Tag Archives: PeerRev

Detonation nanodiamonds to aid bioimaging

6 February 2018:

Tiny 5 nm detonation nanodiamonds glow in different colors and their fluorescence is pH dependent, reports a new paper by CNBP scientists published today in the Nature journal Scientific Reports.

Lead author of the paper Dr Philipp Reineck from RMIT University (Former CNBP Research Fellow and current CNBP Associate Investigator) notes that the research is particulalry exciting as the fluorescence lifetime of the detonation nanodiamonds makes fluorescence lifetime imaging (FLIM) for bioimaging applications feasible.

Journal: Scientific Reports.

Publication title: Visible to near-IR fluorescence from single-digit detonation nanodiamonds: excitation wavelength and pH dependence.

Authors: Philipp Reineck, Desmond W. M. Lau, Emma R. Wilson, Nicholas Nunn, Olga A. Shenderova & Brant C. Gibson.

Abstract: Detonation nanodiamonds are of vital significance to many areas of science and technology. However, their fluorescence properties have rarely been explored for applications and remain poorly understood. We demonstrate significant fluorescence from the visible to near-infrared spectral regions from deaggregated, single-digit detonation nanodiamonds dispersed in water produced via post-synthesis oxidation. The excitation wavelength dependence of this fluorescence is analyzed in the spectral region from 400 nm to 700 nm as well as the particles’ absorption characteristics. We report a strong pH dependence of the fluorescence and compare our results to the pH dependent fluorescence of aromatic hydrocarbons. Our results significantly contribute to the current understanding of the fluorescence of carbon-based nanomaterials in general and detonation nanodiamonds in particular.

Diabetes and early pregnancy

1 February 2018:

CNBP and Robinson Research Institute researcher Dr Hannah Brown, University of Adelaide is lead author on a newly published paper that looks to understand why pregnancy failure and pregnancy loss occurs in women with diabetes. The paper was published in the Nature journal Scientific Reports.

Publication titlePericonception onset diabetes is associated with embryopathy and fetal growth retardation, reproductive tract hyperglycosylation and impaired immune adaptation to pregnancy.

Authors: Hannah M. Brown, Ella S. Green, Tiffany C. Y. Tan, Macarena B. Gonzalez, Alice R. Rumbold, M. Louise Hull, Robert J. Norman, Nicolle H. Packer, Sarah A. Robertson & Jeremy G. Thompson.

Abstract: Diabetes has been linked with impaired fertility but the underlying mechanisms are not well defined. Here we use a streptozotocin-induced diabetes mouse model to investigate the cellular and biochemical changes in conceptus and maternal tissues that accompany hyperglycaemia. We report that streptozotocin treatment before conception induces profound intra-cellular protein β-O-glycosylation (O-GlcNAc) in the oviduct and uterine epithelium, prominent in early pregnancy. Diabetic mice have impaired blastocyst development and reduced embryo implantation rates, and delayed mid-gestation growth and development. Peri-conception changes are accompanied by increased expression of pro-inflammatory cytokine Trail, and a trend towards increased Il1a, Tnf and Ifng in the uterus, and changes in local T-cell dynamics that skew the adaptive immune response to pregnancy, resulting in 60% fewer anti-inflammatory regulatory T-cells within the uterus-draining lymph nodes. Activation of the heat shock chaperones, a mechanism for stress deflection, was evident in the reproductive tract. Additionally, we show that the embryo exhibits elevated hyper-O-GlcNAcylation of both cytoplasmic and nuclear proteins, associated with activation of DNA damage (ɣH2AX) pathways. These results advance understanding of the impact of peri-conception diabetes, and provide a foundation for designing interventions to support healthy conception without propagation of disease legacy to offspring.

Magnetically sensitive optical fibre demonstrated

19 January 2018:

A new paper featuring CNBP researchers demonstrates magnetically sensitive nanodiamond-doped tellurite glass fibres. This work is a first step towards magneto-sensitive fibre devices which could be used in medical magneto-endoscopy and remote mineral exploration sensing. First author of the paper is CNBP AI, Dr Yinlan Ruan from the University of Adelaide.

Journal: Scientific Reports.

Publication titleMagnetically sensitive nanodiamond-doped tellurite glass fibers.

