Selective biofunctionalization of all-(111) surface silicon nanowires

Selective biomolecular functionalization of our all-(111) surface silicon nanowire (SiNW) biosensors using covalently linked alkyl- monolayers is demonstrated. Monolayers were made using a commercially available six member carbon precursor N-(5-Hexynyl) phthalimide and UV based hydrosylilation reaction. Contact angle and x-ray photoelectron spectroscopy (XPS) measurements were used to characterize the monolayer at different stages on planar Si (111) samples. Terminal amine groups on the monolayer surface were used for further conjugation with (+)-Biotin N-hydroxysuccinimide ester after deprotection of the phthalimide group with a methylamine solution. Selective biofunctionalization was demonstrated by reacting the SiNW-monolayer-biotin surface with 5 run gold nanoparticles conjugated with streptavidin and subsequent high resolution scanning electron microscopy imaging.