Diagnosing strokes with biosensors
MONS, Belgium – Whether a patient is in an ambulance, emergency room or hospital, point-of-care diagnosis
of cerebrovascular disease could soon be possible with a novel biosensor system
that uses photonic crystal technology.
The P3SENS consortium was formed to develop an immunoassay detection
device suitable for emergency stroke diagnosis. Co-funded by the Seventh European
Union Framework Program, the €3.6 million project anticipates that the combination
of highly sensitive photonic crystals, a panel of clinically proven biorecognition
elements, and low-cost production technologies will result in a biosensor system
that can make a real difference to stroke patients worldwide.
A photonic chip fabricated from nanocomposite polymeric materials
using highly scalable nanoimprint lithography (NIL) is at the core of the biosensor.
Including nanoparticles of metal oxides within the polymers allows the refractive
index to be modified so as to optimize the biosensor’s inherent sensitivity.
The photonic crystal optical circuitry that is used to route light around the chip
and to interact it with the medium being sensed is defined via arrays of features
on the order of 100 nm in size. Although a challenge, the optimization of the nanocomposite
polymers for both inherent optical properties and processability via NIL has been
tackled by the consortium.
An imprinted structure in a polymeric high-index nanocomposite thin film. Courtesy
of Multitel asbl.
A range of polymer host materials and nanoparticles have been
screened to identify suitable systems for the formation of nanocomposites and subsequent
processing via NIL. The findings show that the refractive index of the polymer can
be increased significantly by the incorporation of the correct nanoparticles. Thin
films (<500 nm) of polymeric materials with a refractive index of up to 1.74
have been prepared. Initial tests have indicated that the high-index nanocomposite
can be structured by NIL.
By showing the development of new materials suitable for the production
of polymer photonic crystals, the consortium has moved toward its goal of producing
a biosensor platform and demonstrating applicability in the point-of-care diagnosis
of strokes. It will continue its multidisciplinary approach by driving forward development
in polymer materials, photonic crystal fabrication, optical and fluidic systems,
and biomedical proteomics.
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