ORCID Profile
0000-0003-1669-4302
Current Organisation
University of Adelaide
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Materials engineering | Glass | Lasers and quantum electronics | Photonics optoelectronics and optical communications |
Publisher: Elsevier BV
Date: 02-2023
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2NR32583G
Abstract: We investigate a powerful new sensing platform based on the excitation of upconversion luminescence from NaYF(4):Yb/Er nanocrystals loaded in solution within a suspended-core microstructured optical fiber. We demonstrate a substantial improvement in the detection limit that can be achieved in a suspended-core fiber sensor for solution-based measurements using these nanocrystals as an alternative to more traditional fluorophores, with sensing of concentrations as low as 660 fM demonstrated compared with the 10 pM obtained using quantum dots. This nanocrystal loaded suspended core fiber platform also forms the basis for a novel and robust nanoscale spectrometry device capable of capturing power-dependent spectra over a large dynamic range from 10(3) W cm(-2) to 10(6) W cm(-2) using a laser diode. This serves as a useful tool to study the multiple energy levels of rare earth luminescent nano-materials, allowing the two sharp emission bands to be studied in detail over a large dynamic range of excitation powers. Thus, in addition to demonstrating a highly sensitive dip sensor, we have devised a powerful new approach for characterizing upconversion nanoparticles.
Publisher: Cold Spring Harbor Laboratory
Date: 22-06-2023
DOI: 10.1101/2023.06.21.545939
Abstract: Cellular metabolism is a key regulator of energetics, cell growth, regeneration and homeostasis. Spatially mapping the heterogeneity of cellular metabolic activity is of great importance for unraveling the overall cell and tissue health. In this regard, imaging the endogenous metabolic co-factors NAD(P)H and FAD with sub-cellular resolution and in a non-invasive manner would be useful to determine tissue and cell viability in a clinical environment, but practical use is limited by current imaging techniques. In this article, we demonstrate the use of phasor-based hyperspectral light-sheet (HS-LS) microscopy using a single UVA excitation wavelength as a route to mapping metabolism in three dimensions. We show that excitation solely at a UVA wavelength of 375 nm can simultaneously excite NAD(P)H and FAD autofluorescence, while their relative contributions can be readily quantified using a hardware-based spectral phasor analysis. We demonstrate the potential of our HS-LS system by capturing dynamic changes in metabolic activity during pre-implantation embryo development. To validate our approach, we delineate metabolic changes during pre-implantation embryo development from volumetric maps of metabolic activity. Importantly, our approach overcomes the need for multiple excitation wavelengths, two-photon imaging or significant post-processing of data, paving the way towards clinical translation, such as in situ, non-invasive assessment of embryo viability.
Publisher: SPIE
Date: 09-12-2016
DOI: 10.1117/12.2244645
Publisher: The Optical Society
Date: 05-04-2017
DOI: 10.1364/OME.7.001496
Publisher: OSA
Date: 2016
Publisher: Wiley
Date: 30-05-2016
Publisher: OSA
Date: 2013
Publisher: SPIE
Date: 05-10-2009
DOI: 10.1117/12.835350
Publisher: IEEE
Date: 07-2012
Publisher: The Optical Society
Date: 20-11-2012
DOI: 10.1364/BOE.3.003304
Publisher: Wiley
Date: 19-05-2020
Publisher: Wiley
Date: 21-07-2015
DOI: 10.1111/IJAG.12128
Publisher: Elsevier BV
Date: 12-2010
Publisher: Wiley
Date: 29-03-2022
Abstract: A new fiber functionalization architecture for single‐fiber imaging and sensing is presented. 5(6)Carboxy‐seminaphthorhodafluor‐2 (a fluorescent pH sensor) is attached to a silk‐binding peptide and the complex added to aqueous silk fibroin protein. These bind with a K d of 36 µM as determined by a fluorescence polarization assay. The fiber is dip‐coated into the silk and peptide mixture, and scanning electron microscopy images reveal a uniform silk coating on the fiber tip. The coating is stable to repeated washes and does not affect the imaging light emitted from the fiber, which allows concurrent optical coherence tomography (OCT) imaging and pH sensing. Oocytes are metabolically stimulated with CoCl 2 to produce lactic acid, and a pH reduction of 0.04 is measured using the probe. The distance between fiber tip and oocyte is monitored by simultaneous OCT acquisitions to precisely position the probe. Lastly, OCT imaging of an ovary revealed the presence/absence of an oocyte within a follicle, an important step toward improving patient outcomes during in vitro fertilization, by limiting the number of invasive follicle punctures required. These results demonstrate the utility of this new coating to enable simultaneous OCT imaging and sensing, which provides significant insight into complex biological systems.
