Category Archives: MQ

New nanoparticle discovery to aid super-resolution imaging

Prof Jim Piper26 April 2017:

Researchers at the ARC Centre of Excellence for Nanoscale BioPhotonics (CNBP), Macquarie University, the University of Technology Sydney (UTS), Peking University and Shanghai Jiao-tong University have made a breakthrough in the development of practical super-resolution optical microscopy that will pave the way for the detailed study of live cells and organisms, on a scale 10 times smaller than can currently be achieved with conventional microscopy.

Reported in Nature, the international team of researchers has demonstrated that bright luminescent nanoparticles can be switched on and off using a low-power infrared laser beam, and used to achieve images with a super resolution of 28nm.

Professor Jim Piper (pictured), leader of the research team at Macquarie University and the CNBP sees these nanoparticles as having new unique properties. “These allow researchers to see well beyond normal limits of standard microscopes. It will let you see deeper and more clearly at the cellular and intra- cellular level—where proteins, antibodies and enzymes ultimately run the machinery of life.”

The research featured in BioPhotonics World.

Light-triggerable liposomes

21 April 2017:

A new paper from CNBP researchers (lead author Wenjie Chen pictured) reports on the design of a new light-triggerable liposome. The work has just been published in the journal ‘Molecular Therapy: Nucleic Acid’ and is accessible online.

Journal: Molecular Therapy: Nucleic Acid.

Title: Light-triggerable liposomes for enhanced endo/lysosomal escape and gene silencing in PC12 cells.

Authors: Wenjie Chen, Wei Deng, Ewa M. Goldys.

Abstract: Liposomes are an effective gene/drug delivery system, widely used in biomedical applications including gene therapy and chemotherapy. Here we designed a photo-responsive liposome (lipVP) loaded with a photosensitizer verteporfin (VP). This photosensitizer is clinically approved for photodynamic therapy (PDT). LipVP was employed as a DNA carrier for pituitary adenylyl cyclase-activating polypeptide (PACAP) receptor 1 (PAC1R) gene knockdown in PC12 cells. This has been done by incorporating PAC1R antisense oligonucleotides inside the lipVP cavity. Cells which have taken up the lipVP were exposed to light from a UV light source. As a result of this exposure, reactive oxygen species (ROS) were generated from VP, destabilising the endo/lysosomal membranes and enhancing the liposomal release of antisense DNA into the cytoplasm. Endo/lysosomal escape of DNA was documented at different time points based on quantitative analysis of colocalization between fluorescently labelled DNA and endo/lysosomes. The released antisense oligonucleotides were found to silence PAC1R mRNA. The efficiency of this photo-induced gene silencing was demonstrated by a 74 ± 5% decrease in PAC1R fluorescence intensity. Following the light-induced DNA transfer into cells, cell differentiation with exposure to two kinds of PACAP peptides was observed to determine the cell phenotypic change after PAC1R gene knockdown.

Nanoscale sensor to spot disease

28 March 2017:

A new nanoscale sensor has been developed that can help detect cytokines – molecules that play a critical role in cellular response to infection, inflammation, trauma and disease.

Reported in the science journal ‘Nanoscale’, the sensor consists of a modified graphene quantum dot (or GQD) which has been designed by researchers at the ARC Centre of Excellence for Nanoscale BioPhotonics (CNBP). It allows ultra-small amounts of cytokines to be identified in and around cells, with the work potentially opening up an exciting new avenue of biomedical research.

“Cytokines are molecules secreted by the cells of the immune system,” explains lead CNBP project scientist Guozhen Liu, Associate Professor at Macquarie University.

“The release of certain cytokines by the body is frequently symptomatic of a disease or health related issue, such as arthritis, inflammatory disorder or even cancer. Consequently, monitoring cytokine secretions at the cellular and sub-cellular level, has enormous value in our understanding of basic physiology and how the body is actually working.”

Traditionally, cytokine molecules have been extremely hard to measure and quantify.

“This has been due to their small size and their dynamic and transient nature,” says A/Prof Liu.

“What we’ve been able to do is to design and make a sensor that is so small that it can easily penetrate inside cells. Moreover, unlike other sensors it only responds when the cytokine is present. To this aim we have connected GQDs to cytokine sensing DNA molecules known as aptamers.”

