Encapsulated Multi-vesicle Assemblies of Programmable Architecture: Towards Personalized Healthcare

Specific and Reversible DNA-Directed Self-Assembly of Modular Vesicle-Droplet Hybrid Materials

Modular hybrid structures functionalized to assemble in a controlled manner possess diverse properties necessary for a new generation of complex materials and applications. Here, we functionalized giant unilamellar vesicles and emulsion droplets with biotinylated single-stranded DNA oligonucleotides using streptavidin as an intermediary linker to demonstrate specific and reversible DNA-directed self-assembly into vesicle-droplet hybrid structures. A low molar percentage of PEGylated phospholipids independent of the DNA-based recognition machinery at the supramolecular surface modulated the stability of the system. The reversibility of the aggregation was demonstrated by heating the hybrid structures above the melting temperature of the conjoining double-stranded DNA in the presence of excess biotin. The application of this general assembly control system to diverse multiphase soft materials provides the mechanism to assemble complex modular hybrid systems in a controllable and reversible way, which may provide an advantage where multifunctionality is a target property.

A quantitative analytical method to test for salt effects on giant unilamellar vesicles

Today, free-standing membranes, i.e. liposomes and vesicles, are used in a multitude of applications, e.g. as drug delivery devices and artificial cell models. Because current laboratory techniques do not allow handling of large sample sizes, systematic and quantitative studies on the impact of different effectors, e.g. electrolytes, are limited. In this work, we evaluated the Hofmeister effects of ten alkali metal halides on giant unilamellar vesicles made of palmitoyloleoylphosphatidylcholine for a large sample size by combining the highly parallel water-in-oil emulsion transfer vesicle preparation method with automatic haemocytometry. We found that this new quantitative screening method is highly reliable and consistent with previously reported results. Thus, this method may provide a significant methodological advance in analysis of effects on free-standing model membranes.