Immobilization of DNA via oligonucleotides containing an aldehyde or carboxylic acid group at the 5' terminus

A general method for the immobilization of DNA through its 5′-end has been developed. A synthetic oligonucleotide, modified at its 5′-end with an aldehyde or carboxylic acid, was attached to latex microspheres containing hydrazide residues. Using T4 polynucleotide ligase and an oligonucleotide splint, a single stranded 98mer was efficiently joined to the immobilized synthetic fragment. After impregnation of the latex microspheres with the fluorescent dye, Nile Red, and attachment of an aldehyde 16mer, 5×105 bead-DNA conjugates could be detected with a conventional fluorimeter.