A combinatorial approach to surface-confined cation sensors in water

Abstract

A novel material for sensing cations in water via fluorescence spectroscopy is presented. The material consists of a glass substrate functionalized with a series of fluorescent self-assembled monolayers. Parallel modification with pairs of fluorophore-binding molecules of monolayers formed on glass yield a library of sensitive glass substrates. Measurements of the changes in fluorescence intensity of the layers upon addition of aqueous solutions of Cu 2+ , Co 2+ , Ca 2+ and Pb 2+ confirmed the ability of the monolayer library to produce a ''fingerprint'' response for separate analytes with a high reproducibility. This new protocol for fabrication of sensitive probes in glass is suitable for array fabrication in small size substrates. Additionally, the covalent attachment of the fluorophore moieties to the monolayer allows monitoring of the integrity of the monolayer in time in contact with solutions. To the best of our knowledge this is the first example of sensing of cations in water by a self-assembled monolayer on glass.

Design of fluorescent materials for chemical sensing

“…The selectivity of these systems is not large but their performance is enhanced by the realization of cross reactive sensor arrays. 218 This sensitive monolayers libraries have been used for the fluorescent sensing of inorganic anions in organic solvents, 219 of metal ions in organic solvents 44,219 and water, 220 and for the fabrication of metal ion and luminescent patterns in glass surfaces. 221 Using this approach they have also shown the fabrication of microfluidic devices for optical sensing of metal ions.…”

Electrochemical and Photophysical Properties of Ruthenium(II) Bipyridyl Complexes with Pendant Alkanethiol Chains in Solution and Anchored to Metal Surfaces

“…Consequently, the attachment of photoactive molecules to metal surfaces to develop molecular devices [15][16][17][18][19], nanowire transitor [20,21], sensors [22,23] or photovoltaic systems, able to mimic natural light harvesting and charge separation [24][25][26][27] step for the development of electroluminescent devices or high-density sensor arrays.…”

Rhodamine‐Based “Turn‐On” Fluorescent Chemodosimeter for Cu(II) on Ultrathin Platinum Films as Molecular Switches

“…[14] SAMs on glass result in monolayers that are not highly ordered, and it is likely that the lack of a well-ordered hydrophobic layer will allow water to penetrate and hydrolyze the Si-O bonds, thus destroying the layer. [23] With those reasons in mind, in our study platinum substrates were used for SAMs instead of gold or glass, exhibiting the maximum of the plasmon absorption band in the UV at around 260 nm, whereas gold substrates show a plasmon absorption band with a maximum at 600 nm.…”

“…[12,13] SAMs offer several advantages, such as fast response times, ease and reproducibility of synthesis, unidirectional responding surface, and minimization of analyte sorption time to the receptor. [14] A surface chemosensor using SAMs is more practical than a fluorescent probe used in solution phase in terms of actual device implementation, [12] as the surface chemosensor can be used conveniently to achieve real-time monitoring. Reversible fluorescent switches of the chemosensor between OFF and ON states are also easier on a surface.…”