Monthly Archives: August 2017

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.

 

CNBP attracts the crowds at RMIT Open Day

13 August 2017:

Over 400 interested members of the public, including prospective students,  dropped by the CNBP laboratories as a part of RMIT University’s annual Open Day event, Sunday 13th August, 2017.

The Centre had two optics laboratories open and both were fully staffed by researchers eager to share their knowledge and enthusiasm for science.

In the first laboratory, an Olympus wide field microscope was on display with a live-cell incubation chamber and a daphnia (water flea), with brightfield and fluorescence videos.

In the other, a cryogenic confocal microscope was on show, which is able to look at the optical properties of nanomaterials, down to temperatures of 4K (which is -269 deg C).

According to CNBP node leader at RMIT, A/Prof Brant Gibson, the day was a great success.

“We saw a large, interested and engaged crowd who really wanted to find out more about our research and activity, and were curious as to how nanoscale biophotonics was going to impact society over coming years.”

There was also a large number of prospective students who visited and talked with CNBP team members. They had a wonderfully diverse range of interests ranging across the physics, chemistry, biology, IT and engineering disciplines.”

“It was fantastic to see the next generation of excited young scientist!”

Cambridge visit furthers research

10 August 2017:

After successfully receiving an ANN Overseas Travel Fellowship, CNBP researcher Dr Peipei Jia has arrived back at the University of Adelaide after a two month visit to the MRC Laboratory of Molecular Biology (LMB) in Cambridge, UK.

While there, Peipei had the opportunity to test both techniques and potential application for his work on the fabrication of large-area freestanding gold nanomembranes.

More specifically, tests undertaken while at Cambridge showed that the gold membrane had the size, quality and robustness  for the critical application of resolving molecular structures in Cryo-electron microscopy (cryo-EM).

Work continues but the nanophotonics structure is expected to have significant impact on both structural biology and electron microscopy.

CNBP at ‘Science meets Policymakers’

8 August 2017:

CNBP was well represented at the STA ‘Science meets Policymakers’ event held in Canberra, August 8, 2017.

Researchers A/Prof Guozhen Liu, Dr Alf Garcia-Bennett, Dr Sanam Mustafa and Dr Hannah Brown all attended and heard a number of talks on topics ranging from ‘A Whole Government approach to Science Policy’, to ‘A Crash-course in STEM and Policy Making’ through to discussion on ‘Positive and Meaningful Contributions to Policy.’

A/Prof Guozhen Liu particularly enjoyed the ‘Working Round Table’ discussion. “We discussed the 2030 Strategic Plan for the Australian Innovation, Science and Research System, which will help shape future science activity in Australia. It was emphasized that Australia encourages both fundamental and applied research, and that research excellence is key.”

A/Prof Liu also noted the importance of effective communication between stakeholders. “Methods and approaches to drive effective and engaged connections between Universities, Government and Industry were topics that were explored and discussed in depth throughout the day.”

The ‘Science meets Policymakers’ event brought together researchers and practitioners from a range of science and technology disciplines, with policymakers from across government departments and agencies. Objectives included to make connections and to examine the intersection between the evidence base and actual policy development.