New probe to detect hydrogen peroxide

10 June 2019

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

Research award for Ms Megan Lim

5 June 2019:  Congratulations to PhD Student Ms Megan Lim who was awarded the Robinson’s Research Institute Prize for Best presentation in the field of reproduction, pregnancy or child health at The Australian Society for Medical Research (ASMR) conference.

Megan’s oral presentation was titled “Investigation of haemoglobin as an antioxidant to reduce reactive oxygen species during the in vitro maturation of moues cumulus-oocyte com.

Megan would like to thank my supervisor Dr Kylie Dunning and lab colleagues for their feedback during her practice talks, and also the Biological Challenges meeting attendees who gave her  helpful insights for her project.  “Thank you for your words of encouragement and support!”

What is the potential for CRISPT/Cas Multiplex Biosensing?

29 May 2019

Recent publication by CNBP PhD student Mr Yi Li and team at the University of New South Wales explores the challenges and opportunities of working with CRISPR /Cas for multiplex detection

Journal: Trends in Biotechnology

Publication TitleCRISPR/Cas Multiplexed Biosensing: A Challenge or an Insurmountable Obstacle?

Authors: Yi Li, Linyang Liu, Guozhen Liu

Abstract:  Performing multiplex detection is still an elusive goal for molecular diagnostics. CRISPR/Cas-based biosensing has demonstrated potential for multiplex detection. Instead of being an insurmountable obstacle, CRISPR/Cas multiplexed biosensing is a realistic challenge with some recent successful applications. Strategic considerations are required to fully explore its potential in multiplex diagnostics.

Key Words:

CRISPR/Cas; multiplex; biosensing; diagnostics; nucleic acid detection

 

Pop-up science

25 May 2019:

CNBP researchers Dr Georgina Sylvia and Dr Erin Smith (in conjunction with Children’s University Adelaide) have taken their love of science to the public, demonstrating fun-filled experiments to budding young scientists at a ‘pop-up’ event titled ‘The Magic and Wonder of Science’. The event took place as part of the biennial ‘Dream Big Children’s Festival’, held in South Australia, May-June, 2019.

Attendees at the ‘pop-up’ outreach event saw science working in practice as well as real-life applications of differing scientific elements.

“We demonstrated numerous experiments to our audience including creating ‘Elephant’s Toothpaste’. This is a foamy substance caused by the rapid decomposition of hydrogen peroxide,” says Georgina.

“Other experiments included a demonstration of atmospheric pressure with a jar of water, as well as the use of liquid nitrogen to freeze an everyday egg in a fry-pan. We wanted to inspire our young audience and to open their minds to the everyday science that exists all around them,” she says.

“Our show aimed to be a blend of entertainment and education with plenty of humor and laughs as well.”

Below – Erin and Georgina putting on their scientific show!

 

Cancer research to the public

20 May 2019:

CNBP AI at Macquarie University and Early Career Fellow at the Cancer Institute NSW, Dr Andrew Care, has presented his research to a packed house at a ‘Pint of Science’ public outreach and engagement event, 20th May 2019.

Held at the Nags Head Hotel, Glebe, Sydney, Dr Care talked about the latest in cancer research with a particular focus on a newly discovered class of biologically-derived nanoparticles (protein nanocages), and how they can be genetically-engineered to target and destroy tumours.

“Taking my science out to the public was great fun,” he says. “But more importantly it was a good opportunity to highlight that positive advances we are making in the fight against disease thanks to ongoing research investment in Australia,” he said.

Dr Care added, “I checked out Pint of Science for the first time last year. I saw a great talk by Dr Orazio Vittorio a cancer biologist from Children’s Cancer Institute Australia. After a chat at the pub about our research, we started a collaboration. A year later Orazio and I are developing an exciting new tool for cancer treatment! Together, we’ve also obtained research funding, and we’re about to file a patent and to publish our first paper together. None of this would have possible without Pint!”

“Talking at Pint of Science this year is my way of giving back and saying thanks for making a great collaboration happen…and maybe to find another awesome collaborator lurking in the pub again,” he concludes.

Dr Care’s research group combines techniques from synthetic biology and nanomedicine for the targeted treatment of cancer. More information on his exciting work can be found in his profile here.

Below – Dr Care presenting his research at Pint of Science, Sydney 2019.

