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Browsing by Author "Vongsvivut, JP"

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Biochemical interaction of few layer black phosphorus with microbial cells using synchrotron macro-ATR-FTIR
(Materials Australian and The Australian Ceramic Society, 2022-06-01) Shaw, ZL; Cheeseman, S; Huang, LZY; Penman, R; Ahmed, T; Bryant, SJ; Bryant, G; Christofferson, AJ; Orwell-Twigg, R; Dekiwadia, C; Truong, VK; Vongsvivut, JP; Walia, S; Elbourne, A
In the fight against drug-resistant pathogenic microbial cells, low dimensional materials are emerging as a promising alternative treatment. Specifically, few-layer black phosphorus (BP) has demonstrated its effectiveness against a wide range of pathogenic microbial cells with studies suggesting low cytotoxicity towards healthy mammalian cells. However, the antimicrobial mechanism of action of BP is not well understood and further in-depth investigations are required. In this work, the complex biochemical interaction between BP and a series of microbial cells is investigated using advanced, high-resolution microscopy techniques to provide a greater understanding of the antimicrobial mechanism. Synchrotron macro-attenuated total reflection–Fourier transform infrared (ATR-FTIR) micro-spectroscopy is used to elucidate the chemical changes occurring outside and within the cell of interest after exposure to BP nanoflakes. The ATR-FTIR data, coupled with microscopy, reveals chemical changes to the cellular phospholipids, proteins, structural polysaccharides and nucleic acids when compared to untreated cells. These changes can be attributed to the physical interaction combined with the oxidative stress induced by the degradation of the BP nanoflakes. This study provides an insight into the biochemical interaction of BP nanoflakes with microbial cells, allowing for a better understanding of the antimicrobial mechanism of action.
Femtosecond laser fabrication of diffractive optics for spatial and spectral imaging at synchrotron infrared beamlines
(Society of Photo-Optical Instrumentation Engineers (SPIE), 2021-03-06) Anand, V; Katkus, T; Ng, SH; Vongsvivut, JP; Maksimovic, J; Klein, AR; Bambery, KR; Lundgaard, S; Linklater, D; Ivanova, EP; Tobin, MJ; Juodkazis, S
Infrared (IR) microspectroscopy is a powerful molecular fingerprinting tool widely used for the identification of structural and functional composition of biological and chemical samples. The IR microspectroscopy beamline at the Australian Synchrotron can be operated either with a single-point narrow-band mercury cadmium telluride (MCT) detector or a focal plane array (FPA) imaging detector with 64 × 64 pixels. For the implementation of indirect nonscanning imaging technology, the system was operated with the FPA detector. In this study, we propose an indirect IR imaging technique based on the principles of correlation optics using diffractive optical elements such as random pinhole array (RPA) and Fresnel zone plate (FZP). The spatial and spectral variations of point spread functions (PSFs) of the RPA and FZP were simulated for the synchrotron configuration. Intensity responses for 2D objects were simulated using the same simulation conditions and reconstructed using Lucy-Richardson algorithm. Fabrication of diffractive elements for IR wavelengths is often a challenging task as the IR transparent material substrates, such as barium fluoride and calcium fluoride, are highly susceptible to thermal shocks and brittle by nature. The diffractive elements were fabricated by ablating directly on a 100 nm thick gold coated substrate using femtosecond laser pulses. The simulation results and the fabrication outcomes demonstrate the feasibility of indirect imaging at the synchrotron IR beamline. © 2021 Society of Photo-Optical Instrumentation Engineers (SPIE)
Fire-induced shifts in stalagmite organic matter mapped using synchrotron infrared microspectroscopy
(Elsevier, 2024-09) McDonough, LK; Campbell, M; Treble, PC; Marjo, CE; Frisia, S; Vongsvivut, JP; Klein, AR; Kovacs-Kis, V; Baker, AA
