Poster Topics
Posters were submitted on any subject relevant to Biophotonics.
The following poster abstracts were reviewed by the BIA committee and accepted as poster presentations:
1. Is Melanin Fluorescence the Key to Non-invasive Diagnosis of Melanoma?
Name: Stephen Nighswander-Rempel
Email: snighrem@physics.uq.edu.au
Organisation: University of Queensland
Phone: (61 07) 3365 3406
Fax: 3365 1421
Abstract:
This study is aimed at characterising natural melanin autofluorescence in normal and cancerous melanocyte cell lines. Samples of melanoma, amelanotic melanoma, and normal skin cell lines were mapped using confocal fluorescence microscopy. Fluorescence was observed in pigmented melanoma and normal skin cells, but not in the amelanotic cell lines, indicating that melanin is indeed the cause of the fluorescence. Furthermore, emission spectra of melanin were similar to that obtained for synthetic melanin samples, further demonstrating that melanin is the cause of the fluorescence. The fluorescence intensity in cancerous cells was much stronger than in the non-cancerous cells, suggesting that melanin fluorescence may provide a non-invasive diagnostic test for melanoma.
2. Multi-functionnal fluorescence fiber probe
Name: Frederique Vanholsbeeck
Email: f.vanholsbeeck@auckland.ac.nz
Organisation: University of Auckland
Phone: +64-9-3737599 x 88881
Fax: +64-9-3737445
Abstract:
We have developed a novel fluorescence imaging system using optical fibers that allows intramural functional imaging to be carried out in real time. Thanks to this probe, cellular-level electrical activities in cardiac muscles can be recorded in both in-vivo and in-vitro preparations. Currently, the system is under modifications to perform multi-functional imaging so as to make possible the identification of a particular group of cells and to record its electrical functionality at the same time. This can be helpful for studying, for instance, the recovering progress of in-vivo scared cells. Preliminary results will be presented at the workshop.
3. Growing an Artificial Artery: Adhesion Force Measurements on Living Cells with Optical Tweezers
Name: Gregor Knöner
Email: knoener@physics.uq.edu.au
Organisation: Centre for Biophotonics and Laser Science, The University of Queensland
Phone: +61 7 336 53406
Abstract:
We grow tubes of living tissue in vivo and use them as grafts for the replacement of diseased blood vessels. Cell adhesion to a polymer template initiates the growth of this so-called artificial artery. We investigate this cell adhesion by quantifying the adhesion force with optical tweezers. We measure adhesion force distributions for different template materials and for different proteins in the system. We identify the specific binding forces between matrix proteins like fibronectin and fibrinogen and their integrin receptors on living macrophages. The characteristics of the force distributions correlate to the success rates of in vivo graft formation.
4. A time-lapse microscopy revelation: The dynamic helical nature of the bacterial division protein FtsZ
Name: Phoebe Peters
Emai: phoebe.c.peters@student.uts.edu.au
Organisation: University of Technology, Sydney
Phone: +61 (0)2 9514 4175
Abstract:
The first stage of bacterial cell division is polymerization of the tubulin-like FtsZ protein at the midcell division site into a ring, called the Z-ring. It has previously been proposed that the Z-ring forms by bidirectional growth from a midcell nucleation site. Using improved fluorescence microscopy techniques for bacteria we have now discovered that, in addition to forming a ring, FtsZ forms a dynamic helical structure along the length of the cell. Time-lapse microscopy using an FtsZ-YFP fusion protein revealed a helix-to-ring transition of FtsZ just prior to cell division. This discovery revolutionizes a Z-ring assembly model which dominated the field for over a decade.
5.
Characterising yeast populations using image and statistical analysis on fluorescence images
Name: Hemant Bhatta
Email: hbhatta@ics.mq.edu.au
Organisation: Macquarie University
Abstract:
We characterised populations of baking and brewing yeast cells using intrinsic fluorescence and fluorescence lifetime microscopy (405nm excitation), to obtain quantitative identifiers of different strains. The images were analyzed to obtain information on cell size, intensity and texture-related features. In light of significant cell-to-cell variability, statistical method (Kolmogorov-Smirnov test) was utilized to assess the validity of the proposed quantitative identifiers for strain differentiation. High variability of lifetime values within cells was observed however a lifetime texture feature in the strains was statistically different. Finally we demonstrate a simple method of finding the percentage content of yeast cells in mixed populations.