Publisher: SPIE
Date: 02-06-2014
DOI: 10.1117/12.2071261
Publisher: Elsevier BV
Date: 11-2016
DOI: 10.1016/J.BBI.2016.04.014
Abstract: The importance of neuro-immune interactions in both physiological and pathophysiological states cannot be overstated. As our appreciation for the neuroimmune nature of the brain and spinal cord grows, so does our need to extend the spatial and temporal resolution of our molecular analysis techniques. Current imaging technologies applied to investigate the actions of the neuroimmune system in both health and disease states have been adapted from the fields of immunology and neuroscience. While these classical techniques have provided immense insight into the function of the CNS, they are however, inherently limited. Thus, the development of innovative methods which overcome these limitations are crucial for imaging and quantifying acute and chronic neuroimmune responses. Therefore, this review aims to convey emerging novel and complementary imaging technologies in a form accessible to medical scientists engaging in neuroimmune research.
Publisher: Elsevier BV
Date: 05-2016
Publisher: Informa UK Limited
Date: 13-09-2017
Publisher: Springer Science and Business Media LLC
Date: 23-06-2022
DOI: 10.1007/S10815-022-02555-4
Abstract: A current focus of the IVF field is non-invasive imaging of the embryo to quantify developmental potential. Such approaches use varying wavelengths to gain maximum biological information. The impact of irradiating the developing embryo with discrete wavelengths of light is not fully understood. Here, we assess the impact of a range of wavelengths on the developing embryo. Murine preimplantation embryos were exposed daily to wavelengths within the blue, green, yellow, and red spectral bands and compared to an unexposed control group. Development to blastocyst, DNA damage, and cell number/allocation to blastocyst cell lineages were assessed. For the longer wavelengths (yellow and red), pregnancy/fetal outcomes and the abundance of intracellular lipid were investigated. Significantly fewer embryos developed to the blastocyst stage when exposed to the yellow wavelength. Elevated DNA damage was observed within embryos exposed to blue, green, or red wavelengths. There was no effect on blastocyst cell number/lineage allocation for all wavelengths except red, where there was a significant decrease in total cell number. Pregnancy rate was significantly reduced when embryos were irradiated with the red wavelength. Weight at weaning was significantly higher when embryos were exposed to yellow or red wavelengths. Lipid abundance was significantly elevated following exposure to the yellow wavelength. Our results demonstrate that the impact of light is wavelength-specific, with longer wavelengths also impacting the embryo. We also show that effects are energy-dependent. This data shows that damage is multifaceted and developmental rate alone may not fully reflect the impact of light exposure.
