Biological and Biomimetic Membranes: New Materials and Emerging Processes 2021

A special issue of Membranes (ISSN 2077-0375). This special issue belongs to the section "Biological Membrane Functions".

Deadline for manuscript submissions: closed (31 July 2021) | Viewed by 7427

Special Issue Editor


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Guest Editor
Department of Environmental Engineering, Technical University of Denmark, Bygningstorvet, Building 115, room 140, 2800 Kgs, Lyngby, Denmark
Interests: biomimetic membranes; membrane transport; membrane channel and transporter proteins; lipid–protein interactions, electrophysiology
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Special Issue Information

Dear Colleagues,

The last decade witnessed a strong interest in new membrane materials and processes. While the last century witnessed productive synergy between physics/chemistry and engineering, this century is likely to witness the development of novel technology driven by synergy between biology and engineering. Successful advances in membrane development will be based on atomistic insights gained from fundamental structural and functional studies of molecular structures capable of efficient separation.

A particularly promising area is research within membrane materials and membrane processes, where new technologies are inspired directly or indirectly by the natural membrane realm. One manifestation of this in membrane material development is based on using additives—either in the form of natural proteins or artificially made molecules with desired sensing and separation properties—in the polymeric matrix. Another manifestation is based on the de novo design of membrane functionalities with cues taken from one or more specific biological molecular structures.

The aim of this Special Issue is to highlight recent advances in biomimetic membrane materials and designs. We welcome original research papers and review articles related to the design of, materials for, and methods for the synthesis of biomimetic membranes.

Prof. Dr. Claus Hélix-Nielsen
Guest Editor

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Membranes is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • biomimetics
  • selective permeability
  • biomolecular sensing
  • de novo functional membrane design
  • passive and active transport
  • new materials

Published Papers (3 papers)

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Research

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17 pages, 2588 KiB  
Article
The Antimicrobial Peptide Gramicidin S Enhances Membrane Adsorption and Ion Pore Formation Potency of Chemotherapy Drugs in Lipid Bilayers
by Md. Ashrafuzzaman
Membranes 2021, 11(4), 247; https://doi.org/10.3390/membranes11040247 - 30 Mar 2021
Cited by 10 | Viewed by 1823
Abstract
We recently published two novel findings where we found the chemotherapy drugs (CDs) thiocolchicoside (TCC) and taxol to induce toroidal type ion pores and the antimicrobial peptide gramicidin S (GS) to induce transient defects in model membranes. Both CD pores and GS defects [...] Read more.
We recently published two novel findings where we found the chemotherapy drugs (CDs) thiocolchicoside (TCC) and taxol to induce toroidal type ion pores and the antimicrobial peptide gramicidin S (GS) to induce transient defects in model membranes. Both CD pores and GS defects were induced under the influence of an applied transmembrane potential (≈100 mV), which was inspected using the electrophysiology record of membrane currents (ERMCs). In this article, I address the regulation of the membrane adsorption and pore formation of CDs due to GS-induced possible alterations of lipid bilayer physical properties. In ERMCs, low micromolar (≥1 μM) GS concentrations in the aqueous phase were found to cause an induction of defects in lipid bilayers, but nanomolar (nM) concentration GS did nothing. For the binary presence of CDs and GS in the membrane-bathing aqueous phase, the TCC pore formation potency is found to increase considerably due to nM concentration GS in buffer. This novel result resembles our recently reported finding that due to the binary aqueous presence of two AMPs (gramicidin A or alamethicin and GS), the pore or defect-forming potency of either AMP increases considerably. To reveal the underlying molecular mechanisms, the influence of GS (0–400 nM) on the quantitative liposome (membrane) adsorption of CD molecules, colchicine and TCC, was tested. I used the recently patented direct detection method, which helps detect the membrane active agents directly at the membrane in the mole fraction relative to its concentrations in aqueous phase. We find that GS, at concentrations known to do nothing to the lipid bilayer electrical barrier properties in ERMCs, increases the membrane adsorption (membrane uptake) of CDs considerably. This phenomenological finding along with the GS effects on CD-induced membrane conductance increase helps predict an important conclusion. The binary presence of AMPs alongside CDs in the lipid membrane vicinity may work toward enhancing the physical adsorption and pore formation potency of CDs in lipid bilayers. This may help understand why CDs cause considerable cytotoxicity. Full article
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18 pages, 2625 KiB  
Article
Biofouling Mitigation Approaches during Water Recovery from Fermented Broth via Forward Osmosis
by Stavros Kalafatakis, Agata Zarebska, Lene Lange, Claus Hélix-Nielsen, Ioannis V. Skiadas and Hariklia N. Gavala
Membranes 2020, 10(11), 307; https://doi.org/10.3390/membranes10110307 - 27 Oct 2020
Cited by 10 | Viewed by 1824
Abstract
Forward Osmosis (FO) is a promising technology that can offer sustainable solutions in the biorefinery wastewater and desalination fields, via low energy water recovery. However, microbial biomass and organic matter accumulation on membrane surfaces can hinder the water recovery and potentially lead to [...] Read more.
Forward Osmosis (FO) is a promising technology that can offer sustainable solutions in the biorefinery wastewater and desalination fields, via low energy water recovery. However, microbial biomass and organic matter accumulation on membrane surfaces can hinder the water recovery and potentially lead to total membrane blockage. Biofouling development is a rather complex process and can be affected by several factors such as nutrient availability, chemical composition of the solutions, and hydrodynamic conditions. Therefore, operational parameters like cross-flow velocity and pH of the filtration solution have been proposed as effective biofouling mitigation strategies. Nevertheless, most of the studies have been conducted with the use of rather simple solutions. As a result, biofouling mitigation practices based on such studies might not be as effective when applying complex industrial mixtures. In the present study, the effect of cross-flow velocity, pH, and cell concentration of the feed solution was investigated, with the use of complex solutions during FO separation. Specifically, fermentation effluent and crude glycerol were used as a feed and draw solution, respectively, with the purpose of recirculating water by using FO alone. The effect of the abovementioned parameters on (i) ATP accumulation, (ii) organic foulant deposition, (iii) total water recovery, (iv) reverse glycerol flux, and (v) process butanol rejection has been studied. The main findings of the present study suggest that significant reduction of biofouling can be achieved as a combined effect of high-cross flow velocity and low feed solution pH. Furthermore, cell removal from the feed solution prior filtration may further assist the reduction of membrane blockage. These results may shed light on the challenging, but promising field of FO process dealing with complex industrial solutions. Full article
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Review

