Porous Silicon based rugate filters as transducer for biosensing platform

Rugate filters are Porous Silicon (PSi) based materials which have been often employed as transducers for optical biosensors in diagnostics and pharmacogenomics for sensitivity, cheapness and straightforward fabrication [1-4]. In this work the employment of rugate filters as transducer for immunosensing platform (BSA bovine serum albumin, anti-BSA) was assessed. Rugate filters with high-reflectivity peaks in four region of the visible spectrum (red, yellow, green and blue) were fabricated with high reproducibility in HF-ethanol solution with electrochemical etching of boron-doped p(++)-type crystalline silicon. As result reflectivity peaks showed a good Q factor (about 30), thus envisaging a high sensitivity for biosensors. Then APTES (3-Aminopropyl)triethoxysilane) was employed to covalently immobilize biomolecules to the rugate filter surface. Finally covalent immobilization of BSA was optimized for a competitive immunoassay with BSA antibody. In all the three steps wavelength changes of reflectivity peaks were recorded as analytical signals. Optimizations for anti BSA-BSA model are here applied as model system for the future development of a high sensitive device for clinical and diagnostics analysis. References [1] Jane A, Dronov R, Hodges A, Voelcker NH, Trends Biotechnol., 27(4)(2009), 230-239. [2] Kilian KA, Böcking T, Gooding JJ, Chem. Commun., 6(2009), 630-640. [3] Lin VS, Motesharei K, Dancil KP, Sailor MJ, Ghadiri MR, Science, 278(5339)(1997), 840-843. [4] Dhanekar S, Jain S, Biosens. Bioelectron., 41(2013), 54-64.