Monthly Archives: October 2017

Surface chemistry and nanodiamond fluorescence

31 October 2017:

Surface chemistry is vital for nanodiamond fluorescence, reports a new paper published by CNBP researchers (lead author Dr Philipp Reineck pictured). The paper was published in the journal ‘ACS Nano’ and is available online.

Journal: ACS Nano.

Publication title: Effect of Surface Chemistry on the Fluorescence of Detonation Nanodiamonds.

Authors: Philipp Reineck, Desmond W. M. Lau, Emma R. Wilson, Kate Fox, Matthew R. Field, Cholaphan Deeleepojananan, Vadym N. Mochalin, and Brant C. Gibson.

Abstract: Detonation nanodiamonds (DNDs) have unique physical and chemical properties that make them invaluable in many applications. However, DNDs are generally assumed to show weak fluorescence, if any, unless chemically modified with organic molecules. We demonstrate that detonation nanodiamonds exhibit significant and excitation-wavelength-dependent fluorescence from the visible to the near-infrared spectral region above 800 nm, even without the engraftment of organic molecules to their surfaces. We show that this fluorescence depends on the surface functionality of the DND particles. The investigated functionalized DNDs, produced from the same purified DND as well as the as-received polyfunctional starting material, are hydrogen, hydroxyl, carboxyl, ethylenediamine, and octadecylamine-terminated. All DNDs are investigated in solution and on a silicon wafer substrate and compared to fluorescent high-pressure high-temperature nanodiamonds. The brightest fluorescence is observed from octadecylamine-functionalized particles and is more than 100 times brighter than the least fluorescent particles, carboxylated DNDs. The majority of photons emitted by all particle types likely originates from non-diamond carbon. However, we locally find bright and photostable fluorescence from nitrogen-vacancy centers in diamond in hydrogenated, hydroxylated, and carboxylated detonation nanodiamonds. Our results contribute to understanding the effects of surface chemistry on the fluorescence of DNDs and enable the exploration of the fluorescent properties of DNDs for applications in theranostics as nontoxic fluorescent labels, sensors, nanoscale tracers, and many others where chemically stable and brightly fluorescent nanoparticles with tailorable surface chemistry are needed.

New microfluidic needle-like device developed

31 October:

A new paper from CNBP researchers (lead author Shilun Feng pictured) reports on the development of a microfluidic needle-like device that can extract and deliver nanoliter samples.

The paper, published in ‘Applied Physics Letters’ is accessible online.

Journal: Applied Physics Letters.

Publication title: A microfluidic needle for sampling and delivery of chemical signals by segmented flows.

Authors: Shilun Feng, Guozhen Liu, Lianmei Jiang, Yonggang Zhu, Ewa M. Goldys, and David W. Inglis.

Abstract: We have developed a microfluidic needle-like device that can extract and deliver nanoliter samples. The device consists of a T-junction to form segmented flows, parallel channels to and from the needle tip, and seven hydrophilic capillaries at the tip that form a phase-extraction region. The main microchannel is hydrophobic and carries segmented flows of water-in-oil. The hydrophilic capillaries transport the aqueous phase with a nearly zero pressure gradient but require a pressure gradient of 19 kPa for mineral oil to invade and flow through. Using this device, we demonstrate the delivery of nanoliter droplets and demonstrate sampling through the formation of droplets at the tip of our device. During sampling, we recorded the fluorescence intensities of the droplets formed at the tip while varying the concentration of dye outside the tip. We measured a chemical signal response time of approximately 3 s. The linear relationship between the recorded fluorescence intensity of samples and the external dye concentration (10–40 μg/ml) indicates that this device is capable of performing quantitative, real-time measurements of rapidly varying chemical signals.

 

CNBP researchers edit new book

30 October 2017:

A new book edited by A/Prof Anwar Sunna (CNBP Associate Investigator), Dr Andrew Care (CNBP Research Fellow) and Peter Bergquist (Macquarie University) as been published by Springer.

The book, “Peptides and Peptide-based Biomaterials and their Biomedical Applications”, highlights new developments in the applications of peptide and peptide-based biomaterials in biomedicine.

“This is a fast-moving and rapidly expanding research area, which promises to be one of the most significant fields of research in applied biomedicine”, says A/Prof Sunna.

“The work introduces readers to direct applications and translational research at the interface between materials science, protein chemistry and biomedicine.”

CI joins ARC College of Experts

27 October 2017:

Professor Andrew Greentree, CNBP Chief Investigator from RMIT University has been announced as a member of the prestigious ARC College of Experts.

Members of the College of Experts assess and rank ARC grant applications submitted under the National Competitive Grants Program, make funding recommendations to the ARC and provide strategic advice to the ARC on emerging disciplines and cross-disciplinary developments.

Membership of the College is limited to experts of international standing drawn from the Australian research community.

Further information on this key ARC committee and its contribution to national innovation is available online.

 

Quantifying nanoparticles in colloidal suspension

26 October 2017:

A new paper featuring CNBP researchers (lead author Sandhya Clement pictured top left), demonstrates a simple, non-destructive method suitable for rapid evaluation of nanoparticles in colloidal suspension.

