Hossain, MA, Canning, J, Yu, Z, Ast, S, Rutledge, PJ, Wong, JK-H, Jamalipour, A & Crossley, MJ 2017, 'Time-resolved and temperature tuneable measurements of fluorescent intensity using a smartphone fluorimeter', ANALYST, vol. 142, no. 11, pp. 1953-1961.View/Download from: UTS OPUS or Publisher's site
Wong, JKH, Ast, S, Yu, M, Flehr, R, Counsell, AJ, Turner, P, Crisologo, P, Todd, MH & Rutledge, PJ 2016, 'Synthesis and Evaluation of 1,8-Disubstituted-Cyclam/Naphthalimide Conjugates as Probes for Metal Ions', ChemistryOpen, vol. 5, no. 4, pp. 375-385.View/Download from: Publisher's site
© 2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. Fluorescent molecular probes for metal ions have a raft of potential applications in chemistry and biomedicine. We report the synthesis and photophysical characterisation of 1,8-disubstituted-cyclam/naphthalimide conjugates and their zinc complexes. An efficient synthesis of 1,8-bis-(2-azidoethyl)cyclam has been developed and used to prepare 1,8-disubstituted triazolyl-cyclam systems, in which the pendant group is connected to triazole C4. UV/Vis and fluorescence emission spectra, zinc binding experiments, fluorescence quantum yield and lifetime measurements and pH titrations of the resultant bis-naphthalimide ligand elucidate a complex pattern of photophysical behaviour. Important differences arise from the inclusion of two fluorophores in the one probe and from the variation of triazole substitution pattern (dye at C4 vs. N1). Introducing a second fluorophore greatly extends fluorescence lifetimes, whereas the altered substitution pattern at the cyclam amines exerts a major influence on fluorescence output and metal binding. Crystal structures of two key zinc complexes evidence variations in triazole coordination that mirror the solution-phase behaviour of these systems.
Hossain, MA, Canning, J, Ast, S, Rutledge, PJ & Jamalipour, A 2015, 'Early Warning Smartphone Diagnostics for Water Security and Analysis Using Real-Time pH Mapping', PHOTONIC SENSORS, vol. 5, no. 4, pp. 289-297.View/Download from: UTS OPUS or Publisher's site
Ast, S, Kuke, S, Rutledge, PJ & Todd, MH 2015, 'Using click chemistry to tune the properties and the fluorescence response mechanism of structurally similar probes for metal ions', European Journal of Inorganic Chemistry, vol. 2015, no. 1, pp. 58-66.View/Download from: Publisher's site
Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Four cyclam-based fluorescent molecular probes were prepared using "click" chemistry and investigated to determine the effect of the triazole connectivity and fluorophore substitution on the photophysical properties and metal-ion response mechanism. The fluorescence of the ligands is turned on in the presence of ZnII but varies in intensity depending on the solvent; the highest signal changes are found in MeCN. Complexation with CuII leads to fluorescence quenching, but only in the aqueous solvent, in which the triazole is involved in coordination of the metal. The length of the pendant triazole arm influences the ligand field around pentacoordinate CuII to yield a distorted square-planar coordination geometry in the ligands with an ethylene linker. The quantum yield (QY) of the emission intensity can be tuned by the triazole substitution, thereby resulting in increases in QY of more than one order of magnitude (ligand 1 versus 3). Changing the fluorophore opens up alternative radiative processes, thus leading to phosphorescence-like behavior in coumarin probe 2. Steady-state fluorescence emission spectra of the free ligands and their respective CuII complexes in a "glass environment" reveal two different inherent fluorescence quenching mechanisms. In the free ligands an electron-transfer deactivates the excited chromophore, whereas in the CuII complexes it is energy transfer that results in complete quenching of the emission of the ligands.
Hossain, MA, Canning, J, Ast, S, Cook, K, Rutledge, PJ & Jamalipour, A 2015, 'Combined "dual" absorption and fluorescence smartphone spectrometers', OPTICS LETTERS, vol. 40, no. 8, pp. 1737-1740.View/Download from: UTS OPUS or Publisher's site
Hossain, MA, Canning, J, Ast, S, Rutledge, PJ, Yen, TL & Jamalipour, A 2015, 'Lab-in-a-Phone: Smartphone-Based Portable Fluorometer for pH Measurements of Environmental Water', IEEE SENSORS JOURNAL, vol. 15, no. 9, pp. 5095-5102.View/Download from: UTS OPUS or Publisher's site
Canning, J, Ast, S, Hossain, MA, Chan, H, Rutledge, PJ & Jamalipour, A 2015, 'Bend and twist intramolecular charge transfer and emission for selective metal ion sensing', OPTICAL MATERIALS EXPRESS, vol. 5, no. 11, pp. 2675-2681.View/Download from: UTS OPUS or Publisher's site
© The Royal Society of Chemistry. We report fluorescence measurements of three quantum dots (QDs) of different sizes functionalised with the same pH responsive naphthalimide dye. QD size strongly influences energy transfer between dye and dot. Using QDs with an emission maximum of 570 nm gives rise to an interesting transfer of energy from dye to dot, while QDs with an emission maximum at 670 nm give unexpected enhancement of the dye emission. Titrations of QDs with the dye provide a means to establish the loading and hence an approximation of the surface dye density, which varies in proportion to QD size. Quenching effects are observed beyond the loading limit, and may indicate non-specific interactions between the excess dye and the nanoparticle. Attachment of the dye to the QD core is achieved by a thiol/disulfide exchange process that has been interrogated with Raman spectroscopy. The stability of these QD-dye conjugates over time and across a physiological pH range has been investigated to provide an assessment of their performance and robustness. This journal is
Ast, S, Rutledge, PJ & Todd, MH 2014, 'pH-Responsive quantum dots (RQDs) that combine a fluorescent nanoparticle with a pH-sensitive dye', Physical Chemistry Chemical Physics, vol. 16, no. 46, pp. 25255-25257.View/Download from: Publisher's site
A quantum dot conjugated to a dye through an experimentally simple process of self-assembly exhibits an enhanced emission when the dye is attached, and this effect is pH-sensitive. © the Owner Societies.