6. Hyperpolarised noble gas production for imaging and surface analysis
Name: Cavin Talbot
Email: talbot@physics.uq.edu.au
Organisation: Centre for Biophotonics and Laser Science, School of Physical Sciences, the University of Queensland
Phone: +61 (0)7 3365 3541
Fax: +61 (0)7 3365 1242
Abstract:
Hyperpolarised noble gases have been used to image volume spaces such as lungs and for analysis of biopolymer surfaces. Hyperpolarsied gases are produced using two techniques - spin exchange optical pumping(SEOP) and metastability exchange. We have constructed an apparatus to produce hyperpolarised helium and xenon using the SEOP method in which a laser is used to electronically polarise rubidium atoms in a magnetic field and through collisions transfer the polarisation to the nucleus of the noble gas. We have produced polarisations of 25% for helium and 10% for xenon and produced preliminary rat lung images and surface analysis.
7. Inducing Calcium Responses and Mechanical Strains in Cells by use of Femtosecond Laser Targeting
Name: Charles Cranfield
Email: ccranfield@swin.edu.au
Organisation: Centre for Micro-Photonics, Swinburne University of Technology
Phone: +61 (0)3 9214 4323
Abstract:
The nature of fsec pulsed lasers is such that it can deliver very precise and highly localised forces to target cells or tissues. We demonstrate how femtosecond (fsec) pulsed lasers can be used to induce precise mechanical strains and stresses in cells as measured using Digital Image Correlation. As well, we show how fsec pulsed lasers can be used to control intracellular calcium ion fluctuations in individual cells. From our experiments we can demonstrate how fsec pulsed lasers can be used for investigating the mechanotransduction mechanisms involved in cellular signalling.
8. Establishment of a New Imaging Method to Correlate Fluorescence- and Sanning Electron Microscopic Information on the Same Biological Samples
Name: Filip Braet
Email: filip.braet@emu.usyd.edu.au
Organisation: The University of Sydney / NANO-AKCMM
Phone: 093517619
Fax: 02 9351 7682
Abstract:
A protocol will be presented in which a fluorescence signal is reconciled with a signal from the scanning electron microscope (SEM). In this method hepatic endothelial cells (HECs) cultured on collagen-coated CELLocate-microgridÒ glass cover slips were stained with rhodamine-phalloidin to visualize actin, and fluorescent images were then taken and cells located simultaneously by using the marked grids. Subsequently, samples were recovered and processed for SEM. Previously visualized cells in the confocal microscope were relocated and SEM micrographs of the corresponding cells were taken at an identical end magnification. By using this technique we could clearly illustrate a functional relation between actin and the dynamic surface topology of HECs.
9. The Effect of Mode Launching on Light Absorption in Vertebrate Photoreceptors
Name: Leigh Fischer
Email: fischer@physics.uq.edu.au
Organisation: University of Queensland
Phone: 0422 262 659
Fax: +61 (0)7 3392 6409
Abstract:
The absorption characteristics of individual photoreceptors determine the spectral sensitivity available within some visual system. In practice, a homogenous field approximation is applied to an experimentally determined photopigment absorption function to account for photoreceptor self-screening. Due to the waveguiding characteristics of photoreceptors, this model offers an insufficient description of the spectral sensitivity. We propose a new absorption model which is obtained by employing both standard optical waveguide theory and Finite-Difference Time-Domain numerical methods. The model takes into account the bulk absorption characteristics of photoreceptors as well as the lateral power flow due to absorption of bound and radiative waveguide modes.
