Monthly Archives: April 2017

Maximizing particle concentration

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.

Journal: Biomicrofluidics.

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.

 

New nanoparticle discovery to aid super-resolution imaging

Prof Jim Piper26 April 2017:

Researchers at the ARC Centre of Excellence for Nanoscale BioPhotonics (CNBP), Macquarie University, the University of Technology Sydney (UTS), Peking University and Shanghai Jiao-tong University have made a breakthrough in the development of practical super-resolution optical microscopy that will pave the way for the detailed study of live cells and organisms, on a scale 10 times smaller than can currently be achieved with conventional microscopy.

Reported in Nature, the international team of researchers has demonstrated that bright luminescent nanoparticles can be switched on and off using a low-power infrared laser beam, and used to achieve images with a super resolution of 28nm.

Professor Jim Piper (pictured), leader of the research team at Macquarie University and the CNBP sees these nanoparticles as having new unique properties. “These allow researchers to see well beyond normal limits of standard microscopes. It will let you see deeper and more clearly at the cellular and intra- cellular level—where proteins, antibodies and enzymes ultimately run the machinery of life.”

The research featured in BioPhotonics World.

Light-triggerable liposomes

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.

Social media for research engagement

21 April 2017:

CNBP’s Dr Hannah Brown (pictured), together with Prof Ben Mol, the University of Adelaide and Melinda Cruz, CEO and Founder of Miracle Babies Foundation, believe that social media interaction and scientific activity should go hand-in-hand.

They argue that increased social engagement by scientists with collaborators, the media, governing and funding bodies, government and consumers underlies research success.

Check out their latest written piece, ‘Social media is essential for research engagement‘ in BJOG, an International Journal of Obstetrics and Gynaecology.