Professor at Macquarie University, Ewa Goldys, Deputy Director at the Centre for Nanoscale BioPhotonics, also on the project team, noted that the detection of cytokines in body fluids, cells, tissues and organisms was attracting considerable attention in the biomedical research field. “Being able to track cytokine levels in real time opens new ways to monitor body physiology. This will ultimately lead to new diagnostic tools and new ways of treatment monitoring.”

Goldys believes that the innovative GQD sensing technology developed by the CNBP has potential widespread applications, due to the universal nature of the sensor design.

“We see these graphene quantum dot sensors as being excellent candidates for many other biomedical applications such as DNA and protein analysis, intracellular tracking as well as for monitoring of other cell secreted products in the body.”

Although still some years away from clinical study Goldys and Liu are both excited by the research. “Operating at the nanoscale we’re creating entirely new windows into the body and will gain valuable insights into the body, health, wellbeing and disease,” concludes Goldys.

RESEARCH PAPER:
http://pubs.rsc.org/en/content/articlelanding/2017/nr/c6nr09381g#!divAbstract

Below: CNBP Researcher A/Prof Guozhen Liu. Click on the image to access image download.

Centre CI at Gordon Glycobiology conference

25 March 2017:

CNBP Chief Investigator Professor Nicki Packer was an invited chair of a session and leader of the Power Hour (gender equality workshop)  at the Gordon Glycobiology conference at Ventura, California 19-24 March, 2017.

As session Chair, Prof Packer led discussion on advances in omics, integrated omics, bioinformatics for glycobiology and the impact of altered glycosylation for human disorders.

The Power Hour was an informal session designed to help address the challenges women face in science and to support the professional growth of women by providing an open forum for discussion and mentoring.

Further conference information is accessible online.

 

CNBP talks to the pollies at SmP

24 March 2017:

A chance to talk science with Australian politicians and policy influencers was an opportunity seized by CNBP with Centre Investigator Prof Heike Ebendorff-Heidepriem and Centre Research Fellow Dr Andrew Care both in attendance at the annual ‘Science meets Parliament’ (SmP) event, Canberra, 21-22 March, 2017.

Established by Science and Technology Australia, SmP provides 200 scientists with a unique professional development opportunity to get a clear sense of the competing rationalities of science, politics and public policy. The two-day gathering also includes a day at Parliament House, where delegates get the chance to meet privately with parliamentarians.

As part of this activity, Prof Ebendorff-Heidepriem met with Senator Chris Back and Senator Chris Ketter, and also spoke with Shadow Minister of Defence, Richard Marles. In addition, she spoke with many researchers and entrepreneurs from both the University and industry sectors.

“Improving collaboration between the research community and industry was a hot topic in many of the discussions that I had”, said Heike. “Particularly in my meeting with Senator Chris Back. People were also extremely excited about our approach, in using fibres and light to create exciting new windows into the body.”

CNBP’s Dr Andrew Care met with Opposition Leader Bill Shorten’s advisor, discussing gender equality and early education for STEM and also touching on ECR opportunities and improving research and industry ties. He also met MP Adam Bandt, the Greens spokesperson for science.

“Overall it was an extremely rewarding experience,” says Andrew. “Attending SmP gave me the opportunity to explore the political process and to network with many other researchers from academia, industry, and governance. It was fantastic to see science and innovation so high on the government’s agenda.”

A full round up from both days of SmP can be found on the STA web site – Day 1 and Day 2.

Below – MP Adam Bandt and CNBP’s Dr Andrew Care.

 

Gold nanoparticles for bioimaging

22 March 2017:

A new publication from CNBP researchers (lead author Sandhya Clement pictured) reports on a more effective and less harmful gold-based nano-agent for bioimaging and photodynamic therapy treatment for deep tissue tumors.

The work has just been reported in the journal ‘Microchimica Acta ’ and is accessible online.

Journal: Microchimica Acta.

Title: Verteprofin conjugated to gold nanoparticles for fluorescent cellular bioimaging and X-ray mediated photodynamic therapy.

Authors: Sandhya Clement, Wenjie Chen, Ayad G. Anwer & Ewa M. Goldys.

