Anthrylmethylamine functionalised mesoporous silica-based materials as hybrid fluorescent chemosensors for ATP

A number of functionalised mesoporous solids containing anchored anthrylmethylamine groups have been prepared using different co-hydrolysis or grafting synthetic routes. The solids have been characterised using standard solid-state techniques. Solids with a low loading of the anthrylmethylamine probe show typical well defined and structured emission bands centred at ca. 415 nm. Addition of ATP to suspensions of these solids at pH 2.8 resulted in a quenching of the anthracene emission. These solids showed a cooperative effect that resulted in quite a remarkable improvement in ATP response with respect to the free anthrylmethylamine probe in solution. Certain prepared solids showed a remarkable detection limit for ATP detection in the micromolar range. An equation based on a Langmuir-type analysis has been developed and used to obtain binding constants ( adsorption constants) for the interaction of the solids with ATP and with some related anions. Some other solids containing larger amounts of anthrylmethylamine groups have also been prepared. In these cases a dual monomer-excimer fluorescence emission was observed. ATP addition to these solids resulted in an enhancement of the excimer emission band.