15 June 2017:
Researchers from CNBP (lead author Dr Sabrina Heng pictured), have just had a paper published, reporting on three new spiropyran-based reversible sensors for calcium ion.
Journal: Sensors and Actuators B: Chemical.
Publication title: Photoswitchable calcium sensor: ‘On’–‘Off’ sensing in cells or with microstructured optical fibers.
Authors: Sabrina Heng, Adrian M. Mak, Roman Kostecki, Xiaozhou Zhang, Jinxin Peia, Daniel B. Stubing, Heike Ebendorff-Heidepriema, Andrew D. Abell.
Abstract: Calcium is a ubiquitous intracellular signaling ion that plays a critical role in the modulation of fundamental cellular processes. A detailed study of these processes requires selective and reversible sensing of Ca2+ and an ability to quantify and monitor concentration changes in a biological setting. Three new, rationally designed, synthesized and photoswitchable spiropyran-based reversible sensors for Ca2+ are reported. Sensor 1a is highly selective for Ca2+ with an improved profile relative to the other two analogues, 1b and 1c. Formation of the merocyanine–Ca2+ complex is proportional to an increase in Ca2+ released from HEK293 cells on stimulation with ionomycin. The photophysical processes surrounding the binding of Ca2+ to compound 1a were further explored using computational methods based on density functional theory (DFT). The ability of sensor 1a to bind Ca2+ and photoswitch reversibly was also characterized using silica suspended-core microstructured optical fiber (SCF). These SCF experiments (with 100 nM Ca2+) represent a first step toward developing photoswitchable, minimally invasive and highly sensitive Ca2+ sensing platforms for use in a biological setting.
The paper is accessible online.
7 June 2017:
With a focus on STEM learning and the need for innovative outreach approaches, Learning Environments Australia (SA chapter) have coordinated a forum at the University of Adelaide, 7 June 2017, which saw significant support from the CNBP.
Prof Mark Hutchinson (CNBP Director), Tony Crawshaw (CNBP Communications and Outreach Coordinator) and Dr Sabrina Heng (CNBP Researcher, pictured) all participated in the LEA forum, providing talks and answering questions as to the Centre’s successful approach to engaging with schools and students and inspiring the next generation of young scientist.
Joanne Rogers, Head of Science, Concordia College who has been closely involved with CNBP outreach activity, talked about the real life changes experienced by her students, resulting from engagement with CNBP scientists. Students she said, had picked up additional science subjects on the back of CNBP school and laboratory visits.
Other University of Adelaide presenters at the event included Kiri Hagenus, Director, Children’s University; Dr Claudia Szabo, Associate Dean, Faculty of ECMS – MOOC in digital literacy for teachers; and Science’s Prof Bob Hill, who discussed successful Faculty outreach initiatives.
30 November 2016:
CNBP Research Fellows, Associate Professor Guozhen Liu (pictured), Dr Lindsay Parker and Dr Sabrina Heng have undertaken talks at the School of Biomedical Sciences at the University of Melbourne as part of a Biosensor Symposium, Wednesday 30th November, 2016.
Talks were as follows:
Guozhen Liu – Biophotonic Tools for Cytokine Sensing: From an on-cell surface ELISA to a spatial ELISA device.
Lindsay Parker – Biosensors and glycoproteins: linking nanoscience to neuroscience.
Sabrina Heng – Reversible Sensing with a Flip of the Switch.
The symposium shone a spotlight on multidisciplinary research into developing, applying and using biosensors for biomedical sciences.
23 August 2016
CNBP researchers from the University of Adelaide, Michelle Zhang and Sabrina Heng, have undertaken a school outreach session at St. Ignatius College, Adelaide, August 23, 2016.
The scientists spoke to two groups of children in an early-learning program about the science of light and the use of light in medicine. Several hands-on activities were also then run for the children to demonstrate that science can be fun as well as educational.
- the use of UV-sensitive beads for making into a bracelet that was then worn for several outdoor activities
- sunscreen applied to the beads to teach how sunscreen protects against sun-burn
- the use of spectroscopes that can diffract room-light into a series of colourful bands at differing wavelengths (the students were asked to draw what they saw)
- a simple kit that converted youtube videos to holograms
- and CNBP colouring-in sheets that demonstrate life at the nanoscale
Positive feedback from the teachers at St. Ignatius College and also the parents of the children that attended the session was received over the course of a very fulfilling day!
