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2. Democratizing University Research

Author

Jones, Nick S. and Ces, Oscar

Subjects
Physics - Physics Education
Abstract

We detail an experimental programme we have been testing in our university. Our Advanced Hackspace, attempts to give all members of the university, from students to technicians, free access to the means to develop their own interdisciplinary research ideas, with resources including access to specialized fellows and biological and chemical hacklabs. We assess the aspects of our programme that led to our community being one of the largest collectives in our university and critically examine the successes and failures of our trial programmes. We supply metrics for assessing progress and outline challenges. We conclude with future directions that advance interdisciplinary research empowerment for all university members.

Published
2020

4. Measuring Bilayer Surface Energy and Curvature in Asymmetric Droplet Interface Bilayers

Author

Barlow, Nathan E., Kusumaatmaja, Halim, Salehi-Reyhani, Ali, Brooks, Nick, Barter, Laura M. C., Flemming, Anthony J., and Ces, Oscar

Subjects
Physics - Biological Physics
Abstract

For the past decade, droplet interface bilayers (DIBs) have had an increased prevalence in biomolecular and biophysical literature. However, much of the underlying physics of these platforms are poorly characterized. To further the understanding of these structures, a study of lipid membrane tension on DIB membranes is measured by analysing the equilibrium shape of asymmetric DIBs. To this end, the morphology of DIBs is explored for the first time using confocal laser scanning fluorescence microscopy (CLSM). The experimental results confirm that, in accordance with theory, the bilayer interface of a volume asymmetric DIB is curved toward the smaller droplet and a lipid asymmetric DIB is curved toward the droplet with the higher monolayer surface tension. Moreover, the DIB shape can be exploited to measure complex bilayer surface energies. In this study, the bilayer surface energy of DIBs composed of lipid mixtures of phosphatidylgylcerol (PG) and phosphatidylcholine (PC) are shown to increase linearly with PG concentrations up to 25%. The assumption that DIB bilayer area can be geometrically approximated as a spherical cap base is also tested, and it is discovered that the bilayer curvature is negligible for most practical symmetric or asymmetric DIB systems with respect to bilayer area.

Published
2018

5. Microfluidic technologies for lipid vesicle generation.

Author

Cheng, Yu, Hay, Callum D., Mahuttanatan, Suchaya M., Hindley, James W., Ces, Oscar, and Elani, Yuval

Subjects
SYNTHETIC biology, ORIGIN of life, DRUG carriers, BIOMATERIALS, INDUSTRIAL capacity, POLYMERSOMES, BIOLOGICALLY inspired computing, NANOMEDICINE
Abstract

Encapsulating biological and non-biological materials in lipid vesicles presents significant potential in both industrial and academic settings. When smaller than 100 nm, lipid vesicles and lipid nanoparticles are ideal vehicles for drug delivery, facilitating the delivery of payloads, improving pharmacokinetics, and reducing the off-target effects of therapeutics. When larger than 1 μm, vesicles are useful as model membranes for biophysical studies, as synthetic cell chassis, as bio-inspired supramolecular devices, and as the basis of protocells to explore the origin of life. As applications of lipid vesicles gain prominence in the fields of nanomedicine, biotechnology, and synthetic biology, there is a demand for advanced technologies for their controlled construction, with microfluidic methods at the forefront of these developments. Compared to conventional bulk methods, emerging microfluidic methods offer advantages such as precise size control, increased production throughput, high encapsulation efficiency, user-defined membrane properties (i.e., lipid composition, vesicular architecture, compartmentalisation, membrane asymmetry, etc.), and potential integration with lab-on-chip manipulation and analysis modules. We provide a review of microfluidic lipid vesicle generation technologies, focusing on recent advances and state-of-the-art techniques. Principal technologies are described, and key research milestones are highlighted. The advantages and limitations of each approach are evaluated, and challenges and opportunities for microfluidic engineering of lipid vesicles to underpin a new generation of therapeutics, vaccines, sensors, and bio-inspired technologies are presented. [ABSTRACT FROM AUTHOR]

Published
2024
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27. Correction: Reusable snorkel masks adapted as particulate respirators

Author

Seligman, Henry, primary, Zaman, Sameer, additional, Pitcher, David S., additional, Shun-Shin, Matthew J., additional, Lloyd, Freya Hepworth, additional, Androshchuk, Vitaliy, additional, Sen, Sayan, additional, Al-Lamee, Rasha, additional, Miller, David M., additional, Barnett, Harry W., additional, Haji, Gulam S., additional, Howard, Luke S., additional, Nijjer, Sukhjinder, additional, Mayet, Jamil, additional, Francis, Darrel P., additional, Ces, Oscar, additional, Linton, Nicholas W. F., additional, Peters, Nicholas S., additional, and Petraco, Ricardo, additional

