9 March 2017:
A new publication from CNBP researchers (lead author Jonathan Hall pictured) presents a new model for generating whispering gallery mode spectra for multilayer microspheres.
The work has just been reported in the journal ‘Optics Express’ and is accessible online.
Journal: Optics Express.
Title: Unified theory of whispering gallery multilayer microspheres with single dipole or active layer sources.
Authors: Jonathan M. M. Hall, Tess Reynolds, Matthew R. Henderson, Nicolas Riesen, Tanya M. Monro, and Shahraam Afshar.
Abstract: The development of a fast and reliable whispering gallery mode (WGM) simulator capable of generating spectra that are comparable with experiment is an important step forward for designing microresonators. We present a new model for generating WGM spectra for multilayer microspheres, which allows for an arbitrary number of concentric dielectric layers, and any number of embedded dipole sources or uniform distributions of dipole sources to be modeled. The mode excitation methods model embedded nanoparticles, or fluorescent dye coatings, from which normalized power spectra with accurate representation of the mode coupling efficiencies can be derived. In each case, the emitted power is expressed conveniently as a function of wavelength, with minimal computational load. The model makes use of the transfer-matrix approach, incorporating improvements to its stability, resulting in a reliable, general set of formulae for calculating whispering gallery mode spectra. In the specific cases of the dielectric microsphere and the single-layer coated microsphere, our model simplifies to confirmed formulae in the literature.
30 November 2016:
Exciting translational work by CNBP researchers (project leader Dr Erik Schartner pictured left) has resulted in the development of an optical fibre probe that distinguishes breast cancer tissue from normal tissue – potentially allowing surgeons to be much more precise when removing breast cancer. The work has just been reported in the journal ‘Cancer Research’ and is accessible online.
Journal: Cancer Research.
Title: Cancer Detection in Human Tissue Samples Using a Fiber-Tip pH Probe.
Authors: Erik P. Schartner, Matthew R. Henderson, Malcolm Purdey, Deepak Dhatrak, Tanya M. Monro, P. Grantley Gill and David F. Callen.
Intraoperative detection of tumorous tissue is an important unresolved issue for cancer surgery. Difficulty in differentiating between tissue types commonly results in the requirement for additional surgeries to excise unremoved cancer tissue or alternatively in the removal of excess amounts of healthy tissue. Although pathologic methods exist to determine tissue type during surgery, these methods can compromise postoperative pathology, have a lag of minutes to hours before the surgeon receives the results of the tissue analysis, and are restricted to excised tissue. In this work, we report the development of an optical fiber probe that could potentially find use as an aid for margin detection during surgery. A fluorophore-doped polymer coating is deposited on the tip of an optical fiber, which can then be used to record the pH by monitoring the emission spectra from this dye. By measuring the tissue pH and comparing with the values from regular tissue, the tissue type can be determined quickly and accurately. The use of a novel lift-and-measure technique allows for these measurements to be performed without influence from the inherent autofluorescence that commonly affects fluorescence-based measurements on biological samples. The probe developed here shows strong potential for use during surgery, as the probe design can be readily adapted to a low-cost portable configuration, which could find use in the operating theater. Use of this probe in surgery either on excised or in vivo tissue has the potential to improve success rates for complete removal of cancers.
10 August 2016:
Researchers from the CNBP have published a paper representing the first major study of the stability and compatibility of the major classes of photochromic compounds within the microstructured optical fibre (MOF) environment.
In developing light-responsive surfaces, investigators face several challenges, not only in achieving high photostationary states and fully reversible switching, but also in fluorescence properties and fatigue resistance upon continuous exposure to high intensity light. However, information on the latter two are often lacking as studies on photochromic compounds are often focused on photoswitching, or absorbance and colour changes. To address this gap in literature, the fluorescence and photostability of four major types of photochromic molecules (azobenzene, spiropyran, indolyfulgide and diarylalkene) when dissolved in DMSO, or acetonitrile, or adsorbed to a MOF silica surface were investigated.
Journal: Sensors and Actuators B: Chemical.
Publication title: A Comparative Study of the Fluorescence and Photostability of Common Photoswitches in Microstructured Optical Fibre.
Authors: Daniel B. Stubing (pictured top left), Sabrina Heng, Tanya M. Monro and Andrew D. Abell.
Abstract: The fluorescence spectra and photostability under 532 nm laser excitation of four different common photoswitches (an azobenzene, spiropyran, indolylfulgide, and a diarylperfluorocyclopentene) were investigated in a silica microstructured optical fibre. An example of each photoswitch was examined in solution and physically adsorbed to the silica fibre surface. This comparison was made to define fluorescence behaviour in these two states and to determine which photoswitch has the best performance in this light intense microenvironment. The azobenzene and the spiropyran switches demonstrated the strongest fluorescence response and the least degradation of the fluorescence signal.
The paper is available online.
13 May 2016:
CNBP researchers have created nanoscale biosensors that are capable of sensing Zn2+ ions in biological samples. Such sensors have potential application in disease diagnosis and study, as well as in environmental sensing. The study was published in the journal ACS Applied Materials and Interfaces, May 13th, 2016.
Publication title: Microstructured Optical Fiber-based Biosensors: Reversible and Nanoliter-Scale Measurement of Zinc Ions.
Authors: Sabrina Heng (pictured), Christopher A. McDevitt, Roman Kostecki, Jacqueline R. Morey, Bart A. Eijkelkamp, Heike Ebendorff-Heidepriem, Tanya M. Monro, and Andrew D. Abell.