10. The final count-down. Timing the kinetics of BAX and Smac/DIABLO with homeostatic confocal microscopy (HCM)
Name: Michal Godlewski
Email: mickgodl@hotmail.com
Organisation: Warsaw Agricultural University
Michał M. Godlewski1›, Magdalena Górka1, Monika Lamparska-Przybysz1, Barbara Gajkowska2, Urszula Wojewódzka2 and Tomasz Motyl1
1Department of Physiological Sciences, Faculty of Veterinary Medicine, Warsaw Agricultural University, Nowoursynowska 159, 02-776 Warsaw; 2 Laboratory of Cell Ultrastructure, Medical Research Centre, Polish Academy of Science, Pawińskiego 5, 02-106 Warsaw; POLAND; ›: mickgodl@hotmail.com
Abstract:
During apoptosis permeability of mitochondrial membranes is mediated by megachannels formed in outer mitochondrial layer. The process involves BAX-BID interactions with VDAC-1 complexes. This enables efflux of cytochrome-c, Smac/DIABLO and other proapoptotic proteins from mitochondria. Traditional methods of observation allowed barely indirect time-sequence analysis of fixed cell populations. HCM was applied for analysis of minute pattern of changes occurring at the mitochondria of live cells double-transfected with BAX-GFP or Smac/DIABLO-GFP and mito-RFP. Coincidence between BAX aggregation on mitochondria and Smac/DIABLO release in the cells indicated that BAX-BID-formed megachannels are responsible for Smac/DIABLO release. Acquired data was confirmed by immunogold TEM.
11. Spectral Dependence of a Light Mediated Function in Giardia
Name: Justin Ross
Email: justinr@physics.uq.edu.au
Organisation: University of Queensland
Phone: (07) 3346 9583
Fax: (07) 3365 1242
Abstract:
We report on a new experimental technique suitable for measurement of light-activated processes, such as fluorophore transport. The usefulness of this technique is derived from its capacity to decouple the imaging and activation processes allowing fluorescent imaging of fluorophore transport at a convenient activation wavelength.
We have demonstrated the efficiency of this new technique in determination of the action spectrum of the light mediated transport of rhodamine 123 into the parasitic protozoan Giardia duodenalis. The spectrum obtained consists of two peaks, centred around 381 nm and 502 nm and is significantly different from the excitation spectrum of Rhodamine 123.
12. Synthesis and characterization of disodium ethylenediaminetetraacetic acid capped and europium doped CdS nanoparticles
Name: Guanghua Zhu
Email:
ghuazhu@yahoo.com.cn
Organisation: Southeast University
Abstract:
We present a novel two-step chemical synthesis route to produce of disodium ethylenediaminetetraacetic acid (EDTA) capped and europium doped CdS nanoparticles. First EDTA was applied to chelate with cadmium on the surface of cadmium-rich CdS nanoparticles and act as a capping agent. Further, the purified EDTA-capped particles were used to bind with Eu3+. The purified and redispersed particles were characterized by UV/VIS absorption, photoluminescence, TEM and SEM. It was observed that Eu3+ on the nanoparticle surface significantly increased the band gap emission intensity of the CdS nanoparticles.
13. Novel Optical Labels based on Luminescent Nanodiamonds for Cellular Imaging
Name: Andrei Zvyagin
Email: zvyagin@physics.uq.edu.au
Organisation: The University of Queensland
Abstract:
In biological imaging, site-specific luminescent optical labelling provides superb discrimination between the sites of interest and the cell background. However, photoinstability, low cross-section, and toxicity of these labels present a problem, especially for tracking individual labels. A luminescent label, nitrogen-associated vacancy defect in a diamond nanocrystal represents an attractive alternative, since it is extremely photostable, biocompatible, and highly visible in the cell autofluorescence environment. We report on production of such luminescent nanodiamonds (LND), and preliminary investigations of their optical properties, as applied to cellular imaging.
14. Photochemical behaviour and Na+,K+-ATPase sensitivity of voltage-sensitive styrylpyridinium fluorescent membrane probes
Name: Ron Clarke
Email: r.clarke@chem.usyd.edu.au
Organisation: School of Chemistry, University of Sydney
Abstract:
Styrylpyridinium dyes are widely used probes of electric field strength changes in membranes, e.g. imaging electrical activity and the investigation of ion pumps. A limit to their application is their photochemical stability. Probes with improved stability and voltage sensitivity are required.
