Yuxiu Chen

Dr Yuxiu (Phil) Chen


Research Fellow

Academic and research departments

School of Mathematics and Physics, Soft Matter Group.

Publications

H. Meng, NIALL CALUM BAILEY, YUXIU CHEN, LINGYU WANG, FRANCESCO CIAMPA, A Fabro, Dimitrios Chronopoulos, W Elmadih (2020)3D rainbow phononic crystals for extended vibration attenuation bands, In: Scientific reports10(1)18989 Nature

Abstract We hereby report for the first time on the design, manufacturing and testing of a three-dimensional (3D) nearly-periodic, locally resonant phononic crystal (PnC). Most of the research effort on PnCs and metamaterials has been focused on the enhanced dynamic properties arising from their periodic design. Lately, additive manufacturing techniques have made a number of designs with intrinsically complex geometries feasible to produce. These recent developments have led to innovative solutions for broadband vibration attenuation, with a multitude of potential engineering applications. The recently introduced concept of rainbow metamaterials and PnCs has shown a significant potential for further expanding the spectrum of vibration attenuation in such structures by introducing a gradient profile for the considered unit cells. Given the above, it is expected that designing non-periodic PnCs will attract significant attention from scientists and engineers in the years to come. The proposed nearly-periodic design is based on cuboid blocks connected by curved beams, with internal voids in the blocks being implemented to adjust the local masses and generate a 3D rainbow PnC. Results show that the proposed approach can produce lightweight PnCs of a simple, manufacturable design exhibiting attenuation bandwidths more than two times larger than the equivalent periodic designs of equal mass.

Yuxiu Chen, Simone Krings, Joshua R. Booth, Stefan A.F Bon, Suzie Hingley-Wilson, Joseph Keddie (2020)Introducing Porosity in Colloidal Biocoatings to Increase Bacterial Viability, In: Biomacromolecules American Chemical Society

A biocoating confines non-growing, metabolically-active bacteria within a synthetic colloidal polymer (i.e. latex) film. Bacteria encapsulated inside biocoatings can perform useful functions, such as a biocatalyst in wastewater treatment. A biocoating needs to have high a permeability to allow a high rate of mass transfer for rehydration and the transport of both nutrients and metabolic products. It therefore requires an interconnected porous structure. Tuning the porosity architecture is a challenge. Here, we exploited rigid tubular nanoclays (halloysite) and non-toxic latex particles (with a relatively high glass transition temperature) as the colloidal “building blocks” to tailor the porosity inside biocoatings containing Escherichia coli bacteria as a model organism. Electron microscope images revealed inefficient packing of the rigid nanotubes and proved the existence of nanovoids along the halloysite/polymer interfaces. Single-cell observations using confocal laser scanning microscopy provided evidence for metabolic activity of the E. coli within the biocoatings through the expression of yellow fluorescent protein. A custom-built apparatus was used to measure the permeability of a fluorescein sodium salt in the biocoatings. Whereas there was no measurable permeability in a coating made from only latex particles, the permeability coefficient of the composite biocoatings increased with increasing halloysite content up to a value of 110-4 m h-1. The effects of this increase in permeability was demonstrated through a specially-developed resazurin reduction assay. Bacteria encapsulated in halloysite composite biocoatings had statistically significant higher metabolic activities in comparison to bacteria encapsulated in a non-optimized coating made from latex particles alone.

Yuxiu Chen, Simone Krings, Alexia M. J. M. Beale, Bing Guo, Suzanne Hingley-Wilson, Joseph L. Keddie (2022)Waterborne Coatings Encapsulating Living Nitrifying Bacteria for Wastewater Treatment, In: Advanced Sustainable Systems2200312 Wiley

Biofilm bioreactors are attracting growing interest in the wastewater industry, as they allow higher cell densities and thus higher reaction rates compared to conventional bioreactors. However, some commonly used nitrifying bacteria, such as Nitrosomonas europaea, are slow-growing and need a prolonged period of time to develop a mature biofilm. Here, a biocoating or "living paint" is introduced, which is a synthetic biofilm made from a colloidal polymer (synthetic latex) binder encapsulating viable nitrifying bacteria at high density. Conventionally, the film formation of biocoatings is achieved by drying a bacteria/latex mixture. However, this fabrication is detrimental to the viability of the encapsulated bacteria because of the osmotic stress induced by desiccation. A nondesiccating film formation process is presented for biocoatings, which exploits two colloid science phenomena: coagulation and wet sintering. Desiccation-sensitive, nitrifying bacteria are employed in the biocoatings to convert NH4+ to NO2- and then NO3-. These biocoatings have a conversion rate (NO2- and NO3- production) of 3 mg N g(-1) d(-1) that is five times higher than in conventionally desiccated biocoatings. The reactivity continues over a period of 1 month. The processing method for these living paints is transformative for wastewater treatment and other applications using delicate, desiccation-sensitive microorganisms.

