Biomarkers are getting a lot of attention lately as a means of monitoring health and diagnosing disease, and it’s no surprise that photonics-based sensing techniques are bringing them into the spotlight. A project named BILOBA is a collaboration funded by the European Commission through its Seventh Framework Programme. The acronym is an abbreviation of “Bloch electromagnetic surface wave bio-sensors for early cancer diagnosis”(!)
BILOBA plans to develop and pre-clinically validate a multifunctional point-of-care platform that is capable of performing real-time cancer biomarker detection in a tandem configuration. Such configuration will utilize label-free detection based on the resonance shift, and the spectral analysis of enhanced fluorescence emitted by biomolecules immobilized on the surface. Utilizing both labeled and label-free analysis on the same sensor system can increase the sensitivity and reliability of optically read out surface-bound assays.
The well-established optical standard method for non-labeled detection is the surface plasmon resonance method. Its sensitivity suffers from the strong absorption of surface-bound waves. A similar concept, already at the proof-of-principle stage, will be advantageously implemented by applying the unique properties of Bloch Surface Waves (BSW) sustained on a 1D Photonic Crystal. Therein, a surface wave without absorption is excited, giving rise to an enormous narrowing of resonances and an associated increase in sensitivity. Furthermore, fluorescence enhancement due to near-field effects will be exploited. By utilizing the dispersion of the BSW both detection schemes will be combined.
The major goal of the project is to explore, design, and set-up BSW systems optimized for analytical sensing, associated with the development of a corresponding analytical instrument. For this purpose, the immobilization protocols and biochemical assays have to be established to ensure an optimized binding site density at the surface and to enable the detection of the target biomarkers. Furthermore, a fluidic system will be developed, which will supply and handle the aqueous analyte solutions while ensuring a high signal-to-noise ratio and robust results even in the case of ultralow concentrations. The platform will be validated by pre-clinical tests on the detection of Angiopoietin-1 and -2, and Vascular Endothelial Growth Factor.
The BILOBA project consists of nine participants from different European countries and with different objectives of participating. The three-year project just completed its first year. Its budget is €4.73 million, including €3.6 million from the European Commission.
On a related note, SPIE Newsroom has just published a timely video about the sensing of biomarkers, with Francesco Baldini of Italy’s Institute of Applied Physics. Baldini chairs a conference on Optical Sensing for SPIE and his lab has been working on numerous types and applications of biosensors for years.