Sensor for fluorene based on the incorporation of an environmentally sensitive fluorophore proximal to a molecularly imprinted binding site

A fluorescence-based chemical sensor for fluorene was created by molecularly imprinting a sol-gel comprising the bridged silsesquioxane, bis(trimethoxysilylethyi)benzene. The template was covalently bound to the sol--gel matrix using a fluorene analogue functionalized silane. After chemical removal of template via cleavage of a carbamate linkage, an amine group was left that provided an attachment site for the environmentally sensitive fuorescent probe 7-nitrobenz-2-oxa-1,3-diazole (NBD). Fluorene binding was detected by a change in NBD fluorescence intensity induced by a difference in the local polarity around the probe when the recognition site is filled. Such an approach eliminated response to nonspecific binding to the matrix. Sensing films deposited on glass slides were shown to have response times of