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Journal articleParry C, Turnbull C, Barter L, et al., 2024,
Shedding light on pollination deficits: cueing into plant spectral reflectance signatures to monitor pollination delivery across landscapes
, Journal of Applied Ecology, ISSN: 0021-8901 -
Journal articleZhu KK, Contamina IG, Ces O, et al., 2024,
Magnetic modulation of biochemical synthesis in synthetic cells
, Journal of the American Chemical Society, Vol: 146, Pages: 13176-13182, ISSN: 0002-7863Synthetic cells can be constructed from diverse molecular components, without the design constraints associated with modifying 'living' biological systems. This can be exploited to generate cells with abiotic components, creating functionalities absent in biology. One example is magnetic responsiveness, the activation and modulation of encapsulated biochemical processes using a magnetic field, which is absent from existing synthetic cell designs. This is a critical oversight, as magnetic fields are uniquely bio-orthogonal, noninvasive, and highly penetrative. Here, we address this by producing artificial magneto-responsive organelles by coupling thermoresponsive membranes with hyperthermic Fe3O4 nanoparticles and embedding them in synthetic cells. Combining these systems enables synthetic cell microreactors to be built using a nested vesicle architecture, which can respond to alternating magnetic fields through in situ enzymatic catalysis. We also demonstrate the modulation of biochemical reactions by using different magnetic field strengths and the potential to tune the system using different lipid compositions. This platform could unlock a wide range of applications for synthetic cells as programmable micromachines in biomedicine and biotechnology.
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Journal articleGispert Contamina I, Hindley J, Pilkington C, et al., 2022,
Stimuli-responsive vesicles as distributed artificial organelles for bacterial activation
, Proceedings of the National Academy of Sciences of USA, Vol: 119, Pages: 1-10, ISSN: 0027-8424Intercellular 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.
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Journal articleStrutt R, Sheffield F, Barlow N, et al., 2022,
UV-DIB: label-free permeability determination using droplet interface bilayers
, Lab on a Chip: miniaturisation for chemistry, physics, biology, materials science and bioengineering, Vol: 22, Pages: 972-985, ISSN: 1473-0189Simple diffusion of molecular entities through a phospholipid bilayer, is a phenomenon of great importance to the pharmaceutical and agricultural industries. Current model lipid systems to probe this typically only employ fluorescence as a readout, thus limiting the range of assessable chemical matter that can be studied. We report a new technology platform, the UV-DIB, which facilitates label free measurement of small molecule translocation rates. This is based upon the coupling of droplet interface bilayer technology with implemented fiber optics to facilitate analysis via ultraviolet spectroscopy, in custom designed PMMA wells. To improve on current DIB technology, the platform was designed to be reusable, with a high sampling rate and a limit of UV detection in the low μM regime. We demonstrate the use of our system to quantify passive diffusion in a reproducible and rapid manner where the system was validated by investigating multiple permeants of varying physicochemical properties across a range of lipid interfaces, each demonstrating differing kinetics. Our system permits the interrogation of structural dependence on the permeation rate of a given compound. We present this ability from two structural perspectives, that of the membrane, and the permeant. We observed a reduction in permeability between pure DOPC and DPhPC interfaces, concurring with literature and demonstrating our ability to study the effects of lipid composition on permeability. In relation to the effects of permeant structure, our device facilitated the rank ordering of various compounds from the xanthine class of compounds, where the structure of each permeant differed by a single group alteration. We found that DIBs were stable up to 5% DMSO, a molecule often used to aid solubilisation of pharmaceutical and agrochemical compounds. The ability of our device to rank-order compounds with such minor structural differences provides a level of precision that is rarely seen in current, industr
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Journal articleKalossaka LM, Mohammed AA, Sena G, et al., 2021,
3D printing nanocomposite hydrogels with lattice vascular networks using stereolithography
, JOURNAL OF MATERIALS RESEARCH, Vol: 36, Pages: 4249-4261, ISSN: 0884-2914- Author Web Link
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- Citations: 10
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Journal articleKalossaka LM, Sena G, Barter LMC, et al., 2021,
Review: 3D printing hydrogels for the fabrication of soilless cultivation substrates
, Applied Materials Today, Vol: 24, Pages: 1-16, ISSN: 2352-9407The use of hydrogels in academic research is fast evolving, and becoming more relevant to real life applications across varying fields. Additive Manufacturing (AM) has paved the way towards manufacturing hydrogel substrates with tailored properties which allow for new functionalities and applications. In this review, we introduce the idea of fabricating hydrogels as bioreceptive structures to be used as soilless cultivation substrates. AM is suggested as the fabrication process to achieve structures with features similar to soil. To evaluate this, we first review hydrogel fabrication processes, highlighting their key differences in terms of resolution, printing speed and build volume. Thus, we illustrate the examples from the literature where hydrogels were 3D printed with microorganisms such as algae. Finally, the challenges and future perspectives of printing soilless cultivation substrates are explored.