Hemoglobin and its role in the oocyte and early embryo

6 May 2019:

Hemoglobin expression in reproductive cells and the role of hemoglobin on oocyte and early embryo development is the focus of this latest CNBP review paper published in the journal ‘Biology of Reproduction’ (lead author Megan Lim based at the University of Adelaide).

Journal: Biology of Reproduction.

Publication title: Hemoglobin: potential roles in the oocyte and early embryo.

Authors: Megan Lim, Hannah M Brown, Karen L Kind, Jeremy G Thompson, Kylie R Dunning.

Abstract: Hemoglobin (Hb) is commonly known for its capacity to bind and transport oxygen and carbon dioxide in erythroid cells. However, it plays additional roles in cellular function and health due to its capacity to bind other gases including nitric oxide. Further, Hb acts as a potent antioxidant, quenching reactive oxygen species. Despite its potential roles in cellular function, the preponderance of Hb research remains focused on its role in oxygen regulation. There is increasing evidence that Hb expression is more ubiquitous than previously thought, with Hb and its variants found in a myriad of cell types ranging from macrophages to spermatozoa. The majority of non-erythroid cell types that express Hb are situated within hypoxic environments, suggesting Hb may play a role in hypoxia-inducible factor (HIF)-regulated gene expression by controlling the level of oxygen available or as an adaptation to low oxygen providing a mechanism to store oxygen. Oocyte maturation and preimplantation embryo development occur within the low oxygen environments of the antral follicle and oviduct/uterus, respectively. Interestingly, Hb was recently found in human cumulus and granulosa cells and murine cumulus-oocyte complexes (COCs) and preimplantation embryos. Here, we consolidate and analyze the research generated to-date on Hb expression in non-erythroid cells with a particular focus on reproductive cell types. We outline future directions of this research to elucidate the role of Hb during oocyte maturation and preimplantation embryo development and finally, we explore the potential clinical applications and benefits of Hb supplementation during the in vitro culture of gametes and embryos.

New cytokine sensing device developed

1 May 2019:

A molecular imprinted polymer biosensing device (developed on stainless steel) that can successfully detect cytokines has been reported by CNBP researchers. Cytokines are proteins secreted by cells that stimulate surrounding cells into specific action and are important to an organism’s immune responses. The finding was reported in the journal ‘Sensors and Actuators B: Chemical’ with the lead author of the publication being CNBP’s Fei Deng based at UNSW Sydney.

Journal: Sensors and Actuators B: Chemical.

Publication title: Molecularly imprinted polymer-based reusable biosensing device on stainless steel for spatially localized detection of cytokine IL-1β.

Authors: Fei Deng, Ewa M. Goldys, Guozhen Liu.

Abstract: A molecularly imprinted polymer (MIP) based biosensing device on stainless steel (SS) for detection of locally variable concentration of cytokine interleukin-1β (IL-1β) was successfully developed using a sandwich assay scheme. The SS surface was firstly modified with a layer of polydopamine (PDA) followed by the attachment of a layer of poly(ethyleneimine) (PEI) by electrostatic adsorption. Subsequently, the template protein IL-1β was adsorbed on the PEI terminated SS surface due to electrostatic adsorption. A PDA imprinting film was then in-situ synthesized on the surface of the modified SS substrate with incorporated template cytokine. Finally, the template was washed off the SS substrate leaving behind cavities with specific shape and capable of capturing cytokines thus forming a MIP biosensing interface. After exposure to the analyte IL-1β, the MIP biosensing device was incubated with IL-1β detection antibody-modified fluorescent polystyrene beads allowing to determine the amount of captured IL-1β based on fluorescence intensity. The device has been demonstrated to detect IL-1β with low detection limit of 10.2 pg mL−1, and a linear detection range of 25–400 pg mL−1. This MIP biosensing device can be regenerated more than three times with coefficient of variation 2.08%. The device was applied for the detection of IL-1β secreted by rat macrophages, where the good specificity and selectivity were achieved. MIP serves in this device as a superior substitute of antibody with exceptional stability and reusability. The MIP based biosensing technology presented in our work paves a new way for developing a universal and robust sensing platform for the detection of spatially localised small proteins with low physical concentration.

Collaborative research visit to Peking University

April 2019

CNBP PhD Student Ms Yuan Qi Yeoh enjoyed a two week collaborative visit with Prof Xuefeng Guo’s team at Peking University. Working with Peking University PhD student Xinjiani Chen on a  research project involving the molecular dynamics of the secondary structure of a cyclic photoswitchable peptide.