Understanding organic matter (OM) in cave mineral deposits (speleothems) is essential for interpreting land use and climatic changes, and the incorporation of trace elements associated with organic compounds. However, the sources and composition of OM in speleothems are poorly understood due to challenges associated with measuring OM at low concentrations and the destructive nature of most speleothem OM analysis techniques. Synchrotron Fourier-transform infrared (FTIR) microspectroscopy is a promising non-destructive technique that can be used to investigate stalagmite OM composition. We use FTIR to analyse vegetation, soil, calcium carbonate and ash end-members and demonstrate the use of Synchrotron infrared microspectroscopy (IRM) mapping to detect temporal changes in the OM composition of a stalagmite from a shallow cave in south-west Western Australia. Our analysis reveals predominant FTIR peaks in the stalagmite linked to amides and CH2 groups, suggesting potential microbial contributions, with smaller proportions of aromatic, CH3 and Cdouble bondO groups. High-resolution transmission electron microscopy revealed that this OM is likely hosted in sets of nanopores spaced hundreds of nanometers apart, aligned along calcite crystallographic orientations. Furthermore, we assess the impact of known wildfire events as discrete short term environmental changes on the stalagmite’s OM composition. The temporal variability in OM functional group composition after fires implies complex fire-soil-vegetation-microbial interactions. This research demonstrates the effectiveness of Synchrotron IRM mapping in providing insights into the short and long-term environmental influences on stalagmite OM composition. Expanding this research to other regions and climates could further enhance the interpretation of OM changes in speleothem-based palaeoclimate reconstructions. © Crown Copyright © 2024 Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
Gold nanoparticle adsorption alters the cell stiffness and cell wall bio-chemical landscape of Candida albicans fungal cells
(Elsevier, 2024-01-15) Penman, R; Kariuki, R; Shaw, ZL; Dekiwadia, C; Christofferson, AJ; Bryant, G; Vongsvivut, JP; Bryant, SJ; Elbourne, A
Hypothesis Nanomaterials have been extensively investigated for a wide range of biomedical applications, including as antimicrobial agents, drug delivery vehicles, and diagnostic devices. The commonality between these biomedical applications is the necessity for the nanoparticle to interact with or pass through the cellular wall and membrane. Cell-nanomaterial interactions/uptake can occur in various ways, including adhering to the cell wall, forming aggregates on the surface, becoming absorbed within the cell wall itself, or transversing into the cell cytoplasm. These interactions are common to mammalian cells, bacteria, and yeast cells. This variety of interactions can cause changes to the integrity of the cell wall and the cell overall, but the precise mechanisms underpinning such interactions remain poorly understood. Here, we investigate the interaction between commonly investigated gold nanoparticles (AuNPs) and the cell wall/membrane of a model fungal cell to explore the general effects of interaction and uptake. Experiments The interactions between 100 nm citrate-capped AuNPs and the cell wall of Candida albicans fungal cells were studied using a range of advanced microscopy techniques, including atomic force microscopy, confocal laser scanning microscopy, scanning electron microscopy, transmission electron microscopy, and synchrotron-FTIR micro-spectroscopy. Findings In most cases, particles adhered on the cell surface, although instances of particles being up-taken into the cell cytoplasm and localised within the cell wall and membrane were also observed. There was a measurable increase in the stiffness of the fungal cell after AuNPs were introduced. Analysis of the synchrotron-FTIR data showed significant changes in spectral features associated with phospholipids and proteins after exposure to AuNPs. © 2023 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license.
