ORCID Profile
0000-0002-6845-4653
Current Organisations
Australian National University
,
CSIRO
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Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D0TC05719C
Abstract: EHD printing of discrete conducting polymer arrays, bridging the electrodes for highly sensitive chemiresistive gas sensors.
Publisher: BMJ
Date: 09-2022
DOI: 10.1136/BMJOPEN-2021-060326
Abstract: The terms ‘precision medicine’ and ‘personalised medicine’ have become key terms in health-related research and in science-related public communication. However, the application of these two concepts and their interpretation in various disciplines are heterogeneous, which also affects research translation and public awareness. This leads to confusion regarding the use and distinction of the two concepts. Our aim is to provide a snapshot of the current understanding of these concepts. Our study will use Rodgers’ evolutionary concept analysis to systematically examine the current understanding of the concepts ‘precision medicine’ and ‘personalised medicine’ in clinical medicine, biomedicine (incorporating genomics and bioinformatics), health services research, physics, chemistry, engineering, machine learning and artificial intelligence, and to identify their respective attributes (clusters of characteristics) and surrogate and related terms. A systematic search of the literature will be conducted for 2016–2022 using databases relevant to each of these disciplines: ACM Digital Library, CINAHL, Cochrane Library, F1000Research, IEEE Xplore, PubMed/Medline, Science Direct, Scopus and Web of Science. These are among the most representative databases for the included disciplines. We will examine similarities and differences in definitions of ‘precision medicine’ and ‘personalised medicine’ in the respective disciplines and across (sub)disciplines, including attributes of each term. This will enable us to determine how these two concepts are distinguished. Following ethical and research standards, we will comprehensively report the methodology for a systematic analysis following Rodgers’ concept analysis method. Our systematic concept analysis will contribute to the clarification of the two concepts and distinction in their application in given settings and circumstances. Such a broad concept analysis will contribute to non-systematic syntheses of the concepts, or occasional systematic reviews on one of the concepts that have been published in specific disciplines, in order to facilitate interdisciplinary communication, translational medical research and implementation science.
Publisher: AIP Publishing
Date: 09-2023
DOI: 10.1063/5.0153029
Publisher: Wiley
Date: 13-01-2021
DOI: 10.1002/RMV.2211
Abstract: Coronavirus disease 2019 (Covid‐19), caused by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection, is now pandemic. While most Covid‐19 patients will experience mild symptoms, a small proportion will develop severe disease, which could be fatal. Clinically, Covid‐19 patients manifest fever with dry cough, fatigue and dyspnoea, and in severe cases develop into acute respiratory distress syndrome (ARDS), sepsis and multi‐organ failure. These severe patients are characterized by hyperinflammation with highly increased pro‐inflammatory cytokines including IL‐6, IL‐17 and TNF‐alpha as well as C‐reactive protein, which are accompanied by decreased lymphocyte counts. Clinical evidence supports that gut microbiota dysregulation is common in Covid‐19 and plays a key role in the pathogenesis of Covid‐19. In this narrative review, we summarize the roles of intestinal dysbiosis in Covid‐19 pathogenesis and posit that the associated mechanisms are being mediated by gut bacterial metabolites. Based on this premise, we propose possible clinical implications. Various risk factors could be causal for severe Covid‐19, and these include advanced age, concomitant chronic disease, SARS‐CoV‐2 infection of enterocytes, use of antibiotics and psychological distress. Gut dysbiosis is associated with risk factors and severe Covid‐19 due to decreased commensal microbial metabolites, which cause reduced anti‐inflammatory mechanisms and chronic low‐grade inflammation. The preconditioned immune dysregulation enables SARS‐CoV‐2 infection to progress to an uncontrolled hyperinflammatory response. Thus, a pre‐existing gut microbiota that is erse and abundant could be beneficial for the prevention of severe Covid‐19, and supplementation with commensal microbial metabolites may facilitate and augment the treatment of severe Covid‐19.
