The project will be co-supervised by Dr. David Inglis (research fellow) and Prof. Ewa Goldys.
Microfluidics research involves fabricating micron sized structures to handle fluids and facilitate chemical or biological tasks. Microfluidic or lab-on-a-chip devices are being used in a number of cutting edge biological industries such as DNA sequencing and medical diagnostics. Research in the field is multidiciplinary with most work focussed on making laboratory procedures cheaper and faster.
We are in a position to use recently developed techniques in microfluidics to sort and concentrate microbes. This will allow for earlier detection of dangerous cells in fluids ranging from drinking water to blood. Research using this technique has been used to separate different types of blood cells, including abnormally sized tumor cells, but has not yet been applied to micro organisms.
In this project the student will use the Macquarie University clean room to fabricate microbial and cell sorting devices as well as measurement and testing of the devices with non-infectious microbes. The student will develop skill in microfabrication, advanced microscopy and biology. These skills will be valuable in the growing field of biotechnology.
The microfluidics Phd project on offer is a full-time Macquarie University Research Excellence Scholarships (MQRES) with a current stipend of $20,007 p.a. tax exempt. Tenure is 3.5 years full-time, subject to satisfactory progress. Tuition fees will be sponsored for the scholarship tenure.
MQRES scholarships are available to domestic and international students. Prior to commencing, applicants should have completed a 4 year undergraduate degree in Engineering, Physics, Chemistry or Biology. Early career professionals interested in returning to higher degree studies are also encouraged to apply. Further information regarding this project, may be obtained by contacting the co-supervisor: Dr David Inglis, telephone: +61-2-9850-4167, email: dinglis@mq.edu.au. Application forms (see below) and conditions for awards are available from the Higher Degree Research Office, telephone +61-2-9850 7987, email: hdrschol@vc.mq.edu.au.
The project is carried out with Anne Barnett, Z. Gryczynki, I. Gryczynski, E. Matveeva (Department of Molecular Biology and Immunology, Health Science Centre, University of North Texas, Fort Worth, TX, USA.
The new Nanobiophotonics PhD project on offer in 2006 "Utrasensitive sensors using surface plasmon resonance and coupled emission" will progress the ideas developed here. For more information about the new PhD project please follow this link.
The present research focuses on sensitivity increase of a Surface Plasmon Resonance (SPR) sensor through surface enhancement of SPR and nanoscale surface profiling.
Customisation of the sensor surface is being carried out for the detection of selected analytes, using appropriate active bio-surfaces.The project outcome will be a range
of innovative, sensitive and accurate sensing strategies for selected biochemicals, and associated portable technologies for field use.
The Powerpoint presentation available here presents project background and achievements:
SPR Powerpoint
This project is carried out with Hemant Bhatta, Robert Learmonth (USQ).
The PhD project on offer in 2006 entitled "Advanced laser scanning microscopy for identification of microorganisms" is a continuation of this work. Please click for more detail about the PhD project.
Research has so far concentrated on:
Links to Powerpoint presentations are included here.
BAC Powerpoint
This project is carried out with K. Drozdowicz-Tomsia, Sun Jinjun, Dosi Dosev, Ian Kennedy (University of California), Marek Godlewski (PAN).
Quantum dots are inorganic nanostructures, several nanometers in size, often build from semiconducting materials such as CdSe, or ZnS. They show very string fluorescence and effects due to size quantization. Their key application is as fluorescence probes that are superior to inorganic dyes and fluorescent proteins.
Quantum dots doped with rare earth ions are expected to show:
The present project focuses on synthesis of nanocrystals based on II-VI, III-V and other oxides doped with selected rare earth ions, customized for the use as fluorescent probes. Currently we are developing core-shell structures. Surface modification will be carried out to ensure water solubility, and derivatised to ensure further connectivity. The nanocrystals will be later linked with custom-derived oligonucleotide probes and antibodies and introduced into cells. The project will, ultimately develop a methodology to detect and trace specific DNA molecules, pathogens and proteins.
So far core CdSe and CdSe/CdS core-shell nanoparticles with the following parameters have been synthesized with the follwing properties:
Absorption, fluorescence spectra and ageing characteristics of synthesized core CdSe nanoparticles.
The postgraduate project in this area is entitled "Colloidal quantum dots for biotechnology applications". It will be offered in 2007.
