RECOVERY OF AN OLIGONUCLEOTIDE USING SILVER IONS IMMOBILIZED ONTO PARAMAGNETIC PARTICLES

A 3 '-GCCCCTTTTTAAAAACCCCG-5' oligonucleotide can be recovered from aq ueous solution using paramagnetic particles containing immobilized sil ver ions. Binding and elution experiments were conducted by attaching either fluorescein isothioocyanate (FITC) to the 3'-end or Texas Red o r fluorescein phosphoramidite (FAM) to the 5'-end of the oligonucleoti de. For the 5'-end FAM labeled oligonucleotide, a binding constant of 4.2 x 10(7) was measured at pH 7 using phosphate buffer. The percent o f bound FAM labeled oligonucleotide eluted from the paramagnetic parti cles was found to be 97% using an aqueous solution of thiodiglycol. Wh ile the FAM molecule by itself does not bind to the silver activated p aramagnetic particles, the choice of fluorescent label affects binding affinities and elution recoveries.