29 March 2019:
Liquid-metal nanoparticles can focus ultraviolet light at the nanoscale. Read more in a publication reporting on the UV plasmonic properties of colloidal gallium-indium particles (lead author CNBP Associate Investigator Dr Philipp Reineck, RMIT University).
Journal: Scientific Reports.
Publication title: UV plasmonic properties of colloidal liquid-metal eutectic gallium-indium alloy nanoparticles.
Authors: Philipp Reineck, Yiliang Lin, Brant C. Gibson, Michael D. Dickey, Andrew D. Greentree, Ivan S. Maksymov.
Abstract: Nanoparticles made of non-noble metals such as gallium have recently attracted significant attention due to promising applications in UV plasmonics. to date, experiments have mostly focused on solid and liquid pure gallium particles immobilized on solid substrates. However, for many applications, colloidal liquid-metal nanoparticle solutions are vital. Here, we experimentally demonstrate strong UV plasmonic resonances of eutectic gallium-indium (eGaIn) liquid-metal alloy nanoparticles suspended in ethanol. We rationalise experimental results through a theoretical model based on Mie theory. our results contribute to the understanding of UV plasmon resonances in colloidal liquid-metal eGaIn nanoparticle suspensions. they will also enable further research into emerging applications of UV plasmonics in biomedical imaging, sensing, stretchable electronics, photoacoustics, and electrochemistry.
14 February 2019:
Congratulations to CNBP Associate Investigator Dr Philipp Reineck (RMIT VC Research Fellow), who has been awarded an RMIT University School of Science ‘Early Career Researcher Award’ for his outstanding research outputs and achievements in 2018.
Recognized was Philipp’s publication output. This included ten papers (with three officially published in 2019). Also his four invited talks given at international conferences in the USA, Europe and Australia, together with his successful funding from the Australian Synchrotron to do 3D bioimaging experiments at the Spanish synchrotron.
A fantastic effort Philipp!
Below – Dr Philipp Reineck receiving his award.
28 January 2019:
Hundreds of individual tiny fluorescent diamond particles have been imaged and characterized by CNBP researchers, reported in the journal ‘Particle & Particle Systems Characterization’.
Fluorescent nanodiamonds (FNDs) are vital to many emerging nanotechnological applications, from bioimaging and sensing to quantum nanophotonics.
The study identifies opportunities to improve the properties of single fluorescent nanodiamonds, to develop a better understanding of their underlying physical mechanisms and to advance current nanofabrication technologies.
Lead author on the paper is CNBP Associate Investigator Dr Philipp Reineck at RMIT University.
Journal: Particle & Particle Systems Characterization.
Publication title: Not All Fluorescent Nanodiamonds Are Created Equal: A Comparative Study.
Authors: Philipp Reineck; Leevan Fremiot Trindade, Jan Havlik, Jan Stursa, Ashleigh Heffernan, Aaron Elbourne, Antony Orth, Marco Capelli, Petr Cigler, David A. Simpson, Brant C. Gibson.
Abstract: Fluorescent nanodiamonds (FNDs) are vital to many emerging nanotechnological applications, from bioimaging and sensing to quantum nanophotonics. Yet, understanding and engineering the properties of fluorescent defects in nanodiamonds remain challenging. The most comprehensive study to date is presented, of the optical and physical properties of five different nanodiamond samples, in which fluorescent nitrogen‐vacancy (NV) centers are created using different fabrication techniques. The FNDs’ fluorescence spectra, lifetime, and spin relaxation time (T1) are investigated via single‐particle confocal fluorescence microscopy and in ensemble measurements in solution (T1 excepted). Particle sizes and shapes are determined using scanning electron microscopy and correlated with the optical results. Statistical tests are used to explore correlations between the properties of individual particles and also analyze average results to directly compare different fabrication techniques. Spectral unmixing is used to quantify the relative NV charge‐state (NV− and NV0) contributions to the overall fluorescence. A strong variation is found and quantified in the properties of individual particles within all analyzed samples and significant differences between the different particle types. This study is an important contribution toward understanding the properties of NV centers in nanodiamonds. It motivates new approaches to the improved engineering of NV‐containing nanodiamonds for future applications.
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.
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.
3 July 2017:
Researchers from CNBP’s RMIT University node (lead author CNBP PhD student Marco Capelli pictured), have had a paper published in the journal ‘Nanoscale’.
The researchers report an enhancement of the nitrogen-vacancy (NV) quantum yield by up to 7% in bulk diamond caused by an external magnetic field.
The paper is accessible online.
Publication title: Magnetic field-induced enhancement of the nitrogen-vacancy fluorescence quantum yield .
Authors: M. Capelli, P. Reineck, D. W. M. Lau, A. Orth, J. Jeske, M. W. Doherty, T. Ohshima, A. D. Greentree and B. C. Gibson.