Authors: Yinlan Ruan, David A. Simpson, Jan Jeske, Heike Ebendorff-Heidepriem, Desmond W. M. Lau, Hong Ji, Brett C. Johnson, Takeshi Ohshima, Shahraam Afshar V., Lloyd Hollenberg, Andrew D. Greentree, Tanya M. Monro & Brant C. Gibson.

Abstract: Traditional optical fibers are insensitive to magnetic fields, however many applications would benefit from fiber-based magnetometry devices. In this work, we demonstrate a magnetically sensitive optical fiber by doping nanodiamonds containing nitrogen vacancy centers into tellurite glass fibers. The fabrication process provides a robust and isolated sensing platform as the magnetic sensors are fixed in the tellurite glass matrix. Using optically detected magnetic resonance from the doped nanodiamonds, we demonstrate detection of local magnetic fields via side excitation and longitudinal collection. This is a first step towards intrinsically magneto-sensitive fiber devices with future applications in medical magneto-endoscopy and remote mineral exploration sensing.

New aptasensor able to detect intracellular IFN-γ

8 January 2018:

A new research paper, resulting from a partnership between CNBP and Jilin University has been published, reporting on the development of a new aptasensor which is able to detect ultrasmall concentrations of intracellular IFN-γ. This simple and highly sensitive sensor is able to be used for real-time bio-imaging, providing  a universal sensing platform for monitoring a spectrum of molecules secreted by cells.

Journal: ACS Sensors.

Publication title: “Turn-on” Fluorescent Aptasensor Based on AIEgen Labeling for the Localization of IFN-γ in Live Cells.

Author: Ke Ma, Fengli Zhang, Nima Sayyadi, Wenjie Chen, Ayad G. Anwer, Andrew Care, Bin Xu , Wenjing Tian, Ewa M. Goldys and Guozhen Liu.

Abstract: We report an aggregation-induced emission fluorogen (AIEgen)-based turn-on fluorescent aptasensor able to detect the ultrasmall concentration of intracellular IFN-γ. The aptasensor consists of an IFN-γ aptamer labeled with a fluorogen with a typical aggregation-induced emission (AIE) characteristic, which shows strong red emission only in the presence of IFN-γ. The aptasensor is able to effectively monitor intracellular IFN-γ secretion with the lowest detection limit of 2 pg mL-1, and it is capable of localizing IFN-γ in live cells during secretion, with excellent cellular permeability and biocompatibility as well as low cytotoxicity. This probe is able to localize the intracellular IFN-γ at a low concentration <10 pg mL-1, and it is successfully used for real-time bioimaging. This simple and highly sensitive sensor may enable the exploration of cytokine pathways and their dynamic secretion process in the cellular environment. It provides a universal sensing platform for monitoring a spectrum of molecules secreted by cells.

Multi-LED light source for hyperspectral imaging

15 December 2017:

A multi-LED light source has been investigated by CNBP researchers for use in hyperspectral imaging. The research featured in the journal ‘Optics Express’  with the lead author on the paper, PhD student Kashif Islam, based at Macquarie University.

Journal: Optics Express.

Publication titleMulti-LED light source for hyperspectral imaging.

Author: Kashif Islam, Martin Ploschner, and Ewa M. Goldys.

Abstract: We investigate a novel light source design for efficient collection of UV light from multiple LEDs. The design is based on a truncated cone with a large circular lid incorporating LEDs on one side, and a small circular exit aperture (diameter of 9 mm) on the other side. The exit aperture size allows a simple coupling with secondary optics of a microscope for hyperspectral imaging that requires a wide spectrum of frequencies of illuminating light. The light collection efficiency was optimized with respect to cone length and diameter of the LED lid. In all simulations, we use a highly UV-reflecting aluminum coating on the inner surfaces of the cone. The influence of the LED positions on the cone efficiency is determined by varying the LED distance from the central axis as well as the interLED distance. We found the maximum efficiency of the cone is realized for LEDs positioned at the center, and the shorter is the inter-LED distance, the better is the performance of the light source.

Nanoscale biophotonics for the ‘other’ brain

12 December 2017:

CNBP Director Prof Mark Hutchinson, The University of Adelaide has published a new review and commentary on the future of sensor development in the exciting new world of neuroimmunoscience!

Journal: Microelectronic Engineering.

