Tunable Multifunctional Mesoporous Silica Microdots Arrays by Combination of Inkjet Printing, EISA, and Click Chemistry

A novel technique combining inkjet printing (IJP), evaporation-induced self-assembly (EISA), and click chemistry is implemented for elaborating mesoporous silica-based multifunctional microdots arrays. The microdots are in situ azide-functionalized with (3-azidopropyl)triethoxysilane (AzPTES). AzPTES is directly added to the initial sol before IJP and co-condenses with the silica precursor (TEOS) during the evaporation-induced self-assembly (EISA) of micelles on the substrate. After extracting the surfactants to release the porosity, model alkynes, namely propargyl alcohol, methyl pent-4-ynoate, ethynylferrocene, and N-propargyl-4-amino-1,8-naphthalimide, are grafted by the azide-alkyne CuAAC click reaction. The demonstration is established that the click reaction is nearly quantitative and occurs in the whole volume of the microdots attesting the accessibility of the azide groups. By integrating an alkyne-containing silylated precursor in a similar route, azide-containing functional groups are anchored in the microdots by click reaction. A demonstration of the multifunctionalization of such microdots arrays is achieved by reacting clickable dyes on alternate alkyne- and azide-functionalized lines of microdots, as evidenced by confocal fluorescence microscopy. Such multifunctional mesoporous silica microdots arrays offer promising perspectives for biosensing applications.