Exposure of RH421 to continuous illumination increases its fluorescence in lipid membranes. To suppress this reaction, modifications to the dye are necessary. ANNINE 5 shows no observable photochemical reaction in vesicles. The voltage sensitivity of ANNINE 5 was tested using Na+,K+-ATPase membrane fragments. ANNINE 5 shows a similar sensitivity to RH421 in detecting charge-translocating reactions triggered by phosphorylation.
15. Life and death in the gut epithelium. Light microscopy (LM), image analysis system (IAS) and laser scanning cytometry (LSC) in assessment of intestinal mucosa development
Name: Michal Godlewski
Email: mickgodl@hotmail.com
Organisation: Warsaw Agricultural University
Michał M. Godlewski1›, Daria Dolman1, Agnieszka W. Piastowska1, Mikołaj A. Gralak1, Marzena Biernat2, Romuald Zabielski1,2
1Department of Physiological Sciences, Warsaw Agricultural University, Nowoursynowska 159, 02-766 Warsaw; 2The Kielanowski Institute of Animal Physiology and Nutrition, PAS, 05-110 Jabłonna; POLAND; ›: mickgodl@hotmail.com
Abstract:
Study aimed to evaluate the proliferation and apoptosis markers during maturation of the gut mucosa. Samples from young pigs and rats were analyzed with LM (mitotic index), LSC (DNA-content for quantitative evaluation of apoptosis and mitosis), and IAS (Ki-67 for G2-phase and mitosis). LM was laborious and subjective, and the number of dividing cells was underestimated in comparison with IAS. LSC was found valuable for apoptosis analysis, but not for mitosis as large number of overlapping G1-phase nuclei were attributed to G2M phase. Ki-67-based evaluation of mitosis was found superior to both LM and LSC approaches.
16. Homogeneous Au-Core Silver-Shell Nanoparticles Preparation for Fluorescence Enhancement Application
Name: Fang XIE
Email: fangxie@ics.mq.edu.au
Organisation: Macquarie University
Abstract:
A simple method has been developed for the deposition of uniform Au-core Ag-shell nanoparticles on glass substrate uniformly. A monolayer of FITC-HSA was formed both on a silver nanoparticles covered glass surface as well as on a bare glass surface as a control. Fluorescence was examined in the areas containing the nanoparticles in comparison with those covered only with the monolayer of FITC-BSA and without the nanoparticles. Its shows that, depending on size of these nanoparticles, the fluorescence of FITC are be quenched, not affected or, enhanced in comparison to the control area. Thus these nanostructures can produce promising substrates for fluorescence enhancement. One of the outstanding advantages of this method is that such substrates are spatially homogeneous, which will pave the way for application of such substrates in many areas of biotechnology and life sciences.
17. Single-molecule triangulation
Name: Taras Plakhotnik
Email: taras@physics.uq.edu.au
Organisation: University of Queensland
Abstract:
We discuss in detail a proposal for using single molecules as nano probes capable of detecting the trajectory of an elementary charge. Presented numerical simulations prove that the proposed technique provides 0.006 nm accuracy of 3‑dimensional location of a single electron within a few seconds. Surprisingly, this significantly exceeds the accuracy with which the probe molecules itself can be located (given the same measuring time) by means of single-molecule microscopy. It is also shown that the optimal concentration of probe molecules in the vicinity of the electron (that is the concentration which provides the best accuracy of the electron location) is on the order of 10^-5 M. The technique potentially can be applied to investigate charge transfer in photosynthetic light harvesting complexes and electrical conductivity in biomolecules.
18. Application of rigorous coupled wave analysis to modelling nanoparticle mediated sensitivity enhancement of surface plasmon resonance based sensing systems
Name: Anne Barnett
Email: anneb@ics.mq.edu.au
Organisation: Macquarie University
Abstract:
Label free, optical sensing regimes utilising surface plasmon resonance (SPR) are well placed to make useful measurements of biological and chemical interactions. The full utilisation of this technology has yet to be realised, however, due to sensitivity issues. Recent studies have shown that inclusion of nanoparticles or nanostructures within the optical near field of the sensing surface can have a dramatic impact, with reported sensitivity improvements of up to two orders of magnitude.