Publisher: American Chemical Society (ACS)
Date: 06-10-2015
Publisher: MDPI AG
Date: 24-03-2021
DOI: 10.3390/S21072271
Abstract: An electronic nose (Enose) relies on the use of an array of partially selective chemical gas sensors for identification of various chemical compounds, including volatile organic compounds in gas mixtures. They have been proposed as a portable low-cost technology to analyse complex odours in the food industry and for environmental monitoring. Recent advances in nanofabrication, sensor and microcircuitry design, neural networks, and system integration have considerably improved the efficacy of Enose devices. Here, we highlight different types of semiconducting metal oxides as well as their sensing mechanism and integration into Enose systems, including different pattern recognition techniques employed for data analysis. We offer a critical perspective of state-of-the-art commercial and custom-made Enoses, identifying current challenges for the broader uptake and use of Enose systems in a variety of applications.
Publisher: American Chemical Society (ACS)
Date: 10-05-2022
DOI: 10.1021/ACS.CHEMREV.1C00990
Abstract: Optical metasurfaces are planar metamaterials that can mediate highly precise light-matter interactions. Because of their unique optical properties, both plasmonic and dielectric metasurfaces have found common use in sensing applications, enabling label-free, nondestructive, and miniaturized sensors with ultralow limits of detection. However, because bare metasurfaces inherently lack target specificity, their applications have driven the development of surface modification techniques that provide selectivity. Both chemical functionalization and physical texturing methodologies can modify and enhance metasurface properties by selectively capturing analytes at the surface and altering the transduction of light-matter interactions into optical signals. This review summarizes recent advances in material-specific surface functionalization and texturing as applied to representative optical metasurfaces. We also present an overview of the underlying chemistry driving functionalization and texturing processes, including detailed directions for their broad implementation. Overall, this review provides a concise and centralized guide for the modification of metasurfaces with a focus toward sensing applications.
Publisher: Cold Spring Harbor Laboratory
Date: 18-06-2021
DOI: 10.1101/2021.06.17.448904
Abstract: Electrochemical biosensors allow the rapid, selective, and sensitive transduction of critical biological parameters into measurable signals. However, current electrochemical biosensors often fail to selectively and sensitively detect small molecules due to their small size and low molecular complexity. We have developed an electrochemical biosensing platform that harnesses the analyte-dependent conformational change of highly selective solute-binding proteins to lify the signal generated by analyte binding. Using this platform, we constructed and characterized two biosensors that can sense leucine and glycine, respectively. We show that these biosensors can selectively and sensitively detect their targets over a wide range of concentrations – up to seven orders of magnitude – and that the selectivity of these sensors can be readily altered by switching the bioreceptor’s binding domain. Our work represents a new paradigm for the design of a family of modular electrochemical biosensors, where access to electrode surfaces can be controlled by protein conformational change.
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D1MA00976A
Abstract: Mixed-dimensional 2D/3D perovskite-based NO 2 gas sensors were developed with swift response, great sensitivity and good selectivity. The 2D/3D devices have significantly better moisture stability than the 3D devices.
Publisher: Cold Spring Harbor Laboratory
Date: 12-01-2022
DOI: 10.1101/2022.01.12.22269125
Abstract: Introduction. The terms "precision medicine" and "personalised medicine" have become key terms in health-related research, and in science-related public communication. However, the application of these two concepts and their interpretation in various disciplines are heterogeneous, which also affects research translation and public awareness. This leads to confusion regarding the use and distinction of the two concepts. Methods and analysis. Our study aims at using Rodger's concept analysis method to systematically examine and distinguish the current understanding of the concepts "precision medicine" and "personalised medicine" in clinical medicine, biomedicine (incorporating genomics and bioinformatics), health services research physics, chemistry, engineering machine learning, and artificial intelligence, and to identify their respective attributes (clusters of characteristics) and surrogate and related terms. We will analyse similarities and differences in definitions in the respective disciplines and across different (sub)disciplines. The analysis procedure will include (1) a concept identification, (2) a setting, s le, and data source selection, (3) data collection, (4) data analysis and data summary, (5) identification of ex les, and (6) identification of implications for further concept development. Ethics and dissemination. Following ethical and research standards, we will comprehensively report the methodology for a systematic analysis following Roger's[1] concept analysis method. Our systematic concept analysis will contribute to the clarification of the two concepts and distinction in their application in given settings and circumstances. Such a broader concept analysis will contribute to non-systematic syntheses of the concepts, or occasional systematic reviews on one of the concepts that have been published in specific disciplines, in order to facilitate interdisciplinary communication, translational medical research, and implementation science.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0TC02856H
Abstract: Electrochemically bridging the gap between metallic IDE fingers at the percolation threshold for highly sensitive chemiresistors on PET flexible substrates.
