Microfluidic Fabrication of Vesicles

Abstract

Vesicles are compartments enclosed by a thin membrane, which is made up of amphiphilic molecules arranged into ordered layers. Vesicle-like structures are Nature's choice for encapsulating important biochemical species that enable living processes, and are increasingly important as artificial structures for the encapsulation and release of drugs, biomolecules and other active ingredients for biomedical, pharmaceutical, food and consumer industries. Advances in microfluidic technologies have provided a new set of tools for unraveling the science behind formation of vesicles and fabricating novel vesicles. While traditional approaches for fabricating vesicles rely on self-assembly of amphiphiles, the precise control of flow afforded in microfluidic devices enables directed assembly of the amphiphiles. Thus, techniques such as hydrodynamic flow focusing, controlled emulsion-templating and pulsatile jetting offer unprecedented degree of control over vesicle structures. This creates new opportunities to engineer the structures of vesicles and tailor them for specific applications. In this review, we introduce current understanding behind different kinds of vesicles, survey conventional and microfluidic techniques for their formation, discuss new approaches of encapsulation and release of active ingredients in microfluidic vesicles, and point to future research and development in the area.

Programming chemistry in DNA-addressable bioreactors

“…If the original state at x contains chemtainers, these are equally transferred into the interior of the new chemtainer, leading to nested chemtainers [12]. Microfluidic implementations of this protocol are presented in [33]. We will later analyse the power of this transition system with and without the wrap operation.…”

Microfluidic Tracking of the Growth of Polymeric Vesicles in Hydrodynamic Flow

“…However, the feature and the property of the PVs can be engineered more easily than those of liposomes by manipulating polymer composition. Thus, they have gained high attention due to the variety of applications in the fields of vaccines, diagnosis, drug delivery, − cosmetics, , and so on. Many different payloads can be encapsulated into the PVs such as therapeutic agents, − proteins, , and genes. , Also, there are flavors, colorings, and other active ingredients. , The size and structure can also be adjusted depending on their application .…”

“…To this end, the microfluidic technology employing a hydrodynamic flow has been recently introduced. − The precise control of the flow is obtained in the microfluidic channel to have better control of the self-assembly of the amphiphiles. This also provides a new way for the manipulation and customization of the PV structure suitable for specific applications . Unlike the syntheses of the PVs in the hydrostatic media, the flowing solutes are laminated and the concentration gradient between them is obtained in the hydrodynamic flow.…”

Droplet-based microfluidics for artificial cell generation: a brief review

“…Part of this effort has centred on reconstructing the exact composition of natural membranes and accessing the ability to incorporate protein channels, while others have tried to reproduce the ability to respond to external stimuli through synthetically derived materials [1]. In this respect, vesicle-like structures, made from amphiphilic molecules (assembled to form ordered and closed bilayers) have been used as cell membrane mimics [35,36]. In the following sections, we review recent studies involving the use of droplet-based microfluidic techniques for lipid (liposome) and polymeric ( polymersome) vesicle formation.…”

“…Owing to their similarity to the natural components contained within cell membranes, phospholipidic vesicles represent a useful method for producing cell mimics [53], despite their susceptibility to breakage and oxidation [35]. Polymeric vesicles, also known as polymersomes, are obtained by self-assembly of amphiphilic block copolymers and represent an interesting liposome proxy due to their enhanced stability and functionality [54].…”