All posts by Tony Crawshaw

Concordia students visit CNBP labs

14 September 2017:

Eighty Concordia College students with an interest in STEM undertook a series of educational tours at CNBP laboratories at the University of Adelaide—forty students visiting Wednesday 6th September and a further forty students visiting Wednesday 13th September, 2017.

The students were hosted by a number of CNBP researchers, undertaking laboratory tours in both the Braggs and Health and Medical Sciences buildings.

As well as getting an introduction to CNBP and biophotonic related science, the students were shown a range of CNBP activity and work-spaces. This included demonstrations of advanced needle probes and optical imaging systems, hands-on demonstrations of near-infrared light scanners, use of a 3D metal printer and tours of the Centre’s glass and optical fibre fabrication facilities, as well as tours of the  embryology laboratory where embryo culture and cryopreservation techniques were also able to be shown.

Emily Johnson, Middle Years Programme Coordinator from Concordia College noted, “All of the students (and teachers) really enjoyed the sessions. They came back quite buzzing and extremely interested in what they saw.”

Feedback from the CNBP researchers was also extremely positive with many noting the excellent questions posed by the students during the lab tour demonstrations and activity.

CNBP science at the Calyx

12 September 2017:

CNBP researchers Dr Denitza Denkova and Dr Martin Ploschner took their luminescence and fluorescence science expertise to the general public, at a special after-hours event known as ‘Science at the Calyx’ at the Royal Botanic Garden in Sydney.

Presenting to an audience of approximately sixty people, the CNBP scientists focused on giving members of the public information about the origins of luminescence and examples of it being used – from everyday life to medical applications, and the amazing natural phenomenon of bioluminescence which can be found in plants, animals and fungi.

Following the hour long talk, there were demonstrations including the use of fluorescent bubbles, a ‘magical’ fluorescent screen, the showing of several fluorescent specimens and an examination of fluorescence in money and documents for security purposes. There was also as ample time for attendees to talk to the researchers about their work with fluorescent molecules and nanoparticles.

According to Dr Denkova, the event was highly rewarding.

“There was plenty of opportunity for personal interaction which was embraced by attendees. Many had an interest in the medical applications related to fluorescence, but there were also great questions on practical everyday activities – such as how to paint bikes with fluorescent paint to help improve road safety. Following the talk, people had the chance to walk around the beautiful garden with a UV torch in their hand to discover for themselves which plants are fluorescent. Both Martin and myself enjoyed communicating our science to a wider public!”

First reversible ‘turn-off’ sensor for Glutathione

6 September 2017:

The first reversible ‘turn-off’ sensor for Glutathione has been reported by CNBP researchers in a paper published in the science journal Biosensors.

The paper is accessible online (open access).

Dr Sabrina Heng notes:

γ-Glutamyl-cysteinyl-glycine (GSH) plays a critical role in maintaining redox homeostasis in biological systems and a decrease in its cellular levels is associated with disease. Many diseases including Parkinson’s, cancer, heart diseases and Alzheimer’s are indicated by a decrease in GSH levels. In this case, a ‘turn on’ sensor would result in reduced fluorescence relative to healthy cells. An important advance would come from the development of a sensor that is measurably turned off by GSH and back on by a lower level of GSH. This would then provide an opportunity to sense reduced GSH levels during the onset of important diseases.

With that in mind we have rationally designed, to the best of our knowledge, the first reversible, reaction-based ‘turn-off’ probe that is suitable for sensing decreasing levels of GSH, a situation known to occur at the onset of various diseases.  We have demonstrated that the sensor can be used to detect changes of intracellular GSH in live HEK 293 cells to provide a potentially regenerable sensor for monitoring lower levels of intracellular GSH as associated with the onset of important diseases.

Journal: Biosensors.

Publication title: A Rationally Designed Reversible ‘Turn-Off’ Sensor for Glutathione.

Authors: Sabrina Heng (pictured), Xiaozhou Zhang, Jinxin Pei and Andrew D. Abell.

