Papers by Author: Alex Mason

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Authors: Olga Korostynska, Abbasi A. Gandhi, Alex Mason, Ahmed Al-Shamma'a, Syed A.M. Tofail
Abstract: Hydroxyapatite (HA) is a leading biocompatible material extensively used for bone implants as a porous ceramic graft and as a bioactive coating. Electrical characteristics of HA can be employed in implantable devices for real-time in vivo pressure sensor applications such as in knee or hip prosthesis. In particular, high piezo and pyroelectricity of HA, its polarisation by electron beam and selective adsorption of proteins on polarised domains indicate the potential for real-time biosensing applications of HA. For this purpose, a comprehensive understanding of the dielectric behaviour of different forms of HA over a frequency range relevant for biomedical sensing is critical. Such information for HA, especially its frequency dependent dielectric behaviour over the GHz range, is rare. To this end, we report on novel investigations of properties of HA in powder and film forms in the GHz frequency range.
Authors: Alex Mason, Kazunari Ozasa, Olga Korostynska, Ismini Nakouti, Montserrat Ortoneda-Pedrola, Mizuo Maeda, Ahmed Al-Shammaa
Abstract: Euglena is a naturally occurring algae which can be found in any fresh water source.It is non-toxic, easy to handle, visualize and relatively resilient to variation in environment.This, along with the relatively large size of Euglena, means it can be readily used as a modelfor environmental monitoring of other smaller pathogenic micro-organisms (e.g. Escherichiacoli ). Currently the behavior of Euglena is observed through the use of an optical microscopefor sensing purposes. However, this method su ers from following major pitfalls: (1) the sizeand expense of the microscope; (2) the small observation volume (approx. 1 L); (3) the imageprocessing requirements and (4) need for a skilled human operator to acquire those images. Byusing electromagnetic (EM) wave technology in the GHz frequency range we seek to overcomethese challenges, since it has been demonstrated by the authors to be cost e ective, have alarge sensing volume (> 100L) and produce comparatively simple output data. Furthermoreit is possible to use simple software algorithms to process the sensor output data, and providereal-time information on Euglena gracilis viability and quantity. This paper shows proof ofconcept work to verify the feasibility of the proposed EM wave technology as an alternative tothe current optical microscopy methods.
Authors: Olga Korostynska, Jun Jie Yan, Alex Mason, Khalil Arshak, Ahmed Al-Shamma'a
Abstract: This paper reports on the development of a flexible nanopatterning approach using the NanoeNablerTM to manufacture miniaturised sensor arrays platform for real-time water quality assessment. Traditionally biosensors are fabricated by lithography, screen printing, inkjet printing, spin-or deep-coating methods to immobilize the sensing element onto substrate pre-patterned with electrodes. NanoeNablerTM patterning method is benchmarked against other currently adapted approaches for cost-effective sensors arrays manufacture. Sensors measuring ~1 µm diameter or more can be patterned for further employment in molecularly imprinted polymer structures. Notably, the dimensions of the sensor depend on the fluid being patterned and on the interaction forces between the substrate and the patterning tool. Thus, careful selecting of patterning parameters is vital for repeatable and controlled manufacture of sensors to guarantee superior sensitivity. The reported nanopatterning method is capable of accurately placing attoliter to femtoliter volumes of liquids, including proteins and DNAs, onto any substrate, thus making it an ideal technology for biomedical sensors. A custom-made 1 cm2 silicon wafer with 48 interdigited electrodes sensor heads was used as a platform for the multi-sensor array with potential use in a wide range of real-time monitoring applications.
Authors: Olga Korostynska, Alex Mason, Ahmed Al-Shamma'a
Abstract: At present, water quality control is still dominated by laboratory analysis of grab samples. Sensors are only available for a very limited number of parameters and frequently do not entirely meet the needs of the users. Even a brief overview of the state-of-the-art in the real time water monitoring reveals that it is not possible to achieve adequate detection of water parameters by using only one type of sensor. Accordingly, the solution is to merge various technologies into a single system that would employ the best available methods for the detection of specific water contaminants, so as to provide overall superior sensitivity, selectivity and long-term stability, while enabling real-time wireless data collection for enhanced cost-effectiveness. Namely, multi-sensor platforms that utilise the best available methods combined into a single monitoring process are seen as the only way to achieve the holistic monitoring capabilities. It is suggested that a special role in this development is reserved for microwave technology based sensors a missing piece in the puzzle to potentially solve the issue of real-time water quality control. This paper reviews the capabilities of microwave sensors for real-time water quality monitoring as compared to other alternative methods, namely standard UV-VIS optical methods; fibre optic sensors; amperometric sensors, biosensors, specifically-sensitive microelectrodes and lab-on-chip sensing systems.
Authors: Jung H. Goh, Alex Mason, Mark Field, Paul Browning, Ahmed Al-Shamma'a
Abstract: Lactate is known to be an indicator of neurological impairment during aortic aneurysm surgery. It is suggested that analysis of cerebrospinal fluid (CSF) removed during such surgery could provide useful information in this regard. Medical professionals find the prospect of online detection of such analytes exciting, as current practice is time consuming and leads to multiple invasive procedures. Advancing from the current laboratory based analysis techniques to online methods could provide the basis for improved treatment regimes, better quality of care, and enhanced resource efficiency within hospitals. Accordingly, this article considers the use of a low power microwave sensor to detect varying lactate concentrations. Microwave sensors provide a rapid non-invasive method of material analysis, which is robust, cost-effective, and has huge potential for a wide range of biomedical applications.
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