Based Separation Membranes: State of the Art and Future Trends

“…Due to the multicomponent nature of ferritin, denaturation will induce a more open channel compared with when a single‐component protein structure is used. Van Rijn et al [ 40 ] reported a 5 nm ultrathin membrane, which is composed of a ferritin polymer core–shell microgel‐like structure that self‐assembles at polar–apolar interfaces using an air–water interface for assembly followed by UV‐cross‐linking and slow evaporation of the aqueous phase. In this process, they are desirable for selective separations through controlled pore size and shape.…”