Publisher: SPIE
Date: 05-05-2015
DOI: 10.1117/12.2178825
Publisher: SPIE
Date: 24-11-2016
DOI: 10.1117/12.2242831
Publisher: SPIE
Date: 02-06-2014
DOI: 10.1117/12.2059436
Publisher: Optica Publishing Group
Date: 22-07-2020
DOI: 10.1364/OE.397537
Abstract: Femtosecond laser inscribed fiber Bragg gratings in pure-silica suspended-core optical fibers have previously been demonstrated as a promising platform for high temperature sensing. However, the density of gratings that could be written on a single fiber was limited by undesired reflections associated with higher order modes in these high numerical aperture fibers. This resulted in a complex, broadband reflection spectrum with limited multiplexing capability. In this work we utilize modifications to the fine structure of the suspended core optical fibers to fine tune the relative confinement loss of the optical fiber modes, thus reducing the contribution from such higher order modes. The effects of these changes on mode propagation are modeled, giving a range of fibers with different confinement loss properties which can be tailored to the specific length scale of a desired application. We achieve single-peak reflections from in idual fiber Bragg gratings, significantly improving performance for multipoint sensing and demonstrate this technique by writing 20 gratings onto a single fiber.
Publisher: The Optical Society
Date: 20-07-2016
DOI: 10.1364/BOE.7.003069
Publisher: Royal Society of Chemistry (RSC)
Date: 2021
DOI: 10.1039/D1RA03584C
Abstract: We report a new approach to functionalise optical fibres to enable protein sensing, which controls the sensor molecule location either within the fibre tip coating or isolated to its exterior. This control dictates suitability for protein sensing.
Publisher: Wiley
Date: 04-12-2019
Abstract: Unfertilised eggs (oocytes) release chemical biomarkers into the medium surrounding them. This provides an opportunity to monitor cell health and development during assisted reproductive processes if detected in a non-invasive manner. Here we report the measurement of pH using an optical fibre probe, OFP1, in 5 μL drops of culture medium containing single mouse cumulus oocyte complexes (COCs). This allowed for the detection of statistically significant differences in pH between COCs in culture medium with no additives and those incubated with either a chemical (cobalt chloride) or hormonal treatment (follicle stimulating hormone) both of which serve to induce the release of lactic acid into the medium immediately surrounding the COC. Importantly, OFP1 was shown to be cell-safe with no inherent cell toxicity or light-induced phototoxicity indicated by negative DNA damage staining. Pre-measurement photobleaching of the probe reduced fluorescence signal variability, providing improved measurement precision (0.01-0.05 pH units) compared to previous studies. This optical technology presents a promising platform for the measurement of pH and the detection of other extracellular biomarkers to assess cell health during assisted reproduction.
Publisher: American Association for Cancer Research (AACR)
Date: 30-11-2016
DOI: 10.1158/0008-5472.CAN-16-1285
Abstract: Intraoperative detection of tumorous tissue is an important unresolved issue for cancer surgery. Difficulty in differentiating between tissue types commonly results in the requirement for additional surgeries to excise unremoved cancer tissue or alternatively in the removal of excess amounts of healthy tissue. Although pathologic methods exist to determine tissue type during surgery, these methods can compromise postoperative pathology, have a lag of minutes to hours before the surgeon receives the results of the tissue analysis, and are restricted to excised tissue. In this work, we report the development of an optical fiber probe that could potentially find use as an aid for margin detection during surgery. A fluorophore-doped polymer coating is deposited on the tip of an optical fiber, which can then be used to record the pH by monitoring the emission spectra from this dye. By measuring the tissue pH and comparing with the values from regular tissue, the tissue type can be determined quickly and accurately. The use of a novel lift-and-measure technique allows for these measurements to be performed without influence from the inherent autofluorescence that commonly affects fluorescence-based measurements on biological s les. The probe developed here shows strong potential for use during surgery, as the probe design can be readily adapted to a low-cost portable configuration, which could find use in the operating theater. Use of this probe in surgery either on excised or in vivo tissue has the potential to improve success rates for complete removal of cancers. Cancer Res 76(23) 6795–801. ©2016 AACR.