Publisher: MDPI AG
Date: 22-10-2015
DOI: 10.3390/S151026866
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1RA03648C
Abstract: Reversible NO 2 sensing by controlling the balance of oxidised and over-oxidised PEDOT.
Publisher: American Chemical Society (ACS)
Date: 07-03-2022
Publisher: American Chemical Society (ACS)
Date: 18-04-2022
Publisher: AIP Publishing
Date: 18-06-2018
DOI: 10.1063/1.5023163
Abstract: Au thin films of thicknesses ranging from 5 to 20 nm were grown in UHV through physical vapour deposition on glass substrates decorated with Pt interdigitated electrodes with 5 μm separation. As expected, a gradual decrease in the electrical resistance of the films was observed as growth proceeded however, when the average film thickness was greater than around 11 nm, the resistance decrease was not smooth but occurred in discrete steps. These resistance steps are attributed to the formation of electrical percolation pathways connecting the electrodes. The s les were then annealed at temperatures between 200 °C and 500 °C for periods of 1 to 22 h with the aim of producing insulating nanoparticle films. Dewetting of the Au films produces nanoparticles whose size and separation depend on annealing temperature and time, as well as the initial thickness of the Au film. The complex electrical resistance behaviour of the film was also monitored during the dewetting process.
Publisher: Elsevier BV
Date: 02-2023
Publisher: American Chemical Society (ACS)
Date: 12-08-2014
DOI: 10.1021/JP5061045
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D0AN02403A
Abstract: Ammonium nitrate mixed with fuel oil (ANFO) is commonly used in improvised explosive devices (IEDs). The development of ANFO vapour sensors that are small, inexpensive, and easy to use will enable widespread IED detection in the context of security and humanitarian demining. Because of concealment and the low vapour pressures of most explosive materials, achieving sufficiently high sensitivity and low limits of detection are some of the main challenges of explosives vapour detection. Here ANFO chemiresistive vapour sensors based on polypyrrole (PPy) percolation networks are presented and compared to gas chromatography-mass spectroscopy (GC/MS) results for ANFO. Improved sensitivities are achieved by using a polymer percolation network instead of a thin film for the gas sensors. Vapour concentrations are detected of 13-180 ppb of ammonia emitted by a variety of different ammonium nitrate-containing fertilisers and fertiliser-diesel mixtures.
Publisher: Wiley
Date: 20-10-2021
Abstract: Chemiresistive sensing is one of the most promising technologies for portable and miniaturized chemical sensing, with applications ranging from air quality monitoring to explosive detection and medical diagnostics. Recently, there have been growing efforts in developing microchip based chemical sensors operating at room temperature with high sensitivity, selectivity, spatial and temporal resolution, long‐term stability, and cost‐effectiveness. Here, the engineering of highly performing miniaturized gas sensors consisting of chemiresistive vertical indium phosphide nanowire (NW) arrays is reported for the first time, and their potential for the selective detection of nitrogen dioxide (NO 2 ), a major air pollutant, is demonstrated. By carefully engineering the NW geometry (i.e., diameter and pitch), a superior sensing performance than those previously reported semiconductor‐based NO 2 sensors is achieved, obtaining a limit of detection of 3.1 ppb at room temperature, with outstanding selectivity, and long‐term stability. Kinetic analysis and electrical simulation further reveal the array geometry correlated sensing mechanism, providing insights for the design of future NW array‐based devices. These findings indicate that, owing to their unique nanoscale structures, material properties, and CMOS compatible manufacture processes, III‐V compound semiconductor NW arrays present a new and promising chemical sensing platform for development of future high performance, miniaturized on‐chip sensing system.