High-resolution macro ATR-FTIR chemical imaging capability at Australian Synchrotron Infrared Microspectroscopy (IRM) Beamline
(Australian Nuclear Science and Technology Organisation, 2021-11-25) Vongsvivut, JP; Tobin, MJ; Klein, AR; Bambery, KR
This presentation aims to provide a summary on technical aspects and applications of our synchrotron macro ATR-FTIR microspectroscopy, unique to the Infrared Microspectroscopy (IRM) beamline at ANSTO–Australian Synchrotron.1 The device was developed by modifying the cantilever arm of a standard macro-ATR unit to accept Ge-ATR elements. Coupling synchrotron-IR beam to the Ge-ATR element (n=4), reduces the beam focus size by a factor of 4 (improving lateral resolution), and the mapping step size by 4 times relative to the stage step motion. As a result, the macro ATR-FTIR measurement at our IRM beamline can be performed at minimum projected aperture (sampling spot size) of 1-2 μm using a 20x objective, and minimum mapping step size of 250 nm, allowing high-resolution chemical imaging analysis with the resolution limit beyond those allowed for standard synchrotron-FTIR transmission and reflectance setups. The technique has facilitated many experiments in a diverse range of research disciplinary. Here, there will be presentations based on macro ATR-FTIR technique in archaeology, electrochemistry (battery), biomedical and forensic sciences. Apart from these, we will provide additional applications in the fields of food and pharmaceutical science,2-4 single-fibre analysis,5-6 and dentistry.7 References: [1] J. Vongsvivut, et al., Analyst 144, 10, 3226-323 (2019). [2] A.P. Pax, et al., Food Chemistry, 291, 214-222 (2019). [3] Y.P. Timilsena, et al., Food Chemistry, 275, 457-466 (2019). [4] D.M. Silva, et al., Journal of Colloid and Interface Science, 587, 499-509 (2021). [5] S. Nunna, et al., Journal of Materials Chemistry A, 5, 7372-7382 (2017). [6] C. Haynl, et al., Scientific Reports, 10, 17624 (2020). [7] P.V. Seredin, et al., International Journal of Molecular Sciences, 22, 6510 (2021). © 2021 The Authors
Imaging the molecular orientation at the disperse-continuous interface of a PP-PA6 blend by the Four-Polarization FTIR Method
(POLY-CHAR, 2023-01-24) Bertin, M; Nguyen, D; Verbeek, CJR; Vongsvivut, JP
Fourier-transform infrared spectroscopy (FTIR) is a well-known technique used to analyze the chemical composition of polymeric materials by measuring the absorption of infrared light over a range of wavelengths, where each absorption peak corresponds to a specific chemical bond. A chemical map image can be constructed by acquiring multiple IR spectra with a specified step distance over an area. Furthermore, it is possible to extract information about the molecular orientation by utilizing linearly polarized light, as the absorption intensity varies with the polarization angle of the incident radiation. Recently, a mathematical method was introduced which makes it possible to create a complete vector map of the dipole orientation of a selected vibrational mode by utilizing measurements of IR spectra in four different polarized orientation. In this work, we seek to gain insight into the molecular orientation near the interface between the disperse phase and the continuous matrix of a polypropylene-polyamide 6 (PP-PA6) blend by comparing an uncompatibilized blend with a blend compatibilized with the addition of maleic anhydride grafted polypropylene (PP-g-MA) [4] and another with the application of a novel in-situ plasma treatment. The goal of plasma treatment is to introduce polar oxygen groups such as C−O, C=O, and O−C=O, promoting stronger interactions between phases. Plasma treatment is widely used as a surface treatment to increase wettability and adhesion, but its use as a compatibilization method of blends is relatively new and has already provided positive results. However, the mechanisms behind the improvements in this context are mostly unknown so the current research will provide valuable data for further development of this novel polymer modification method. © 2023 The Authors.
Orientation information added to IR hyperspectral imaging: silk and paracetamol
(Society of Photo-Optical Instrumentation Engineers (SPIE), 2019-12-30) Ryu, M; Ng, SH; Vongsvivut, JP; Tobin, MJ; Morikawa, J; Juodkazis, S
Malus (1809) and Beer-Lambert (1729) laws can be combined to separate birefringence and dichroism contributions in IR hyperspectral imaging. This is achieved by using two optically aligned polarisers for the highest transmittance. By rotation sample between the two aligned polarisers, spectra are taken at several angles for a better fit. This method is shown to resolve orientation of sub-diffraction patterns which are ~50 times smaller than the diffraction limit of 5:1 μm (at the wavelength 3.3 μm). Application potential for very different fields ranging from microscopy of bio- and pharmaceutical materials (silk and paracetamol) to satellite imaging of ocean waves with altimeter at K∝ band of 35.75 GHz or 8.39 cm wavelength will be discussed. © 2019 Society of Photo-Optical Instrumentation Engineers (SPIE).
