Plasma Oxidized Polyhydroxymethylsiloxane—A New Smooth Surface for Supported Lipid Bilayer Formation

Abstract

A novel substrate for preparation of supported lipid bilayers (SLBs), smooth at the subnanometer scale and of variable thickness from ten to several hundred nanometers, was developed by surface oxidation of spin-coated poly(hydroxymethylsiloxane) (PHMS) films. The deposited polymeric thin films were modified by a combination of oxygen plasma and thermal treatment (PHMS(ox)), in order to convert the outermost surface layer of the polymer film to a stable SiO(2) film, suitable for SLB formation. The hydrophilic, SiO(2)-like surfaces were characterized by XPS, wetting angle, ellipsometry, and AFM. Lipid bilayers were formed on this surface using the well-known vesicle adsorption-rupture-fusion process, usually performed on glass or vapor-deposited SiO(2). Reproducible formation of homogeneous SLBs of different compositions (POPC, DOEPC, and POPC/DOPS) was demonstrated on the new SiO(2) surface by quartz crystal microbalance with dissipation (QCM-D), surface plasmon resonance (SPR), and optical reflectometry measurements. The SLB formation kinetics on the PHMS(ox)-coated sensors showed very similar characteristics, for all investigated PHMS thicknesses, as on reference sensors coated with vapor-deposited SiO(2). The good adhesive properties of the PHMS to gold allows for the preparation of thin PHMS(ox) layers compatible with SPR. The much smaller roughness at the nanometer scale of the PHMS(ox) surfaces, compared to standard vapor-deposited SiO(2)-coated sensors, makes them advantageous for AFM and optical experiments and promising for patterning. To benefit optical experiments with the PHMS(ox) surfaces, it was also investigated how the PHMS film thickness influences the SPR and reflectometry responses upon SLB formation.

Preparation of Mica Supported Lipid Bilayers for High Resolution Optical Microscopy Imaging

“…Different substrates might be used for SLB formation (i.e. glass, mica, silicon dioxide, polymers) depending on the nature of the study 4,[6][7][8] . Typical membrane studies rely on microscopy-based imaging techniques, such as TIRFM and AFM.…”

A Survey of the 2010 Quartz Crystal Microbalance Literature

“…Similar SLB compositions were studied by Satriano et al . on novel hydrophilic spin‐coated poly(hydroxymethylsiloxane) films using 1‐palmitoyl‐2‐oleyl‐ sn ‐glycero‐3‐phosphocholine, 1,2‐dioleoyl‐ sn ‐glycero‐3‐[phospho‐l‐serine] and 1,2‐dioleoyl‐ sn ‐glycero‐3‐ethylphopshocholine (Satriano et al ., ). Optical microscopy and QCM‐D were used simultaneously in a sample cell to follow the electroformation of 1,2‐dimyristoyl‐ sn ‐glycero‐3‐phosphocholine vesicles (Niri et al ., ) and 1‐palmitolyl‐2‐oleoyl‐ sn ‐glycero‐3‐phosphocholine vesicles with bilayer formation studied on pitted gold and SiO 2 surfaces (Pfeiffer et al ., ).…”

Graphene Oxide Nanosheets Tailored With Aromatic Dipeptide Nanoassemblies for a Tuneable Interaction With Cell Membranes

“…The dried lipid film was emulsified by using 10 mM PBS, at room temperature, and vortexed to obtain the vesicles. Afterward, in order to obtain the SUVs dispersion, about 80-100 nm of diameter (Satriano et al, 2010), the dispersion was extruded 13 times through a 100 nm-pore size polycarbonate membrane, followed by another 13 times through a 30 nm-pore size membrane (Avanti Polar Lipids). The stock solution of rhodamine-labeled POPC was stored under N 2 and used within 2 weeks, according to an established protocol (Satriano et al, 2010).…”

“…Frequency shifts were normalized by the overtone number. After stabilization of the baseline, 0.5 mL of a temperature-stabilized vesicle solution (100 µg/mL) was injected in the measurement chamber for the formation of the lipid bilayer on the sensor surface, by the spontaneous rupture/fusion processes following the adsorption of the vesicles onto the hydrophilic silica surfaces of the QCM-D sensor (Satriano et al, 2010(Satriano et al, , 2012.…”