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Journal articleKavanagh MA, Karlsson JK, Colburn JD, et al., 2020,
A TDDFT investigation of the Photosystem II reaction center: Insights into the precursors to charge separation
, Proceedings of the National Academy of Sciences of USA, Vol: 117, Pages: 19705-19712, ISSN: 0027-8424Photosystem II (PS II) captures solar energy and directs charge separation (CS) across the thylakoid membrane during photosynthesis. The highly oxidizing, charge-separated state generated within its reaction center (RC) drives water oxidation. Spectroscopic studies on PS II RCs are difficult to interpret due to large spectral congestion, necessitating modeling to elucidate key spectral features. Herein, we present results from time-dependent density functional theory (TDDFT) calculations on the largest PS II RC model reported to date. This model explicitly includes six RC chromophores and both the chlorin phytol chains and the amino acid residues <6 Å from the pigments’ porphyrin ring centers. Comparing our wild-type model results with calculations on mutant D1-His-198-Ala and D2-His-197-Ala RCs, our simulated absorption-difference spectra reproduce experimentally observed shifts in known chlorophyll absorption bands, demonstrating the predictive capabilities of this model. We find that inclusion of both nearby residues and phytol chains is necessary to reproduce this behavior. Our calculations provide a unique opportunity to observe the molecular orbitals that contribute to the excited states that are precursors to CS. Strikingly, we observe two high oscillator strength, low-lying states, in which molecular orbitals are delocalized over ChlD1 and PheD1 as well as one weaker oscillator strength state with molecular orbitals delocalized over the P chlorophylls. Both these configurations are a match for previously identified exciton–charge transfer states (ChlD1+PheD1−)* and (PD2+PD1−)*. Our results demonstrate the power of TDDFT as a tool, for studies of natural photosynthesis, or indeed future studies of artificial photosynthetic complexes.
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Journal articleHaylock S, Friddin M, Hindley J, et al., 2020,
Membrane protein mediated bilayer communication in networks of droplet interface bilayers
, Communications Chemistry, Vol: 3, ISSN: 2399-3669Droplet interface bilayers (DIBs) are model membranes formed between lipid monolayer-encased water droplets in oil. Compared to conventional methods, one of the most unique properties of DIBs is that they can be connected together to generate multi-layered ‘tissue-like’ networks, however introducing communication pathways between these compartments typically relies on water-soluble pores that are unable to gate. Here, we show that network connectivity can instead be achieved using a water-insoluble membrane protein by successfully reconstituting a chemically activatable mutant of the mechanosensitive channel MscL into a network of DIBs. Moreover, we also show how the small molecule activator can diffuse through an open channel and across the neighbouring droplet to activate MscL present in an adjacent bilayer. This demonstration of membrane protein mediated bilayer communication could prove key toward developing the next generation of responsive bilayer networks capable of defining information flow inside a minimal tissue.
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Conference paperKavanagh M, Gould I, Barter L, 2019,
Excited states of the photosystem II reaction center
, ACS Fall National Meeting and Exposition, Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727 -
Journal articleHindley JW, Zheleva DG, Elani Y, et al., 2019,
Building a synthetic mechanosensitive signaling pathway in compartmentalized artificial cells
, Proceedings of the National Academy of Sciences, Vol: 116, Pages: 16711-16716, ISSN: 0027-8424To date reconstitution of one of the fundamental methods of cell communication, the signaling pathway, has been unaddressed in the bottom-up construction of artificial cells (ACs). Such developments are needed to increase the functionality and biomimicry of ACs, accelerating their translation and application in biotechnology. Here we report the construction of a de novo synthetic signaling pathway in microscale nested vesicles. Vesicle cell models respond to external calcium signals through activation of an intracellular interaction between phospholipase A2 and a mechanosensitive channel present in the internal membranes, triggering content mixing between compartments and controlling cell fluorescence. Emulsion-based approaches to AC construction are therefore shown to be ideal for the quick design and testing of new signaling networks and can readily include synthetic molecules difficult to introduce to biological cells. This work represents a foundation for the engineering of multi-compartment-spanning designer pathways that can be utilised to control downstream events inside an artificial cell, leading to the assembly of micromachines capable of sensing and responding to changes in their local environment.
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