Properties of Omp2a-Based Supported Lipid Bilayers: Comparison with Polymeric Bioinspired Membranes

Abstract

Omp2a β-barrel outer membrane protein has been reconstituted into supported lipid bilayers (SLBs) to compare the nanomechanical properties (elastic modulus, adhesion forces, and deformation) and functionality of the resulting bioinspired system with those of Omp2a-based polymeric nanomembranes (NMs). Protein reconstitution into lipid bilayers has been performed using different strategies, the most successful one consisting of a detergent-mediated process into preformed liposomes. The elastic modulus obtained for the lipid bilayer and Omp2a are ∼19 and 10.5 ± 1.7 MPa, respectively. Accordingly, the protein is softer than the lipid bilayer, whereas the latter exhibits less mechanical strength than polymeric NMs. Besides, the function of Omp2a in the SLB is similar to that observed for Omp2a-based polymeric NMs. Results open the door to hybrid bioinspired substrates based on the integration of Omp2a-proteoliposomes and nanoperforated polymeric freestanding NMs.

Self-standing, conducting and capacitive biomimetic hybrid nanomembranes for selective molecular ion separation

“…Similarly, the resistance reported for Omp2a protein supported onto lipid bilayers, which exhibited much less mechanical strength than 3layered films, was of 3.7 kΩ•cm 2 . 19 These results confirm that npPLA/PEDOT/npPLA/VDAC films behave as smart biomimetic membranes fulfilling the self-standing and mechanical integrity requirements of many applications in different areas of the biomedical field, such as nanofluidics, biosensing and energy conversion.…”

“…EIS assays evidenced that, with respect to nanoperforated PLA (npPLA) nanofilms without protein, those loaded with the protein showed enhanced conductivity and selectivity against some ions. 19 In a recent study, we reported a new approach for preparing free-standing films that combines the mechanical strength and flexibility of processed npPLA nanosheets with the electrochemical response of anodically polymerized CPs. 20 More specifically, 5layered membranes made of three npPLA layers separated by two anodically polymerized poly(3,4-ethylenedioxythiophene) (PEDOT) layers were prepared and used as Faradaic motors able to push a huge amount of mass.…”

Facile Generation of Biomimetic-Supported Lipid Bilayers on Conducting Polymer Surfaces for Membrane Biosensing

“…Though PC lipids are not found in bacterial membranes, they are often included in model membrane studies, because of the difficulties using formulations with POPE and POPG alone. A POPC/POPE/POPG (4:3:1) mixture prepared by evaporating the solvent and rehydrating the lipid thin film on an ITO surface results in a membrane with a resistance of 4.2 kΩ cm 2 . In this work, we are able to remove the irrelevant POPC component and demonstrate the formation of the POPE/POPG lipid bilayer by using the SA method on PEDOT:PSS.…”

Free-standing flexible and biomimetic hybrid membranes for ions and ATP transport

“…Despite the capacity of npPLA and npPLA/Omp2a NMs to be free-standing, the difficulties associated with their handling limited ion diffusion and electrical measurements, which were conducted using NMs supported onto ITO substrates [12]. Under these conditions, the conductivity of npPLA/Omp2a membranes was comparable to that of the same protein supported onto lipid bilayers (LB/Omp2a) [13]. However, the suppression of the solid support to have biomimetic and flexible platforms with conducting channels for the metabolite transport is highly desirable.…”

“…Taking advantages of previous studies based on PNMPy/Omp2a, npPLA/Omp2a and LB/Omp2a [11][12][13], the novelty of the present work relies on the design of an advanced functional platform by immobilizing porin proteins onto a smart free-standing biomimetic membrane. This biomimetic membrane consists of three PLA layers with submicrometric perforations (pPLA layers) separated by two layers of a CP, which was prepared by electropolymerization.…”