Project carried out with Fang Xie, Mark Baker (APAF), Z. Gryczynski, I. Gryczynski (University of North Texas)
Amplification of light from reporter fluorophores is a promising strategy to increase the sensitivity of fluorescence biosensing. Recently, new tools have emerged which capture the advantages of nanotechnology and nanostructure engineering to amplify the emission of light at a molecular level. In this project we will use these new approaches to engineer amplified fluorophores and provide a proof of concept by using them in amplified fluorescence bioassays and in electrophoretic gel separation. Such amplified fluorophores will have a range of potential commercial applications. In addition to highly sensitive staining of proteins and nucleic acids in electrophoretic separation and immunoassays, they can be used as probes in multiplex detection of proteins and nucleic acids, medical imaging, immunohistochemical procedures, flow cytometry and high-throughput screenings of ligands using microarray platforms. Such fluorophores can be easily derivatised with a variety of tags, including antibodies and peptides enabling biosensor applications for rapid, multi-analyte detection of biomolecules and microorganisms.
The theme of metal nanostructure mediated amplification of optical phenomena such as Raman scattering, fluorescence, and absorption has been a recurring theme in research
literature since 1980, much of it poorly reproducible and understood. It is only very recently that theoretical understanding and nanostructure design and engineering
produced adequate control of these phenomena so that technological applications have become possible. It is now well established that metal nanostructures possess
characteristic optical properties related to the collective behaviour of their free electrons (plasmons) determined by the nanostructure size, shape, and complex dielectric
functions of the metal and the surrounding medium. Interestingly, whenever a plasmon resonance is excited by light of suitable wavelength, the nanostructures act as
nanoantennas and concentrate electromagnetic fields in their immediate proximity. This process of electromagnetic field enhancement promotes intensified emission of
fluorophores. Fluorophores also interact with nanostructures, and both the absorption and emission rates may be affected, depending on the spectroscopic characteristics and
separation distance. Colloidal nanoparticles, arrays of metal clusters, and ultrathin discontinuous metal films have been demonstrated to produce fluorescence
amplification.
Please see the figure for the details of our approach.
A postgraduate project in this area will be offered in 2007.
Forster energy transfer (FRET) is a phenomenon whereby one fluorescent molecule (donor) transfers electromagnetic energy to another distant fluorophore (acceptor) in a process which has a sharp cutoff at the Forster distance of about 5 nm. It has become an indispensable tool in many biological studies where it helps to optically identify biomolecular interactions. FRET is so important for biology that it has even acquired a popular name 'molecular ruler", in reference to the sharp distance cutoff. This project responds to strong motivations from life sciences to extend this cutoff so that larger biomolecules and complexes can be studied.
Many optical processes such as the Raman effect and fluorescence can now be engineered via the geometry of the environment in which the radiation occurs. However the absence of appropriate experimental information leaves open the issue whether, and to what extent FRET can be controlled by the local optical environment. To explore this question we propose to carry out a sequence of experiments designed at establishing the influence of one such environment, a planar cavity. Our preliminary results and evidence form literature indicate that optical cavities facilitate long-range energy transfer, and therefore will enhance FRET and extend its distance cutoff.
We hypothesise that the following approaches will support enhanced FRET:
The key outcome of this work will be the demonstration of the enhanced FRET distance cutoff in planar cavities. We expect that in cavity-modified FRET the distance cutoff will be perhaps more gradual but it will more than make up for this limitation in both the useable distance range and the maximum detection limit of biomolecular interactions. The detection of fluorophore interactions by the conventional FRET becomes impossible beyond about 10 nm, but we anticipate that FRET in the cavity environment will continue to provide information about fluorophore proximity for distances up to 100 nm. Such increase will greatly facilitate biological experiments by extending the range of molecular interactions that could be optically identified.
On the fundamental physics level, the experimental results to be obtained here will inform the theory concerned with coupled dipole-dipole electromagnetic interactions and steady-state and temporal evolution of coupled two-level atoms which share a single excitation, with special emphasis on interatomic energy transfer. Such theoretical framework cannot be anchored in reality without these experimental data. Specifically it is not known whether the photon-atom coupling is weak or strong which dictates if quantum-mechanical perturbation theory or strong coupling methods are appropriate.
This new understanding can be put to practical use. The demonstration that FRET depends on the local optical environment means that a multiplicity of confining structures designed to alter spontaneous emission will also provide suitable strategies to control energy transfer. This will have broad implications for the development of new optical tools for the study of biological systems. Specifically, we envisage to be able to calibrate planar cavities with respect to the FRET cutoff distance within the range 5-100 nm. In this way this project will yield custom-designed "molecular rulers", in a device format compatible with laser scanning microscopes. Such new rulers will satisfy the needs of the life sciences community to assess biomolecular binding at a variety of length scales hitherho impossible.
A postgraduate project in this area may be offered in 2007.