Surface sensitization techniques and recognition receptors immobilization on biosensors and microarrays

Abstract

The quality of a biosensing system relies on the interfacial properties where bioactive species are immobilized. The design of the surface includes both the immobilization of the bioreceptor itself and the overall chemical preparation of the transducer surface. Hence, the sensitivity and specificity of such devices are directly related to the accessibility and activity of the immobilized molecules. The inertness of the surface that limits the nonspecific adsorption sets the background noise of the sensor. The specifications of the biosensor (signal-to-noise ratio) depend largely on the surface chemistry and preparation process of the biointerface. Lastly, a robust interface improves the stability and the reliability of biosensors. This chapter reports in detail the main surface coupling strategies spanning from random immobilization of native biospecies to uniform and oriented immobilization of site-specific modified biomolecules. The immobilization of receptors on various shapes of solid support is then introduced. Detection systems sensitive to surface phenomena require immobilization as very thin layers (two-dimensional biofunctionalization), whereas other detection systems accept thicker layers (three-dimensional biofunctionalization) such as porous materials of high specific area that lead to large increase of signal detection. This didactical overview introduces each step of the biofunctionalization with respect to the diversity of biological molecules, their accessibility and resistance to nonspecific adsorption at interfaces. © Springer Science+Business Media, LLC 2010.