Category Archives: MQ

New unmixing method to detect and measure fluorophores

17 November 2017:

A new CNBP paper “Statistically strong label-free quantitative identification of native fluorophores in a biological sample,” by Saabah B. Mahbub (first author pictured), Martin Plöschner, Martin E. Gosnell, Ayad G. Anwer and Ewa M. Goldys has just been published in Scientific Reports and is available online.

This work addresses a genuine shortage of methods for real-time continuous monitoring of biochemistry of cells and tissues, especially live cells. Saabah Mahbub and team developed an automated and unbiased unmixing methodology to non-invasively detect the presence and spatial distributions of endogenous fluorophores in retina cells. The method was validated on artificial images, where the addition of a varying known level of noise has allowed to quantify the accuracy of spectral unmixing.

With its capability for high throughput, automation and embedded compatibility with statistical analysis this work will contribute to improved quantification and objectivity in biomedical research.

Microfluidic droplet extraction

16 November 2017:

CNBP and Macquarie University PhD candidate Shilun Feng is first author on a new paper exploring a ‘membrane-on-a-chip’ device. The technology has the potential to form an integral part of a new type of microneedle that would be able to transport tiny and precise amounts of fluid/medication within the body.

Journal: Micromachines.

Publication titleMicrofluidic Droplet Extraction by Hydrophilic Membrane.

Authors: Shilun Feng, Micheal N. Nguyen, and David W. Inglis.

Abstract: Droplet-based microfluidics are capable of transporting very small amounts of fluid over long distances. This characteristic may be applied to conventional fluid delivery using needles if droplets can be reliably expelled from a microfluidic channel. In this paper, we demonstrate a system for the extraction of water droplets from an oil-phase in a polymer microfluidic device. A hydrophilic membrane with a strong preference for water over oil is integrated into a droplet microfluidic system and observed to allow the passage of the transported aqueous phase droplets while blocking the continuous phase. The oil breakthrough pressure of the membrane was observed to be 250 ± 20 kPa, a much greater pressure than anywhere within the microfluidic channel, thereby eliminating the possibility that oil will leak from the microchannel, a critical parameter if droplet transport is to be used in needle-based drug delivery.

New CNBP PhD student

Jagjit Kaur15 November 2017:

CNBP welcomes its latest PhD student Jagjit Kaur who will study under the supervision of CNBP researcher Dr Guozhen Liu at Macquarie University.

Jagjit has recently joined Macquarie University from India to pursue her research which will be focused on the development of nanoelectrodes for single cell analysis.

The main aim of her project is to develop nanotools that will be used for real time monitoring of cell secretions by single cells. The research outcome of this project will be expected to be useful for understanding cell-to-cell communication.

Previously, Jagjit has completed her undergraduate and masters degrees from Punjabi University, India in Biotechnology. Her masters dissertation was based on development of biosensors for detection of asparagine levels in leukemic samples.

Welcome to the CNBP team Jagjit!

DECRA awarded to Centre Research Fellow

13 November 2017:

Congratulations to Dr Lindsay Parker, CNBP Research Fellow at Macquarie University who has just been granted a Discovery Early Career Researcher Award (DECRA) from the Australian Research Council (ARC).

The award will support the following research activity:

“Intelligently linking nanoscience to neuroscience with glycan biology. This project aims to provide a comprehensive description of the unique cell-surface glycan expression on inflamed neurons, astrocytes, microglia and oligodendrocytes. This project will use glycan profiling data to engineer luminescent nanoparticles with superior neuroimaging qualities for cell type-specific in vivo targeting and drug delivery in the central nervous system. The project outcomes are expected to improve our fundamental understanding of neurobiological cell-surfaces.”

Information on successful DECRA grants can be accessed on the ARC website here.

Cytokine detection

6 November 2017:

New research from CNBP scientists reports on a cytokine sensor – fabricated on the surface of an optical fibre. Cytokines are molecules that play a critical role in cellular response to infection, inflammation, trauma and disease. Lead author on the paper, published in the journal ‘Biosensors and Bioelectronics’, is Centre PhD student Kaixin Zhang who is based at Macquarie University.

Journal: Biosensors and Bioelectronics.

