Sensing magnesium

17 April 2018:

A new publication from CNBP researchers (lead author Georgina Sylvia pictured), presents the rational design and photophysical characterisation of spiropyran-based chemosensors for magnesium.

Journal: Chemosensors.

Publication title: A Rationally Designed, Spiropyran-Based Chemosensor for Magnesium.

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

Abstract: Magnesium ions (Mg2+) play an important role in mammalian cell function; however, relatively little is known about the mechanisms of Mg2+ regulation in disease states. An advance in this field would come from the development of selective, reversible fluorescent chemosensors, capable of repeated measurements. To this end, the rational design and fluorescence-based photophysical characterisation of two spiropyran-based chemosensors for Mg2+ are presented. The most promising analogue, chemosensor 1, exhibits 2-fold fluorescence enhancement factor and 3-fold higher binding affinity for Mg2+ (Kd 6.0 µM) over Ca2+ (Kd 18.7 µM). Incorporation of spiropyran-based sensors into optical fibre sensing platforms has been shown to yield significant signal-to-background changes with minimal sample volumes, a real advance in biological sensing that enables measurement on subcellular-scale samples. In order to demonstrate chemosensor compatibility within the light intense microenvironment of an optical fibre, photoswitching and photostability of 1 within a suspended core optical fibre (SCF) was subsequently explored, revealing reversible Mg2+ binding with improved photostability compared to the non-photoswitchable Rhodamine B fluorophore. The spiropyran-based chemosensors reported here highlight untapped opportunities for a new class of photoswitchable Mg2+ probe and present a first step in the development of a light-controlled, reversible dip-sensor for Mg2+.

Successful BioNetwork 2018 symposium

13 April 2018:

The BioNetwork 2018 symposium titled ‘Killing it in Science’ was held Friday, 13th April at Macquarie University with significant CNBP involvement at the event.

The aim of the symposium was to foster interactions across the Macquarie University biosciences researcher community encompassing the Science & Engineering and Medicine & Health Sciences Faculties.

A unique career-building panel session was held in the morning of the symposium and a scientific session was held in the afternoon to create a platform for interdisciplinary research collaborations to commence novel or strengthen existing projects.

CNBP Associate Investigators Dr Alfonso Garcia-Bennett (Macquarie University) and Dr Varun Sreenivasan (University of New South Wales) were both invited speakers at the event speaking to their careers in academia, providing tips for advancement as well as outlining challenges that they had faced.

For the science session, CNBP students Mina Ghanimi Fard and Sameera Iqbal (pictured top left) jointly presented on the brain and the targeting and measuring of central nervous system sugar receptors. Other CNBP students also took part with Piotr Wargocki, Kashif Islam, Minakshi Das and Rachit Bansal presenting their CNBP releated science during the morning and lunch-time poster sessions.

CNBP AI’s Annemarie Nadort and Nima Sayyadi were both key members of the symposium organising committee.

“We had a fantastic engaged crowd of over 150 attendees and a wide range of presenters covering careers in academia, research-industry collaboration, innovative bio-research activity and much much more,” said Annemarie Nadort.

“There was so much positive feedback from participants on the day and we’ve kick-started a great many conversations and discussions which will hopefully build new research relationships and lead to even more innovative science taking place.”

Below – Organiser Annemarie Nadort observing the successful symposium panel discussion from the wings.

Fibre-needle probe for imaging and sensing in deep tissue

6 April 2018:

A world-first tiny fibre-optic probe that can simultaneously measure temperature and sense deep inside the body has been reported by CNBP/IPAS researchers. According to lead author of the research, Dr Jiawen Li at the University of Adelaide, the probe may help researchers find better treatments to prevent drug-induced overheating of the brain, and potentially refine thermal treatment for cancers. Read the media release or click on the publication title below!

Journal: Optics Letters.

Publication title: Miniaturized single-fiber-based needle probe for combined imaging and sensing in deep tissue.

Authors: Jiawen Li, Erik Schartner, Stefan Musolino, Bryden C. Quirk, Rodney W. Kirk, Heike Ebendorff-Heidepriem, and Robert A. McLaughlin.