Abstract: Photodynamic therapy (PDT) uses photosensitizers, light and molecular oxygen to generate cytotoxic reactive oxygen species. Its effectiveness is limited to <1 cm due to the limited penetration depth of light. The present study compares the PDT effectivity of the photosensitizer verteporfin (VP) conjugated to gold nanoparticles (AuNPs) (a) by using deeply penetrating X-rays administered in standard radiotherapy doses, and (b) by using red light (690 nm). VP was conjugated to AuNPs of around 12 nm size to enhance the interaction of ionizing radiation with PS. For comparison, VP also was directly exposed to X-rays. It is found that VP alone is stimulated by X-rays to generate singlet oxygen. The conjugate to AuNPs also generated a significant amount of singlet oxygen on irradiation with X-rays in comparison to illumination with 690-nm light. It is also found that the rate of singlet oxygen generation is amplified in case of AuNP-conjugated VP compared to VP alone. The performance of the AuNP-VP conjugate and of the VP alone was tested in Panc 1 cells. Their viability was impaired much more in these two scenarios than with the X-ray radiation only. This suggests excellent perspectives for PDT based on VP and with X-ray stimulation, both as a stand-alone photosensitizer and in Au-NP conjugates. Moreover, both VP and AuNP-VP conjugates show bright fluorescence in physiological media for excitation/emission wavelengths in the range of 405/690 nm; hence they can also be used for simultaneous bioimaging.

Breaking apart sugars

9 March 2017:

CNBP scientists Chris Ashwood and Prof Nicki Packer at Macquarie University have shown alternative ways to break apart sugars, improving their characterisation in their latest publication in the area of mass spectrometry (Enhancing structural characterisation of glucuronidated O-linked glycans using negative mode ion trap higher energy collision-induced dissociation mass spectrometry).

The work was published online in the journal Rapid Communications in Mass Spectrometry on 9th March 2017 and was funded by the Australian Research Council Centre of Excellence for Nanoscale BioPhotonics.

New PhD student Yuan Liu

2 March 2017:

The Macquarie University node of CNBP welcomes a new PhD student to the team – Yuan Liu.

Yuan will study under the supervision of Center Deputy Director Prof. Ewa Goldys and Centre Research Fellow A/Prof. Guozhen Liu.

Her project will explore the construction of a novel biosensing platform for quantitatively detecting exosomes which can be employed as a potential biomarker for non-invasive disease diagnosis.

Previously, Yuan obtained her Masters Degree of Medicine from Shihezi University, China. During that time she majored in pharmaceutical analysis and her research was focused on the construction, characterization and application of electrochemical and gas sensors under the guidance of Prof. Hui Tang and Prof. Yingchun Li.

Welcome aboard Yuan!

Investigating cell metabolism

Aziz Rehman1 March 2017:

A new publication from CNBP researchers (lead author Aziz Ul Rehman pictured) reports on the application of hyperspectral imaging in combination with fluorescence spectroscopy and chemical quenching to provide a new methodology to investigate cell metabolism.

The work has just been reported in the journal ‘Biomedical Optics Express’ and is accessible online.

Journal: Biomedical Optics Express.

Title: Fluorescence quenching of free and bound NADH in HeLa cells determined by hyperspectral imaging and unmixing of cell autofluorescence.

Authors: Aziz Ul Rehman, Ayad G. Anwer, Martin E. Gosnell, Saabah B. Mahbub, Guozhen Liu, and Ewa M. Goldys.

Abstract: Carbonyl cyanide-p-trifluoro methoxyphenylhydrazone (FCCP) is a well-known mitochondrial uncoupling agent. We examined FCCP-induced fluorescence quenching of reduced nicotinamide adenine dinucleotide / nicotinamide adenine dinucleotide phosphate (NAD(P)H) in solution and in cultured HeLa cells in a wide range of FCCP concentrations from 50 to 1000µM. A non-invasive label-free method of hyperspectral imaging of cell autofluorescence combined with unsupervised unmixing was used to separately isolate the emissions of free and bound NAD(P)H from cell autofluorescence. Hyperspectral image analysis of FCCP-treated HeLa cells confirms that this agent selectively quenches fluorescence of free and bound NAD(P)H in a broad range of concentrations. This is confirmed by the measurements of average NAD/NADH and NADP/NADPH content in cells. FCCP quenching of free NAD(P)H in cells and in solution is found to be similar, but quenching of bound NAD(P)H in cells is attenuated compared to solution quenching possibly due to a contribution from the metabolic and/or antioxidant response in cells. Chemical quenching of NAD(P)H fluorescence by FCCP validates the results of unsupervised unmixing of cell autofluorescence.