Tag Archives: Guozhen Liu

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.

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.

Centre researchers at Biosensor Symposium

guozhen_liu30 November 2016:

CNBP Research Fellows, Associate Professor Guozhen Liu (pictured), Dr Lindsay Parker and Dr Sabrina Heng have undertaken talks at the School of Biomedical Sciences at the University of Melbourne as part of a Biosensor Symposium, Wednesday 30th November, 2016.

Talks were as follows:

Guozhen Liu – Biophotonic Tools for Cytokine Sensing: From an on-cell surface ELISA to a spatial ELISA device.

Lindsay Parker – Biosensors and glycoproteins: linking nanoscience to neuroscience.

Sabrina Heng – Reversible Sensing with a Flip of the Switch.

The symposium shone a  spotlight on multidisciplinary research into developing, applying and using biosensors for biomedical sciences.

Developing novel nano-tools to better understand the brain

guozhen_liu11 November 2016:

Understanding how the brain works is one of the greatest challenges of modern science – A challenge that CNBP Research Fellow Guozhen Liu is certainly up to!

She has recently been awarded an ARC Future Fellowship commencing in 2017 and will work on the creation of a suite of novel biomolecular nano-formulations capable of adaptive responses to the rapidly evolving environment inside of the body.

Read the full ‘Research Impact’ story on the Macquarie University web site!

OLYMPUS DIGITAL CAMERA

 

Cytokine detection based on immunosensing

guozhen_liu8 January 2016:

CNBP researchers Guozhen Liu, Mark Hutchinson and Ewa Goldys are all authors on a recent review paper examining the detection of cytokines  based on immunosensing. The paper was published in the journal Biosensors and Bioelectronics.

Paper Title:  “Recent advances in cytokine detection by immunosensing.”

Abstract: The detection of cytokines in body fluids, cells, tissues and organisms continues to attract considerable attention due to the importance of these key cell signaling molecules in biology and medicine. In this review, we describe recent advances in cytokine detection in the course of ongoing pursuit of new analytical approaches for these trace analytes with specific focus on immunosensing.

We discuss recent elegant designs of sensing interface with improved performance with respect to sensitivity, selectivity, stability, simplicity, and the absence of sample matrix effects. Various immunosensing approaches based on multifunctional nanomaterials open novel opportunities for ultrasensitive detection of cytokines in body fluids in vitro and in vivo.

Methodologies such as suspension arrays also known as bead assays together with optical fiber-based sensors, on their own or in combination with microfluidic devices will continue to have an important role to address the grand challenge of real-time in vivo multiplex cytokine detection.

The paper is available online.

 

Gold and graphene based platform

guozhen_liu30 December 2015:

Guozhen Liu, CNBP Research Fellow, is first author on the paper “Nanocomposites of gold nanoparticles and graphene oxide towards an stable label-free electrochemical immunosensor for detection of cardiac marker troponin-I.”

Co-author of the paper is CNBP Deputy Director Ewa Goldys.

The paper, published in the journal ‘Analytica Chimica Acta’ has been awarded feature article status, being highlighted on the front cover of the journal.

Full details including an abstract are available online.

 

New agreement to open the door to next generation cell therapies

cnbplogosquare124 November 2015:

A new collaboration agreement has been announced today by Macquarie University and clinical-stage regenerative medicine company Regeneus Ltd, to commercialise a breakthrough cell selection technology that for the first time allows high potency secreting stem cells to be identified and selected for the manufacture of next generation cell therapies.

The technology was developed in a research group led by Professor Ewa Goldys and Dr Guozhen Liu at the Australian Research Council’s Centre of Excellence for Nanoscale BioPhotonics (CNBP) at Macquarie, and uses innovative cell labelling technologies to identify and select cells based on the molecules that they are secreting rather than their surface characteristics used currently.

Read more here:

CNBP at International Nanomedicine Conference

cnbplogosquare18 July 2015:

CNBP was certainly well represented at the 6th Annual International Nanomedicine Conference, at Sydney’s Coogee Beach, July 6-8, 2015.

Targeting both researchers and clinicians, the conference saw a large number of CNBP personnel in attendance, with oral and poster presentations undertaken by the following CNBP researchers –

Oral Presentations
Dr. Andrew Care – Building a platform technology for the self-assembly of functional upconversion nanoparticles

Prof. Ewa Goldys – Nanorubies For Ultrasensitive Biomolecular Imaging

Dr. Guozhen Liu – Covalent Functionalization of Gold Nanoparticles as Electronic Bridges and Signal Amplifiers Towards an Electrochemical Immunosensor for Botulinum Neurotoxin Type A

Dr. Annemarie Nadort – Blood circulation of nanoparticles in a chick embryo model

Poster Presentations
Mrs. Sandhya Clement – X-ray induced singlet oxygen generation by nanoparticle-photosensitizer conjugates: direct determination of singlet oxygen quantum yield

Dr. Varun Sreenivasan – Large scale production, characterisation and functionalisation of nanorubies

Dr. Kai Zhang – Study on Porous Silica Nanoparticles to co-Delivery of Drug and siRNA

Further information on the conference, attendees and abstacts can be found from the event web site – http://www.oznanomed.org/