Monthly Archives: November 2017

New hybrid sensor developed

21 November 2017:

A new hybrid sensor combining an organic fluorescent probe bound to a nanodiamond has been developed by CNBP researchers (lead author Dr Malcolm Purdey pictured). Able to detect hydrogen peroxide, the sensor is non-toxic and is also highly photostable.

Journal: Scientific Reports.

Publication title: An organic fluorophore-nanodiamond hybrid sensor for photostable imaging and orthogonal, on-demand biosensing.

Authors: Malcolm S. Purdey, Patrick K. Capon, Benjamin J. Pullen, Philipp Reineck, Nisha Schwarz, Peter J. Psaltis, Stephen J. Nicholls, Brant C. Gibson & Andrew D. Abell.

Abstract: Organic fluorescent probes are widely used to detect key biomolecules; however, they often lack the photostability required for extended intracellular imaging. Here we report a new hybrid nanomaterial (peroxynanosensor, PNS), consisting of an organic fluorescent probe bound to a nanodiamond, that overcomes this limitation to allow concurrent and extended cell-based imaging of the nanodiamond and ratiometric detection of hydrogen peroxide. Far-red fluorescence of the nanodiamond offers continuous monitoring without photobleaching, while the green fluorescence of the organic fluorescent probe attached to the nanodiamond surface detects hydrogen peroxide on demand. PNS detects basal production of hydrogen peroxide within M1 polarised macrophages and does not affect macrophage growth during prolonged co-incubation. This nanosensor can be used for extended bio-imaging not previously possible with an organic fluorescent probe, and is spectrally compatible with both Hoechst 33342 and MitoTracker Orange stains for hyperspectral imaging.

New unmixing method to detect and measure fluorophores

17 November 2017:

A new CNBP paper “Statistically strong label-free quantitative identification of native fluorophores in a biological sample,” by Saabah B. Mahbub (first author pictured), Martin Plöschner, Martin E. Gosnell, Ayad G. Anwer and Ewa M. Goldys has just been published in Scientific Reports and is available online.

This work addresses a genuine shortage of methods for real-time continuous monitoring of biochemistry of cells and tissues, especially live cells. Saabah Mahbub and team developed an automated and unbiased unmixing methodology to non-invasively detect the presence and spatial distributions of endogenous fluorophores in retina cells. The method was validated on artificial images, where the addition of a varying known level of noise has allowed to quantify the accuracy of spectral unmixing.

With its capability for high throughput, automation and embedded compatibility with statistical analysis this work will contribute to improved quantification and objectivity in biomedical research.

Microfluidic droplet extraction

16 November 2017:

CNBP and Macquarie University PhD candidate Shilun Feng is first author on a new paper exploring a ‘membrane-on-a-chip’ device. The technology has the potential to form an integral part of a new type of microneedle that would be able to transport tiny and precise amounts of fluid/medication within the body.

Journal: Micromachines.

Publication titleMicrofluidic Droplet Extraction by Hydrophilic Membrane.

Authors: Shilun Feng, Micheal N. Nguyen, and David W. Inglis.

Abstract: Droplet-based microfluidics are capable of transporting very small amounts of fluid over long distances. This characteristic may be applied to conventional fluid delivery using needles if droplets can be reliably expelled from a microfluidic channel. In this paper, we demonstrate a system for the extraction of water droplets from an oil-phase in a polymer microfluidic device. A hydrophilic membrane with a strong preference for water over oil is integrated into a droplet microfluidic system and observed to allow the passage of the transported aqueous phase droplets while blocking the continuous phase. The oil breakthrough pressure of the membrane was observed to be 250 ± 20 kPa, a much greater pressure than anywhere within the microfluidic channel, thereby eliminating the possibility that oil will leak from the microchannel, a critical parameter if droplet transport is to be used in needle-based drug delivery.

New CNBP PhD student

Jagjit Kaur15 November 2017:

CNBP welcomes its latest PhD student Jagjit Kaur who will study under the supervision of CNBP researcher Dr Guozhen Liu at Macquarie University.

Jagjit has recently joined Macquarie University from India to pursue her research which will be focused on the development of nanoelectrodes for single cell analysis.

The main aim of her project is to develop nanotools that will be used for real time monitoring of cell secretions by single cells. The research outcome of this project will be expected to be useful for understanding cell-to-cell communication.

Previously, Jagjit has completed her undergraduate and masters degrees from Punjabi University, India in Biotechnology. Her masters dissertation was based on development of biosensors for detection of asparagine levels in leukemic samples.

Welcome to the CNBP team Jagjit!

DECRA awarded to Centre Research Fellow

13 November 2017:

Congratulations to Dr Lindsay Parker, CNBP Research Fellow at Macquarie University who has just been granted a Discovery Early Career Researcher Award (DECRA) from the Australian Research Council (ARC).

The award will support the following research activity:

“Intelligently linking nanoscience to neuroscience with glycan biology. This project aims to provide a comprehensive description of the unique cell-surface glycan expression on inflamed neurons, astrocytes, microglia and oligodendrocytes. This project will use glycan profiling data to engineer luminescent nanoparticles with superior neuroimaging qualities for cell type-specific in vivo targeting and drug delivery in the central nervous system. The project outcomes are expected to improve our fundamental understanding of neurobiological cell-surfaces.”

Information on successful DECRA grants can be accessed on the ARC website here.

