Fabrication of substrates with various wettabilities for DNA molecular combing

In this study, we fabricated glass substrates covered with hydrophilic and hydrophobic silanes to investigate the effect of wettability of these surfaces on DNA molecular combing. As the hydrophilic and the hydrophobic silane, a mercapto-terminated (HS(CH2)3Si(OCH3)3) and a methyl-terminated one (CH3(CH2)3Si(OCH3)3) were used, respectively. The wettability was controlled by changing the molar ratio of the two components in the mixed monolayer. From the results of the DNA molecular combing, it was shown that the mercapto terminals on the surfaces were hardly dissociated into S− groups in aqueous buffers with pH 5.5 and 8.0. In addition, it was found that the length of the immobilized DNA molecules on the hydrophilic surfaces was shorter than that on the hydrophobic ones.