30 March 2018:
CNBP scientists Chris Ashwood (pictured) and Prof Nicki Packer at Macquarie University have shown that sugars with exactly the same chemical composition but slightly different structure break apart differently in their latest publication in the area of mass spectrometry. This work is their first step in automating sugar analysis, to understand the role sugars play in human disease.
Journal: Journal of The American Society for Mass Spectrometry.
Publication title: Discrimination of Isomers of Released N- and O-Glycans Using Diagnostic Product Ions in Negative Ion PGC-LC-ESI-MS/MS.
Authors: Christopher Ashwood, Chi-Hung Lin, Morten Thaysen-Andersen, Nicolle H. Packer.
Profiling cellular protein glycosylation is challenging due to the presence of highly similar glycan structures that play diverse roles in cellular physiology. As the anomericity and the exact linkage type of a single glycosidic bond can influence glycan function, there is a demand for improved and automated methods to confirm detailed structural features and to discriminate between structurally similar isomers, overcoming a significant bottleneck in the analysis of data generated by glycomics experiments. We used porous graphitized carbon-LC-ESI-MS/MS to separate and detect released N- and O-glycan isomers from mammalian model glycoproteins using negative mode resonance activation CID-MS/MS. By interrogating similar fragment spectra from closely related glycan isomers that differ only in arm position and sialyl linkage, product fragment ions for discrimination between these features were discovered. Using the Skyline software, at least two diagnostic fragment ions of high specificity were validated for automated discrimination of sialylation and arm position in N-glycan structures, and sialylation in O-glycan structures, complementing existing structural diagnostic ions. These diagnostic ions were shown to be useful for isomer discrimination using both linear and 3D ion trap mass spectrometers when analyzing complex glycan mixtures from cell lysates. Skyline was found to serve as a useful tool for automated assessment of glycan isomer discrimination. This platform-independent workflow can potentially be extended to automate the characterization and quantitation of other challenging glycan isomers.
12 October 2017:
The liquid metal, shape-shifting T-1000 Terminator cyborg, featuring in a 1991 science-fiction film Terminator 2, was made possible due to breakthroughs in computer-generated imagery.
Some 25 years later, using breakthroughs in physics and chemistry CNBP scientists Dr Ivan Maksymov and Prof Andy Greentree at RMIT University have shown reconfigurable liquid-metal optical nanoantennae.
“An optical nanoantenna operates similarly to a conventional radio-frequency antenna, but its size is millions of times smaller” explains Dr Ivan Maksymov, “so it can receive and emit light similar to how a mobile phone antenna receives and emits radio waves.”
“The shape and length of the metal components that form a radio-frequency antenna determine its major properties such as operating frequency and radiation pattern,” explains Prof Andy Greentree, “so a liquid metal that can change its shape by applying voltage allows for changing antenna properties, which otherwise is difficult to achieve with fixed metal parts.”
“However, reconfigurability of optical nanoantennae is even more difficult to achieve than in radio-frequency antennae, because of their small size and lack of technologies enabling us to apply voltage to nanoscale sized objects. Therefore, we proposed a new solution – reconfiguration of liquid-metal nanoparticles using ultrasound.”
Continued Dr Maksymov, “A liquid-metal nanoparticle can change its shape due to capillary oscillations, which can be seen by everybody when observing water drops falling from a leaking kitchen tap. Drops change their shape when they detach from the tap and fall into the sink. In our work, we use ultrasound to change the shape of liquid-metal nanodroplets, which changes the nanoantenna’s operating frequency.”
“But fundamental physics remains the same as in the case of water drops.”
The paper ‘Dynamically reconfigurable plasmon resonances enabled by capillary oscillations of liquid-metal nanodroplets’ is accessible online.
11 October 2017:
A new publication from CNBP researchers explores the integration of an optical coherence tomography (OCT) probe into a flexible needle for lung tissue aspiration. The paper (lead author Jiawen Li pictured), was published in the Journal of Biomedical Optics and is accessible online.
Journal: Journal of Biomedical Optics.