Publication title: Robust immunosensing system based on biotinstreptavidin coupling for spatially localized femtogram mL−1 level detection of interleukin-6.

Authors: Kaixin Zhang, Guozhen Liu, Ewa M. Goldys.

Abstract: Detection of a very low amount of cytokines such as interleukin-6 (IL-6) in clinical fluids is important in biomedical research and clinical applications. Here, we demonstrate spatially-localised ultrasensitive (femtogram mL−1) level detection of IL-6 in serum and in cell culture media. Our approach is based on a sandwich immunosensor fabricated on the surface of an optical fibre. Firstly, the biotinylated IL-6 capture antibody was immobilized on the fibre surface by biotin-streptavidin coupling. Then the fabricated fibre was used for capturing IL-6 followed by exposure to detection antibody which was labeled with the fluorescent magnetic nanoparticles to report the signal. A linear relationship between IL-6 concentration and the fluorescence signal was obtained in the range from 0.4 pg mL−1 to 400 pg mL−1 of IL-6, with the limit of detection down to 0.1 pg mL−1. In addition, this optical fibre sensor was successfully applied for the localized detection of IL-6 with the spatial resolution of 200 µm and a sample volume of 1 μL. Finally, the performance of the fibre sensor was demonstrated by detection of IL-6 secreted by BV-2 cells with comparable performance of the conventional enzyme-linked immunosorbent assay (ELISA).

New microfluidic needle-like device developed

31 October:

A new paper from CNBP researchers (lead author Shilun Feng pictured) reports on the development of a microfluidic needle-like device that can extract and deliver nanoliter samples.

The paper, published in ‘Applied Physics Letters’ is accessible online.

Journal: Applied Physics Letters.

Publication title: A microfluidic needle for sampling and delivery of chemical signals by segmented flows.

Authors: Shilun Feng, Guozhen Liu, Lianmei Jiang, Yonggang Zhu, Ewa M. Goldys, and David W. Inglis.

Abstract: We have developed a microfluidic needle-like device that can extract and deliver nanoliter samples. The device consists of a T-junction to form segmented flows, parallel channels to and from the needle tip, and seven hydrophilic capillaries at the tip that form a phase-extraction region. The main microchannel is hydrophobic and carries segmented flows of water-in-oil. The hydrophilic capillaries transport the aqueous phase with a nearly zero pressure gradient but require a pressure gradient of 19 kPa for mineral oil to invade and flow through. Using this device, we demonstrate the delivery of nanoliter droplets and demonstrate sampling through the formation of droplets at the tip of our device. During sampling, we recorded the fluorescence intensities of the droplets formed at the tip while varying the concentration of dye outside the tip. We measured a chemical signal response time of approximately 3 s. The linear relationship between the recorded fluorescence intensity of samples and the external dye concentration (10–40 μg/ml) indicates that this device is capable of performing quantitative, real-time measurements of rapidly varying chemical signals.

 

CNBP researchers edit new book

30 October 2017:

A new book edited by A/Prof Anwar Sunna (CNBP Associate Investigator), Dr Andrew Care (CNBP Research Fellow) and Peter Bergquist (Macquarie University) as been published by Springer.

The book, “Peptides and Peptide-based Biomaterials and their Biomedical Applications”, highlights new developments in the applications of peptide and peptide-based biomaterials in biomedicine.

“This is a fast-moving and rapidly expanding research area, which promises to be one of the most significant fields of research in applied biomedicine”, says A/Prof Sunna.

“The work introduces readers to direct applications and translational research at the interface between materials science, protein chemistry and biomedicine.”

Quantifying nanoparticles in colloidal suspension

26 October 2017:

A new paper featuring CNBP researchers (lead author Sandhya Clement pictured top left), demonstrates a simple, non-destructive method suitable for rapid evaluation of nanoparticles in colloidal suspension.

The paper, published in Nanotechnology is accessible online.

Journal: Nanotechnology.

Publication title: Quantification of nanoparticle concentration in colloidal suspensions by a non-destructive optical method.

Authors: Sandhya Clement, Brint Gardner, Wan Aizuddin W Razali, Victoria A Coleman, Åsa K Jämting, Heather J Catchpoole, Ewa M Goldys, Jan Herrmann and Andrei Zvyagin.