A spiropyran with enhanced fluorescence

10 November 2017:

A new rationally designed, photostable, red-emitting calcium sensor with enhanced fluorescence intensity has been presented by CNBP researchers in a paper published in the journal ‘Tetrahedron’. Lead author on the paper is CNBP’s Georgina Sylvia (pictured – University of Adelaide).

Journal: Tetrahedron.

Publication titleA spiropyran with enhanced fluorescence: A bright, photostable and red-emitting calcium sensor.

Authors: Georgina M. Sylvia, Sabrina Heng, Akash Bachhuka, Heike Ebendorff-Heidepriem,
Andrew D. Abell.

A rationally designed, pyrene-spiropyran hybrid Ca2+ sensor (Py-1) with enhanced fluorescence intensity compared to a standalone spiropyran analogue is presented. Importantly, Py-1 retains the characteristic red emission profile of the spiropyran, while fibre-based photostability studies show the sensor is stable after multiple cycles of photoswitching, without any sign of photodegradation. Such properties are of real advantage for cell-based sensing applications. An interesting observation is that, Py-1 presents with two excitation options; direct green excitation (532 nm) of the photoswitch for a red emission, and UV excitation (344 nm) of the component pyrene, which gives rise to distinct blue and red emissions. This proof-of-concept hybrid sensing system presents as a more general approach to brighter spiropyran-based sensors.

CNBP at ‘Science meets Business’

9 November 2017:

As silver sponsor at the annual STA ‘Science meets Business’ event held in Sydney, November 9th 2017, CNBP was extremely well represented, supporting a push to improve engagement and collaboration between the research sector and Australian industry.

In addition to having numerous Centre scientists in attendance – those with a strong interest and focus on commercialisation and translation of research, CNBP also had  senior personnel speak and present in a variety of capacities.

This included CNBP Director Prof Mark Hutchinson (pictured top left), who together with  Andrew Grant (Availer) discussed CNBP’s commercialisation success and the taking of ideas from ‘boom to the showroom.’  Deep dive (idea creation), value-add solutions, solving pain points and interesting new jobs were all touched upon in a quick fire exchange of views.

Additionally, Centre Investigator and Miniprobes founder Prof Robert McLaughlin participated in the ‘soapbox sesssion’ where three competitively-selected ‘soapbox leaders’ made compelling pitches, sparking robust discussion as they quizzed delegates for perspectives on new ideas to create useful collaboration.

“It was great to be at this years ‘Science meets Business’, bringing CNBP science and innovation to industry and learnings back again,” concluded Prof Hutchinson. “I look forward to hearing about other successful collaborations at next year’s STA event.”

Below – CNBP Investigator and founder of Miniprobes Prof Robert McLaughlin pitches his smart needle to a science/business audience.



Outreach at Fresh Science

8 November 2017:

The world’s smallest fibre-optic probe that can simultaneously see and sense deeply inside the body (Dr Jiawen Li) and an anti-cancer drug that can be switched ‘on’ and ‘off’ inside the body to help reduce chemotherapy side effects (PhD student Kathryn Palasis). These were the research narratives developed by the two CNBP scientists who attended the ‘Fresh Science’ outreach training program on the 7th-8th November in Adelaide, South Australia.

“I had a great time participating in Fresh Science,” said Kathryn Palasis.

“We had a full day of media training which included practise interviews with journalists from TV, radio and print, who taught us how to best explain our science to the general public. We then had the opportunity to present our work to some very eager and inquisitive school students, and later had to summarise our research to a crowd at the pub in the time it took for a sparkler to burn out! It was a great learning experience and a lot of fun – plus I got to meet some really cool local researchers who are all doing exciting work.”

Dr Jiawen Li also enjoyed the experience. “What I got from the program was the ability to promote my science to the media, knowledge on how to be noticed by journalists and the experience of being interviewed, as well as broader presentation skills aimed at communicating complicated science concepts to a general audience. The two days were extremely rewarding!”

Fresh Science (run by Science in Public) is a national competition helping early-career researchers find, and then share, their stories of discovery. The program takes up-and-coming researchers with no media experience and turns them into spokespeople for science, with a day of media training and a public outreach event in their home state.

Below – Fresh Science participants. Kathryn Palasis fourth from left. Dr Jiawen Li fourth from right. Photo credit: Fresh Science/Science in Public.


A new heuristic search strategy to accelerate imaging

7 November 2017:

CNBP researchers Dr Daniel Drumm (lead author pictured) and Prof Andrew Greentree, both at RMIT University, have analysed microscopy in the contexts of Rényi-Ulam games and half-lies, developing a new family of heuristics. Their research is reported in the journal ‘Scientific Reports.’

Journal: Scientific Reports.

Publication titleMicroscopy as a statistical, Rényi-Ulam, half-lie game: a new heuristic search strategy to accelerate imaging.

Authors: Daniel W. Drumm & Andrew D. Greentree.

Abstract: Finding a fluorescent target in a biological environment is a common and pressing microscopy problem. This task is formally analogous to the canonical search problem. In ideal (noise-free, truthful) search problems, the well-known binary search is optimal. The case of half-lies, where one of two responses to a search query may be deceptive, introduces a richer, Rényi-Ulam problem and is particularly relevant to practical microscopy. We analyse microscopy in the contexts of Rényi-Ulam games and half-lies, developing a new family of heuristics. We show the cost of insisting on verification by positive result in search algorithms; for the zero-half-lie case bisectioning with verification incurs a 50% penalty in the average number of queries required. The optimal partitioning of search spaces directly following verification in the presence of random half-lies is determined. Trisectioning with verification is shown to be the most efficient heuristic of the family in a majority of cases.