Example of DNA printing at the submicronic scale. AFM image (taping mode) of 30-mers 5'-GCATGCTTAGTTGCTATTATCAAAATA-3', corresponding to BCK2 yeast gene printed on an untreated silicon surface. The pitch of the periodic array of lines is 1 μm. Note that the chemical surface states of the silicon was not really controlled: rough native oxide.
Thibault et al. Journal of Nanobiotechnology 2005 3:7 doi:10.1186/1477-3155-3-7