Photocatalytic Lithography with Atomic Layer-Deposited TiO2 Films to Tailor Biointerface Properties

In this article, the use of thin, photocatalytically active TiO2 films deposited using atomic layer deposition (ALD) and a conventional lithography mask are explored for the fabrication of a patterned biointerface. Hereto, a pattern of self-assembled monolayers (SAMs) with different functional groups is created using ALD TiO2 films, anatase-rich as-deposited, with a thickness of 20 nm and a short UV exposure time of 5 min. More specifically, azido-containing SAMs are locally removed upon UV exposure ( = 308 nm) and the created gaps are filled with a polyethylene glycol (PEG) SAM, hereby creating a surface with areas for the selective coupling of biomolecules via the azide groups and antifouling areas due to the presence of the PEG. To demonstrate the effectiveness of this approach, fluorescent-labeled antibodies are immobilized on the well-defined patterns with a resolution in the mu m range.