Publisher: Wiley
Date: 20-02-2019
Abstract: Metal-organic frameworks (MOFs) are very promising host materials for nanoscale guest materials. However, some MOFs such as MIL-53 are known to undergo phase transitions which can complicate the guest particle size control. In this study, Pd nanoparticles embedded in Al-MIL-53 were synthesised via (a) electrodeposition and (b) gas-phase reduction. A thorough structural investigation revealed that each synthesis method most likely favoured a different phase of Al-MIL-53, presenting the possibility of MOF phase selection as a technique for size control of embedded nanoparticles. For the first time, we hereby report the use of pair distribution function analysis to successfully investigate the structure and morphology of guest particles embedded in a MOF host.
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1TC03606H
Abstract: Selective chemiresistive gas sensing using metal–organic framework encapsulated ultra-porous metal oxide nanoparticle network.
Publisher: Wiley
Date: 08-03-2022
Abstract: The development of biosensors has become increasingly important to tackle the spread of potentially pandemic pathogens and for the decentralization of healthcare services. Despite progress, achieving selective detection of ultralow concentrations of biomarkers in complex fluids with point‐of‐care devices is a standing challenge. Here, an efficient material platform for the sensing of biomarkers down to attomolar concentrations with excellent selectivity and a tuneable linear response range is reported. It is demonstrated that by decreasing the Au nanoislands on an elsewhere passivated surface, it is possible to more than double their electrochemical response to low biomarker concentrations via a gate‐type mechanism. As an exemplary application, the first sensing of glycated albumin, a key biomarker for diabetes management, in clinically relevant levels by conjugation of a selective DNA aptamer to the Au nanoisland surface is showcased. With a limit of detection of 0.55 × 10 −18 m , the excellent selectivity of this platform against nonspecific biomolecules is validated. This platform shows exceptional sensitivity and selectivity in mouse serum, further highlighting its potential for clinical utility. The versatility of this platform to detect other biomarkers, like miRNAs, is also showcased. These findings provide a flexible material platform for the scalable and low‐cost engineering of future point‐of‐care biosensors.
Publisher: Public Library of Science (PLoS)
Date: 25-07-2022
DOI: 10.1371/JOURNAL.PONE.0269925
Abstract: Portable breath ketone sensors may help people with Type 1 Diabetes Mellitus (T1DM) avoid episodes of diabetic ketoacidosis however, the design features preferred by users have not been studied. We aimed to elucidate breath sensor design preferences of young people with T1DM (age 12 to 16) and their parents to inform the development of a breath ketone sensor prototype that would best suit their diabetes management needs. To elicit foundational experiences from which design preference ideas could be generated, two commercially available breath ketone sensors, designed for ketogenic diet monitoring, were explored over one week by ten young people with T1DM. Participants interacted with the breath ketone sensing devices, and undertook blood ketone testing, at least twice daily for five days to simulate use within a real life and ambulatory care setting. Semi-structured interviews were conducted post-testing with the ten young participants and their caregivers (n = 10) to elicit preferences related to breath sensor design and use, and to inform the co-design of a breath ketone sensor prototype for use in T1DM self-management. We triangulated our data collection with key informant interviews with two diabetes educators working in pediatric care about their perspectives related to young people using breath ketone sensors. Participants acknowledged the non-invasiveness of breath sensors as compared to blood testing. Affordability, reliability and accuracy were identified as prerequisites for breath ketone sensors used for diabetes management. Design features valued by young people included portability, ease of use, sustainability, readability and suitability for use in public. The time required to use breath sensors was similar to that for blood testing. The requirement to maintain a 10-second breath exhalation posed a challenge for users. Diabetes educators highlighted the ease of use of breath devices especially for young people who tended to under-test using blood ketone strips. Breath ketone sensors for diabetes management have potential that may facilitate ketone testing in young people. Our study affirms features for young people that drive usability of breath sensors among this population, and provides a model of user preference assessment.