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.
1 May 2016:
CNBP researchers Dr Hannah Brown, Dr Sabrina Heng and Dr Erik Schartner (pictured) presented invited talks to a range of researchers and clinicians at the ‘Scientists in Reproductive Technology (SIRT)’ conference in Adelaide on the 1st of May, 2016.
Explored in their talks were differing ways in which upcoming Centre research might find use within the embryology labs of the future – this tying into the meeting theme “From basic research to clinical practice: How to revolutionise IVF practice.”
Talk titles from the CNBP researchers were as follows:
- Hannah: Haemoglobin: Exciting and unexpected roles in fertility.
- Sabrina: Developing light-driven regenerable chemical tools for biological applications.
- Erik: Developing optical fibre probes for biosensing.
Further information on Scientists in Reproductive Technology (SIRT), a sub-group representing the scientific membership of The Fertility Society of Australia, can be found online.
19 April 2016:
CNBP was happy to host the next generation of young scientists at today’s ‘STEMSEL Photonics’ session at the University of Adelaide node.
STEMSEL clubs, standing for ‘Science, Technology, Engineering, Maths and Social Enterprise Learning’ are an arm of the STEMSEL Foundation which is a not for profit organisation that aims to teach every child how to use electronics.
Over twenty Year 3 to Year 9 students were in attendance at this session, with CNBP researchers Roman Kostecki (a physics focus) and Sabrina Heng (a chemistry focus) helping lead the discussion and activities.
Concepts such as photons, light interaction with matter, Fermat’s principle, emission, absorption, lasers, fibre optics and organic chemistry, were all described and demonstrated.
Both researchers enjoyed the afternoon, showing the kids that science, technology and photonics can be awesomely interesting, as well as really good fun!
21 March 2016:
CNBP researchers Daniel Stubing, Sabrina Heng and Andrew Abell recently published a full paper in the journal ‘Organic and Biomolecular Chemistry’.
The published work presents three new spiropyran photoswitchable sensors and compares their sensitivity to different monovalent metal ions to develop a new reversible lithium ion sensor. These sensing molecules are now able to be further used to create optical devices for the sensing of biological lithium ions, which could help further understanding and treatment of neurological diseases such as manic-depressive illness.
Title: Crowned spiropyran fluoroionophores with a carboxyl moiety for the selective detection of lithium ions
Authors: D. B. Stubing, S. Heng and A. D. Abell
Abstract: The absorbance and fluorescence spectra of carboxylated spiropyrans containing methyl-1-aza-12-crown-4, methyl-1-aza-15-crown-5, methyl-1-aza-18-crown-6 moieties are compared. Characteristic changes in spectra after addition of the alkali metal salts of Li+, Na+, K+ and Cs+ were observed. Chromism induced by the binding of the metal cations was observed as an increase in absorbance and fluorescence. Of these metal cations, the Li+ ion produced the largest change in all three spiropyran systems. Reversible photoswitching of the spiropyran-metal complexes was observed on irradiation with alternating 352 nm UV and white light. This results in reversible fluorescence based sensing of lithium ions with potential for use in a biological sensor device.
The paper is accessible online.
10 March 2016:
Dr Sabrina Heng, CNBP researcher has undertaken a further school visit to Lockleys Primary School in Adelaide as a part of her involvement in the Scientists and Mathematicians in Schools (SMiS) outreach program.
SMiS is a national volunteer program bringing real science, mathematics and ICT into the classroom through ongoing flexible partnerships between teachers and scientists, mathematicians and ICT professionals.
Sabrina has been involved with SMiS since 2010 and working with Lockelys Primary School since mid 2014. In her most recent visit to the school, the Year 5/6 science students learned about the concepts of solubility and saturation through a series of simple experiments that Sabrina had designed. Working in groups, the students were taught to ‘think like a scientist’ i.e. ask the question (e.g. how many scoops of NaCl does it take to saturate X amount of water?), perform the experiment and to then come up with a conclusion.
Said Sabrina, “My trips to Lockleys are always rewarding and I look forward to my next visit where we will be performing experiments around the topic of ‘Light’.”