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.

Abstract:
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.

 

 

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.

Cytokine detection

6 November 2017:

New research from CNBP scientists reports on a cytokine sensor – fabricated on the surface of an optical fibre. Cytokines are molecules that play a critical role in cellular response to infection, inflammation, trauma and disease. Lead author on the paper, published in the journal ‘Biosensors and Bioelectronics’, is Centre PhD student Kaixin Zhang who is based at Macquarie University.

Journal: Biosensors and Bioelectronics.

Publication title: Robust immunosensing system based on biotinstreptavidin coupling for spatially localized femtogram mL−1 level detection of interleukin-6.

Authors: Kaixin Zhang, Guozhen Liu, Ewa M. Goldys.

Abstract: Detection of a very low amount of cytokines such as interleukin-6 (IL-6) in clinical fluids is important in biomedical research and clinical applications. Here, we demonstrate spatially-localised ultrasensitive (femtogram mL−1) level detection of IL-6 in serum and in cell culture media. Our approach is based on a sandwich immunosensor fabricated on the surface of an optical fibre. Firstly, the biotinylated IL-6 capture antibody was immobilized on the fibre surface by biotin-streptavidin coupling. Then the fabricated fibre was used for capturing IL-6 followed by exposure to detection antibody which was labeled with the fluorescent magnetic nanoparticles to report the signal. A linear relationship between IL-6 concentration and the fluorescence signal was obtained in the range from 0.4 pg mL−1 to 400 pg mL−1 of IL-6, with the limit of detection down to 0.1 pg mL−1. In addition, this optical fibre sensor was successfully applied for the localized detection of IL-6 with the spatial resolution of 200 µm and a sample volume of 1 μL. Finally, the performance of the fibre sensor was demonstrated by detection of IL-6 secreted by BV-2 cells with comparable performance of the conventional enzyme-linked immunosorbent assay (ELISA).

Concordia College students visit CNBP

6 November 2017:

Thirty-one Year 11 students from Concordia College visited CNBP headquarters at the University of Adelaide, 6th November 2017, further strengthening outreach engagement and linkages between the school and Centre researchers.

The students, part of the  International Baccalaureate Science program, enjoyed presentations from CNBP researchers, participated in a Q&A regarding CNBP science, and undertook lab tours with Dr Jiawen Li who did a show and tell with Miniprobes technology. Students were then able to get hands-on with the mini-probe, experimenting with its capabilities on pieces of fruit which mimicked potential use on the human body.

As part of the outreach session – CNBP’s Dr Kyle Dunning talked about her research and its focus on reproductive health, Patrick Capon and Aimee Horsfall presented chemistry and its use in CNBP sensing technology and Dr Georgios Tsiminis  talked about his own physics journey and the sensing work that he is now working on in the meat and dairy space.

Feedback from Joanne Rogers, Head of Science at Concordia College, noted that she thought this outreach session was, “The best yet with CNBP.”

Below – photos from the visit.