Abstract: γ-Glutamyl-cysteinyl-glycine (GSH) plays a critical role in maintaining redox homeostasis in biological systems and a decrease in its cellular levels is associated with diseases. Existing fluorescence-based chemosensors for GSH acts as irreversible reaction-based probes that exhibit a maximum fluorescence (‘turn-on’) once the reaction is complete, regardless of the actual concentration of GSH. A reversible, reaction-based ‘turn-off’ probe (1) is reported here to sense the decreasing levels of GSH, a situation known to occur at the onset of various diseases. The more fluorescent merocyanine (MC) isomer of 1 exists in aqueous solution and this reacts with GSH to induce formation of the ring-closed spiropyran (SP) isomer, with a measurable decrease in absorbance and fluorescence (‘turn-off’). Sensor 1 has good aqueous solubility and shows an excellent selectivity for GSH over other biologically relevant metal ions and aminothiol analytes. The sensor permeates HEK 293 cells and an increase in fluorescence is observed on adding buthionine sulfoximine, an inhibitor of GSH synthesis.

Exploring small-sized nanoflakes

29 August 2017:

Size-dependent structural and electronic properties of MoSmonolayer nanoflakes, of sizes up to 2nm, have been investigated by CNBP researchers using density-functional theory (DFT). The paper, published in Scientific Reports is accessible online.

Journal: Scientific Reports.

Publication title: A study of size-dependent properties of MoSmonolayer nanoflakes using density-functional theory.

Authors: M. Javaid (pictured), Daniel W. Drumm, Salvy P. Russo & Andrew D. Greentree.

Abstract: Novel physical phenomena emerge in ultra-small sized nanomaterials. We study the limiting small-size-dependent properties of MoS2 monolayer rhombic nanoflakes using density-functional theory on structures of size up to Mo35S70 (1.74 nm). We investigate the structural and electronic properties as functions of the lateral size of the nanoflakes, finding zigzag is the most stable edge configuration, and that increasing size is accompanied by greater stability. We also investigate passivation of the structures to explore realistic settings, finding increased HOMO-LUMO gaps and energetic stability. Understanding the size-dependent properties will inform efforts to engineer electronic structures at the nano-scale.

New technique to aid IVF embryo selection

28 August 2017:

Researchers at the ARC Centre of Excellence for Nanoscale BioPhotonics (CNBP) have successfully developed an advanced new imaging technique, which can help assess the quality of early-stage embryos.

The research, reported in the journal ‘Human Reproduction’ has the potential to significantly benefit the IVF industry of the future, improving assisted reproduction outcomes for women.

“We use a special type of imaging to show differences in the metabolism and chemical make-up of embryos before they’ve been implanted,” says lead author Dr Mel Sutton-McDowall (pictured).

“This technique can give us an objective measure of which embryo to choose as part of the IVF process.”

This ‘hyperspectral imaging’ measures light that cells naturally produce during their normal activities. The light or ‘autoflorescence’ produced changes according to the chemical reactions or metabolism going on in the cell.

Being able to measure embryo metabolism is viewed by many researchers as one of the most important factors as to whether a particular IVF program will be successful.

However, says Dr Sutton-McDowall, fertility specialists take a largely subjective approach in deciding which embryos should be used.

“Pre-implantation screening of embryos generally takes place under a normal optical microscope. Although it’s quite easy to discern poor embryos (due to differences in uniformity), it is far harder for the clinician to determine objectively, the viability of the other embryos,” she says.

“The challenge is how to choose the single healthiest embryo out of this group to maximise the chances of pregnancy.”

Dr Sutton-McDowall sees the use of hyperspectral imaging as a new tool that can be combined with other diagnostic methods to provide a more accurate and objective embryo viability assessment.

“The benefit of hyperspectral imaging is that it can capture information-rich content of inspected objects. It analyses every pixel in an image for its light intensity at differing wavelengths,” she says

“This lets us drill down and analyse the hyperspectral signature of each individual embryo, looking for known or anomalous characteristics. It lets us discriminate between embryos, but also measuring metabolic differences within individual embryos. We predict that embryos that have cells with homogeneous (uniform) metabolic profiles are the healthier ones.”

To date, this imaging technology has only been tested on cattle embryos but Dr Sutton-McDowall notes that the technique is extremely promising.

“It offers benefits of being a non-invasive imaging approach that provides real-time information to the clinician,” she says.

The paper is accessible online.

Journal: Human Reproduction.

Publication title: Hyperspectral microscopy can detect metabolic heterogeneity within bovine post-compaction embryos incubated under two oxygen concentrations (7% versus 20%).

Authors: Melanie L. Sutton-McDowall, Martin Gosnell, Ayad G. Anwer, Melissa White, Malcolm Purdey, Andrew D. Abell, Ewa M. Goldys, Jeremy G. Thompson.

Abstract: 

STUDY QUESTION
Can we separate embryos cultured under either 7% or 20% oxygen atmospheres by measuring their metabolic heterogeneity?