Yuan Qi had the opportunity to participate in the fabrication process of the single-molecule devices. Specifically, they carried out temperature-dependent experiments using their advanced facilities to probe the molecular dynamics of the secondary structure upon photoswitching.

Yuan Qi says that “It was a great opportunity to collaborate with colleagues at Peking University in such high impact research and enjoyed working in their sophisticated research labs”

Towards a deployable device for cytokine sensing

29 April 2019:

A new research publication (lead author CNBP PhD student Fuyuan Zhang) reports on real-time sensing and detection of cytokines using a 3D optical fibre.

Journal: Molecular Systems Design & Engineering.

Publication title: IFN-γ-induced signal-on fluorescence aptasensors: from hybridization chain reaction amplification to 3D optical fiber sensing interface towards a deployable device for cytokine sensing.

Authors: Fuyuan Zhang, Fei Deng, Guo-Jun Liu, Ryan Middleton, David W. Inglis, Ayad Anwer, Shuo Wang and  Guozhen Liu.

Abstract: Interferon-gamma (IFN-γ), a proinflammatory cytokine, has been used as an early indicator of multiple infectious diseases or tumors. In order to explore the detection capability of a commonly used anti-IFN-γ aptamer, a simple target induced strand-displacement aptasensing strategy was tested by introducing three different complementary strands and two different signal/quencher pairs. The Texas red/BHQ2-based sensor showed the best affinity constant (Kd) of 21.87 ng mL−1. It was found that the strand-displacement aptasensing strategy was impacted by the complementary position and length of the complementary strands. Additionally, the hybridization chain reaction (HCR) amplification strategy was introduced, yielding a 12-fold improved sensitivity of 0.45 ng mL−1. In order to further explore the sensing platform for spatially localized cytokine detection, the Texas red/BHQ2-based strand-displacement aptasensor was successfully fabricated on the 3D optical fiber surface to achieve a deployable sensing device for monitoring IFN-γ based on the fluorescence spots counting strategy. Finally, the three developed aptasensing strategies (strand-displacement strategy, HCR amplification strategy, 3D optical fiber aptasensor) were applied for detection of IFN-γ secreted by PBMCs with comparable results to those of ELISA. The deployable 3D optical fiber aptasensor with the superior sensitivity is potential to be used for detection of spatially localized IFN-γ in vivo.

In-body fibre optic imaging to go 3D

26 April 2019:

An advanced new method has been developed by CNBP researchers that may open the door to 3D microscopy in hard-to-reach areas of the human body.

It sees the successful miniaturization of a 3D imaging technique called ‘light field imaging’, taken to extreme new levels, making in-body application possible.

It could find significant application in diagnostic procedures called optical biopsies, where suspicious tissue is investigated during medical endoscopic procedures.

Reported in the journal ‘Science Advances’, project lead of the innovative imaging approach is Dr Antony Orth, Research Fellow at the RMIT University node of the CNBP (pictured).

The paper can be accessed below or read the media release here.

Journal: Science Advances.

Publication title: Optical fiber bundles: Ultra-slim light field imaging probes.

Authors: A. Orth, M. Ploschner, E. R. Wilson, I.S. Maksymov and B. C. Gibson.

Abstract: Optical fiber bundle microendoscopes are widely used for visualizing hard-to-reach areas of the human body. These ultrathin devices often forgo tunable focusing optics because of size constraints and are therefore limited to two-dimensional (2D) imaging modalities. Ideally, microendoscopes would record 3D information for accurate clinical and biological interpretation, without bulky optomechanical parts. Here, we demonstrate that the optical fiber bundles commonly used in microendoscopy are inherently sensitive to depth information. We use the mode structure within fiber bundle cores to extract the spatio-angular description of captured light rays—the light field—enabling digital refocusing, stereo visualization, and surface and depth mapping of microscopic scenes at the distal fiber tip. Our work opens a route for minimally invasive clinical microendoscopy using standard bare fiber bundle probes. Unlike coherent 3D multimode fiber imaging techniques, our incoherent approach is single shot and resilient to fiber bending, making it attractive for clinical adoption.

Below – Modal structure in optical fiber bundles captures light field information. Credit Antony Orth, RMIT University.