Nanostructured porous silicon was prepared by electrochemical etching method. The porous silicon has advantages over planar platforms in biosensor development due to its increased surface area. The high surface area in the porous silicon biosensors will allow for higher biosensor sensitivity while using as a smaller device. The porous silicon optical sensing device works on the basis of changes in its physical properties especially photoluminescence or reflectance, on exposure to the surrounding environment. In the present investigation, porous silicon was bio-functionalized through the deposition of functional groups on its surface by adsorption of chicken blood plasma and serum. SEM, FTIR and photoluminescence studies were carried out for bio-functionalized porous silicon surfaces to study the possibility for utilizing porous silicon as a biomaterial for biosensor applications instead of utilizing porous silicon as a biosensor and biomaterial. (C) 2012 Elsevier B. V. All rights reserved.