SUMMARY ANSWER
Metabolic heterogeneity and changes in metabolic profiles in morula exposed to two different oxygen concentrations were not detectable using traditional fluorophore and two-channel autofluorescence but were detectable using hyperspectral microscopy.

WHAT IS KNOWN ALREADY
Increased genetic and morphological blastomere heterogeneity is associated with compromised developmental competence of embryos and currently forms the basis for embryo scoring within the clinic. However, there remains uncertainty over the accuracy of current techniques, such as PGS and time-lapse microscopy, to predict subsequent pregnancy establishment.

STUDY DESIGN, SIZE, DURATION
The impact of two oxygen concentrations (7% = optimal and 20% = stressed) during post-fertilisation embryo culture was assessed. Cattle embryos were exposed to the different oxygen concentrations for 8 days (D8; embryo developmental competence) or 5 days (D5; metabolism measurements). Between 3 and 4 experimental replicates were performed, with 40–50 embryos per replicate used for the developmental competency experiment, 10–20 embryos per replicate for the fluorophore and two-channel autofluorescence experiments and a total of 21–22 embryos used for the hyperspectral microscopy study.

PARTICIPANTS/MATERIALS, SETTING, METHODS
In-vitro produced (IVP) cattle embryos were utilised for this study. Post-fertilisation, embryos were exposed to 7% or 20% oxygen. To determine impact of oxygen concentrations on embryo viability, blastocyst development was assessed on D8. On D5, metabolic heterogeneity was assessed in morula (on-time) embryos using fluorophores probes (active mitochondria, hydrogen peroxide and reduced glutathione), two-channel autofluorescence (FAD and NAD(P)H) and 18-channel hyperspectral microscopy.

MAIN RESULTS AND THE ROLE OF CHANCE
Exposure to 20% oxygen following fertilisation significantly reduced total blastocyst, expanded and hatched blastocyst rates by 1.4-, 1.9- and 2.8-fold, respectively, compared to 7% oxygen (P < 0.05), demonstrating that atmospheric oxygen was a viable model for studying mild metabolic stress. The metabolic profiles of D5 embryos was determined and although metabolic heterogeneity was evident within the cleavage stage (i.e. arrested) embryos exposed to fluorophores, there were no detectable difference in fluorescence intensity and pattern localisation in morula exposed to the two different oxygen concentrations (P > 0.05). While there were no significant differences in two-channel autofluorescent profiles of morula exposed to 7% and 20% oxygen (main effect, P > 0.05), morula that subsequently progressed to the blastocyst stage had significantly higher levels of FAD and NAD(P)H fluorescence compared to arrested morula (P < 0.05), with no change in the redox ratio. Hyperspectral autofluorescence imaging (in 18-spectral channels) of the D5 morula revealed highly significant differences in four features of the metabolic profiles of morula exposed to the two different oxygen concentrations (P < 0.001). These four features were weighted and their linear combination revealed clear discrimination between the two treatment groups.

LIMITATIONS, REASONS FOR CAUTION
Metabolic profiles were assessed at a single time point (morula), and as such further investigation is required to determine if differences in hyperspectral signatures can be detected in pre-compaction embryos and oocytes, using both cattle and subsequently human models. Furthermore, embryo transfers should be performed to determine the relationship between metabolic profiles and pregnancy success.

WIDER IMPLICATIONS OF THE FINDINGS
Advanced autofluorescence imaging techniques, such as hyperspectral microscopy, may provide clinics with additional tools to improve the assessment of embryos prior to transfer.

Nano-diamond arrays on glass

23 August 2017:

Researchers from CNBP’s RMIT University node (lead author Ashleigh Heffernan), have published a paper demonstrating a directed self-assembly method to position nanodiamonds on glass. The method, allowing for the statistical quantification of fluorescent nanoparticles provides a step towards fabrication of hybrid photonic devices for applications from quantum cryptography to sensing.

The paper is accessible online.

Journal: Scientific Reports.

Publication title: Nanodiamond arrays on glass for quantification and fluorescence characterisation.

Authors: Ashleigh H. Heffernan, Andrew D. Greentree & Brant C. Gibson.

