Category Archives: UNSW

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

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

 

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.

Non-invasive assessment of islet cells

2 April 2019:

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.

Cutting-edge biosensing applications of CRISPR reviewed

14 January 2019:

A new paper by CNBP researchers and colleagues (including CNBP Associate Investigator Guozhen Liu, UNSW Sydney) reviews cutting-edge biosensing applications of CRISPR.

Journal: Trends in Biotechnology.

Publication title:  CRISPR/Cas Systems towards Next-Generation Biosensing.

Authors: Yi Li, Shiyuan Li, Jin Wang and Guozhen Liu.

Abstract: Beyond its remarkable genome editing ability, the CRISPR/Cas9 effector has also been utilized in biosensing applications. The recent discovery of the collateral RNA cleavage activity of the Cas13a effector has sparked even greater interest in developing novel biosensing technologies for nucleic acid detection and promised significant advances in CRISPR diagnostics. Now, along with the discovery of Cas12 collateral cleavage activities on single stranded DNA (ssDNA), several CRISPR/Cas systems have been established for detecting various targets, including bacteria, viruses, cancer mutations, and
others. Based on key Cas effectors, we provide a detailed classification of CRISPR/Cas biosensing systems and propose their future utility. As the field continues to mature, CRISPR/Cas systems have the potential to become promising candidates for next-generation diagnostic biosensing platforms.