Published
2021
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30. Reusable snorkel masks adapted as particulate respirators

Author

Seligman, Henry, primary, Zaman, Sameer, additional, Pitcher, David S., additional, Shun-Shin, Matthew J., additional, Hepworth Lloyd, Freya, additional, Androschuk, Vitaliy, additional, Sen, Sayan, additional, Al-Lamee, Rasha, additional, Miller, David M., additional, Barnett, Harry W., additional, Haji, Gulam S., additional, Howard, Luke S., additional, Nijjer, Sukhjinder, additional, Mayet, Jamil, additional, Francis, Darrel P., additional, Ces, Oscar, additional, Linton, Nicholas W. F., additional, Peters, Nicholas S., additional, and Petraco, Ricardo, additional

Published
2021
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31. Characterisation of enzymatic reactions in coacervate-based synthetic cells

Author

Tang, Dora, Diez, Stefan, Ces, Oscar, Technische Universität Dresden, Max Planck Institut für molekulare Zellbiologie und Genetik, Barr Love, Celina Elizabeth, Tang, Dora, Diez, Stefan, Ces, Oscar, Technische Universität Dresden, Max Planck Institut für molekulare Zellbiologie und Genetik, and Barr Love, Celina Elizabeth

Abstract

Recently, there has been a growing drive towards the bottom-up development of synthetic cells that mimic key cellular features. A cellular feature ubiquitous amongst cells is that of compartmentalisation. Compartmentalisation enables the spatiotemporal control of biochemical reactions and is thus vital for the development of synthetic cells. To date, most synthetic cell models have utilised classical membrane bound containers as model compartments. However, recent advances in cell biology have highlighted the importance of membraneless compartments formed via liquid-liquid phase separation (LLPS) as organisation centres. It has been suggested that these organelles play a critical role in regulating cell biochemistry, yet very little is known about their interactions with enzymatic reactions. Thus, aiming to develop novel synthetic capabilities, the work presented in this thesis designs and characterises synthetic cells which include features of membraneless compartmentalisation. These systems utilise complex coacervates, a specific type of LLPS that is driven by the electrostatic attraction of oppositely charged polymers, as model membraneless compartments. These low complexity systems subsequently provide ideal platforms for systematic investigations of the interaction of membraneless coacervate compartments with enzymatic reactions. In Chapter 3 and 4, I focus on developing a responsive synthetic cell system that recapitulates features of membrane-bound and membraneless compartmentalisation. I generate a pH-responsive system by exploiting the intrinsic pKa of cationic polylysine to trigger coacervation within a liposome. This synthetic cell is then functionalised with the enzyme formate dehydrogenase (FDH). I show that coacervate properties can be utilized to locally concentrate and activate the FDH reaction at low enzyme concentrations, thus demonstrating that membraneless compartments can activate reactions via sequestration into coacervate reaction centres. In, ‘Bottom-up'’ Modelle synthetischer Zellen, die Schlüsselmerkmale zellbasierten Lebens imitieren, rücken immer mehr in den Fokus. Von zentraler Bedeutung ist hier die Kompartmentbildung. Sie erst ermöglicht die räumliche und zeitliche Kontrolle biochemischer Abläufe und ist daher entscheidend bei der Entwicklung synthetischer Zellen. Bisher wurden in der Mehrzahl der synthetischen Zellmodelle klassische, membrangebundene Reaktionsräume als Modellkompartimente verwendet. Jüngste Fortschritte in der Zellbiologie belegen jedoch die Bedeutung von membranlosen Kompartimenten, die durch Flüssig-Flüssig-Phasentrennung (LLPS) gebildet werden. Es wird angenommen, dass diese membranlosen Kompartimente eine zentrale Rolle bei der Regulierung der Zellchemie spielen. Jedoch ist bisher nur sehr wenig über ihren Einfluss auf enzymatische Reaktionen bekannt und experimentell belegt. Mit dem Ziel, die Bandbreite und das Verständnis synthetischer Modelle zu erweitern, wurden in dieser Arbeit neue Methoden entwickelt und dargestellt, die membranlose Kompartmentbildung benutzen. Es wurden hierfür komplexe Koazervate eingesetzt, eine spezielle Art der LLPS, welche durch die elektrostatische Anziehung von entgegengesetzt geladenen Polymeren angetrieben wird. Diese verhältnismäßig einfachen Systeme bieten eine ideale Plattform für systematische Untersuchungen des Einflusses von membranlosen Koazervatkompartimenten auf enzymatische Reaktionen. In den Kapiteln 3 und 4 konzentrierte ich mich auf die Entwicklung eines reaktionsfähigen synthetischen Modellsystems, das die Phänomene sowohl membrangebundener als auch membranfreier Kompartmentbildung vereint. Zur Steuerung der Koazervierung innerhalb von Liposomen wurde ein pH-reaktives System verwendet, welches sich den intrinsischen pKa von kationischen Polylysin zunutze macht. Diese synthetis- che Zelle wurde im folgenden Schritt mit dem Enzym Formiat-Dehydrogenase (FDH) funktionalisiert. Ich konnte damit zeigen, dass es die Ei

