Hybridization of an immobilized PNA probe with its complementary oligodeoxyribonucleotide on the surface of silica glass.

A 16mer sequence of peptide nucleic acid (PNA) was immobilized onto the surface of silica glass to supply solid supports for DNA chip and biosensor constructions. To the surface, 3-aminopropyltriethoxysilane (APTES), succinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxy-(6-amidocaproate) (LC-SMCC), and cysteinyl-PNA were introduced in order. Hybridization of the immobilized PNA with its complementary oligodeoxyribonucleotide (ODN) should be done in a solution containing 15-20% dimethylformamide (DMF) at pH 9.5. This combination of hybridization conditions enabled specific adsorption of the target ODN of at least 50 pM to the surface.