Multi-functional silica microdot arrays by inkjet printing for biosensor applications

O. De Los Cobos, M. Lejeune, F. Rossignol, C. Carrion, C. Boissière, F. Ribot, C. Sanchez, X. Cattoën, M. Wong Chi Man, J.-O. Durand
SPCTS, FR

Keywords: inkjet printing, mesoporous silica, click chemistry, biosensor

Summary:

Silica-based microarrays for molecular recognition are realized using a piezoelectric drop-on-demand inkjet printer. A sol containing tetraethyl orthosilicate (TEOS) and (3-azidopropyl)triethoxysilane is used as ink to print azido-functionalized mesoporous silica microdots arrays clickable with various alkyno-peptides, in accordance with the Huisgen 1,3 dipolar cycloaddition commonly called “click reaction”. In a similar route, a second ink is formulated integrating an alkyne silylated precursor. By using a multi-printhead system, a bi-material of intercrossed azido and alkyno-functionalized network can be built. The successive reactions with clickable peptides lead to the array multi-functionalization. Thereafter, peptides interactions with target biomolecules enable to perform multi-detection analyses. The success of the click chemistry, EISA and inkjet printing combination highly depends on the ink formulation, which is adjusted in regards to the viscosity and surface tension in the appropriate range for inkjet printing. Moreover, the aging time is carefully studied by 29Si NMR and DLS. Besides, the ink interactions at the printhead nozzle are investigated in terms of hydrophobicity and wettability. The use of an inox and a gold coated printheads are compared. Both require the addition of a hydrophobic agent to avoid the printhead wetting, however its rate can be reduced with the gold coated printhead.