Publisher: Wiley
Date: 19-05-2014
Publisher: Elsevier BV
Date: 02-2018
Publisher: Wiley
Date: 20-02-2023
Abstract: Room‐temperature detection of volatile organic compounds in particle‐per‐billion concentrations is critical for the development of wearable and distributed sensor networks. However, sensitivity and selectivity are limited at low operating temperatures. Here, a strategy is proposed to substantially improve the performance of semiconductor sensors. Tunable oxygen vacancies in thick 3D networks of metal oxide nanoparticles are engineered using deep ultraviolet photoactivation. High selectivity and sensitivity are achieved by optimizing the electronic structure and surface activity while preserving the 3D morphology. Cross‐sectional depth analysis reveals oxygen vacancies present at various depths (≈24% at a depth of 1.13 µm), with a uniform distribution throughout the thick films. This results in ≈58% increase in the sensitivity of ZnO to 20‐ppb ethanol at room temperature while ≈51% and 64% decrease in the response and recovery times, respectively. At an operating temperature of 150 °C, oxygen‐vacant nanostructures achieve a lower limit of detection of 2 ppb. Density functional theory analysis shows that inducing oxygen vacancies reduces activation energy for ethanol adsorption and dissociation, leading to improved sensing performance. This scalable approach has the potential for designing low‐power wearable chemical and bio‐sensors and tuning the activity and band structure of porous, thick oxide films for multiple applications.
Publisher: Elsevier BV
Date: 02-2097
Publisher: Wiley
Date: 2023
Abstract: The fast development of the Internet of Things (IoT) has driven an increasing consumer demand for self‐powered gas sensors for real‐time data collection and autonomous responses in industries such as environmental monitoring, workplace safety, smart cities, and personal healthcare. Despite intensive research and rapid progress in the field, most reported self‐powered devices, specifically NO 2 sensors for air pollution monitoring, have limited sensitivity, selectivity, and scalability. Here, a novel photovoltaic self‐powered NO 2 sensor is demonstrated based on axial p–i–n homojunction InP nanowire (NW) arrays, that overcome these limitations. The optimized innovative InP NW array device is designed by numerical simulation for insights into sensing mechanisms and performance enhancement. Without a power source, this InP NW sensor achieves an 84% sensing response to 1 ppm NO 2 and records a limit of detection down to the sub‐ppb level, with little dependence on the incident light intensity, even under % of 1 sun illumination. Based on this great environmental fidelity, the sensor is integrated into a commercial microchip interface to evaluate its performance in the context of dynamic environmental monitoring of motor vehicle exhaust. The results show that compound semiconductor nanowires can form promising self‐powered sensing platforms suitable for future mega‐scale IoT systems.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/C9CP06801E
Abstract: Morphological control of gold nanocrystals is important as their catalytic and optical properties are highly shape dependent.
Publisher: Elsevier BV
Date: 02-2023
Publisher: Wiley
Date: 17-06-2023
Abstract: Gas sensors are of great interest to portable and miniaturized sensing technologies with applications ranging from air quality monitoring to explosive detection and medical diagnostics, but the existing chemiresistive NO 2 sensors still suffer from issues such as poor sensitivity, high operating temperature, and slow recovery. Herein, a high‐performance NO 2 sensors based on all‐inorganic perovskite nanocrystals (PNCs) is reported, achieving room temperature operation with ultra‐fast response and recovery time. After tailoring the halide composition, superior sensitivity of ≈67 at 8 ppm NO 2 is obtained in CsPbI 2 Br PNC sensors with a detection level down to 2 ppb, which outperforms other nanomaterial‐based NO 2 sensors. Furthermore, the remarkable optoelectronic properties of such PNCs enable dual‐mode operation, i.e., chemiresistive and chemioptical sensing, presenting a new and versatile platform for advancing high‐performance, point‐of‐care NO 2 detection technologies.
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5CP06656E
Abstract: The behaviour of HCl in six RTILs reveals significant reactions with [PF 6 ] − anions, but electrochemical sensing is still possible in RTILs with [NTf 2 ] − anions.
Location: United Kingdom of Great Britain and Northern Ireland
Location: Australia
No related grants have been discovered for Krishnan Murugappan.