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Microcavity supported lipid membranes: versatile platforms for building asymmetric lipid bilayers and for protein recognition

Berselli, Guilherme orcid logoORCID: 0000-0002-4112-1218, Sarangi, Nirod Kumar, Ramadurai, Sivaramakrishnan, Murphy, Paul V. and Keyes, Tia E. orcid logoORCID: 0000-0002-4604-5533 (2019) Microcavity supported lipid membranes: versatile platforms for building asymmetric lipid bilayers and for protein recognition. ACS Appl. Bio Mater., 2 (8). pp. 3404-3417. ISSN 25766422

Abstract
Microcavity supported lipid bilayers (MSLB) are contact-free membranes suspended across aqueousfilled pores that maintain the lipid bilayer in a highly fluidic state and free from frictional interactions with substrate. Such platforms offer the prospect of liposome-like fluidity with the compositional versatility and addressability of supported lipid bilayers and thus offer significant opportunity for modelling membrane asymmetry, protein-membrane interactions and aggregation at the membrane interface. Herein, we evaluate their performance by studying the effect of transmembrane lipid asymmetry on lipid diffusivity, membrane viscosity and cholera toxin- ganglioside recognition across six symmetric and asymmetric membranes including binary compositions containing both fluid and gel phase, and ternary phase separated membrane compositions. Fluorescence lifetime correlation spectroscopy (FLCS) was used to determine the lateral mobility of lipid and protein, and electrochemical impedance spectroscopy (EIS) enabled detection of protein-membrane assembly over the nanomolar range. Transmembrane leaflet asymmetry was observed to have profound impact on membrane electrochemical resistance where the resistance of a ternary symmetric phase separated bilayer was found to be at least 2.6 times higher than the asymmetric bilayer with analogous composition at the distal leaflet but where the lower leaflet comprised only 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). Similarly, the diffusion coefficient for MSLBs was observed to be 2.5 fold faster for asymmetric MSLBs where the lower leaflet is DOPC alone. Our results demonstrate that interplay of lipid packing across both membrane leaflets and concentration of GM1 both affect the extent of cholera toxin aggregation and consequent diffusion of the cholera-GM1 aggregates. Given that true biomembranes are both fluidic and asymmetric, MSLBs offer the opportunity for building greater biomimicry into biophysical models and the approach described demonstrates the value of MSLBs in studying aggregation and membrane associated multivalent interactions prevalent in many carbohydrates mediated processes.
Metadata
Item Type:Article (Published)
Refereed:Yes
Subjects:Physical Sciences > Chemistry
DCU Faculties and Centres:DCU Faculties and Schools > Faculty of Science and Health > School of Chemical Sciences
Research Initiatives and Centres > National Centre for Sensor Research (NCSR)
Publisher:American Chemical Society
Official URL:https://pubs.acs.org/doi/10.1021/acsabm.9b00378
Funders:Science Foundation of Ireland
ID Code:24260
Deposited On:04 Mar 2020 11:56 by Nirod Kumar Sarangi . Last Modified 12 Apr 2022 16:14
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