Platform Leader: Wallace Wong
Deputy Platform Leader: Rebecca McCallum (DSTG)
The risk of terror attacks has prompted scientists to invest time and effort in developing smart materials to detect chemical and biological warfare agents. The field of sensors for these materials is extremely broad, encompassing very simple paper-based test strips for liquid chemicals, to large high-tech instruments for detecting biological agents.
In partnership with the Defence Science and Technology Group (DSTG), the Centre is in a unique position to develop portable and robust chemical sensors with high sensitivity and specificity. DST has developed a prototype portable chemical sensor device known as the Black Canary. Having shown interest in expanding the device’s capability, DST is investigating other technologies that can be included in such a device, with particular focus on a photoluminescence-based response system.
This Centre platform brings together expertise in photoluminescent materials, host-guest chemistry, material nanostructuring and gas-flow modelling to aid in the development of this next-generation chemical sensor.
Platform 3.1 will specifically involve the development of a photoluminescent-based chemical sensor with DST. This will be addressed across two main activities:
In addition to defence, chemical sensing also covers applications in medical and environmental fields. Of particular interest are fluorescent materials as reporters for sensing events which can offer improved sensitivity. The capability of the Centre has allowed investigation of organic, inorganic and nanocrystal materials. The standout material developed thus far is inorganic caesium lead halide perovskite nanocrystals. These nanocrystals can detect halide anions with high sensitivity and fast response time through large changes to their fluorescence spectrum.
Initial collaboration between Monash, UoM and DST has shown that these fluorescent nanocrystal reporters can be used to sense methyl bromide, a pest control fumigant. The concept has been patented jointly in 2019. In addition to the development of fluorescent probes, the Centre has started to examine substrates for gas and aerosol sensing.
|Anupama Gulur Srinivas||UniMelb|
|Tze Cin Owyong||UniMelb||PhD|
While Platform 3.1 is one of the Centre’s smallest platforms the research groups of Mulvaney (UniMelb), Wong (UniMelb) and Jasieniak (Monash) work tightly together with DSTG to achieve the platform aims. The particular strengths of the platform are the optical characterisation and sensing test platforms which can assess the performance of chemical probes towards vapours with a focus on methyl bromide and mustards. Mulvaney and team have been able to assess the chemical probes from both the Wong and Jasieniak groups, from state-of-the-art fluorescent organic probes that can detect vapours, the Wong Group have synthesised and developed, to the perovskite probes of the Jasieniak Group at Monash. The team also have the capacity at Monash to perform detailed spectroscopic analysis of chemical probes and develop and assess the performance of perovskite nanocrystal materials as potential probes for halides.
Defence Science and Technology Group (DSTG) has been involved in this platform since establishment and have provided information and guidance on the state-of-the-art application aspects of the platform. DSTG has been developing prototype chemical sensing devices. The main goal of this research platform is to develop chemical probes that can be used to improve prototype devices. To this end, there has been continuous exchange of information and discussions between DSTG and the platform to ensure appropriate focus on problems that DSTG want to solve. Dr Genevieve Dennison, a Defence Scientist and Chemistry Specialist at DSTG, was added as a Partner Investigator to the Centre in late 2019 and is the primary contact point between DSTG and the Centre.
There was consistent progress on the two main research activities in the platform – materials development and materials characterisation. A range of chemical sensor materials were tested including state-of-the-art fluorescent organic probes as well as novel inorganic nanocrystals. The inorganic nanocrystal material provided the breakthrough result showing parts per billion sensitivity towards halide anions in solution (Figure Y). A patent application has been submitted and a research publication is in progress. The characterisation and testing of the chemical probes were enabled by the equipment established at The University of Melbourne and Monash University, which began operations at the start of 2019. While a decision was made to suspend the theory and modelling activities in this platform, a research activity was added involving a new DSTG sensor (Figure Y). This prototype sensor device is extremely compact, the size of a USB stick, and has real-time wireless data transfer capability. The Centre has started work to help improve the optical aspects of the device and has recruited a PhD student starting in 2020 to focus on this prototype device.
The focus for 2020 will be the promising inorganic nanocrystal materials. While these probes perform very well in solution, the reactivity and sensitivity in solid state require optimisation for device applications. Once the solid state and interface chemistry has been optimised, performance in devices will be assessed. Stability and performance tests will be completed for new optical and sensing components of the DSTG compact sensor device.
There have been some changes in personnel in this platform. Dr Genevieve Dennison has been added as a Partner Investigator improving the participation of DSTG in Centre activities. A new PhD student has been recruited to focus on the sensor device project addressing some of the personnel shortage issues. With the completion of a PDRA from the Wong group, CI Wong will step down as the platform leader in 2020 with the promotion of PDRA Wenping Yin filling the position.