Co-operative Research projects for SMEs - European Commission ...

Exciting developments for diagnostics
“As SMEs, we find it hard to have large
Although many standard biochemical analyses
R&D programmes. This project is helping
use fluorescence, the technique tends to have
us to develop new technologies
problems with sensitivity, often caused by high levels of
and applications.”
background noise. The Biotphex Co-operative Research project aims
to improve assays using a phenomenon called two-photon excitation (TPX).
Two SMEs are developing infra-red laser technologies, while three others are applying
TPX in a variety of systems with significant commercial opportunities, including small clinical
diagnostic devices. They are aided by the expertise of three European universities, which are
involved in improving the basic assaying system, developing the instrumentation, and testing and trialling
prototype products and protocols.
The phenomenon of fluorescence – the emission of light from a substance
when it is exposed to radiation – is commonly used in biochemical
research. A scan of scientific journals quickly uncovers
many images of cells glowing green, red or blue.
The basic technique is quite simple: you take antibodies specific to
your molecule of interest, label them with a fluorescent dye, and
add them to your sample. If your target molecule is present the antibodies
‘stick’. When exposed to a radiation source, usually ultraviolet
light, the marker molecules attach to the antibodies fluoresce.
The coloured light tells you that your target molecule is
present in the sample.
Although fluorescence-based techniques are a mainstay of biochemical
research and clinical diagnosis, their lack of sensitivity is a particular
problem. All biological material is naturally fluorescent to some
extent, which creates high levels of background noise in these assays.
Fluorescence from the sample container can also sometimes reduce
sensitivity or produce other experimental artefacts.
Exciting partnership
A group of European SMEs (small and medium-sized enterprises)
and universities are currently working together in a Co-operative
Research project on an innovative method of fluorescence assaying
that they claim will be ‘background-free’. Instead of exposing
samples to ultraviolet or visible light, the Biotphex project uses a
phenomenon called two-photon excitation (TPX) to illuminate samples
with infra-red radiation. Under normal circumstances, the
wavelength of infra-red radiation is too long to be able to cause
fluorescence. However, by using a laser in short pulses (less that
10 million millionths of a second) of infra-red light it is possible to
deliver sufficient energy for marker molecules to fluoresce.
The basic TPX system is being supplied by Finland’s Arctic
Diagnostics, which is coordinating the project. This will be improved
and developed for new applications with the assistance of the other
project participants.
Two companies are developing the laser technology. Standa
Optomechanical Products in Lithuania has produced a relatively
cheap, finger-sized TPX laser that could be incorporated into small
diagnostic equipment. Fianium in the UK is working on a high-performance
fibre-optic-based laser system that could be used for research
applications. Both companies will supply the laser components for any
commercial products that result from the research project.
Another area of research in the project, being conducted by the
University of Jyväskylä in Finland, is the development of binding proteins
that can be used to coat microscopic latex beads with targetspecific
binding proteins (e.g. antibodies or DNA binding proteins)
linked to fluorescent dyes. These beads move through the sample
solution and ‘mop up’ target molecules. As the laser beam delivers
its energy to just a minute volume of the sample – about the same
volume as that of a bead – only single beads are excited at a time.
The brightness of each bead’s fluorescence indicates the concentration
of target molecule in the sample.
University College Cork in Ireland is playing an important role in
testing and trialling the Biotphex technique and prototype technologies,
especially in DNA assays, and is helping to optimise assay
procedures and protocols.
In collaboration with the University of Turku in Finland, three SMEs are
focusing on new applications for TPX assaying. Luxcel Biosciences in
Dublin, Ireland, is adapting the technology to count cells in samples
by measuring oxygen uptake. German-based
Merlin Technologies is working
on a microfluidics
‘chip’ so that many
parallel assays can
be run from a
single sample
in a portable
device.
Scientists
frequently use
fluorescent markers
to identify target
cells and molecules.
© Roche, 2002 – 2005
BIOTPHEX