Reinforcement and deformation behaviors of polyvinyl alcohol/graphene/montmorillonite clay composites
(Elsevier, 2015-10-30) Li, CP; Li, YZ; She, XD; Vongsvivut, JP; Li, JH; She, FH; Gao, WM; Kong, LX
We report the synergistic reinforcement and deformation of polyvinyl alcohol (PVA)/graphene/montmorillonite clay (MMT) composites with the tensile properties being improved greatly. Particularly, the tensile strength and modulus of PVA composite with 0.9 wt% graphene and 0.3 wt% of MMT were improved by more than 58% and 43% when compared to the neat PVA, respectively, and were at least 10% higher than the enhanced sum of dual PVA composites with 0.9 wt% graphene and 0.3 wt% MMT. This reinforcement was resulted from the good dispersion and effective interfacial interactions as confirmed from morphology investigation, increased glass transition temperature and the shift of O–H stretching. When there were no fillers i.e. in situ reduced graphene (IRG) or MMT or their loading was low, high alignment of PVA could be observed, with increased crystallinity, melting point, lamellae thickness but narrowed crystallite size distribution. The synergistic reinforcement of PVA achieved from combined incorporation of IRG and MMT will pave the way for the development of stronger PVA composites in various applications. © 2015 Elsevier Ltd.
Simultaneous crystallization and decomposition of PVA/MMT composites during non-isothermal process
(Elsevier, 2015-10-20) Li, CP; Hou, TT; Vongsvivut, JP; Li, YZ; She, XD; She, FH; Gao, WM; Kong, LX
Decomposition of poly(vinyl alcohol)/montmorillonite clay (PVA/MMT) composites during melting-crystallization was experimentally confirmed by morphology and molecular structure changes. In particular, FTIR spectra show the shift of O-H stretching band as well as enhanced intensities of C-O stretching and CH2 rocking vibrational modes. Furthermore, Raman deconvolution indicates that C-H wagging, CH2-CH wagging, CH-CO bending and CH2 wagging modes in amorphous domains were all decreased greatly. Moreover, this decomposition leads to decreased melting enthalpy, melting point, crystallization enthalpy and crystallization temperature. Crystallization analysis shows that the MMT incorporated slows down the crystallization process in the PVA matrix regardless of the nucleation capability of MMT. Despite the severe decomposition, the crystallization kinetics still corroborated well with common classical models. As a result, molecular structure changes and crystallization retardation observed in this study clearly indicate the strong effects of the thermal degradation on the non-isothermal crystallization of PVA/MMT composites. © 2015 Elsevier B.V.
Single-shot mid-infrared incoherent holography using Lucy-Richardson-Rosen algorithm
(Institute of Optics and Electronics, Chinese Academy of Sciences, 2022-03-18) Anand, V; Han, Ml; Maksimovic, J; Ng, SH; Katkus, T; Klein, AR; Bambery, KR; Tobin, MJ; Vongsvivut, JP; Juodkazis, J
In recent years, there has been a significant transformation in the field of incoherent imaging with new possibilities of compressing three-dimensional (3D) information into a two-dimensional intensity distribution without two-beam interference (TBI). Most of the incoherent 3D imagers without TBI are based on scattering by a random phase mask exhibiting sharp autocorrelation and low cross-correlation along the depth. Consequently, during reconstruction, high lateral and axial resolutions are obtained. Imaging based on scattering requires an astronomical photon budget and is therefore precluded in many power-sensitive applications. In this study, a proof-of-concept 3D imaging method without TBI using deterministic fields has been demonstrated. A new reconstruction method called the Lucy-Richardson-Rosen algorithm has been developed for this imaging concept. We believe that the proposed approach will cause a paradigm-shift in the current state-of-the-art incoherent imaging, fluorescence microscopy, mid-infrared fingerprinting, astronomical imaging, and fast object recognition applications. © The Author(s) 2022. Open Access: This article is licensed under a Creative Commons Attribution 4.0 International License.
Sloths: the unusual hairs from these shaggy heteroclites
(Elsevier, 2023-12) Tridico, SR; Vongsvivut, JP; Kirkbride, KP
Modern sloths, comprising six species within the Bradipopidae and Choloepodidae families, together with the anteaters and armadillos represent an ancient order of distinctive and remarkable placental mammals. Unfortunately, these animals are both endangered and trafficked. Whilst there have been many in-depth studies surrounding the physical and genetic adaptations of sloths required in order to live an almost exclusive arboreal lifestyle, in comparison, literature describing another remarkable feature that they are renowned for – their hair – are somewhat varied in their conclusions. In keeping with their distinctiveness among mammals, sloths exhibit striking and unusual morphological features in their hair. Microscopical images of these features captured using transmitted visible light microscopy and scanning electron microscopy (SEM) are presented, which it is hoped will assist those carrying out forensic wildlife examinations or those called upon to identify the origins of unknown hairs that they may encounter, for example in cultural heritage investigations or animal tracking studies. Although the hairs from Bradipus spp and Choloeps spp exhibit unusual morphology, the results obtained using both laboratory-based and synchrotron-sourced Fourier transform infrared (FTIR) spectrometry indicated that the keratin composition of their hairs did not differ greatly from each other or from that found in other mammals. © 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.
