Highly sensitive biosensors based on amorphous silicon-carbon alloys
|Larbi Touahir 1, Anne Chantal Gouget-Laemmel 1, Philippe Allongue 1, Rabah Boukherroub 2,3, Jean-Nöel Chazalviel 1, Elisabeth Galopin 2,3, Catherine Henry de Villeneuve 1, Anne Moraillon 1, Joanna Niedziolka-Jönsson 2,3, Ionel Solomon 1, Sabine Szunerits 2,3, François Ozanam 1|
1. Physique de la Matière Condensée (CNRS), Palaiseau 91128, France
Biosensors based on fluorescence and/or surface plasmon resonance (SPR) detection schemes are widely used owing to their ease of processing and good sensitivity. Their performance is frequently limited by the control of the surface chemistry. In this framework, the use of silicon substrates offers a promising alternative route for the grafting of functionalized organic monolayers through Si-C covalent bonding, providing robust immobilization chemistry. First, a carboxyl-terminated monolayer is grafted on hydrogenated surfaces via hydrosilylation. Then, the carboxyl groups are activated using NHS/EDC, followed by amidation with biological probes bearing a primary amine linker. By combining Atomic Force Microscopy (AFM) imaging and infrared quantitative spectroscopy, we have optimized these multi-step modifications.
To combine the advantages of well-controlled surface chemistry and sensitive detection, we have designed fluorescent and SPR biosensors based on a thin layer of hydrogenated amorphous silicon-carbon alloy (a-SixC1-x:H) deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD) on a metal layer. Chemical protocols developed on crystalline silicon surfaces were successfully transferred onto a-SixC1-x:H. The sensitivity is maximized by optimization of the amorphous layer thickness and its carbon content. In this way, a fluorescence-based microarray on aluminium exhibits an efficient amplification of the fluorescent signal by over one order of magnitude as compared to commercial slides. Novel Au- or Ag-based sensitive plasmonic interfaces were also developed.
In either case, the obtained sensitivity allows for monitoring the hybridization of DNA probes with their complementary DNA in situ and in real time. Many successive hybridization/dehybridization cycles have been recorded without measurable changes in performance.
Presentation: Keynote lecture at SMCBS'2009 International Workshop, by Larbi Touahir
See On-line Journal of SMCBS'2009 International Workshop
Submitted: 2009-07-08 09:07 Revised: 2009-08-13 17:07