This poster explores the issues facing SPR based sensors with respect to their sensitivity limitations and the role that nanoparticle enhancement can play in pushing SPR to previously unrealised sensing levels. The latest developments in modelling the nanoparticle mediated response enhancement using rigorous coupled wave analysis (RCWA) are discussed and results from the application of the RCWA approach to modelling the response of sensors enhanced by gold colloids are presented.
19. Manipulation of Protein Crystals using Optical Tweezers
Name: Wolfgang Singer
Email: singer@physics.uq.edu.au
Organisation: Centre for Biophotonics and Laser Sciences, Schoolof Physical Sciencs, University of Queensland
Abstract:
Optical tweezers can trap and move dielectric materials non-invasively at length scales ranging from tens of nanometres to tens of micrometres. We have shown that also protein (lysozyme) crystals can be held in an optical trap without measurable degradation of the crystal. This permits studies of modifications of single crystals while gradually changing the conditions in the growth solution. Studies performed included increasing the protein concentration and thermal cycling. We furthermore demonstrated that our optical tweezers setup can be used to determine optical properties, like birefringence and refractive index, of the crystal.
20. High Intensity UV LED for Time-gated Luminescence Flow Cytometer
Name: Dayong Jin
Email: Jin@ics.mq.edu.au
Organisation: Centre for Lasers & Applications, Macquarie University
Abstract:
In flow cytometry, naturally occurring, intrinsically fluorescent substances (autofluorophores) can severely compromise the unique discriminative ability of immunofluorescent probes. The desired signal can be efficiently distinguished from the bulk autofluorescence when the fluorescence lifetime (t) of the probe is sufficiently different from that of the autofluorescent matrix. A novel time-gated luminescence flow cytometry (TGL FCM) design is presented that employs a rapid-pulsed ultra-violet (UV) light emitting diode (LED) and a time-gated channel photomultiplier tube (CPM). In such a system, the 5.7-micro europium luminescent microspheres were detected with sufficient signal-to-noise ratio. The inexpensive, easily powered UV LEDs were found as excellent excitation source for TGL FCM.
21. Optical Microrheology of Biopolymers
Name: Simon Parkin
Email: parkin@physics.uq.edu.au
Organisation: University of Queensland
Abstract:
We present a technique based on optical tweezers to determine microrheological properties of biopolymers. Biopolymers can be used as models for biological fluids or medical samples. Microrheology is an important tool for studying such fluids as changes in their rheological properties can be an indicator of disease or other abnormalities.
In our technique optical tweezers are used to trap and rotate a birefringent spherical particle in the fluid of interest. The shear stress applied to surrounding fluid is directly controlled by the torque applied to the sphere. Varying the torque allows the viscoelastic properties of the fluid to be measured.
22. A computer-vision based method for analysing Scribble dynamics in T cells
Name: Ze'ev Bomzon
Email: zbomzon@groupwise.swin.edu.au
Organisation: Centre for MicroPhotnics, Swinburne University of Technology
Abstract:
Polarity is important for T-cell function, and is regulated by a scaffolding protein, Scribble. Understanding Scribble function requires analysis of its movement. Here we present a study in which time-lapse images of dividing Mouse T cells (MD45) over-expressing Scribble fused to GFP were analysed using a shape recognition algorithm.
Throughout the experiments Scribble was predominantly found in the mid-body and at the distal pole, but was excluded from the central regions of the daughter cells. This behavior contrasted with the behaviour observed in cells expressing GFP alone. Ongoing work will define the movement of Scribble during other T cell behaviours.
