Monodisperse Giant Unilamellar Niosomes as Minimal Synthetic Cells.

Giant unilamellar vesicles (GUVs) such as liposomes, polymersomes, and fatty acid vesicles are widely studied as synthetic cell models. However, liposomes suffer from limited membrane permeability, instability, and high material cost, while polymersomes lack membrane fluidity, and fatty acid vesicles are sensitive to ions and pH. Here, we introduce giant unilamellar niosomes (GUNs), nonionic surfactant-based vesicles, as a robust, cost-effective platform for synthetic cells.

Solving Mazes of Organelle-Targeted Therapies with DNA Nanomachines.

Despite decades of research, cancer remains a growing global health challenge. Nanomaterials-based therapeutics have shown promise, but their clinical applications are often limited by poor selectivity and undesirable side effects. Recently, deoxyribonucleic acid (DNA) based nanomachines have gained attention as intelligent drug carriers due to their ability to precisely target specific organelles.

Static and transient vacuolation in protein-based coacervates induced by charged amino acids.

Vacuolation is a common phenomenon observed in many subcellular membrane-less organelles, such as paraspeckles, granules and nucleoli. Previous work suggests that such dynamic sub-structuration can be a result of charge disproportion at super-stoichiometric ratios of the assembling component. In this work, we demonstrate that other than remodeling the large coacervate-constituting components, the introduction of small charged motifs, amino acids, can also lead to the formation of static vacuoles in the coacervate droplets.

Transient Structural Coloration During Dewetting Transition of Water-In-Oil-In-Water Droplets.

Structural coloration based on microscale concave interfaces provides a versatile method for generating iridescent colors, yet it remains challenging to achieve in water-based droplet systems. Here, it is reported a transient structural coloration process during the dewetting transition of water-in-oil-in-water emulsion droplets. It is demonstrated that the total internal reflection (TIR) and structural coloration are restricted to a narrow operational window, primarily dictated by droplet size ratios and dewetting morphologies.

DNA photofluids show life-like motion.

As active matter, cells exhibit non-equilibrium structures and behaviours such as reconfiguration, motility and division. These capabilities arise from the collective action of biomolecular machines continuously converting photoenergy or chemical energy into mechanical energy. Constructing similar dynamic processes in vitro presents opportunities for developing life-like intelligent soft materials.

Wetting-induced interfacial instability: A mechanism for droplet emission at air-liquid interfaces.

High-throughput production of monodisperse microdroplets has revolutionized many fields, typically relying on shear-induced emulsification in intricate microfluidic channels to induce the Rayleigh-Plateau instability. This mechanism exhibits low robustness due to its high dependence on the physical properties and flow conditions of fluids. Here, we report a robust emulsification mechanism-wetting-induced interfacial instability-for droplet emission.

Tunable Structural Coloration in Eccentric Water-in-Oil-in-Water Droplets.

Structural colors show diverse advantages such as fade resistance, eco-friendliness, iridescence, and high saturation in comparison with chemical pigments. In this paper, we show tunable structural coloration in colorless water-in-oil-in-water double emulsion droplets via total internal reflection and interference at the microscale concave interfaces. Through experimental work and simulations, we demonstrate that the shell thickness and the eccentricity of the core-shell structures are key to the successful formation of iridescent structural colors.

Division in synthetic cells.

The bottom-up construction of a living cell using non-living materials represents a grand challenge in science and technology. Reproduction of cells into similar offspring is key to life, and therefore, building a synthetic cell that can autonomously divide is one of the most fundamental tasks that need to be achieved in bottom-up synthetic biology. In this review, we summarize the strategies of inducing synthetic division by using physical, chemical, and biological stimuli, and highlight the future challenges to the construction of autonomous synthetic cell division.

Elastic-instability-enabled locomotion.

Locomotion of an organism interacting with an environment is the consequence of a symmetry-breaking action in space-time. Here we show a minimal instantiation of this principle using a thin circular sheet, actuated symmetrically by a pneumatic source, using pressure to change shape nonlinearly via a spontaneous buckling instability. This leads to a polarized, bilaterally symmetric cone that can walk on land and swim in water.

Complex coacervates as artificial membraneless organelles and protocells.

Complex coacervates are water droplets dispersed in water, which are formed by spontaneous liquid-liquid phase separation of an aqueous solution of two oppositely charged polyelectrolytes. Similar to the membraneless organelles that exist in biological cells, complex coacervate droplets are membraneless and have a myriad of features including easy formation, high viscosity, selective encapsulation of biomolecules, and dynamic behaviors in response to environmental stimuli, which make coacervates an excellent option for constructing artificial membraneless organelles. In this article, I first summarize recent advances in artificial compartments that are built from coacervates and their response to changes in the surrounding environment and then show the advantages of microfluidic techniques in the preparation of monodisperse coacervates and encapsulation of coacervates in droplets and liposomes to construct complex cell-like compartments, and finally discuss the future challenges of such membraneless aqueous compartments in cell mimics and origin of life.