Publisher: IEEE
Date: 10-2017
Publisher: The Optical Society
Date: 16-10-2014
DOI: 10.1364/BOE.5.003975
Publisher: MDPI AG
Date: 17-12-2015
DOI: 10.3390/S151229893
Publisher: Springer Science and Business Media LLC
Date: 09-2013
Abstract: Upconversion nanocrystals convert infrared radiation to visible luminescence, and are promising for applications in biodetection, bioimaging, solar cells and three-dimensional display technologies. Although the design of suitable nanocrystals has improved the performance of upconversion nanocrystals, their emission brightness is limited by the low doping concentration of activator ions needed to avoid the luminescence quenching that occurs at high concentrations. Here, we demonstrate that high excitation irradiance can alleviate concentration quenching in upconversion luminescence when combined with higher activator concentration, which can be increased from 0.5 mol% to 8 mol% Tm(3+) in NaYF₄. This leads to significantly enhanced luminescence signals, by up to a factor of 70. By using such bright nanocrystals, we demonstrate remote tracking of a single nanocrystal with a microstructured optical-fibre dip sensor. This represents a sensitivity improvement of three orders of magnitude over benchmark nanocrystals such as quantum dots.
Publisher: Elsevier BV
Date: 04-2015
DOI: 10.1016/J.FREERADBIOMED.2015.01.015
Abstract: Human spermatozoa are compromised by production of reactive oxygen species (ROS), and detection of ROS in spermatozoa is important for the diagnosis of male infertility. The probes 2',7'-dichlorohydrofluorescein diacetate (DCFH), dihydroethidium (DHE), and MitoSOX red (MSR) are commonly used for detecting ROS by flow cytometry however, these probes lack sensitivity to hydrogen peroxide (H2O2), which is particularly damaging to mammalian sperm cells. This study reports the synthesis and use of three aryl boronate probes, peroxyfluor-1 (PF1), carboxyperoxyfluor-1, and a novel probe, 2-(2-ethoxyethoxy)ethoxyperoxyfluor-1 (EEPF1), in human spermatozoa. PF1 and EEPF1 were effective at detecting H2O2 and peroxynitrite (ONOO(-)) produced by spermatozoa when stimulated with menadione or 4-hydroxynonenal. EEPF1 was more effective at detection of ROS in spermatozoa than DCFH, DHE, or MSR furthermore it distinguished poorly motile sperm as shown by greater ROS production. EEPF1 should therefore have a significant role in the diagnosis of oxidative stress in male infertility, cryopreservation, age, lifestyle, and exposure to environmental toxicants.
Publisher: SPIE
Date: 22-02-2013
DOI: 10.1117/12.2004236
Publisher: SPIE
Date: 09-12-2016
DOI: 10.1117/12.2244620
Publisher: OSA
Date: 2016
Publisher: SPIE
Date: 09-12-2016
DOI: 10.1117/12.2244625
Publisher: MDPI AG
Date: 04-03-2011
DOI: 10.3390/S110302961
Publisher: The Optical Society
Date: 25-01-2019
DOI: 10.1364/OL.44.000626
Publisher: The Optical Society
Date: 24-10-2017
DOI: 10.1364/OL.42.004395
Publisher: IEEE
Date: 2011
Publisher: Springer Science and Business Media LLC
Date: 09-2022
DOI: 10.1038/S41566-022-01067-Y
Abstract: Silica-based optical fibres are a workhorse of nonlinear optics, providing ready access to a range of nonlinear phenomena including solitons and self-phase modulation. However, they have one fundamental limitation: due to the amorphous nature of silica, they do not exhibit second-order nonlinearity, except for negligible contributions from surfaces. Here we demonstrate second-harmonic generation in functionalized optical fibres by using a monolayer of highly nonlinear MoS 2 directly grown on the fibre’s core. The MoS 2 -functionalized fibre exhibits a second-order susceptibility ( χ (2) ) value of 44 pm V –1 and a second-harmonic generation conversion efficiency of 0.2 × 10 –3 m −2 W −1 . This approach is scalable and can be generalized to other transition metal dichalcogenides and a wide range of waveguide systems. Our results demonstrate a new approach towards efficient in-fibre second-harmonic generation sources and may establish a platform for χ (2) -based nonlinear fibre optics, optoelectronics, photonics platforms, integrated optical architectures and active fibre networks.
