Australia is the sunniest continent on Earth — which is why it also has the highest rates of skin cancer. But plentiful sunlight is also likely responsible for the lesser known ‘ocular surface cancer’, which occurs when abnormal cells on the eye grow and divide in an uncontrolled way. Continue reading
How do you measure the tenderness, juiciness and flavour of beef without eating it? It’s a challenge faced by everyone from meat inspectors at abattoirs to consumers looking through a butcher’s window. And they’re all subjective – until now. Continue reading
Researchers have found a way to identify multiple cell signalling proteins using a single cell rather than the billions of cells used previously.
The new measurement technology, developed by researchers at the ARC Centre of Excellence for Nanoscale Biophotonics, brings precision medicine a step closer.
“Cells secrete various messenger molecules, such as cytokines. They may indicate the presence of a disease or act as a driver of key therapeutic effects,” says Dr Guozhen Liu, lead author of paper detailing the technology.
The method, termed OnCELISA, uses antibodies attached on specially engineered cell surfaces to capture cytokine molecules before they have a chance to disperse away from the cell.
The secreted messenger proteins such as cytokines are reported, at the single cell level, by using fluorescent magnetic nanoparticles.
Cytokines secreted from cells play a critical role in controlling many physiological functions, including immunity, inflammation, response to cancer, and tissue repair.
The OnCELISA system can be used for ultrasensitive monitoring of cytokine release by individual cells, and it can also help discover cell populations with therapeutic value.
“The ability to identify and select cell populations based on their cytokine release is particularly valuable in commercial cell technologies and it can help develop unique products, such as future non-opioid pain relief” says Dr Liu.
“Importantly, our design uses commercially available reagents only, so it can be easily reproduced by others,” she adds.
While the published work focuses on specific proinflammatory cytokines IL-6 and IL-1β, the method is potentially suitable for a broad range of other secreted proteins and cell types.
The new technique represents an advance on traditional methods such as the enzyme-linked immunosorbent assays (ELISA) that detect average levels of secreted molecules from cell ensembles.
The OnCELISA takes the ELISA approach to its absolute extreme, by detecting cytokines on the surface of individual, single live cells.
The publication has been reported by prestigious iScience journal and can be found at https://www.sciencedirect.com/science/article/pii/S2589004219303578.
Publication Title: A Nanoparticle-Based Affinity Sensor that Identifies and Selects Highly Cytokine-Secreting Cells
Authors: Guozhen Liu; Christina Bursill; Siân P.Cartland; Ayad G.Anwer; Lindsay M.Parker; Kaixin Zhang; Shilun Feng; Meng He; David W.Inglis; Mary M.Kavurma; Mark R.Hutchinson; Ewa M.Goldys
Summary: We developed a universal method termed OnCELISA to detect cytokine secretion from individual cells by applying a capture technology on the cell membrane. OnCELISA uses fluorescent magnetic nanoparticles as assay reporters that enable detection on a single-cell level in microscopy and flow cytometry and fluorimetry in cell ensembles. This system is flexible and can be modified to detect different cytokines from a broad range of cytokine-secreting cells. Using OnCELISA we have been able to select and sort highly cytokine-secreting cells and identify cytokine-secreting expression profiles of different cell populations in vitro and ex vivo. We show that this system can be used for ultrasensitive monitoring of cytokines in the complex biological environment of atherosclerosis that contains multiple cell types. The ability to identify and select cell populations based on their cytokine expression characteristics is valuable in a host of applications that require the monitoring of disease progression.
CNBP has officially welcomed UNSW, one of the world’s leaders at translational engineering research, as its newest node.
In addition to the official open by UNSW Engineering Dean Professor Mark Hoffman, CNPB Director Professor Mark Hutchinson took the opportunity to lay out the CNBP mission and its accomplishments at an industry showcase. Continue reading
A team of CNBP researchers have published a new paper discussing the design and application of a micro fabricated needle-like probe to measure hydrogen peroxide. This new microfluidic tool has applications for monitoring dynamic chemical reactions in analytical chemistry and biological systems.