Abstract: The ability to visualize structure while simultaneously measuring chemical or physical properties of a biological tissue has the potential to improve our understanding of complex biological processes. We report the first miniaturized single-fiber-based imaging+sensing probe capable of simultaneous optical coherence tomography (OCT) imaging and temperature sensing. An OCT lens is fabricated at the distal end of a double-clad fiber, including a thin layer of rare-earth-doped tellurite glass to enable temperature measurements. The high refractive index of the tellurite glass enables a common-path interferometer configuration for OCT, allowing easy exchange of probes for biomedical applications. The simultaneous imaging+sensing capability is demonstrated on rat brains.

Below – Dr Jiawen Li.

Understanding the role that sugars play

30 March 2018:

CNBP scientists Chris Ashwood (pictured) and Prof Nicki Packer at Macquarie University have shown that sugars with exactly the same chemical composition but slightly different structure break apart differently in their latest publication in the area of mass spectrometry. This work is their first step in automating sugar analysis, to understand the role sugars play in human disease.

Journal: Journal of The American Society for Mass Spectrometry.

Publication title: Discrimination of Isomers of Released N- and O-Glycans Using Diagnostic Product Ions in Negative Ion PGC-LC-ESI-MS/MS.

Authors: Christopher Ashwood, Chi-Hung Lin, Morten Thaysen-Andersen, Nicolle H. Packer.

Abstract:
Profiling cellular protein glycosylation is challenging due to the presence of highly similar glycan structures that play diverse roles in cellular physiology. As the anomericity and the exact linkage type of a single glycosidic bond can influence glycan function, there is a demand for improved and automated methods to confirm detailed structural features and to discriminate between structurally similar isomers, overcoming a significant bottleneck in the analysis of data generated by glycomics experiments. We used porous graphitized carbon-LC-ESI-MS/MS to separate and detect released N- and O-glycan isomers from mammalian model glycoproteins using negative mode resonance activation CID-MS/MS. By interrogating similar fragment spectra from closely related glycan isomers that differ only in arm position and sialyl linkage, product fragment ions for discrimination between these features were discovered. Using the Skyline software, at least two diagnostic fragment ions of high specificity were validated for automated discrimination of sialylation and arm position in N-glycan structures, and sialylation in O-glycan structures, complementing existing structural diagnostic ions. These diagnostic ions were shown to be useful for isomer discrimination using both linear and 3D ion trap mass spectrometers when analyzing complex glycan mixtures from cell lysates. Skyline was found to serve as a useful tool for automated assessment of glycan isomer discrimination. This platform-independent workflow can potentially be extended to automate the characterization and quantitation of other challenging glycan isomers.

Miniprobes innovation featured

20 March 2018:

The CNBP spin-out company Miniprobes and its development of an inexpensive handheld scanner that can undertake microscopic analysis of surfaces has featured as a ‘success story’ as a part of the AUSInnovates campaign.

The handheld imaging device is able to accurately measure the thickness of surface coatings applied to products – often less than a tenth of a millimetre in thickness.

“We’re exploring two major international markets,” explained Dr McLaughlin, Miniprobes Managing Director.

“Our scanheads can examine metal parts in microscopic detail, and that’s important for industrial manufacturers working to fine tolerances, such as in the car and aerospace industries.”

“Another important application is in controlling the absorption rate of drugs, which is achieved by coating the drug with a thin chemical layer. Our device enables precise measurement of these layers by pharmaceutical manufacturers.”

The AUSinnovates campaign celebrates successful Australian commercialisation and is championed by gemaker, research-industry engagement and commercialisation specialists.

Detecting hydrogen peroxide

19 March 2018:

A nanosensor that can detect hydrogen peroxide has been developed by CNBP/IPAS researchers by combining fluorescent nanodiamonds with organic fluorescent probes.

Importantly, cellular imbalance of hydrogen peroxide has been connected to aging and various severe diseases, including cancer, cardiovascular disorders, and Alzheimer’s.

The work is featured in the latest edition of MRS Bulletin with Patrick Capon from the University of Adelaide, co-author of the research study interviewed for the article (available here).

CINSW Fellowship awarded

16 March 2018:

It has been formally announced that Dr Andrew Care, former CNBP Research Fellow and now Centre Associate Investigator, has been awarded a 2018 Early Career Fellowship from the Cancer Institute New South Wales (CINSW) to fund the research project, ‘Biological nanoparticles for the targeted delivery and light-triggered release of drugs’.

This project aims to develop novel protein nanocages for the targeted co-delivery and controlled release of therapeutics in the multimodal treatment of cancer.

In addition, PhD Candidate Ms Dennis Diaz, who is part of the team working on this exciting project, was recently awarded a Research Scholarship Award from the translational cancer research centre, Sydney Vital.