Spectroscopic analysis of age-related changes in the brain lateral ventricles during ageing
(Australian Nuclear Science and Technology Organisation, 2021-11-24) Hollings, A; Hackett, MJ; Tobin, MJ; Klein, AR; Vongsvivut, JP; de Jonge, MD; Bone, S; Webb, S; Lam, V; Takechi, R; Mamo, J
Alzheimer’s disease is the most common form of dementia and poses significant health and economic concerns. Currently, the disease has no cure, and it is expected that over 1 million people could be affected by 2058 in Australia alone. The content and distribution of metals such as Fe, Cu, Zn is known to change in the ageing brain and thus, increased understanding of the mechanistic role of metal dis-homeostasis may illuminate new therapeutic strategies. The brain lateral ventricles, which play a role in controlling metal and ion transport, have shown increasing levels of copper surrounding their walls with ageing. As a redox active metal, copper can induce oxidative stress which is a process that occurs during Alzheimer’s disease onset and progression. Our research group has been interested in determining whether the age-related elevation of copper surrounding the lateral ventricles is inducing oxidative stress in that region. In this study, we have utilised X-Ray Absorption Spectroscopy (XAS) at the Stanford Synchrotron Radiation Lightsource to analyse different chemical forms of sulfur and measure oxidative stress by analysis of disulfides. Additionally, we used the infrared microscopy beamline at the Australian Synchrotron to identify whether any other markers of oxidative stress were present around the ventricles. Further insights into metal dis-homeostasis and its influence on other biochemical pathways, may help to reveal some of the neurochemical mechanisms involved in progression of Alzheimer’s disease. In turn, this may help pave the way for potential preventative or therapeutic models.
Spectroscopic examination of dentine and gingival fluids and their diagnostic capability for the preventive treatment of pathology carious processes in dentine
(Institute of Physics Publishing, 2019-10-22) Seredin, PV; Goloshchapov, DL; Ippolitov, YA; Vongsvivut, JP
Abstract. IR-spectra of the samples of the dentine and gingival fluids obtained with the use of synchrotron radiation can be applied for the diagnostics of the pathological processes of the caries character in a dentine. Vibrations within the range of 2100-2050 cm-1 observed in the spectra of dentine and gingival fluids characteristic of thiocyanates mean the development of the carious pathology. At the same time vibration modes of the carboxyl group of a complex ether detected within the range of 1765 – 1725 cm-1 in the spectra of dentine and gingival fluids certainly confirm the development of caries in dentine. These spectrometric signatures can be certainly and reliably detected also in the gingival fluid, indicating at the fact that the changes proceeding in its molecular composition are referred just to the development of pathological processes in the deep dental tissues. © The Authors - Open Access CC-BY Licence by IOP Publishing Ltd.