Publication titleThe importance of knowing you are sick: Nanoscale biophotonics for the ‘other’ brain.

Author: Mark R. Hutchinson.

Abstract: A great new frontier in biomedical science has recently been discovered that requires the attention of technologists from diverse backgrounds to equip scientists with the tools needed to explore this great uncharted area. This new expanding domain is the exploration of the neuroimmune cells of the central nervous system, and their real-time function and contributions to the health and disease of the brain and spinal cord. Glia, once thought of as mere structural supports for the brain, are now appreciated to actively contribute to brain function. However, the true complexity of this system is still hidden from close examination, owing to a range of technological and methodological limitations. Here, some of these opportunities and challenges are outlined to expose the micro and nanoengineering community to this dynamic area of research, and to encourage innovation and technology application in the research of the “other brain”.

Copper oxide nanocubes good for bioimaging

Nafisa Zohora4 December 2017:

New CNBP research determines that copper oxide nanocubes are suitable for long-term bioimaging experiments. Lead author on the paper – CNBP PhD student Zafisa Zohora (RMIT University).

Journal: Scientific Reports.

Publication titleFluorescence brightness and photostability of individual copper (I) oxide nanocubes.

Authors: Nafisa Zohora, Ahmad Esmaielzadeh Kandjani, Antony Orth, Hannah M. Brown, Mark R. Hutchinson & Brant C. Gibson.

Abstract:
Conventional organic fluorophores lose their ability to fluoresce after repeated exposure to excitation light due to photobleaching. Therefore, research into emerging bright and photostable nanomaterials has become of great interest for a range of applications such as bio-imaging and tracking. Among these emerging fluorophores, metal oxide-based nanomaterials have attracted significant attention as a potential multifunctional material with photocatalytic and angeogenisis abilities in addition to fluorescnce applications. However, most of these applications are highly dependent on size, morphology, and chemo-physical properties of individual particles. In this manuscript, we present a method to study the intrinsic optical characteristics of individual copper (I) oxide (Cu2O) nanocubes. When excited at 520 nm using only 11 µW excitation power (1.7 W/cm2), individual nanocubes were observed to emit light with peak wavelengths ~760 nm which is conveniently within the near-infrared 1 (NIR1) biological window where tissue autofluorescence is minimal. Bright and photostable fluorescence was observed with intensities up to 487 K counts/s under constant illumination for at least 2 minutes with a brightness approximately four times higher than the autofluorescence from a fixed cumulus-oocyte complex. With near-IR emission, high fluorescence brightness, and outstanding photostability, Cu2O nanocubes are attractive candidates for long-term fluorescent bioimaging applications.

New hybrid sensor developed

21 November 2017:

A new hybrid sensor combining an organic fluorescent probe bound to a nanodiamond has been developed by CNBP researchers (lead author Dr Malcolm Purdey pictured). Able to detect hydrogen peroxide, the sensor is non-toxic and is also highly photostable.

Journal: Scientific Reports.

Publication title: An organic fluorophore-nanodiamond hybrid sensor for photostable imaging and orthogonal, on-demand biosensing.

Authors: Malcolm S. Purdey, Patrick K. Capon, Benjamin J. Pullen, Philipp Reineck, Nisha Schwarz, Peter J. Psaltis, Stephen J. Nicholls, Brant C. Gibson & Andrew D. Abell.

Abstract: Organic fluorescent probes are widely used to detect key biomolecules; however, they often lack the photostability required for extended intracellular imaging. Here we report a new hybrid nanomaterial (peroxynanosensor, PNS), consisting of an organic fluorescent probe bound to a nanodiamond, that overcomes this limitation to allow concurrent and extended cell-based imaging of the nanodiamond and ratiometric detection of hydrogen peroxide. Far-red fluorescence of the nanodiamond offers continuous monitoring without photobleaching, while the green fluorescence of the organic fluorescent probe attached to the nanodiamond surface detects hydrogen peroxide on demand. PNS detects basal production of hydrogen peroxide within M1 polarised macrophages and does not affect macrophage growth during prolonged co-incubation. This nanosensor can be used for extended bio-imaging not previously possible with an organic fluorescent probe, and is spectrally compatible with both Hoechst 33342 and MitoTracker Orange stains for hyperspectral imaging.

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.