Detection of nucleic acids in the attomole range using polybiotinylated oligonucleotide probes

This article describes the optimization of the hybridization signal obtained with biotinylated oligonucleotides. Optimal number and positions of biotin moieties on a 33-base oligonucleotide probe were determined. The quality of avidin-peroxidase conjugate and the choice of chromogenic substrate influenced detection sensitivity. A signal amplification method was also developed for avidin enzymatic conjugates. These improvements allowed the detection of less than 0.02 fmol of target DNA.