Biochips for Fluorescence and Localized Surface Resonance Combined Detection

< 10/01/2009 - by DRIP >

Background

Microarrays are widely used in biotechnologies because a large number of biochemical reactions can be tested in a single assay. The fabrication process of the biochip will determine the efficiency and the reliability of the microarray platform.

Technology / Novelty

The biochip is fabricated on silicon or glass substrates, covered or not with dielectric or etallic mirror to improve reflectivity and signal to noise ratio. Then, thin films of amorphous ilicon alloys (a-SixC1-x:H) are deposited by Plasma Enhanced Chemical Deposition so that covalent chemistry can be used to immobilize the probes on the substrate. Chemical eaction paths that lead to the formation of Si-C bonds rather than Si-O-C or Si-O-Si-C are favoured for improved performances. The biochip can be compatible with two detection techniques, namely fluorescence and localized surface plasmon resonance (LSPR). For SPR mode, gold or metallic nanoparticules are trapped between the substrate and the thin film, resulting in a robust and re-usable biochip. The nanoparticles are obtained by using a cost-effective process consisting in annealing a thin metallic layer.

Advantages

Possibility of high-sensitivity detection of labelled and non-labelled targets by combination of fluorescence and LSPR detection.
Real time and in-situ detection in solution.
Possibility of cleaning and using the biochip several times without signal-amplitude alteration.

Developement stage

5nm thin layers of a-Si0,80C 0,20:H have been deposited on commercially available Amplislide® products, resulting in a gain of 70 on the fluorescence signal, due to both optical effects and improved immobilization chemistry. Carbon content is the result of a trade-off between optical reflectivity (higher if high Carbon content) and chemistry control (better if lower Carbon content). Samples are available for evaluation.

Need more info? please contact :

francois.plais@polytechnique.edu