Abstract: The estimation of nanoparticle number concentration in colloidal suspensions is a prerequisite in many procedures, and in particular in multi-stage, low-yield reactions. Here, we describe a rapid, non-destructive method based on optical extinction and dynamic light scattering (DLS), which combines measurements using common bench-top instrumentation with a numerical algorithm to calculate the particle size distribution (PSD) and concentration. These quantities were derived from Mie theory applied to  measurements of the optical extinction spectrum of homogeneous, non-absorbing nanoparticles, and the relative PSD of a colloidal suspension. The work presents
an approach to account for PSDs achieved by DLS which, due to the underlying model, may not be representative of the true sample PSD. The presented approach estimates the absolute particle number concentration of samples with mono-, bi-modal and broad size distributions with <50% precision. This provides a convenient and practical solution for number concentration estimation required during many applications of colloidal nanomaterials.

New light source developed for fluorescent microscopy imaging

Aziz Rehman16 October 2017:

A tuneable and programmable integrating sphere light source for wide-field fluorescent microscopy imaging, employing nine light-emitting diodes (LEDs), has been successfully demonstrated and reported by CNBP researchers in a new paper (lead author Aziz ul Rehman pictured).

The paper, published in ‘Photodiagnosis and Photodynamic Therapy’ is accessible online.

Journal: Photodiagnosis and Photodynamic Therapy.

Publication title: Programmable LED-Based Integrating Sphere Light Source for Wide-Field Fluorescence Microscopy.

Authors: Aziz ul Rehman, Ayad G.Anwer, Ewa M.Goldys.

Abstract: Wide-field fluorescence microscopy commonly uses a mercury lamp, which has limited spectral capabilities. We designed and built a programmable integrating sphere light (PISL) source which consists of nine LEDs, light-collecting optics, a commercially available integrating sphere and a baffle. The PISL source is tuneable in the range 365–490 nm with a uniform spatial profile and a sufficient power at the objective to carry out spectral imaging. We retrofitted a standard fluorescence inverted microscope DM IRB (Leica) with a PISL source by mounting it together with a highly sensitive low- noise CMOS camera. The capabilities of the setup have been demonstrated by carrying out multispectral autofluorescence imaging of live BV2 cells.

Prof Goldys elected as ATSE Fellow

11 October 2017:

Fluorescence expert Ewa Goldys, Deputy Director at the CNBP and Professor at Macquarie University, has been elected as a Fellow of the Australian Academy of Technological Sciences and Engineering (ATSE).

The Fellowship recognises Professor Goldys’ pioneering research in non-invasive medical diagnostics, and her work associated with fluorescence, advanced materials and biomedicine, supporting clinicians in making improved diagnosis and health decisions for patients.

“It’s a great pleasure to be recognised with this Fellowship”, says Professor Goldys.

“The ATSE is a respected Australian body which provides informed and visionary views to decision-makers across a wide range of technology focused areas. I look forward to providing my input and advice as a member of this prestigious organisation.”

As a world leader in the study of cellular fluorescence, Professor Goldys is also a former Eureka Prize winner for her innovative use of technology. This prize was awarded for her work in developing revolutionary imaging techniques, allowing for the extraction of biomolecular information hidden in fluorescent colour signatures of living cells and tissues.

“Modern day microscopes and powerful computer analysis enables colour to be used as a uniquely powerful diagnostic tool in medicine,” she says.

“Exploring the subtle colour differentiations of cells and tissue lets us distinguish between healthy and diseased cells in areas as diverse as embryology, neurodegeneration, cancer and diabetes.”

As an ATSE Fellow, Professor Goldys will provide expertise across biomedical, nanotechnology and biophotonics areas. She will also be able to tap into the knowledge and capability of her research and industry collaborators.

“Australia needs to harness technology and innovation as part of its successful transition to a knowledge based economy,” says Professor Goldys. “This is what the ATSE mandate is all about.”

Recognising Australia’s leading minds in technology, science and engineering, the prestigious ATSE Fellowships are awarded to people who apply technology in smart, strategic ways for social, environmental and economic benefit.

Fellows advise government, industry and the community on how technology can improve the quality of life of all Australians and are drawn from academia, government, industry and research sectors.

The ATSE Fellowship announcement is accessible online from the ATSE web site.