Journal: RSC Advances
Publication Title: Microfabricated needle for hydrogen peroxide detection
Authors: Shilun Feng, Sandhya Clement, Yonggang Zhu, Ewa M. Goldys and David W. Inglis
Abstract: A microfabricated needle-like probe has been designed and applied for hydrogen peroxide (H2O2) sampling and detection using a commercial, single-step fluorescent H2O2 assay. In this work, droplets of the assay reagent are generated and sent to the needle tip using a mineral-oil carrier fluid. At the needle tip, the sample is drawn into the device through 100 mm long hydrophilic capillaries by negative pressure. The sampled fluid is immediately merged with the assay droplet and carried away to mix and react, producing a sequence of droplets representing the H2O2 concentration as a function of time. We have characterized the assay fluorescence for small variations in the sample volume. With the calibration, we can calculate the concentration of H2O2 in the sampled liquid from the size and intensity of each merged droplet. This is a microfluidic data-logger system for on-site continuous sampling, controlled reaction, signal storage and on-line quantitative detection. It is a useful tool for monitoring dynamic chemical reactions in analytical chemistry and biological applications.
Key words: Microfluidics, probe, H2O2, analytics chemistry
Professor Ewa Goldys, CNBP Deputy Director, UNSW Sydney, in partnership with Associate Professor Shane Grey from the Garvan Institute have received an international grant from JDRC for “Noninvasive assessment of islet cells”.
This project will develop a non-invasive method for real-time monitoring of encapsulated beta cells in vitro and in vivo. This will help assess the fate of implanted cells and define the conditions required to produce high quality insulin-producing cells for implantation and their precursors.
The results will lay the foundations for in vivo assessment of islet transplantation success.
A new paper with CNBP co-authors Prof Mark Hutchinson, Prof Ewa Goldys and Dr Guozhen Liu demonstrates an amperometric sensing device based on graphene oxide (GO) and structure-switching aptamers for long-term detection of cytokines in a living organism.
Journal: ACS Applied Materials and Interfaces.
Authors: Chaomin Cao, Ronghua Jin, Hui Wei, Wenchao Yang, Ewa M. Goldys, Mark R. Hutchinson, Shiyu Liu, Xin Chen, Guangfu Yang, and Guozhen Liu.
Abstract: Cytokine sensing is challenging due to their typically low abundances in physiological conditions. Nanomaterial fabricated interfaces demonstrated unique advantages in ultrasensitive sensing. Here, we demonstrate an amperometric sensing device based on graphene oxide (GO) and structure-switching aptamers for long-term detection of cytokines in a living organism. The device incorporates a single layer of GO acting as a signal amplifier on glassy carbon electrodes. The hairpin aptamers specific to interferon-γ (IFN-γ), which were loaded with redox probes, are covalently attached to GO to serve as biorecognition moieties. IFN-γ was able to trigger the configuration change of aptamers while releasing the trapped redox probes to introduce the electrochemical signal. This in vivo device was capable of quantitatively and dynamically detecting IFN-γ down to 1.3 pg mL–1 secreted by immune cells in cell culture medium with no baseline drift even at a high concentration of other nonspecific proteins. The biocompatible devices were also implanted into subcutaneous tissue of enteritis mice, where they performed precise detection of IFN-γ over 48 h without using physical barriers or active drift correction algorithms. Moreover, the device could be reused even after multiple rounds of regeneration of the sensing interface.
Researchers from CNBP have developed an X-ray-induced photodynamic therapy (PDT) system where nanoparticles incorporating a photosensitizer, verteporfin, were triggered by X-ray radiation to generate cytotoxic singlet oxygen. This system offers the possibility of enhancing the radiation therapy commonly prescribed for the treatment of cancer by simultaneous PDT.
Lead author on the paper was Dr Sandhya Clement (pictured).
Journal: International Journal of Nanomedicine.
Publication title: X-ray radiation-induced and targeted photodynamic therapy with folic acid-conjugated biodegradable nanoconstructs.
Authors: Sandhya Clement, Wenjie Chen, Wei Deng, Ewa M Goldys.
