Modifications of glass surface for microchip application and comparison of immobilization efficiency

Abstract

Surface density of functional group on a solid substrate is an important parameter to determine the immobilization efficiency of biomolecules such as DNA and Protein. In the present study, we compared the immobilization and hybridization efficiencies of oligonucleotide microchips modified with different surface chemistries. We first prepared aminosilylated, aldehyde, isothiocyanate and epoxide-activated glass slides and amine modified oligonocleotides were attached through their amines onto surface functional groups by noncovalent or covalent attachment. We then optimized the coupling chemistries for immobilization of oligonucleotides and compared their immobilization and hybridization efficiencies of these glasses with fluorescently labeled oligonucleotide probes. All the homemade glasses showed desirable discrimination capacity in BRCA chip test which means that that are good candidate supports for routine oligonucleotidechip tests. Among the activated glasses, epoxide glass showed the highest coupling capacity; however, the hybridization efficiency was diminished due to their hydrophobicity and steric hindrance. Although the hybridization efficiency of epoxide glass was not as high as expected, epoxide glass was chosen as the best candidate support for the microarray application due to its low background signal and high discrimination capacity in BRCA chip test.