Trojan-Horse-Like Stimuli-Responsive Microcapsules.

Multicompartment microcapsules, with each compartment protected by a distinct stimuli-responsive shell for versatile controlled release, are highly desired for developing new-generation microcarriers. Although many multicompartmental microcapsules have been created, most cannot combine different release styles to achieve flexible programmed sequential release. Here, one-step template synthesis of controllable Trojan-horse-like stimuli-responsive microcapsules is reported with capsule-in-capsule structures from microfluidic quadruple emulsions for diverse programmed sequential release.

Macromolecularly Crowded Protocells from Reversibly Shrinking Monodisperse Liposomes.

The compartmentalization of cell-free gene expression systems in liposomes provides an attractive route to the formation of protocells, but these models do not capture the physical (crowded) environment found in living systems. Here, we present a microfluidics-based route to produce monodisperse liposomes that can shrink almost 3 orders of magnitude without compromising their stability. We demonstrate that our strategy is compatible with cell-free gene expression and show increased protein production rates in crowded liposome protocells.

Microfluidic Formation of Monodisperse Coacervate Organelles in Liposomes.

Coacervates have been widely studied as model compartments in protocell research. Complex coacervates composed of disordered proteins and RNA have also been shown to play an important role in cellular processes. Herein, we report on a microfluidic strategy for constructing monodisperse coacervate droplets encapsulated within uniform unilamellar liposomes.

Continuous fabrication of polymeric vesicles and nanotubes with fluidic channels.

Fluidic channels were employed to induce the self-assembly of poly(ethylene glycol)-b-polystyrene into polymeric vesicles and nanotubes. The laminar flow in the device enables controlled diffusion of two miscible liquids at the phase boundary, leading to the formation of homogeneous polymeric structures of different shapes. These structures could be easily loaded with small molecule cargoes and functionalized with nanometer sized catalytic platinum nanoparticles.

Microfluidic Assembly of Monodisperse Vesosomes as Artificial Cell Models.

Vesosomes are nested liposomal structures with high potential as advanced drug delivery vehicles, bioreactors and artificial cells. However, to date no method has been reported to prepare monodisperse vesosomes of controlled size. Here we report on a multistep microfluidic strategy for hierarchically assembling uniform vesosomes from dewetting of double emulsion templates.

Spontaneous transfer of droplets across microfluidic laminar interfaces.

The precise manipulation of droplets in microfluidics has revolutionized a myriad of drop-based technologies, such as multiple emulsion preparation, drop fusion, drop fission, drop trapping and drop sorting, which offer promising new opportunities in chemical and biological fields. In this paper, we present an interfacial-tension-directed strategy for the migration of droplets across liquid-liquid laminar streams. By carefully controlling the interfacial energies, droplets of phase A are able to pass across the laminar interfaces of two immiscible fluids from phase B to phase C due to a positive spreading coefficient of phase C over phase B.

Monodisperse Uni- and Multicompartment Liposomes.

Liposomes are self-assembled phospholipid vesicles with great potential in fields ranging from targeted drug delivery to artificial cells. The formation of liposomes using microfluidic techniques has seen considerable progress, but the liposomes formation process itself has not been studied in great detail. As a result, high throughput, high-yielding routes to monodisperse liposomes with multiple compartments have not been demonstrated.

Plug-n-play microfluidic systems from flexible assembly of glass-based flow-control modules.

In this study, we report on a simple and versatile plug-n-play microfluidic system that is fabricated from flexible assembly of glass-based flow-control modules for flexibly manipulating flows for versatile emulsion generation. The microfluidic system consists of three basic functional units: a flow-control module, a positioning groove, and a connection fastener. The flow-control module that is based on simple assembly of low-cost glass slides, coverslips, and glass capillaries provides excellent chemical resistance and optical properties, and easy wettability modification for flow manipulation.

In situ fabrication of a temperature- and ethanol-responsive smart membrane in a microchip.

Here we report a simple and versatile strategy for the in situ fabrication of nanogel-containing smart membranes in microchannels of microchips. The fabrication approach is demonstrated by the in situ formation of a chitosan membrane containing poly(N-isopropylacrylamide) (PNIPAM) nanogels in a microchannel of a microchip. The PNIPAM nanogels, that allow temperature- and ethanol-responsive swelling-shrinking volume transitions, serve as smart nanovalves for controlling the diffusional permeability of solutes across the membrane.

Wetting-induced coalescence of nanoliter drops as microreactors in microfluidics.

Controllable one-to-one coalescence of surfactant-stabilized nanoliter water drops is successfully achieved from wetting-induced drop engulfing in microfluidics by surrounding one of the drops with a thin layer of immiscible wetting fluid. This wetting layer can spread over the other drop to drain away the liquid film between the two drops, thereby inducing coalescence. This innovative approach is totally spontaneous and highly potential in a myriad of fields, such as quantitative analysis, microreaction, and high-throughput injection.