Introduction: The depth limitation of conventional photodynamic therapy (PDT) with visible electromagnetic radiation represents a challenge for the treatment of deep-seated tumors. Materials and methods: To overcome this issue, we developed an X-ray-induced PDT system where poly(lactide-co-glycolide) (PLGA) polymeric nanoparticles (NPs) incorporating a photosensitizer (PS), verteporfin (VP), were triggered by 6 MeV X-ray radiation to generate cytotoxic singlet oxygen. The X-ray radiation used in this study allows this system to breakthrough the PDT depth barrier due to excellent penetration of 6 MeV X-ray radiation through biological tissue. In addition, the conjugation of our NPs with folic acid moieties enables specific targeting of HCT116 cancer cells that overexpress the folate receptors. We carried out physiochemical characterization of PLGA NPs, such as size distribution, zeta potential, morphology and in vitro release of VP. Cellular uptake activity and cell-killing effect of these NPs were also evaluated. Results and discussion: Our results indicate that our nanoconstructs triggered by 6 MeV X-ray radiation yield enhanced PDT efficacy compared with the radiation alone. We attributed the X-ray-induced singlet oxygen generation from the PS, VP, to photoexcitation by Cherenkov radiation and/or reactive oxygen species generation facilitated by energetic secondary electrons produced in the tissue. Conclusion: The cytotoxic effect caused by VP offers the possibility of enhancing the radiation therapy commonly prescribed for the treatment of cancer by simultaneous PDT.
CNBP researchers have announced the development of a state-of-the-art sensor that can for the first time detect signalling molecules, called cytokines, which operate in the living brain. Cytokines in the brain are secreted by glia cells that make up nearly 90% of all brain cells. Cytokines play a central role in controlling mood and cognition and may also contribute to a number of mental health disorders.
“What we’ve developed is the first sensor capable of monitoring the release of these cytokines in the brain,” says lead researcher Kaixin Zhang, a PhD candidate at the ARC Centre of Excellence for Nanoscale BioPhotonics (CNBP) at Macquarie University.
“Critically, there is mounting evidence that these glial-released cytokines play a central role in regulating a range of brain functions. In particular they are responsible for affecting mood, cognition and behaviour.”
“Our innovative new sensor has the potential to increase our knowledge not only of how the brain works, but may be able to shed light on conditions such as depression, stress, anxiety and even schizophrenia,” he says.
The sensor consists of a modified optical fibre which has had its surface treated with a capture protein. The protein reacts to the presence of cytokine molecules and is capable of monitoring local cytokine release in discrete and targeted parts of the brain.
Professor Ewa Goldys, CNBP Deputy Director, and a senior researcher on the project, notes that brain functionality is an extremely complex area where scientific knowledge is still limited.
“Our research in understanding cytokine secretion, neural circuits and how these two work together is essential to improving our understanding of the brain, in health and disease. Our sensor has opened a new window to the brain, but we still have far more to discover,” she says.
“The key benefit of our new sensor is that it enables the detection of cytokine release precisely as it happens, in living, naturally behaving animals, which is the key step on this discovery journey. To date, suitable tools have not been available to do this as the living brain is an incredibly difficult part of the body to access, and these cytokines are very difficult to measure.”
Published in the leading scientific journal ‘Brain, Behavior, and Immunity’, the cytokine sensor research was undertaken by an international team of scientists at the ARC Centre of Excellence for Nanoscale BioPhotonics (CNBP), Macquarie University, University of Colorado Boulder, Central China Normal University and The University of Adelaide.
“This is a really fantastic example of the work which we do at the CNBP, which is all about creating state-of-the-art sensing tools that can measure the inner workings of the living organism,” says Prof Goldys.
“It may be early days in this research but it will be fascinating to see where this cytokine detection takes us. It may prove to be a pivotal point in the understanding, and eventual diagnostic and clinical treatment, of a whole range of health conditions.”
A novel platform for in vivo detection of cytokine release within discrete brain regions. https://www.sciencedirect.com/science/article/pii/S0889159118301302
AUTHORS: Kaixin Zhang, Michael V. Baratta, Guozhen Liu, Matthew G. Frank, Nathan R. Leslie, Linda R. Watkins, Steven F. Maier, Mark R. Hutchinson, Ewa M. Goldys.
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.
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.