I developed a universal Polymer-Assisted Graphene Transfer (PAGT) process for monolayer and multilayer sheets on any substrate including silicon, silicon dioxide, and Complementary Metal Oxide Semiconductor (CMOS) chips.
Suspended graphene gas sensor
I pioneered the suspend graphene gas sensor that uses both top and bottom surfaces for sensing. Using the PAGT process, I suspended graphene over centimetres of area on silicon nanowire arrays fabricated by metal-assisted chemical etching (MACE). This device offers faster signal response, and more than double signal response compared to supported graphene gas sensors. With electronics the smart sensor included automatic zeroing, curve fitting and temperature control for higher efficiency. This device finds application in ammonia and acetone gas detection in breath that are correlated to kidney failure and diabetes, respectively. This work has delivered one journal publication and three conference proceedings.
CMOS ISFET pH sensing system plasma-etching
I pioneered a material selective plasma-etch process for post-processing of CMOS Ion-Sensitive Field-Effect Transistors (ISFETs) sensor system on chip. Using this process, I improved the time stability of the CMOS ISFET sensors while identifying the physical location of trapped charge within the device. This process can be used to optimise the sensing membrane and signal readout of any biochemical sensor integrated in CMOS. This work was in collaboration with Dr P. Georgiou in the Centre of Bio-Inspired Technology (CBIT) and has produced two journal publications and two conference proceedings.
Graphene on CMOS ISFET pH sensing systems
I pioneered the world’s first graphene on CMOS ISFET chip using the developed PAGT process. Taking advantage of graphene’s ultra thin, very high mechanical robustness and adsorption site capacity, the ISFET sensors showed 50% reduction in drift while maintaining pH sensitivity. Further development of this work is being carried out and graphene can be the key to stop the drift of ISFET sensors due to exposure to electrolyte solutions. This work has produced one journal publication and one conference proceeding.
Environmentally Friendly Quasi-Ambient Temperature bonding process
I am leading the hardware development of an environmentally friendly and room-temperature process to bond and package electronic devices and systems. This project is in collaboration with Universities of Manchester and Loughborough and industrial partners in the UK including Indium Corporation©, TT Electronics©, Dynex Semiconductor© and more. In this work I am using lasers to process the nonmaterial Nanofoil® and characterise the bonded system performance. This work has produced one journal paper so far.
My dream is to contribute and make an impact in science and improve the healthcare technology through research in smart systems. My current research focus is on the design, fabrication, implementation and data processing of smart gas sensing systems for breath analysis. More specifically, my research is guided by the following principal areas:
Chemical detection of exhaled gases at trace concentrations
With the advancement of Gas Chromatography Mass Spectrometry (GC-MS) and Ion-Mobility Spectrometer (IMS) technologies we are able to detect thousands of gases from the exhaled breath and the breath analysis research has shown correlations of those gases with chronic diseases such as lung cancer, diabetes, kidney failure and many more. Using this knowledge, smart systems can be developed to monitor in real-time and non-invasively the human body to combat chronic diseases and save lives.
Mechanical monitoring of respiratory patterns and their interpretation
Our breath is a bank of information about our body. The chemical analysis of the exhaled gases is not the only path for information extraction. The mechanics of breath are a very good source of information for asthma patients, Chronic Obstructive Pulmonary Disease (COPD) and more. This research field is approached using smart breath monitoring systems that log in real-time the respiratory rate and cycle and analyse the data.
Point-of-Care smart systems for early disease diagnosis
The GC-MS and IMS systems are big, expensive and slow and require experts to operate them. Therefore, there is a gap to develop Point-of-Care (PoC) smart systems that are cheap, portable and easy to use by clinicians and even the public. Breath analysis is being used for years, for example, the alcohol test using a breathalyser to provide non-invasive measurement of alcohol in the blood stream. The world needs more PoC systems that advance the healthcare technology and combat diseases to save lives.