Publication title: Flexible needle with integrated optical coherence tomography probe for imaging during transbronchial tissue aspiration.
Authors: Jiawen Li; Bryden C. Quirk; Peter B. Noble; Rodney W. Kirk; David D. Sampson; Robert A. McLaughlin.
Abstract: Transbronchial needle aspiration (TBNA) of small lesions or lymph nodes in the lung may result in nondiagnostic tissue samples. We demonstrate the integration of an optical coherence tomography (OCT) probe into a 19-gauge flexible needle for lung tissue aspiration. This probe allows simultaneous visualization and aspiration of the tissue. By eliminating the need for insertion and withdrawal of a separate imaging probe, this integrated design minimizes the risk of dislodging the needle from the lesion prior to aspiration and may facilitate more accurate placement of the needle. Results from in situ imaging in a sheep lung show clear distinction between solid tissue and two typical constituents of nondiagnostic samples (adipose and lung parenchyma). Clinical translation of this OCT-guided aspiration needle holds promise for improving the diagnostic yield of TBNA.
1 September 2017:
Understanding the electronic properties inherent to peptides is crucial for controlling charge transfer, and precursory to the design and fabrication of bio-inspired next generation electronic components.
However, to achieve this objective one must first be able to predict and control the associated charge transfer mechanisms.
Here CNBP researchers demonstrate for the first time a controllable mechanistic transition in peptides resulting directly from the introduction of a side-bridge.
Journal: RSC Advances.
Publication title: A controllable mechanistic transition of charge transfer in helical peptides: from hopping to superexchange.
Authors: Jingxian Yu (pictured), John R. Horsley and Andrew D. Abell.
For more information, access the paper here.
28 April 2017:
A new paper from CNBP researchers reports on an improvement to deterministic lateral displacement arrays, which allows for higher particle concentration enhancement. The work has just been published in the journal ‘Biomicrofluidics’ and is accessible online.
Title: Maximizing particle concentration in deterministic lateral displacement arrays.
Authors: Shilun Feng, Alison M. Skelley, Ayad G. Anwer (pictured top left), Guozhen Liu and David W. Inglis.
Abstract: We present an improvement to deterministic lateral displacement arrays, which allows higher particle concentration enhancement. We correct and extend previous equations to a mirror-symmetric boundary. This approach allows particles to be concentrated into a central channel, no wider than the surrounding gaps, thereby maximizing the particle enrichment. The resulting flow patterns were, for the first time, experimentally measured. The performance of the device with hard micro-spheres and cells was investigated. The observed flow patterns show important differences from our model and from an ideal pattern. The 18 μm gap device showed 11-fold enrichment of 7 μm particles and nearly perfect enrichment—of more than 50-fold—for 10 μm particles and Jurkat cells. This work shows a clear path to achieve higher-than-ever particle concentration enhancement in a deterministic microfluidic separation system.
27 April 2017:
Researchers from CNBP and The Institute of Photonic Technology (lead author Stephen Warren-Smith pictured), have just had a paper published on tuning third harmonic light generated within exposed-core fibres.
Journal: Optics Letters.
Publication title: Nanofilm-induced spectral tuning of third harmonic generation.
Authors: Stephen C. Warren-Smith, Mario Chemnitz, Henrik Schneidewind, Roman Kostecki, Heike Ebendorff-Heidepriem, Tanya M. Monro and Markus A. Schmidt.
Abstract: Intermodal third-harmonic generation using waveguides is an effective frequency conversion process due to the combination of long interaction lengths and strong modal confinement. Here we introduce the concept of tuning the third harmonic phase-matching condition via the use of dielectric nanofilms located on an open waveguide core. We experimentally demonstrate that tantalum oxide nanofilms coated onto the core of an exposed core fiber allow tuning the third harmonic wavelength over 30 nm, as confirmed by qualitative simulations. Due to its generic character, the presented tuning scheme can be applied to any form of exposed core waveguide and will find applications in fields including microscopy, biosensing, and quantum optics.
