FUTRESynthesis (Poland)

Controlled pore glass (CPG), differing in pore size and subsequent specific surface, was chemically modified by: (1) increasing surface susceptibility for amine functionalization via reaction with oxirane-type (active) and alkyl/aryl-type (inactive towards amine compounds) silane pro-adhesive compounds, and (2) immobilization of trimethylolpropane tris[poly(propylene glycol), amine terminated] ether, comb-like 8-arm octa[poly(ethylene glycol) amine] with each branch amine terminated, and a poly(propylene imine) amine-terminated second-generation dendrimer. The increase in surface density of amine functions - monitored by UV-Vis technique adopted for quantitative measurements of Ruhemann's purple intensity - improved final loading capacity, characterized by dimethoxytrityl cation absorption. Obtained materials proved their applicability in automatic oligonucleotide (ON) synthesis, especially when silanized 2000 Å CPG modified with 8-arm octa[poly(ethylene glycol) amine], with deduced empirical formula CPG - silane - (NH)6.4PEG-(NH2)1.6, was used for long-chain (150 nucleotides) ONs synthesis. This can be regarded as a good CPG support for this purpose. Moreover, hybrid supports with different porosity allowed the synthesis of shorter ONs with satisfactory yield and purity, monitored by RP-HPLC and MALDI-TOF. On the molecular level, two competitive mechanisms seem to influence the utility of the final hybrid support: spatial availability of active sites and the propensity of the functionalizer to bond with the CPG surface.

Solid-phase synthesis is, to date, the preferred method for the manufacture of oligonucleotides, in quantities ranging from a few micrograms for research purposes to several kilograms for therapeutic or commercial use. But for large-scale oligonucleotide manufacture, scaling up and hazardous waste production pose challenges that necessitate the investigation of alternate synthetic techniques. Despite the disadvantages of glass supports, using soluble supports as a substitute presents difficulties because of their high overall yield and complex purification steps. To address these challenges, various independent approaches have been developed; however, other problems such as insufficient cycle efficiency and synthesis of oligonucleotide chains of desired length continue to exist. In this study, we present a review of the current developments, advantages, and difficulties of recently reported alternatives to supports based on controlled pore glass, and discuss the importance of a support choice to resolve issues arising during oligonucleotide synthesis.