Surface-structured molecular sensor for the optical detection of acidity

In this letter, we report on the development of a surface molecular sensor for the detection of acidity. Lithographically controlled wetting deposition has been applied to form the nanostructure of a new fluorescent compound with three protonation states featuring different optical properties on a glass substrate. Atomic force microscopy demonstrates the functionalization of fee surface with ordered arrays of the sensor molecules. The fluorescence properties of the resulting nanopattern at different pH values have been investigated by confocal fluorescene microsopy, thus revealing the fast, sensitive, reversible response of the prepared nanosensor to gas flows of varying acidity.We acknowledge the financial support of the Ministerio de Educación y Ciencia (MEC) through projects MAT2006-13765-C02-01, CTQ2004-02539, and CTQ2006-01040. F.B. and J.H. thank the MCyT-ERDF for their Ramon y Cajal contracts, and A.M.-O. and E.E. thank the Generalitat de Catalunya and MEC for their predoctoral grants, respectively.Peer Reviewe