Canning, J, Hossain, M, Cook, K & Ast, S 2017, 'Photo- and thermal degradation of olive oil measured using an optical fibre smartphone spectrofluorimeter', Proceedings of SPIE, Optical Fiber Sensors Conference, Society of Photo-optical Instrumentation Engineers, Jeju, South Korea.View/Download from: UTS OPUS or Publisher's site
Degradation of olive oil under light and heat are analysed using an optical fibre based low-cost portable smartphone spectrofluorimeter. Visible fluorescence bands associated with phenolic acids, vitamins and chlorophyll centred at λ ~ 452, 525 and 670 nm respectively are generated using near-UV excitation (LED λ ex ~370 nm), of extra virgin olive oil are degraded more likely than refined olive oil under light and heat exposure. Packaging is shown to be critical when assessing the origin of degradation.
Canning, J, Hossain, MA & Ast, S 2016, 'Smart sensing: Combining photonics, smart devices and chemosensor dyes for characterising and separating metal ions', Optics InfoBase Conference Papers.View/Download from: Publisher's site
© OSA 2016.A review of work in smart sensing, photonics and smartphone instrumentation, focusing on adding functionality with chemosensor dyes, is presented. Article not available.
Hossain, MA, Canning, J, Cook, K, Ast, S, Rutledge, PJ & Jamalipour, A 2015, 'Absorption and fluorescence spectroscopy on a smartphone', Proceedings of SPIE - The International Society for Optical Engineering, Asia Pacific Optical Sensors Conference (APOS), SPIE, Noyeon-ro Jeju, South Korea.View/Download from: UTS OPUS or Publisher's site
© 2015 Copyright SPIE. A self-powered smartphone-based field-portable "dual" spectrometer has been developed for both absorption and fluorescence measurements. The smartphone's existing flash LED has sufficient optical irradiance to undertake absorption measurements within a 3D-printed case containing a low cost nano-imprinted polymer diffraction grating. A UV (λ < inf > ex < /inf > ∼ 370 nm) and VIS (λ < inf > ex < /inf > ∼ 450 nm) LED are wired into the circuit of the flash LED to provide an excitation source for fluorescence measurements. Using a customized app on the smartphone, measurements of absorption and fluorescence spectra are demonstrated using pH-sensitive and Zn < sup > 2+ < /sup > -responsive probes. Detection over a 300 nm span with 0.42 nm/pixel spectral resolution is demonstrated. Despite the low cost and small size of the portable spectrometer, the results compare well with bench top instruments.
Hossain, MA, Ast, S, Canning, J, Cook, K, Rutledge, PJ & Jamalipour, A 2015, 'Fluorescent measurements of Zn2+ on a smartphone', Proceedings of SPIE - The International Society for Optical Engineering, Asia Pacific Optical Sensors Conference (APOS), SPIE, Jeju, South Korea.View/Download from: Publisher's site
© 2015 Copyright SPIE. Using a smartphone-based portable spectrofluorimeter, measurement of metal ion concentration in water is reported. A UV LED (λ < inf > ex < /inf > ∼ 370 nm), which is powered by the internal source of the smartphone was implemented to function as the excitation source. The emission peak of the UV LED overlaps well with the absorption peak of the Zn < sup > 2+ < /sup > -responsive molecular probe 6-(1,4,8,11-cyclam-1-yl)ethyl-1,2,3-triazol-4-yl)2-ethyl-naphthalimide fluoro-ionophore (λ < inf > abs < /inf > ∼ 358 nm). The fluorescence emission of this dye at λ < inf > em < /inf > ∼ 458 nm is enhanced upon coordination of Zn < sup > 2+ < /sup > . A customized Android application digitally processes the image from a nano-imprinted polymer diffraction grating and analyses the spectral changes. Zn < sup > 2+ < /sup > concentration in water samples were measured with a detection limit of δ ∼ 5 μM.
We report the first contained portable field fluorometer using a smartphone and a 3D printed sample holder. The white optical source used for camera and torch applications is filtered to enable blue excitation of a customised dye which fluoresces green as a function of pH. The green intensity is measured using an RGB app. Field measurements of water pH around Sydney are compared with laboratory results. © 2014 OSA.
Hossain, MA, Canning, J, Ast, S, Rutledge, PJ, Webster, R & Jamalipour, A 2014, 'Centralised and portable 'network forensics' using smartphone-based diagnostics: Case study - The mapping of tap water pH across Sydney, Australia', 2014 IEEE Photonics Conference, IPC 2014, 2014 IEEE Photonics Conference, IPC 2014, pp. 564-565.View/Download from: UTS OPUS or Publisher's site
© 2014 IEEE. Using a field portable, smartphone fluorometer for assessing water quality, a pH map of drinking water around Sydney is obtained. The work demonstrates a new security concept - network forensics - based on a novel smartgrid approach for the potential detection of water quality disruption.
Hossain, MA, Yu, Z, Canning, J, Ast, S, Wong, J, Rutledge, P, Crossley, M & Jamalipour, A 2014, 'Temperature controlled portable smartphone fluorimeter', Optics InfoBase Conference Papers.View/Download from: Publisher's site
© OSA 2016. A self-powered temperature-controlled smartphone fluorimeter is demonstrated. The device measures fluorescence for a temperature range of T = 10 to 40 °C with a precision of 0.1 °C. Results can be shared via wireless networking.