Published
2020

34. Controlled Dendrimersome Nanoreactor System for Localized Hypochlorite-Induced Killing of Bacteria

Author

Potter, Michael, primary, Najer, Adrian, additional, Klöckner, Anna, additional, Zhang, Shaodong, additional, Holme, Margaret N., additional, Nele, Valeria, additional, Che, Junyi, additional, Massi, Lucia, additional, Penders, Jelle, additional, Saunders, Catherine, additional, Doutch, James J., additional, Edwards, Andrew M., additional, Ces, Oscar, additional, and Stevens, Molly M., additional

Published
2020
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38. Light-triggered enzymatic reactions in nested vesicle reactors

Author

Hindley, James W., Elani, Yuval, McGilvery, Catriona M., Ali, Simak, Bevan, Charlotte L., Law, Robert V., Ces, Oscar, and Engineering & Physical Science Research Council (EPSRC)

Subjects
RELEASE, Science & Technology, Ultraviolet Rays, Science, Hydrolysis, fungi, food and beverages, LIPOSOMES, beta-Galactosidase, Article, Multidisciplinary Sciences, POLYMERIZATION, SIZE, Biocatalysis, Science & Technology - Other Topics, lcsh:Q, lcsh:Science
Abstract

Cell-sized vesicles have tremendous potential both as miniaturised pL reaction vessels and in bottom-up synthetic biology as chassis for artificial cells. In both these areas the introduction of light-responsive modules affords increased functionality, for example, to initiate enzymatic reactions in the vesicle interior with spatiotemporal control. Here we report a system composed of nested vesicles where the inner compartments act as phototransducers, responding to ultraviolet irradiation through diacetylene polymerisation-induced pore formation to initiate enzymatic reactions. The controlled release and hydrolysis of a fluorogenic β-galactosidase substrate in the external compartment is demonstrated, where the rate of reaction can be modulated by varying ultraviolet exposure time. Such cell-like nested microreactor structures could be utilised in fields from biocatalysis through to drug delivery., Matryoshka doll-like, nested vesicles, each containing a different ingredient to a chemical reaction, can serve as microreactors. Here, the authors developed a system in which mixing of the ingredients can be induced by irradiation with ultraviolet light.

Published
2018

39. Supplementary Information from Measuring bilayer surface energy and curvature in asymmetric droplet interface bilayers

Author

Barlow, Nathan E., Kusumaatmaja, Halim, Salehi-Reyhani, Ali, Brooks, Nick, Barter, Laura M. C., Flemming, Anthony J., and Ces, Oscar

Subjects
fungi
Abstract

For the past decade, droplet interface bilayers (DIBs) have had an increased prevalence in biomolecular and biophysical literature. However, much of the underlying physics of these platforms are poorly characterized. To further the understanding of these structures, a study of lipid membrane tension on DIB membranes is measured by analysing the equilibrium shape of asymmetric DIBs. To this end, the morphology of DIBs is explored for the first time using confocal laser scanning fluorescence microscopy. The experimental results confirm that, in accordance with theory, the bilayer interface of a volume asymmetric DIB is curved toward the smaller droplet and a lipid asymmetric DIB is curved toward the droplet with the higher monolayer surface tension. Moreover, the DIB shape can be exploited to measure complex bilayer surface energies. In this study, the bilayer surface energy of DIBs composed of lipid mixtures of phosphatidylgylcerol (PG) and phosphatidylcholine are shown to increase linearly with PG concentrations up to 25%. The assumption that DIB bilayer area can be geometrically approximated as a spherical cap base is also tested, and it is discovered that the bilayer curvature is negligible for most practical symmetric or asymmetric DIB systems with respect to bilayer area.

Published
2018
Full Text
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