The present application relates to a method for preparing a functionalized surface and the use in DNA sequencing and other diagnostic applications. A substrate with a surface comprising a silane or a silane derivative covalently attached to optionally substituted cycloalkene or optionally substituted heterocycloalkene can be used for direct conjugation with a functionalized molecule of interest, such as a polymer, a hydrogel, an amino acid, a nucleoside, a nucleotide, a peptide, a polynucleotide, or a protein. In some embodiments, the silane or silane derivative contains optionally substituted norbornene or norbornene derivatives.