Antibody-coated nanoparticles in microfluidic chip improve cancer detection 100 fold
5 February 2010
The Fraunhofer Institute for Silicate Research is developing a
highly sensitive method for detecting cancer that can detect single
molecules of compounds in
the blood that accompany specific types of tumour.
The new diagnostic method aims to detect cancer in its initial
stages so that treatment can start early and improve a patient's
chance of recovery.
The technology is based on a microfluidic chip with tiny channels
into which a blood sample is drawn. Specially sensitised nanoparticles
in the channels capture marker proteins in the blood that are indicative
Similar testing systems already exist but their measurements are not
very precise and they can only detect molecules that are present in the
blood in large quantities. What’s more, the tests have to be carried out
in a laboratory, which is time-consuming and costly. The key technology
is the biofunctionalized nanoparticles developed by the Institute that
give the greatly increased sensitivity .
The research is being conducted by scientists at the Fraunhofer
Institute for Silicate Research ISC in Würzburg and funded by the German Ministry of Education and Research.
Nanoparticles connected to antibodies are luminescent
in two spectral
ranges. This makes it possible to check
the homogeneous occupation of
the sensor electrodes.
"We have improved the detection limit compared with the present state
of the art by a factor of one hundred," explains Dr Jörn Probst, Head
of the Business Unit Life Science at the ISC. "Whereas previously a
hundred molecules were needed in a certain quantity of blood to detect
tumour markers, we now need only one. This means that diseases can be
diagnosed much earlier than with present methods."
"We have placed antibody-occupied nanoparticles on the sensor
electrode which 'fish' out the relevant proteins. For this purpose, we
repeatedly pump the blood across the electrode surface. As with a river,
the flow is fastest in mid-channel and the water runs more slowly near
the bank. We have therefore made a sort of fishing rod using
nanoparticles which registers the antibodies in the middle of the blood
flow where most proteins swim by per unit of time."
If an antibody catches the matching protein that indicates a tumour,
the electrical charge distribution shifts and this is picked up by the
The researcher groups are now developing a first demonstrator
combining four independent single-molecule-sensitive biosensors. The
experts are also working on the simultaneous detection of several tumour
markers, which will increase the clarity of tests. The system will be