OLIGONUCLEOTIDE SYNTHESIS ON MALEIC-ANHYDRIDE COPOLYMERS COVALENTLY BOUND TO SILICA SPHERICAL SUPPORT AND CHARACTERIZATION OF THE OBTAINED CONJUGATES

A new route was proposed to make polymer-oligonucleotide conjugates of potential applications in diagnostics. It consisted in direct synthes is of oligonucleotides onto controlled pore glass surface grafted with poly(maleic anhydride-alt-methyl vinyl ether) (P[MAMVE]) or poly(male ic anhydride-alt-ethylene) (P[MAE]). The anhydride moieties were used for both the covalent coupling of the copolymer via ester bond and bin ding of 5'-dimethoxytrityl thymidine 3'-(6-aminohexyl phosphate) (I) i nitiator of oligodeoxynucleotide (ODN) synthesis via amide bond. The d ifference of stability between ester and amide links under basic treat ment was used for the selective cleavage of (polymer-oligonucleotide) conjugates after DNA synthesis completion. We succeeded in grafting fu nctionalized copolymer onto silica surface and Polythymidine 26-mer OD N was performed. After concentrated ammonium hydroxide treatment, conj ugate crude materials were characterized by size exclusion chromatogra phy coupled to multiangle laser light scattering detection. The number average molecular weight (Mn) for conjugate with P[MAMVE] was abnorma lly lower than expected and was assigned to polymer degradation using high pH conditions. Such a phenomenon did not occur with P[MAE]-polyth ymidine conjugate. However, in both cases, parasite ODN synthesis was also evidenced, which was attributed to thymidine phosphoramidite adso rption side reaction during DNA synthesis. (C) 1998 John Wiley & Sons, Inc.