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16 pages, 10154 KiB  
Review
S-Layer Ultrafiltration Membranes
by Bernhard Schuster and Uwe B. Sleytr
Membranes 2021, 11(4), 275; https://doi.org/10.3390/membranes11040275 - 08 Apr 2021
Cited by 11 | Viewed by 3092
Abstract
Monomolecular arrays of protein subunits forming surface layers (S-layers) are the most common outermost cell envelope components of prokaryotic organisms (bacteria and archaea). Since S-layers are periodic structures, they exhibit identical physicochemical properties for each constituent molecular unit down to the sub-nanometer level. [...] Read more.
Monomolecular arrays of protein subunits forming surface layers (S-layers) are the most common outermost cell envelope components of prokaryotic organisms (bacteria and archaea). Since S-layers are periodic structures, they exhibit identical physicochemical properties for each constituent molecular unit down to the sub-nanometer level. Pores passing through S-layers show identical size and morphology and are in the range of ultrafiltration membranes. The functional groups on the surface and in the pores of the S-layer protein lattice are accessible for chemical modifications and for binding functional molecules in very precise fashion. S-layer ultrafiltration membranes (SUMs) can be produced by depositing S-layer fragments as a coherent (multi)layer on microfiltration membranes. After inter- and intramolecular crosslinking of the composite structure, the chemical and thermal resistance of these membranes was shown to be comparable to polyamide membranes. Chemical modification and/or specific binding of differently sized molecules allow the tuning of the surface properties and molecular sieving characteristics of SUMs. SUMs can be utilized as matrices for the controlled immobilization of functional biomolecules (e.g., ligands, enzymes, antibodies, and antigens) as required for many applications (e.g., biosensors, diagnostics, enzyme- and affinity-membranes). Finally, SUM represent unique supporting structures for stabilizing functional lipid membranes at meso- and macroscopic scale. Full article
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