The paper is accessible online.
21 April 2017:
A new paper from CNBP researchers (lead author Wenjie Chen pictured) reports on the design of a new light-triggerable liposome. The work has just been published in the journal ‘Molecular Therapy: Nucleic Acid’ and is accessible online.
Journal: Molecular Therapy: Nucleic Acid.
Title: Light-triggerable liposomes for enhanced endo/lysosomal escape and gene silencing in PC12 cells.
Authors: Wenjie Chen, Wei Deng, Ewa M. Goldys.
Abstract: Liposomes are an effective gene/drug delivery system, widely used in biomedical applications including gene therapy and chemotherapy. Here we designed a photo-responsive liposome (lipVP) loaded with a photosensitizer verteporfin (VP). This photosensitizer is clinically approved for photodynamic therapy (PDT). LipVP was employed as a DNA carrier for pituitary adenylyl cyclase-activating polypeptide (PACAP) receptor 1 (PAC1R) gene knockdown in PC12 cells. This has been done by incorporating PAC1R antisense oligonucleotides inside the lipVP cavity. Cells which have taken up the lipVP were exposed to light from a UV light source. As a result of this exposure, reactive oxygen species (ROS) were generated from VP, destabilising the endo/lysosomal membranes and enhancing the liposomal release of antisense DNA into the cytoplasm. Endo/lysosomal escape of DNA was documented at different time points based on quantitative analysis of colocalization between fluorescently labelled DNA and endo/lysosomes. The released antisense oligonucleotides were found to silence PAC1R mRNA. The efficiency of this photo-induced gene silencing was demonstrated by a 74 ± 5% decrease in PAC1R fluorescence intensity. Following the light-induced DNA transfer into cells, cell differentiation with exposure to two kinds of PACAP peptides was observed to determine the cell phenotypic change after PAC1R gene knockdown.
3 April 2017:
A new publication from CNBP researchers (lead author Dr Ivan Maksymov pictured) demonstrates a new scheme for synthesis of optical spectra from nonlinear ultrasound harmonics using a hybrid liquid-state and nanoplasmonic device compatible with fibre-optic technology.
The work has just been reported in the journal ‘Optics Express’ and is accessible online.
Journal: Optics Express.
Title: Synthesis of discrete phase-coherent optical spectra from nonlinear ultrasound.
Authors: Ivan S. Maksymov and Andrew D. Greentree.
Abstract: Nonlinear acoustic interactions in liquids are effectively stronger than nonlinear optical interactions in solids. Thus, harnessing these interactions will offer new possibilities in the design of ultra-compact nonlinear photonic devices. We theoretically demonstrate a new scheme for synthesis of optical spectra from nonlinear ultrasound harmonics using a hybrid liquid-state and nanoplasmonic device compatible with fibre-optic technology. The synthesised spectra consist of a set of equally spaced optical Brillouin light scattering modes having a well-defined phase relationship between each other. We suggest that these spectra may be employed as optical frequency combs whose spectral composition may be tuned by controlling the nonlinear acoustic interactions.
22 March 2017:
Cell Systems has published an invited preview article authored by CNBP Research Fellow Dr Antony Orth along with collaborators from Harvard University and Massachussetts General Hospital.
The commentary article discusses how data-driven methods are poised to shake-up how we approach bio-microscopy. Microscopy-based assays can be made more informative and more predictive when paired with a library of reference images. The preview puts new results in this field into context and suggests further avenues of research.
The article is accessible online although a subscription is required.
9 March 2017:
CNBP scientists Chris Ashwood and Prof Nicki Packer at Macquarie University have shown alternative ways to break apart sugars, improving their characterisation in their latest publication in the area of mass spectrometry (Enhancing structural characterisation of glucuronidated O-linked glycans using negative mode ion trap higher energy collision-induced dissociation mass spectrometry).
The work was published online in the journal Rapid Communications in Mass Spectrometry on 9th March 2017 and was funded by the Australian Research Council Centre of Excellence for Nanoscale BioPhotonics.