Simone Krings, Yuxiu Chen, Joseph Louis Keddie, Suzanne M. Hingley-Wilson (2023)Oxygen evolution from extremophilic cyanobacteria confined in hard biocoatings, In: Microbiology spectrum

ABSTRACT Biocoatings, in which viable bacteria are immobilized within a waterborne polymer coating for a wide range of potential applications, have garnered greater interest in recent years. In bioreactors, biocoatings can be ready-to-use alternatives for carbon capture or biofuel production that could be reused multiple times. Here, we have immobilized cyanobacteria in mechanically hard biocoatings, which were deposited from polymer colloids in water (i.e ., latex). The biocoatings are formed upon heating to 37°C and fully dried before rehydrating. The viability and oxygen evolution of three cyanobacterial species within the biocoatings were compared. Synechococcus sp. PCC 7002 was non-viable inside the biocoatings immediately after drying, whereas Synechocystis sp. PCC 6803 survived the coating formation, as shown by an adenosine triphosphate (ATP) assay. Synechocystis sp. PCC 6803 consumed oxygen (by cell respiration) for up to 5 days, but was unable to perform photosynthesis, as indicated by a lack of oxygen evolution. However, Chroococcidiopsis cubana PCC 7433, a strain of desiccation-resistant extremophilic cyanobacteria, survived and performed photosynthesis and carbon capture within the biocoating, with specific rates of oxygen evolution up to 0.4 g of oxygen/g of biomass per day. Continuous measurements of dissolved oxygen were carried out over a month and showed no sign of decreasing activity. Extremophilic cyanobacteria are viable in a variety of environments, making them ideal candidates for use in biocoatings and other biotechnology. IMPORTANCE As water has become a precious resource, there is a growing need for less water-intensive use of microorganisms, while avoiding desiccation stress. Mechanically robust, ready-to-use biocoatings or “living paints” (a type of artificial biofilm consisting of a synthetic matrix containing functional bacteria) represent a novel way to address these issues. Here, we describe the revolutionary, first-ever use of an extremophilic cyanobacterium ( Chroococcidiopsis cubana PCC 7433) in biocoatings, which were able to produce high levels of oxygen and carbon capture for at least 1 month despite complete desiccation and subsequent rehydration. Beyond culturing viable bacteria with reduced water resources, this pioneering use of extremophiles in biocoatings could be further developed for a variety of applications, including carbon capture, wastewater treatment and biofuel production. As water has become a precious resource, there is a growing need for less water-intensive use of microorganisms, while avoiding desiccation stress. Mechanically robust, ready-to-use biocoatings or “living paints” (a type of artificial biofilm consisting of a synthetic matrix containing functional bacteria) represent a novel way to address these issues. Here, we describe the revolutionary, first-ever use of an extremophilic cyanobacterium ( Chroococcidiopsis cubana PCC 7433) in biocoatings, which were able to produce high levels of oxygen and carbon capture for at least 1 month despite complete desiccation and subsequent rehydration. Beyond culturing viable bacteria with reduced water resources, this pioneering use of extremophiles in biocoatings could be further developed for a variety of applications, including carbon capture, wastewater treatment and biofuel production.

JR Varcoe, RCT Slade, GL Wright, Y Chen (2006)Steady-state dc and impedance investigations of H-2/O-2 alkaline membrane fuel cells with commercial Pt/C, Ag/C, and Au/C cathodes, In: JOURNAL OF PHYSICAL CHEMISTRY B110(42)pp. 21041-21049 AMER CHEMICAL SOC
H Aihara, CA Prieto, D An, SF Anderson, E Aubourg, E Balbinot, TC Beers, AA Berlind, SJ Bickerton, D Bizyaev, M Blanton, JJ Bochanski, AS Bolton, J Bovy, WN Brandt, J Brinkmann, P Brown, JR Brownstein, NG Busca, H Campbell, MA Carr, Y Chen, C Chiappini, J Comparat, N Connolly, M Cortes, RAC Croft, A Cuesta, LN Da Costa, JRA Davenport, K Dawson, S Dhital, A Ealet, G Ebelke, EM Edmondson, DJ Eisenstein, S Escoffier, M Esposito, ML Evans, X Fan, BF Castellá, A Font-Ribera, P Frinchaboy, J Ge, BA Gillespie, G Gilmore, JIG Hernández, JR Gott, A Gould, EK Grebel, JE Gunn, JC Hamilton, P Harding, DW Harris, SL Hawley, FR Hearty, S Ho, DW Hogg, JA Holtzman, K Honscheid, N Inada, II Ivans, L Jiang, JA Johnson, C Jordan, W Jordan, EA Kazin, D Kirkby, MA Klaene, GR Knapp, JP Kneib, CS Kochanek, L Koesterke, JA Kollmeier, RG Kron, H Lampeitl, D Lang, JM Le Goff, YS Lee, YT Lin, DC Long, CP Loomis, S Lucatello, B Lundgren, RH Lupton, Z Ma (2011)Erratum: The eighth data release of the sloan digital sky survey: First data from SDSS-III (The Astrophysical Journal Supplement Series (2011) 193 (29)), In: Astrophysical Journal, Supplement Series195(2)
JS Sharpe, YL Chen, RM Gwilliam, AK Kewell, CN McKinty, MA Lourenco, G Shao, KP Homewood, KR Kirkby (1999)Ion beam synthesized Ru2Si3, In: APPLIED PHYSICS LETTERS75(9)pp. 1282-1283 AMER INST PHYSICS
BB Skorodumov, GV Rogachev, P Boutachkov, A Aprahamian, VZ Goldberg, A Mukhamedzhanov, S Almaraz, H Amro, FD Becchetti, S Brown, Y Chen, H Jiang, JJ Kolata, LO Lamm, M Quinn, A Woehr (2007)Lowest excited states of O-13, In: PHYSICAL REVIEW C75(2)ARTN 0pp. ?-? AMERICAN PHYSICAL SOC
JS Sharpe, YL Chen, RM Gwilliam, AK Kewell, S Ledain, CN McKinty, MA Lourenco, T Butler, KP Homewood, KJR Kirkby, G Shao (2000)Structural characterisation of ion beam synthesised Ru2Si3, In: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS161pp. 937-940