Colloidal supported lipid bilayers for self-assembly

TL;DR

This paper thoroughly characterizes colloidal supported lipid bilayers (CSLBs), focusing on their fabrication, properties, and potential for flexible self-assembly, using microscopy and fluorescence techniques.

Contribution

It provides a detailed analysis of how particle properties affect CSLB quality and introduces methods to enhance stability and mobility for advanced applications.

Findings

Lipopolymer insertion affects bilayer homogeneity and fluidity.

Lipopolymers and inert DNA improve colloidal stability.

FRAP confirms lateral mobility of surface DNA linkers.

Abstract

The use of colloidal supported lipid bilayers (CSLBs) has recently been extended to create colloidal joints, that - in analogy to their macroscopic counterparts - can flexibly connect colloidal particles. These novel elements enable the assembly of structures with internal degrees of flexibility, but rely on previously unappreciated properties: the simultaneous fluidity of the bilayer, lateral mobility of inserted (linker) molecules and colloidal stability. Here we characterize every step in the manufacturing of CSLBs in view of these requirements using confocal microscopy and fluorescence recovery after photobleaching (FRAP). Specifically, we have studied the influence of different particle properties (roughness, surface charge, chemical composition, polymer coating) on the quality and mobility of the supported bilayer. We find that the insertion of lipopolymers in the bilayer can affect its homogeneity and fluidity. We improve the colloidal stability by inserting lipopolymers or double-stranded inert DNA into the bilayer. Finally, we include surface-mobile DNA linkers and use FRAP to characterize their lateral mobility both in their freely diffusive and bonded state. Our work offers a collection of experimental tools for working with CSLBs in applications ranging from controlled bottom-up self-assembly to model membrane studies.