Photo-patterning of DNA oligonucleotides on silicon surfaces with micron-scale dimensions

A method is presented for the covalent attachment of oligonucleotides to silicon (100) surfaces patterned with micron-scale features. UV light exposure of hydrogen-terminated silicon (100) coated with alkenes functionalized with N-hydroxysuccinimide ester groups results in Si-C bonded monolayers. The N-hydroxysuccinimide ester surfaces act as a template for the subsequent covalent attachment of DNA oligonucleotides. In order to create patterns of surface attached DNA oligonucleotides with high density, the surface attachment chemistry has been investigated and optimised. Micron-scale patterning of surfaces was achieved by exposure with UV laser light via a mask. DNA oligonucleotide patterns, with feature sizes of several microns, were reliably produced over large areas. The patterned surfaces were characterised with scanning electron microscopy, epifluorescence microscopy and ellipsometry. Hybridisation with fluorescent label- and gold nanoparticle-conjugates of the complementary oligonucleotide is achieved. The methods offer reliable approaches for the creation of micron-scale motifs of DNA on surfaces.