The study of molecular composition in biomimetic interface of biocomposite/dentin
(Institute of Physics, 2021-12-06) Goloshchapov, DL; Kashkaro, VM; Ippolitov, IY; Ippolitov, YA; Nikitkov, K; Vongsvivut, JP; Seredin, PV
The aim of the study is the problem of formation of the biomimetic interface between the dental product and dentin of the human tooth as well as the investigations of molecular-chemical features in biointerface with the use of molecular multivariate IR-visualization. The data on synchrotron IR-mapping made enabled to differentiate the regions of sound dentin tissue and biomimetic transition layer and also to determine molecular groups responsible for the process of integration. © 2021 The Authors by IOP Publishing Ltd. Open Access - CC-BY 3.0 licence
Synchrotron infrared micro-spectroscopy of single cells at the Australian Synchrotron
(Australian Microscopy and Microanalysis Society, 2016-02-04) Bambery, KR; Tobin, MJ; Puskar, L; Martin, D; Vongsvivut, JP
Infrared Microspectroscopy is increasingly revealing valuable bio-chemical information of biological and biomedical systems beyond the tissue level at the single cell level. At the Australian Synchrotron Infrared Microscopy beamline, FTIR spectroscopy provides sensitive molecular fingerprinting for tissues and cells without the need for sample pre-treatment with stains or external markers. Due to the brightness of a synchrotron source, good signal to noise at high spatial resolution (diffraction limited) can routinely be performed at the single cell level. In the study of live microbiological systems the principal restriction on the application of infrared microspectroscopy is the strong absorbance by water in the region of 1650 cm-1, overlaying the Amide I absorption band of proteins. The combination of a highly focused synchrotron beam with liquid cells constructed with microfabricated spacers of 6 to 8 microns in thickness have enabled complete mid-IR spectra to be obtained of single live cells under aqueous media within short scan times. Some applications include analysis of spectral changes in normal single living cells, diagnosing different disease states, discrimination of cell types and monitoring the effects of drug treatment at the single cell level. Details of these studies conducted at the infrared microscopy beamline at the Australian Synchrotron are presented.
Synchrotron IR-microspectroscopy-based visualization of molecular and chemical interactions between dental cement, biomimetic composite and native dental tissue
(Pirogov Russian National Research Medical University, 2019-08-01) Goloshchapov, DL; Kashkarov, VM; Ippolitov, YA; Ippolitov, IY; Vongsvivut, JP; Seredin, PV
The low affinity of composite materials for the hard tissue of human teeth poses a challenge to restorative dentists. This study was undertaken to explore molecular and chemical characteristics of the interface between the dental cement, the buffer layer formed from a next generation biomimetic material that mimics the organic mineral composition of human enamel and dentin, and the intact native hard dental tissue. Seven plane-parallel dental slices were analyzed using synchrotron IR microspectroscopy. The obtained absorption spectra of functional molecular groups were organized into cluster maps. This allowed us to identify the intact tissue, the adhesive agent and the biomimetic layer at their interface and to localize and measure concentrations of functional groups involved in the integration of the biomimetic composite into the hard tissue of the human tooth. The proposed biomimetic material is based on nanocrystal carbonate-substituted calcium hydroxyapatite synthesized from a biogenic calcium source and a complex of basic polar amino acids copying the composition of the human tooth and can form a functional bond with hard dental tissue. © 2019 The Authors. Open access under Creative Commons Attribution 4.0 International (CC BY 4.0) License.
Synchrotron macro ATR-FTIR: where we are and what’s next for live-cell measurement
(Australian Nuclear Science and Technology Organisation, 2020-11-19) Vongsvivut, JP; Pérez-Guaita, D; Nankervis, L; Massey, A; Ampt, C; McKinlay, J; Sandt, C; Tobin, MJ
This presentation aims to provide a summary on the recent applications of our synchrotron macro ATR-FTIR microspectroscopy, unique to the Australian Synchrotron’s Infrared Microspectroscopy (IRM) beamline. The technique provides molecular information with sub-cellular resolution down to 1-2 m beyond the resolution limit allowed for standard synchrotron-FTIR setups and further simplifies otherwise complicated sample preparation [1]. Since the technique was made available for users in 2016, this high-resolution chemical mapping capability has facilitated diverse experiments on the beamline expanding its applications into many new areas. Some of the recent examples include novel environmental sustainable geopolymer concretes [2,3], archaeological