Surface layer reflective index changes of Au nanoparticle functionalized porous silicon microcavity for DNA detection |
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Institution: | 1. School of Physical Science and Technology, Xinjiang University, Urumqi 830046, PR China;2. Colleges of Information Science and Engineering, Xinjiang University, Urumqi 830046, PR China |
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Abstract: | A technique is demonstrated to detect DNA hybridization based on surface layer of Au/porous silicon microcavity (Au/PSM) substrate for very small amount of biomolecules. Simulations show that the increase of effective refractive index for the first layer of PSM will cause a blue shift for its reflectance spectrum, and the blue shift becomes less with the increase of refractive index for one more layers. In experiments, such a blue shift of reflectance spectrum of PSM comes from the increase of refractive index by DNA hybridization on the surface. The detection limit of Au/PSM biosensor is 15.15 nM for 19-base pair DNA, which is comparable to that of reported biosensors based on porous silicon (PS). Therefore such an Au/PSM could be very useful to develop simple, rapid and sensitive optical biosensors when the amount of target is very small. |
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Keywords: | Porous silicon microcavity Au nanoparticle Reflectance spectrum Blue shift DNA biosensor |
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