Oscar Ces

Enteropathogenic Escherichia coli (EPEC) and Citrobacter rodentium (CR) are extracellular enteric attaching and effacing (A/E) pathogens of humans and mice, respectively. Their virulence relies on intimate bacterial attachment and a network of type III secretion system effectors. Here, through systematic reduction and redesign of the effector network in CR, we develop an attenuated strain, CRV (CR Vaccine), encoding a subset of ten effectors. CRV colonises C57BL/6 mice ~100-fold lower than wild type CR (CR _WT ) without causing overt pathogenesis. Moreover, C3H/HeN mice, which succumb to CR _WT infection, survive CRV challenge. Vaccination with CRV confers protection against subsequent CR _WT infection in both mouse strains. Serological analysis reveals a repertoire of dominant CR antigens, including the O-antigen, the virulence factors intimin, EspA and Tir and the outer membrane proteins Lpp, OmpA, MetQ and CARC (an AIDA-like autotransporter). We show that CR _WT and CRV immunisation elicits comparable B cell and antibody responses, which is contingent on intimate bacterial attachment. A corresponding EPEC strain ( E. coli Vaccine, ECV) effectively colonises epithelial cells in a gut-on-chip model. These findings establish effector network minimisation as a generalisable strategy for rational bacterial attenuation and live-attenuated vaccine design.

Affordable, clean room-free PMMA vertical flow-focusing device assembly enables the production of targeted lipid nanocarriers, democratising millifluidic nanocarrier production.

Stimuli‐responsive polymeric vesicles offer a versatile platform for mimicking dynamic cell‐like behaviors for synthetic cell applications. In this study, thermally responsive polymeric droplets derived from poly(ethylene oxide)‐poly(butylene oxide) (PEO‐PBO) polymersomes, aiming to create synthetic cell models that mimic key biological functions are developed. Upon heating, the nanoscale vesicles undergo fusion, transforming into sponge‐like microscale droplets enriched with membrane features. By modulating the temperature, these droplets display dynamic properties such as contractility, temperature‐induced fusion, and cargo trapping, including small molecules and bacteria, thereby demonstrating their ability to dynamically interface with biological entities. The findings demonstrate the potential of our sponge‐like droplets in synthetic cell applications, contributing to the understanding of PEO‐PBO polymersomes’ unique characteristics, expanding the capabilities of synthetic cell structures, and representing an exciting possibility for advancing soft matter engineering to cell‐like behaviors.

Artificial lipids have become increasingly important in generating novel nanoenzymes and nanoparticles. Imidazole has been well established as a versatile catalyst in synthetic chemistry and through its related amino acid histidine in enzymes. By exploiting the transphosphatidylation reaction of phospholipase D, the choline headgroup of phosphatidyl choline was exchanged for the imidazole moiety containing histidinol. Here, we introduce a novel phosphatidylhistidinol (PtdHisOH) lipid and characterise it with respect to its catalytic abilities and its ability to modulate vesicle size. Our data reveal a zinc-dependent esterase activity that was strongest in vesicles and micelles, with slower catalytic rates being observed in flat lipid presentation systems and two-phase systems, indicating the importance of surface presentation and curvature effects on the catalytic activity of PtdHisOH. Such lipids offer the opportunity to impart de novo catalytic functionality to self-assembled lipid systems such as synthetic cells, leading to the development of new technologies for biocatalysis applications.

Synthetic cells have emerged as a promising tool for understanding cellular processes and developing novel biotechnological applications. In this study, we engineer dynamic and biomimetic behaviours in polymersomes, aiming to create synthetic cells that mimic key biological functions. These vesicles exhibit a temperature-driven fusogenic property, enabling the transformation of nanoscale vesicles into microsized sponge-like polymeric droplets. These droplets, rich in membrane content, can act as synthetic cells analogues with the capability for controlled cargo release. Moreover, the thermoresponsive nature of our polymersomes makes them versatile components for the construction of lipid-based synthetic cells, allowing for controllable cargo release and dynamic organelle-like functionalities. We also demonstrate that the microscale polymer droplets possess biomimetic properties including contractility, a behaviour typically observed in biological systems. By modulating the temperature, it is possible to induce these contractile behaviours as well as other functions, including controlled fusion and efficient bacteria capture.

Encapsulating molecular materials in lipid vesicles via microfluidics provides control over size, morphology, and compartmentalisation, enabling their use in cell biology research and for applications in biomedicine, synthetic biology, and beyond.

Artificial cells are biomimetic structures formed from molecular building blocks that replicate biological processes, behaviors, and architectures. Of these building blocks, hydrogels have emerged as ideal, yet underutilized candidates to provide a gel-like chassis in which to incorporate both biological and nonbiological componentry which enables the replication of cellular functionality. Here, we demonstrate a microfluidic strategy to assemble biocompatible cell-sized hydrogel-based artificial cells with a variety of different embedded functional subcompartments, which act as engineered synthetic organelles. The organelles enable the recreation of increasingly biomimetic behaviors, including stimulus-induced motility, content release through activation of membrane-associated proteins, and enzymatic communication with surrounding bioinspired compartments. In this way, we showcase a foundational strategy for the bottom–up construction of hydrogel-based artificial cell microsystems which replicate fundamental cellular behaviors, paving the way for the construction of next-generation biotechnological devices.

Intercellular communication is a hallmark of living systems. As such, engineering artificial cells that possess this behavior has been at the heart of activities in bottom-up synthetic biology. Communication between artificial and living cells has potential to confer novel capabilities to living organisms that could be exploited in biomedicine and biotechnology. However, most current approaches rely on the exchange of chemical signals that cannot be externally controlled. Here, we report two types of remote-controlled vesicle-based artificial organelles that translate physical inputs into chemical messages that lead to bacterial activation. Upon light or temperature stimulation, artificial cell membranes are activated, releasing signaling molecules that induce protein expression in Escherichia coli . This distributed approach differs from established methods for engineering stimuli-responsive bacteria. Here, artificial cells (as opposed to bacterial cells themselves) are the design unit. Having stimuli-responsive elements compartmentalized in artificial cells has potential applications in therapeutics, tissue engineering, and bioremediation. It will underpin the design of hybrid living/nonliving systems where temporal control over population interactions can be exerted.

Recent years have seen substantial efforts aimed at constructing artificial cells from various molecular components with the aim of mimicking the processes, behaviours and architectures found in biological systems. Artificial cell development ultimately aims to produce model constructs that progress our understanding of biology, as well as forming the basis for functional bio-inspired devices that can be used in fields such as therapeutic delivery, biosensing, cell therapy and bioremediation. Typically, artificial cells rely on a bilayer membrane chassis and have fluid aqueous interiors to mimic biological cells. However, a desire to more accurately replicate the gel-like properties of intracellular and extracellular biological environments has driven increasing efforts to build cell mimics based on hydrogels. This has enabled researchers to exploit some of the unique functional properties of hydrogels that have seen them deployed in fields such as tissue engineering, biomaterials and drug delivery. In this Review, we explore how hydrogels can be leveraged in the context of artificial cell development. We also discuss how hydrogels can potentially be incorporated within the next generation of artificial cells to engineer improved biological mimics and functional microsystems.

Lipid membranes are vital in a wide range of biological and biotechnical systems; underpinning functions from modulation of protein activity to drug uptake and delivery. Rapid in situ determination of phase behaviour is a key experimental objective.