Porous silicon waveguides biosensor

Here we focus on the capabilities of a porous silicon waveguide biosensor for the detection of small molecules. The porous silicon waveguide, shown schematically in Figure 3a, consists of two porous silicon layers. Light is trapped in the top, high refractive index layer, based on total internal reflection at the interfaces with air and the bottom, low refractive index porous silicon... 

Calculations have been performed to estimate the detection limit of the porous silicon waveguide biosensor based on the percent of optical power interacting with biomolecules in the waveguide (25). The sensor is capable of detecting pictogram quantities of small molecules in a 1 mm surface area. The detection limit depends on the number of probe molecules immobiUzed on the pore walls, the size of the biomolecules relative to the size of the pores, and the efficiency at which the probe molecules capture the target species. 

Porous silicon in photodynamic and photothermal therapy , 83, Porous silicon optical biosensors , 84, Porous silicon optical waveguides , and 85, Porous silicon phononic crystals ). In the case of optics, low roughness at the external surface and the substrate interface is mandatory to achieve good quality optical layers. 

Wei X, Weiss SM (2011a) Guided mode biosensor based on grating coupled porous silicon waveguide. Opt Express 19(12) 11330-11339... 

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Hiraoui M, Haji L, Guendouz M, Lorrain N, Moadhen A, Oueslati M (2012b) Towards a biosensor based on anti resonant reflecting optical waveguide fabricated from porous silicon. Biosens Bioelectron 36(1) 212-216... 

Wei X, Weiss SM (2011b) Grating coupled waveguide biosensor based on porous silicon. MRS Proc 1301 219-224... 

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