Publisher: SPIE
Date: 05-05-2015
DOI: 10.1117/12.2178680
Publisher: The Optical Society
Date: 06-04-2018
DOI: 10.1364/OL.43.001682
Publisher: SPIE
Date: 13-05-2011
DOI: 10.1117/12.883826
Publisher: OSA
Date: 2016
Publisher: SPIE
Date: 13-05-2011
DOI: 10.1117/12.883829
Publisher: IEEE
Date: 10-2021
Publisher: MDPI AG
Date: 17-11-2014
DOI: 10.3390/S141121693
Publisher: SPIE
Date: 31-01-2012
DOI: 10.1117/12.915968
Publisher: SPIE
Date: 15-05-2011
DOI: 10.1117/12.886080
Publisher: The Optical Society
Date: 19-06-2019
DOI: 10.1364/OE.27.018601
Publisher: Optica Publishing Group
Date: 2021
DOI: 10.1364/CLEO_QELS.2021.FTH1J.6
Abstract: Depositing high refractive index nanofilms with controlled thicknesses on exposed core fibers enables thickness tunable supercontinuum generation. Thickness gradients along the fiber allow for optimizing for spectral flatness and extension of bandwidth toward the infrared.
Publisher: Optica Publishing Group
Date: 2007
DOI: 10.1364/OE.15.017819
Abstract: The detection of quantum-dot labeled proteins is demonstrated within lead silicate soft glass microstructured optical fibers using near infrared light. The protein concentration is measured using a new fluorescence capture approach. Light guided within the fiber is used both to excite and collect fluorescent photons, and the detection limit achieved without optimization of the fiber geometry is 1 nM, using just 3% of the guided mode of the fiber. Issues that currently restrict the detection of lower protein concentrations are discussed.
Publisher: SPIE
Date: 24-11-2016
DOI: 10.1117/12.2248685
Publisher: SPIE
Date: 23-04-2017
DOI: 10.1117/12.2263263
Publisher: The Optical Society
Date: 09-03-2016
DOI: 10.1364/OE.24.005911
Publisher: IEEE
Date: 10-2017
Publisher: Wiley
Date: 17-01-2022
Abstract: Widely wavelength‐tunable femtosecond light sources in a compact, robust footprint play a central role in many prolific research fields and technologies, including medical diagnostics, biophotonics, and metrology. Fiber lasers are on the verge in the development of such sources, yet widespan spectral tunability of femtosecond pulses remains a pivotal challenge. Dispersive wave generation, also known as Cherenkov radiation, offers untapped potentials to serve these demands. In this work, the concept of quasi‐phase matching for multi‐order dispersive wave formation with record‐high spectral fidelity and femtosecond durations is exploited in selected, partially conventionally unreachable spectral regions. Versatile patterned sputtering is utilized to realize height‐modulated high‐index nano‐films on exposed fiber cores to alter fiber dispersion to an unprecedented degree through spatially localized, induced resonances. Nonlinear optical experiments and simulations, as well as phase‐mismatching considerations based on an effective dispersion, confirm the conversion process and reveal unique emission features, such as almost power‐independent wavelength stability and femtosecond duration. This resonance‐empowered approach is applicable to both fiber and on‐chip photonic systems and paves the way to instrumentalize dispersive wave generation as a unique tool for efficient, coherent femtosecond multi‐frequency conversion for applications in areas such as bioanalytics, life science, quantum technology, or metrology.
Publisher: IEEE
Date: 06-2007
Publisher: The Optical Society
Date: 03-08-2016
DOI: 10.1364/OE.24.018541
Start Date: 2023
End Date: 12-2025
Amount: $898,904.00
Funder: Australian Research Council
View Funded Activity