Systematic Comparison of the Strategies for Oligonucleotide Immobilization on Ta2O5 Surface

Abstract

AbstractThe immobilization of oligonucleotides is an essential step for the development of various biosensors and DNA microarrays. Different methods were developed for the immobilization of oligonucleotides. Here we report a systematic comparison of several popular approaches for oligonucleotide immobilization on Ta2O5 surface: Cu(I)‐catalyzed azide‐alkyne cycloaddition, amine‐to‐sulfhydryl coupling via asymmetric heterobifuctional spacer in two directions, amine‐to‐amine coupling via homobifunctional spacer and disulfide linkage. The performance of these methods was analyzed for the efficiency and specificity of DNA immobilization and subsequent complementary strand hybridization using fluorescent imaging and ELONA with the assistance of atomic force microscopy. Azide‐alkyne cycloaddition and disulfide linkage demonstrated the highest load of immobilized and hybridized DNA and low rate of non‐specific DNA attachment. Both procedures allow the retention of DNA functionality and thus can be applied for the development of oligonucleotide‐based biosensors and microarrays.