23. Computational Characterization of Red Fluorescent Protein Chromophores
Name: Seth Olsen
Email: s.olsen1@uq.edu.au
Organisation: Centre for Computational Molecular Science, The University of Queensland
Abstract:
The discovery and application of the family of GFP homologues has spawned a revolution in biotechnology and biological research. Among the GFP homologues, the subfamily of 'DsRed-like' red fluorescent proteins (RFPs) is drawing special interest due to the decreased absorbance and background fluorescence of biological tissue at the red end of the visual spectrum. These proteins possess an N-acylimine substituent which expands the  electron network of the p-hydroxybenzylideneimidazolinone motif which is common to all functional fluorescent protein chromophores(Gross, 2000). We will present multireference ab initio (CASSCF, CASPT2 and MR-CI) and time-dependent density functional theory calculations of a model RFP chromophore in vacuo and in simple environments designed to mimic the protein microenvironment. With these calculations we explore the bridge isomerization which competes with fluorescence in the RFPs, and the mechanisms by which different RFPs can tune the chromophore over the broad range of absorbances and emissions observed in natural and engineered proteins. Implications for the interpretation of experiments based upon olefin-substituted synthetic models(He, 2002, Boye 2003)are also discussed.
24. Live Cell Bioimaging: Application of a novel latent fluorophore for the visualization of intracellular enzyme activity in vivo
Name: Edit Pleskonics
Email: kasmir@bigpond.com
Organisation: Macquarie University CBMS
Abstract:
Rhodamine 110 Trimethyl Lock is a novel latent fluorophore that was recently designed for the in vivo detection of esterase activity. The pro-fluorophore is stable in standard biological buffers, non-toxic to live cells, and can be used together with other in vivo stains for multiple labeling. Moreover, the probe tends to accumulate in yet unidentified cytosolic compartments, which feature might be useful for compartment-specific staining. Due to these properties the probe could be a valuable tool for the real time observation of metabolic activity in living cells.
25. Spectroscopy On Small Space & Time Domains
Name: Trevor Smith
Email: trevoras@unimelb.edu.au
Organisation: University of Melbourne
Abstract:
Advanced optical techniques applied to small space and time domains are becoming increasingly important in the investigation of photo-initiated processes in systems of biological, chemical and physical relevance. We will outline the range of ultrafast laser and advanced microscopic techniques and facilities being applied to the study of quantum dots, protein (thin film) adsorption, coated particles and other systems. Techniques include:
. Time-resolved confocal & two photon fluorescence imaging
. Scanning near field optical microscopy
. Time-resolved fluorescence depolarisation measurements
. Total internal reflection fluorescence imaging.
. Single molecule detection methods
. Ultrafast laser measurements
26. Optical Characterisation of Gd2O3 Nanoparticles Doped with Eu
Name: Krystina Drozdowicz-Tomsia
Email: ktomsia@ics.mq.edu.au
Organisation: Macquarie University
Abstract:
Lanthanide-doped nanoparticles are novel fluorescent materials with application in fluorescence labelling. Long fluorescence lifetimes make them suitable candidates for time-gated techniques, with much increased sensitivity. We have assessed the optical properties of these novel fluorophores, with specific emphasis on full spectral characterization and fluorescence kinetics. Time-gated spectroscopy of doped nanopowders revealed a broad band in the visible region, corresponding with a similar band in undoped Gd2O3. All the examined nanopowders showed very short lifetimes, in the order of 2 ns, and much longer, ms decay times characteristic to lanthanide ions. At intermediate times, in the order of 20-100 ns, the decay characteristics showed a complex behaviour, indicative of progressive energy transfer to the lanthanide ion, that varied with different intrashell transitions.
27. Photoresponsive GFP-like proteins from reef corals and their applications in imaging and biosensor technologies
Name: Anya Salih
Email Address: anya@emu.usyd.edu.au
Organisation: University of Sydney
Abstract:
We have identified a variety of fluorescent and chromophoric proteins homologous to the green fluorescent protein (GFP) in corals from the Great Barrier Reef. Several of these proteins respond to light of various wavelength by rapidly changing their optical properties. Such proteins include photoactivatory fluorescence amplifying (PAFA) proteins, green-to-red converters, red-to-green converters and kindling proteins. Here, we report on their optical characteristics and discuss their potential applications for bio-imaging.
Companies participating:
- Invitrogen Pty Ltd, Lavinia Taliana
- Raymax Applications, Rudolf Salib,
- Coherent Scientific Pty Ltd, Gerri Springfield
- Lastek Pty Ltd, Stuart Rumble
- Olympus Australia Pty Ltd, Sarah Humphrey
- PerkinElmer Life and Analytical Sciences, Chris Mylo
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