bones [4] and spider silk cross-sections [5]. The second part of the presentation will highlight further development of the macro ATR-FTIR technique specifically for live-cell measurement in an aqueous environment. Through the collaboration with the SMIS beamline at SOLEIL (France), we undertook a beamtime experiment using their inverted ATR-FTIR accessory to acquire spectra from live red blood cells. The experience and knowledge gained from this international beamtime experiment, together with the effort from our mechanical engineering team, have resulted in an optical design to be developed into the first prototype of ATR-FTIR setup for live-cell measurement. References [1] J. Vongsvivut, D. Pérez-Guaita, B. R. Wood, P. Heraud, K. Khambatta, D. Hartnell, M. J. Hackett, and M. J. Tobin, “Synchrotron Macro ATR-FTIR Microspectroscopy for High-Resolution Chemical Mapping of Single Cells,” Analyst 144, 10, 3226-3238 (2019). [2] A. Hajimohammadi, T. Ngo, J. L. Provis, T. Kim, and J. Vongsvivut, “High Strength/Density Ratio in a Syntactic Foam Made from One-Part Mix Geopolymer and Cenospheres,” Composites Part B, 173, 106908 (2019). [3] A. Hajimohammadi, T. Ngo, and J. Vongsvivut, “Interfacial Chemistry of a Fly Ash Geopolymer and Aggregates,” Journal of Cleaner Production, 231, 980-989 (2019). [4] J. J. Miszkiewicz, C. Rider, S. Kealy, C. Vrahnas, N. A. Sims, J. Vongsvivut, M. J. Tobin, M. J. L. A. Bolunia, A. S. De Leon, A. L. Peñalosa, P. S. Pagulayan, A. V. Soriano, R. Page, and M. F. Oxenham, “Asymmetric Midshaft Femur Remodelling in an Adult Male with Left Sided Hip Joint Ankylosis, Metal Period Nagsabaran, Philippines,” International Journal of Palaeopathology, 31, 14 (2020). [5] C. Haynl, J. Vongsvivut, K. R. H. Mayer, H. Bargel, V. J. Neubauer, M. J. Tobin, M. A. Elgar, and T. Scheibel, “Dimensional Stability of a Remarkable Spider Foraging Web Achieved by Synergistic Arrangement of Silk Fibers,” accepted for publication in Scientific Reports (2020)
Three-dimensional phase imaging with near infrared synchrotron beam using phase-retrieval algorithm
(Society of Photo-Optical Instrumentation Engineers (SPIE), 2023-03-08) Han, M; Smith, D; Ng, SH; Katkus, TA; Simon, A; Rajeswary, JF; Praveen, PA; Tobin, MJ; Vongsvivut, JP; Juodkazis, S; Anand, V
The near infrared (NIR) part of the infrared synchrotron beam is usually dumped to improve the signal to noise ratio of spectral imaging. In this study, this NIR synchrotron beam has been extracted and used for three-dimensional (3D) phase imaging. A pinhole was inserted in the path of the fork shaped NIR synchrotron beam and the Airy diffraction pattern was aligned with biochemical samples and the diffracted intensity distribution was captured using an image sensor sensitive to NIR. A phase retrieval algorithm was used to estimate the 3D phase distribution at the object plane from the recorded intensity distribution. © (2023) Society of Photo-Optical Instrumentation Engineers (SPIE)
Transforming spirulina maxima biomass into ultrathin bioactive coatings using an atmospheric plasma jet: a new approach to healing of infected wounds
(Wiley, 2023-09-15) Pham, T; Nguyen, TT; Nguyen, NH; Hayles, A; Li, WS; Pham, DQ; Nguyen, CK; Nguyen, T; Vongsvivut, JP; Ninan, N; Sabri, YM; Zhang, W; Vasiliev, K; Truong, VK
The challenge of wound healing, particularly in patients with comorbidities such as diabetes, is intensified by wound infection and the accelerating problem of bacterial resistance to current remedies such as antibiotics and silver. One promising approach harnesses the bioactive and antibacterial compound C-phycocyanin from the microalga Spirulina maxima. However, the current processes of extracting this compound and developing coatings are unsustainable and difficult to achieve. To circumvent these obstacles, a novel, sustainable argon atmospheric plasma jet (Ar-APJ) technology that transforms S. maxima biomass into bioactive coatings is presented. This Ar-APJ can selectively disrupt the cell walls of S. maxima, converting them into bioactive ultrathin coatings, which are found to be durable under aqueous conditions. The findings demonstrate that Ar-APJ-transformed bioactive coatings show better antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa. Moreover, these coatings exhibit compatibility with macrophages, induce an anti-inflammatory response by reducing interleukin 6 production, and promote cell migration in keratinocytes. This study offers an innovative, single-step, sustainable technology for transforming microalgae into bioactive coatings. The approach reported here has immense potential for the generation of bioactive coatings for combating wound infections and may offer a significant advance in wound care research and application. © 2023 The Authors. Small published by Wiley-VCH GmbH. This is an open access article under the terms of the Creative Commons Attribution License.

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