Sensing platforms that allow rapid and efficient detection of metal ions would have applications in disease diagnosis and study, as well as environmental sensing. Here, we report the first microstructured optical fiber-based biosensor for the reversible and nanoliter-scale measurement of metal ions. Specifically, a photoswitchable spiropyran Zn2+ sensor is incorporated within the microenvironment of a liposome attached to microstructured optical fibers (exposed-core and suspended-core microstructured optical fibers). Both fiber-based platforms retains high selectivity of ion binding associated with a small molecule sensor, while also allowing nanoliter volume sampling and on/off switching. We have demonstrated that multiple measurements can be made on a single sample without the need to change the sensor. The ability of the new sensing platform to sense Zn2+ in pleural lavage and nasopharynx of mice was compared to that of established ion sensing methodologies such as inductively coupled plasma mass spectrometry (ICP-MS) and a commercially available fluorophore (Fluozin-3), where the optical-fiber-based sensor provides a significant advantage in that it allows the use of nanoliter (nL) sampling when compared to ICP-MS (mL) and FluoZin-3 (μL). This work paves the way to a generic approach for developing surface-based ion sensors using a range of sensor molecules, which can be attached to a surface without the need for its chemical modification and presents an opportunity for the development of new and highly specific ion sensors for real time sensing applications.
The paper is available online.
30 March 2016:
CNBP Chief Investigator Prof. Tanya Monro was one of three top tier scientists presenting today, at the Australian National Press Club in Canberra. The topic under discussion, gender inequalities in the scientific workplace and what can be done to best stop the science brain drain that is forcing out some of Australia’s best and most talented minds.
Joining Prof. Tanya Monro in discussion, were Professors Emma Johnston and Nalini Joshi.
You can view the full Press Club address from these three inspiring scientists via this ABC online stream.
14 March 2016:
One of Australia’s favourite outdoor festivals – WOMADelaide -has featured CNBP Advocate and CI Tanya Monro.
Tanya joined internationally celebrated American academic and award winning author, Naomi Oreskes and Australia’s Dr Karl Kruzelnicki, in a panel discussion that examined the theme – ‘Should We Trust Scientists?’
The discussion featured as part of the WOMADelaide Planet Talks 2016 program and can be viewed online in its entirety.
Some of the big questions asked of the panel – Who should we trust and why? When should we accept what scientists say? How is that scientists do not always agree when analyzing the same information? Issues covered – the role of deep empathy, big brains and peer reviewed consideration.
21 November 2015:
CNBP Advocate and Chief Investigator, Prof Tanya Monro, was one of a select group of speakers presenting at the Adelaide TEDx event for 2015.
Tanya’s talk – on the intriguing topics of beauty and science – captured the imagination of a packed Adelaide Town Hall with discussion points including, “Physics is really about the art.”
A huge success, the Adelaide TEDx event incorporated a program of talks, video and live speakers, sparking deep discussion and connection.
See the web site for additional information.
27 August 2015:
A team headed up by CNBP Chief Investigators Prof. Dayong Jin and Prof. Tanya Monro has been recognised for its innovative research in developing super-bright nanocrystals (termed Super Dots), winning the Eureka 2015 Prize for Excellence in Interdisciplinary Scientific Research.
The Super Dots team, consisting of Dayong Jin, CNBP, University of Technology Sydney and Macquarie University; Tanya Monro, CNBP, University of South Australia and University of Adelaide; and Bradley Walsh, Minomic International and Macquarie University, was awarded the prize for its work in the creation and use of nanocrystals that can illuminate hidden diseased cells in a living body and which also has application in the labeling, coding and authentication space.
Based on advances in diverse fields including material chemistry, optical physics, nanotechnology, biotechnology, computational modelling and instrumentation engineering, Super Dot technology is truly interdisciplinary in nature explained Prof. Jin.
“Our invention is a typical example of an interdisciplinary approach. By sourcing advances in physics, chemistry and biology, we have been able to breakthrough bottleneck issues in material sciences and optical physics, allowing us to develop a new transformational technology.”
He added, “Research within a single discipline is interesting, but interdisciplinary research, working with collaborators with a shared focus as a team, is far more exciting and rewarding.”
Additional information on this winning team is available online from the Australian Museum – Eureka web site.
02 June 2015:
CNBP Advocate and Chief Investigator, Prof Tanya Monro was Moderator at the RiAus ECR Network event entitled Beyond Competitive Grants. The event featured a number of speakers who presented case studies of effective approaches to getting non-competitive funding.
Further information available from the RiAus web site : http://riaus.org.au/events/beyond-competitive-grants/
13 April 2015: CNBP talks to Science Teachers:
Dr Georgios Tsiminis was invited to represent the University of Adelaide at the Science Teachers Association of South Australia Annual Conference and Expo 2015 as an invited Cutting Edge Speaker. Hosted at Brighton Secondary School with an audience of Science teachers from around South Australia.
The talk was titled “Listening to molecules using light: optical detection of chemicals” and co-authors include Dr Joanna Brooks (ARC Centre for Research on Ageing, Health and Wellbeing at the Australian National University), Nigel Spooner (IPAS), Tanya Monro (UniSA/CNBP), Fenghong Chu (Shanghai University of Electric Power).
The talk gave an overview of how light can be used as a tool for detecting chemicals in complex samples and focused on using optical fibres as photonic tools for chemical sensing by Raman spectroscopy. Two examples were given, measuring vitamin B12 in the scope of exploring vitamin B12 deficiency as a modifiable risk factor for dementia and Alzheimer’s; and explosives detection, where Raman spectroscopy was performed using microstructtured suspended core optical fibres to enhance the signal and enable the detection of fundamentally different explosives (TNT and hydrogen peroxide) using the same sensor at quantities of less than a microgram. Both examples highlight the great flexibility of photonic technologies for chemical sensing and establish the cross-disciplinary nature of research undertaken within the CNBP, IPAS and the University of Adelaide.