Tag Archives: Ewa Goldys

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.

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.

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.

Hyperspectral unmixing methodology validated

Aziz Rehman10 February 2017:

A new publication from CNBP researchers Aziz Ul Rehman (pictured), Ayad Anwer, Martin Gosnell, Saabah Mahbub, Guozhen Liu and Ewa Goldys demonstrates the validation of an innovative hyperspectral unmixing methodology, that can derive chemical information from cell colour.

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.

Gold-loaded liposomes with photosensitizers for PDT

2 February 2017:

A new publication from CNBP researchers Wei Deng (pictured), Sandhya Clement and Ewa Goldys indicates that gold-loaded liposomes incorporating photosensitizers may serve as improved agents in photodynamic therapy and chemotherapy. The work has just been reported in the International Journal of Nanomedicine and is accessible online.

Journal: International Journal of Nanomedicine.

Title: Light-triggered liposomal cargo delivery platform incorporating photosensitizers and gold nanoparticles for enhanced singlet oxygen generation and increased cytotoxicity

Authors: Zofia Kautzka, Sandhya Clement, Ewa M Goldys and Wei Deng.

Abstract: We developed light-triggered liposomes incorporating 3–5 nm hydrophobic gold
nanoparticles and Rose Bengal (RB), a well-known photosensitizer used for photodynamic
therapy. Singlet oxygen generated by these liposomes with 532 nm light illumination was
characterized for varying the molar ratio of lipids and gold nanoparticles while keeping
the amount of RB constant. Gold nanoparticles were found to enhance the singlet oxygen
generation rate, with a maximum enhancement factor of 1.75 obtained for the molar ratio of hydrogenated soy l-α-phosphatidylcholine:1,2-dioleoyl-sn-glycero-3-hosphoethanolamineN-(hexanoylamine): gold of 57:5:17 compared with liposomes loaded with RB alone. The experimental results could be explained by the local electric field enhancement caused by gold nanoparticles. We further assessed cellular cytotoxicity of gold-loaded liposomes by encapsulating an antitumor drug, doxorubicin (Dox); such Dox-loaded liposomes were applied to human colorectal cancer cells (HCT116) and exposed to light. Gold-loaded liposomes containing RB and Dox where Dox release was triggered by light were found to exhibit higher cytotoxicity compared with the liposomes loaded with RB and Dox alone. Our results indicate that goldloaded liposomes incorporating photosensitizers may serve as improved agents in photodynamic therapy and chemotherapy.

CNBP takes centre stage at Biofocus Conference

15 December 2016:

CNBP researchers were at the forefront of this year’s Biofocus Conference held at Macquarie University, 15 December 2016.

Early career Centre researchers Annemarie Nadort, Lindsay Parker and Nima Sayyadi sat on the conference organising committee, Centre Deputy Director Ewa Goldys (pictured) opened proceedings while CNBP Chief Investigator Prof Andrew Abell (from the University of Adelaide) delivered an extremely well received plenary talk titled, “Defining biomolecular structure and function in solution and on surfaces: new therapeutics and biological probes.”

The annual conference provides a platform for the multidisciplinary community at Macquarie University to present and communicate research, discuss research outcomes and facilitate interdisciplinary collaborations spanning the fields of of biomedical sciences, biomedical engineering, physics, chemistry and medicine.

Feedback from attendees at this year’s event was extremely positive with plenty of formal and informal scientific discussion taking place between sessions.

 

Deputy Director presents at Wagga Wagga

Ewa Goldys Low Res Edit 015929 November 2016:

CNBP Deputy Director Prof Ewa Goldys has given a talk at the School of Biomedical Sciences, Charles Sturt University, Wagga Wagga on her research success “A Eureka Moment for Cell Colour Technology.”

The talk results from Prof Goldys being awarded the recent Australian Museum Eureka Prize for ‘Innovative Use of Technology’.

Prof Goldys, together with Dr Martin Gosnell, developed a hyperspectral imaging technique that allows for the successful extraction of specific biomolecular information hidden in fluorescent colour signatures of living cells and tissues.

The talk examined the technology and the real world translational outcomes that will result from this exciting area of study that will support clinicians in making improved diagnosis and health decisions for patients.

 

NeuRA Invited Seminar Series

Ewa Goldys Low Res Edit 015925 November 2016:

Professor Ewa Goldys, Deputy Director of the CNBP, has given an invited talk at the Neuroscience Research Australia (NeuRA) Invited Lecture series, 25th November 2016, Sydney.

The talk was titled “A Eureka moment for cell colour technology” and explored the research behind Prof Goldys and her success in being awarded the 2016 Australian Museum Eureka Prize for ‘Innovative Use of Technology’.

Professor Goldys and her team were recognised for their innovative colour-focused research (and pioneering hyperspectral imaging technique), able to distinguish between healthy and diseased cells, in areas as diverse as embryology, neurodegeneration, cancer and diabetes.

Real-world translational outcomes that will result from this exciting area of study, that will support clinicians in making improved diagnosis and health decisions for patients, was also discussed.

The NeuRA lecture series attracts leading national and international researchers from all fields of neuroscience.

 

Goldys gives public talk on cell colour

Ewa Goldys Low Res Edit 01594 October 2016:

CNBP Deputy Director Prof Ewa Goldys gave a colourful and illuminating public talk at Macquarie University today, discussing a pioneering hyperspectral imaging technique that is helping researchers better understand the composition of cells, right down at a molecular level.

The talk, entitled, ‘A Eureka Moment for Cell Colour Technology’, explored the use of colour information to differentiate between cells – applying photonics to biology.

Goldys believes that this next-generation methodology offers a new window to non-invasively and rapidly detect major health conditions including neurodegeneration, cancer and diabetes.

The research won Goldys and her colleague Martin Gosnell, the 2016 ANSTO Eureka Prize for Innovative Use of Technology.

Below: Ewa Goldys presenting her work on the fluorescent colour signatures of living cells and tissues, using big data techniques and innovative computing technology .

OLYMPUS DIGITAL CAMERA