Abstract: The nitrogen-vacancy (NV) centre in diamond is a unique optical defect that is used in many applications today and methods to enhance its fluorescence brightness are highly sought after. We observed experimentally an enhancement of the NV quantum yield by up to 7% in bulk diamond caused by an external magnetic field relative to the field-free case. This observation is rationalised phenomenologically in terms of a magnetic field dependence of the NV excited state triplet-to-singlet transition rate. The theoretical model is in good qualitative agreement with the experimental results at low excitation intensities. Our results significantly contribute to our fundamental understanding of the photophysical properties of the NV defect in diamond.
18 January 2017:
Researchers at CNBP’s RMIT University node were busy doing light-based demonstrations on Wednesday Jan 18th, as part of the ‘RMIT University Experience Day’ program, whereby students from years 10, 11 and 12 get to engage in hands-on workshops and explore life on campus while experiencing the differing aspects of University discipline areas.
As part of the ‘experience’ activity, over seventy high school students (predominantly in Year 10) visited the CNBP researchers in their physics laboratories. While there, students were given an overview of biophotonic science as well as laboratory research, and shown the exciting things that can be done with light including 3D scanning, fluorescence microscopy and more.
Below – CNBP researcher Philipp Reineck talks and demonstrates photonics to students.
5 December 2016:
A new publication from CNBP researchers (lead author Philipp Reineck pictured) demonstrates bright and photostable fluorescence from nitrogen-vacancy centers in unprocessed nanodiamond particle aggregates. The work has just been reported in the journal ‘Nanoscale’ and is accessible online.
Title: Bright and photostable nitrogen-vacancy fluorescence from unprocessed detonation nanodiamond.
Authors: P. Reineck, M. Capelli, D. W. M. Lau, J. Jeske, M. R. Field, T. Ohshim, A. D. Greentree and B. C. Gibson.
Abstract: Bright and photostable fluorescence from nitrogen-vacancy (NV) centers is demonstrated in unprocessed detonation nanodiamond particle aggregates. The optical properties of these particles is analyzed using confocal fluorescence microscopy and spectroscopy, time resolved fluorescence decay measurements, and optically detected magnetic resonance experiments. Two particle populations with distinct optical properties are identified and compared to high-pressure high-temperature (HPHT) fluorescent
nanodiamonds. We find that the brightness of one detonation nanodiamond particle population is on the same order as that of highly processed fluorescent 100 nm HPHT nanodiamonds. Our results may open the path to a simple and up-scalable route for
the production of fluorescent NV nanodiamonds for use in bioimaging applications.
20 July 2016:
A research team at the ARC Centre of Excellence for Nanoscale BioPhotonics (CNBP) – led by Dr Philipp Reineck (pictured) from RMIT University’s School of Science – tested ruby and diamond particles, more than a thousand times smaller than the diameter of a hair, alongside other nanoparticles for use in biological imaging, and found that they have a higher degree of stability, critical to achieving imaging success. You can read more about it in the online publication ‘Science meets Business’.
23 June 2016:
CNBP Research Fellow Dr Philipp Reineck (RMIT University node) is lead author on a new research paper, reporting on ‘Brightness and Photostability of Emerging Red and Near-IR Fluorescent Nanomaterials for Bioimaging.’
The work was co-authored by CNBP researchers A/Prof Brant Gibson, Dr Antony Orth and Dr Desmond Lau.
Journal: Advanced Optical Materials
Publication title: Brightness and photostability of emerging red and near-IR fluorescent nanomaterials for bioimaging.
Authors: Philipp Reineck, Adam Francis, Antony Orth, Desmond Wai Mo Lau, Reece David Valmont Nixon-Luke, Ishan Das Rastogi, Wan Aizuddin Wan Razali, Nicole Maree Cordina, Lindsay Marie Parker, Varun Kumaraswamy Annayya Sreenivasan, Louise Jennifer Brown and Brant Cameron Gibson.
Many novel fluorescent nanomaterials exhibit radically different optical properties compared to organic fluorophores that are still the most extensively used class of fluorophores in biology today. Assessing the practical impact of these optical differences for bioimaging experiments is challenging due to a lack of published quantitative benchmarking data. This study therefore directly and quantitatively compares the brightness and photostability of representatives from seven classes of fluorescent materials in spectroscopy and fluorescence microscopy experiments for the first time. These material classes are: organic dyes, semiconductor quantum dots, fluorescent beads, carbon dots, gold nanoclusters, nanodiamonds, and nanorubies. The relative brightness of each material is determined and the minimum material concentrations required to generate sufficient contrast in a fluorescence microscopy image are assessed. The influence of optical filters used for imaging is also discussed and suitable filter combinations are identified. The photostability of all materials is determined under typical imaging conditions and the number of images that can be acquired is inferred. The results are expected to facilitate the transition of novel fluorescent materials from physics and chemistry into biology laboratories.
The publication is accessible online.
Below – An artistic representation of nano-diamonds being used to light up and image a long chain of proteins. Image courtesy of Dr Carlo Bradac.