The paper, published in Nanotechnology is accessible online.

Journal: Nanotechnology.

Publication title: Quantification of nanoparticle concentration in colloidal suspensions by a non-destructive optical method.

Authors: Sandhya Clement, Brint Gardner, Wan Aizuddin W Razali, Victoria A Coleman, Åsa K Jämting, Heather J Catchpoole, Ewa M Goldys, Jan Herrmann and Andrei Zvyagin.

Abstract: The estimation of nanoparticle number concentration in colloidal suspensions is a prerequisite in many procedures, and in particular in multi-stage, low-yield reactions. Here, we describe a rapid, non-destructive method based on optical extinction and dynamic light scattering (DLS), which combines measurements using common bench-top instrumentation with a numerical algorithm to calculate the particle size distribution (PSD) and concentration. These quantities were derived from Mie theory applied to  measurements of the optical extinction spectrum of homogeneous, non-absorbing nanoparticles, and the relative PSD of a colloidal suspension. The work presents
an approach to account for PSDs achieved by DLS which, due to the underlying model, may not be representative of the true sample PSD. The presented approach estimates the absolute particle number concentration of samples with mono-, bi-modal and broad size distributions with <50% precision. This provides a convenient and practical solution for number concentration estimation required during many applications of colloidal nanomaterials.

New CNBP PhD student

20 October 2017:

CNBP welcomes its latest PhD student Lu Peng who will study under the supervision of Center Investigators Prof Heike Ebendorff-Heidepriem and Dr Stephen Warren-Smith at the University of Adelaide.

Lu’s project is focused on the use of exposed-core microstructured optical fibre to do two-dimensional fibre imaging. This research has the potential to be used in both biological and medical fields. The aim is to get high resolution and accurate information realized in a single exposed fibre.

Following an undergraduate degree in physics, Lu gained her Master’s degree in optics from South China Normal University. Her thesis at that time, examined a micro-structured fibre refractive index sensor, based on surface plasmon resonance.

Welcome to the CNBP team Lu!

Centre AI awarded prestigious Malcolm McIntosh Prize

18 October 2017:

CNBP Associate Investigator Professor Dayong Jin, at the University of Technology Sydney, has been awarded the Malcolm McIntosh Prize for Physical Scientist of the Year.

The award recognises Professor Jin’s innovative work with nanocrystals which allow for enhanced molecular imaging deep within the cellular environment, aiding early stage detection of cancer and disease.

The Prize, part of the ‘Prime Minister’s Prizes for Science’ series, are awarded annually and are a public recognition and tribute to the contributions that scientists, innovators and science teachers are making to Australia’s current and future scientific and commercialisation capabilities.

Full award details as well as a video and summary of Professor Jin’s work is available from the Australian Government web site.

New light source developed for fluorescent microscopy imaging

Aziz Rehman16 October 2017:

A tuneable and programmable integrating sphere light source for wide-field fluorescent microscopy imaging, employing nine light-emitting diodes (LEDs), has been successfully demonstrated and reported by CNBP researchers in a new paper (lead author Aziz ul Rehman pictured).

The paper, published in ‘Photodiagnosis and Photodynamic Therapy’ is accessible online.

Journal: Photodiagnosis and Photodynamic Therapy.

Publication title: Programmable LED-Based Integrating Sphere Light Source for Wide-Field Fluorescence Microscopy.

Authors: Aziz ul Rehman, Ayad G.Anwer, Ewa M.Goldys.

Abstract: Wide-field fluorescence microscopy commonly uses a mercury lamp, which has limited spectral capabilities. We designed and built a programmable integrating sphere light (PISL) source which consists of nine LEDs, light-collecting optics, a commercially available integrating sphere and a baffle. The PISL source is tuneable in the range 365–490 nm with a uniform spatial profile and a sufficient power at the objective to carry out spectral imaging. We retrofitted a standard fluorescence inverted microscope DM IRB (Leica) with a PISL source by mounting it together with a highly sensitive low- noise CMOS camera. The capabilities of the setup have been demonstrated by carrying out multispectral autofluorescence imaging of live BV2 cells.

Ecolinc STEM program

16 October 2017:

Centre Associate Investigator, Dr Kate Fox from RMIT University has participated in the Ecolinc STEM for Women program in Melbourne, Oct 16th, 2017.

Ninety students (Years 9 and 10) attended the event where they  got to learn of the experiences from a range of women who work in a variety of STEM related areas. They also heard from education providers about potential career pathways in STEM and listened to the career journeys of successful women in science.

The students were from Upper Yarra, St Albans, Dandenong, Southern Cross Grammar, Bacchus Marsh, Overnewton College, Highview College, Bellarine and Whittlesea.

 

Student poster award

14 October 2017:

Aimee Horsfall, CNBP PhD student at the University of Adelaide has been awarded a student Poster Award (of four), with cash prize, for her poster titled “Introduction of a new fluorescent constraint on-resin” at the 6th Modern Solid-Phase Peptide Synthesis Symposium, held at Fraser Island from the 12-14th of October. The symposium is a satellite conference of the 12th Australian Peptide Conference which was held in Noosa from the 15-20th October which Aimee also attended.