Dennis is working under the supervision of Dr Andrew Care and A/Prof. Anwar Sunna (also a CNBP Associate Investigator).

Further information on the CINSW and its recent grants announcement is available here.

Reducing interference with cellular autofluorescence

14 March 2018:

CNBP Research Fellow Nicole Cordina is first author on a new study that reports on two novel methods for reducing interference with cellular autofluorescence for bio-imaging.

Journal: Scientific Reports.

Publication title: Reduced background autofluorescence for cell imaging using nanodiamonds and lanthanide chelates.

Authors: Nicole M. Cordina, Nima Sayyadi, Lindsay M. Parker, Arun Everest-Dass, Louise J. Brown & Nicolle H. Packer.

Abstract:
Bio-imaging is a key technique in tracking and monitoring important biological processes and fundamental biomolecular interactions, however the interference of background autofluorescence with targeted fluorophores is problematic for many bio-imaging applications. This study reports on two novel methods for reducing interference with cellular autofluorescence for bio-imaging. The first method uses fluorescent nanodiamonds (FNDs), containing nitrogen vacancy centers. FNDs emit at near-infrared wavelengths typically higher than most cellular autofluorescence; and when appropriately functionalized, can be used for background-free imaging of targeted biomolecules. The second method uses europium-chelating tags with long fluorescence lifetimes. These europium-chelating tags enhance background-free imaging due to the short fluorescent lifetimes of cellular autofluorescence. In this study, we used both methods to target E-selectin, a transmembrane glycoprotein that is activated by inflammation, to demonstrate background-free fluorescent staining in fixed endothelial cells. Our findings indicate that both FND and Europium based staining can improve fluorescent bio-imaging capabilities by reducing competition with cellular autofluorescence. 30 nm nanodiamonds coated with the E-selectin antibody was found to enable the most sensitive detective of E-selectin in inflamed cells, with a 40-fold increase in intensity detected.

New CNBP visiting researcher

Ashley Grant12 March 2018:

CNBP welcomes visiting researcher Ashley Grant to the University of Adelaide.

Ashley graduated magna cum laude with the highest university honors from Virginia Commonwealth University in Richmond, Virginia, USA with a Bachelor’s degree in Exercise Science with a minor in Psychology.

She will be based at the University of Adelaide for 12 months in the School of Medicine. While there she will be supervised by CNBP Director Prof Mark Hutchinson and will work in pain and alcohol research.

“I’m looking forward to being exposed to studies that focus on the molecular level of pain during my stay,” says Ashley.

Ashley is an avid yogi and blogger who loves the outdoors and exploration, meeting new people and trying new things. She has a strong past history in nonprofit work including being the Development Director for a nonprofit group called Camp Kesem which provides free summer camps for children who have been affected by a parent’s cancer.

“I think there is a lot of pain in this world, physically and emotionally, and my goal in life is to help alleviate some of the pain that can be managed,” says Ashley.

Aptasensors and cytokine detection

10 March 2018:

A new review paper summarising recent advances in aptamer-based biosensors with a specific focus on cytokine sensing has been published in the journal ‘Trends in Analytical Chemistry’. The paper includes CNBP coauthors Fuyuan Zhang, Ewa M.Goldys and Guozhen Liu (pictured).

Journal: Trends in Analytical Chemistry.

Publication title: Advances in Structure-Switching Aptasensing Towards Real Time Detection of Cytokines.

Authors: C. Cao, F. Zhang, E.M. Goldys, G. Liu.

Abstract: Structure-switching aptamer-based biosensors (aptasensors) provide a promising strategy for real-time or near real-time monitoring of analytes in vivo, owing to their reversibility, the versatility of methods available to engineer the aptamer switches, and the ability to tune their dynamic range. Monitoring cell-to-cell communication through cytokine secretions has enormous value in biology and medicine. However, cytokine detection is challenging due to the extremely dynamic, transient cytokine secretion process, and typically low abundances in physiological conditions. Here, we summarise recent advances in structure-switching signaling aptamer-based biosensing with specific focus on cytokine sensing. This Review begins with the survey of cytokine-specific aptamers followed by the designs of elegant sensing platforms based on structure-switching aptamers with different signal readouts such as optic, electrochemistry, and other types. We describe the strategies of signal amplification in aptasensors, and highlight future perspectives of aptasensors for real-time or near real-time detection of cytokines.