Abstract: Quantifying the variation in emission properties of fluorescent nanodiamonds is important for developing their wide-ranging applicability. Directed self-assembly techniques show promise for positioning nanodiamonds precisely enabling such quantification. Here we show an approach for depositing nanodiamonds in pre-determined arrays which are used to gather statistical information about fluorescent lifetimes. The arrays were created via a layer of photoresist patterned with grids of apertures using electron beam lithography and then drop-cast with nanodiamonds. Electron microscopy revealed a 90% average deposition yield across 3,376 populated array sites, with an average of 20 nanodiamonds per site. Confocal microscopy, optimised for nitrogen vacancy fluorescence collection, revealed a broad distribution of fluorescent lifetimes in agreement with literature. This method for statistically quantifying fluorescent nanoparticles provides a step towards fabrication of hybrid photonic devices for applications from quantum cryptography to sensing.

Talking science at UoA Open Day

20 August 2017:

CNBP volunteers at the University of Adelaide Open Day took the opportunity to set-up a stand and to demonstrate Centre related science, Sunday 20th August, 2017.

The Open Day, showcasing programs, facilities, and options for student study at the University, saw many thousands of visitors to Campus and the CNBP team was ready!

CNBP experiments and demonstrations were on offer, ranging from the opportunity to play with lasers, through to checking out spinal-cord cells through a microscope.

And for those visitors to the stand who really wanted to know more about the innovative biophotonics science that the CNBP undertakes, there were giveaway goodies including t-shirts, drink bottles, pens and brochures.

Below: CNBP researcher Vicky Staikopoulos encouraging members of the public to ‘Ask about science.’

CNBP at Macquarie Uni Open Day

19 August 2017:

‘The power of light to measure’ was the phrase commonly expressed by Centre researchers staffing the CNBP stand at this year’s Macquarie University Open Day.

This was in response to potential University students and their family members, who were looking to find out more about nanoscale biophotonics as well as to better understand potential opportunities that might be open to graduates who successfully gain a degree in biology, physics or chemistry.

Many of the visitors left the CNBP stand impressed as to the broad application of biophotonics in the healthcare, food safety and manufacturing sectors. They also learnt more about the current activities of the CNBP, particularly in creating new sensing and imaging technologies to better understand molecular activity taking place within the living body.

The Open Day at Macquarie University saw many thousands of people visit Campus and engage with both staff and current students, in their exploration of courses open for undergraduate study.

Below, CNBP researchers Dr Wei Deng (left) and Dr Lianmei Jiang (right) get ready to talk nanoscale biophotonics as the doors open at the 2017 MQ Uni Open Day.

 

Outreach at Concordia College

16 August 2017:

Students from Concordia College got the low-down on STEM careers—as well as learnt more about lasers, laboratories and the life of a scientist at a school outreach event organised and run by CNBP researchers from the University of Adelaide.

The event, celebrating National Science Week, saw a team of CNBP scientists and researchers visit Concordia College and present a variety of talks, DIY laboratory videos and science demonstrations, to over 150 Year 9 students with an interest in science, technology, engineering and maths (STEM).

CNBP’s Dr Hannah Brown, present on the day, sees outreach as a key responsibility for the science community.

“Getting high school students interested and engaged in STEM subjects is critical—not only to inspire future generations of young scientists but also in supporting the Australian economy more generally. What we hope to do with our outreach efforts is to show that science and technology can be fun and exciting, and potentially rewarding as a future career choice as well.”

Following the event, feedback from both students and teachers present was hugely positive with the CNBP team also gaining a great deal of satisfaction from their interactions and demonstration efforts.

Below: CNBP researchers Hannah Brown, Georgios Tsiminis, Patrick Capon and Aimee Horsfall with students, at the conclusion of a successful session of science outreach at Concordia College.

Launch of CNBP and CU partnership

15 August 2017:

The University of Colorado Boulder (CU) and the Centre for Nanoscale BioPhotonics (CNBP) have officially announced their research partnership status at a launch event that took place at CU today.

The collaboration between the CNBP, an Australian Research Council Centre of Excellence, and the University of Colorado Boulder, will explore the use of novel CNBP biophotonics tools and techniques to examine in real-time, neuroinflammatory processes that govern behavior.

The novel immune sensing technologies developed at CNBP will allow circuit-specific measurement of immune molecule release during stress-related paradigms in rodents performed at the University of Colorado Boulder.

The overarching goal of the collaboration is to better inform intervention efforts
focused on stress- and ageing-related diseases.

Partner Investigators at CU are Professor Steven Maier and Professor Linda Watkins with CU’s Dr Michael Baratta (the successful recipient of the CNBP-American Australian Association Fellowship in 2016), also working closely with this partnership.

Below: CNBP Director Prof Mark Hutchinson (left) presents a partner plaque to Partner Investigators – Professor Steven Maier and Professor Linda Watkins.