On-Demand Formation of Supported Lipid Membrane Arrays by Trehalose-Assisted Vesicle Delivery for SPR Imaging

Abstract

The fabrication of large-scale, solid-supported lipid bilayer (SLB) arrays has traditionally been an arduous and complex task, primarily due to the need to maintain SLBs within an aqueous environment. In this work, we demonstrate the use of trehalose vitrified phospholipid vesicles that facilitate on-demand generation of microarrays, allowing each element a unique composition, for the label-free and high-throughput analysis of biomolecular interactions by SPR imaging (SPRi). Small, unilamellar vesicles (SUVs) are suspended in trehalose, deposited in a spatially defined manner, with the trehalose vitrifying on either hydrophilic or hydrophobic SPR substrates. SLBs are subsequently spontaneously formed on-demand simply by in situ hydration of the array in the SPR instrument flow cell. The resulting SLBs exhibit high lateral mobility, characteristic of fluidic cellular lipid membranes, and preserve the biological function of embedded cell membrane receptors, as indicated by SPR affinity measurements. Independent fluorescence and SPR imaging studies show that the individual SLBs stay localized at the area of deposition, without any encapsulating matrix, confining coral, or boundaries. The introduced methodology allows individually addressable SLB arrays to be analyzed with excellent label-free sensitivity in a real-time, high-throughput manner. Various protein–ganglioside interactions have been selected as a model system to illustrate discrimination of strong and weak binding responses in SPRi sensorgrams. This methodology has been applied toward generating hybrid bilayer membranes on hydrophobic SPR substrates, demonstrating its versatility toward a range of surfaces and membrane geometries. The stability of the fabricated arrays, over medium to long storage periods, was evaluated and found to be good. The highly efficient and easily scalable nature of the method has the potential to be applied to a variety of label-free sensing platforms requiring lipid membranes for high-throughput analysis of their properties and constituents.

Plasmonic Sensing with 3D Printed Optics

“…Binding patterns for cholera toxin are strong and specific, with signal intensities comparable to established SPR sensors in the literature. 25,26 …”

Mix and Match: Coassembly of Amphiphilic Dendrimers and Phospholipids Creates Robust, Modular, and Controllable Interfaces

“…20 The SPR setup utilized a running buffer of 1 × PBS set to a flow rate of 5 mL/h (ca. 83 μ L/min) unless otherwise noted.…”

“…15–18 In this line, we investigated the coassembly processes of amphiphilic dendrimers 1 – 3 with palmitoyloleoylphosphocholine (POPC), a major component of the plasma membrane (Figure 1). We used surface plasmon resonance (SPR) spectroscopy to characterize the dendrimer and lipid coassembly processes on nanoglassified sensor chips 19,20 and performed confocal fluorescence microscopy studies to inspect the spatial organization of embedded and tagged components. Our results demonstrate that the amphiphilic dendrimers and POPC are capable of coassembling into uniform nanovesicles in solution, while also forming bilayer structures on hydrophilic glass supports.…”

Bioinspired assemblies and plasmonic interfaces for electrochemical biosensing

“…5). More recent efforts have been made to preserve membrane structure during storage and transport, which may have important implications toward advancing commercialization and widespread adaptation of these biomimetic interfaces [77, 78]. …”