Solid‐Phase Supports for Oligonucleotide Synthesis

Abstract

This unit begins with a discussion of the advantages and disadvantages of oligonucleotide synthesis using solid supports. The physical and chemical properties of solid-phase supports are discussed in terms of their suitability for oligonucleotide synthesis. In addition, the unit outlines the properties of linkers used for transient or permanent attachment of properly protected nucleosides to the derivatized support, as well as strategies for coupling nucleosides to linkers and conditions for the release of synthetic oligonucleotides from specific supports.

Direct oligonucleotide synthesis onto super-paramagnetic beads

“…We developed the magnetic approach to oligonucleotide synthesis because containment of micro- and nanometer-sized beads is not possible using a filtered well or column (as in traditional DNA synthesis (18)), due to flow restrictions and excess sample loss. It would require a filter porosity of < 1 um to retain the beads; however, oligonucleotide synthesis reagents (e.g.…”

“…Since traditional solid-phase chemical synthesis is a filter-based platform (18), retaining micro- and nanometer-sized beads is not possible. Commercial solid supports for oligonucleotide synthesis (e.g.…”

Solid-Phase Supports for Oligonucleotide Synthesis

“…The chemical properties of the rest of the surface should be either inert or capable of being made inert by silylation, benzoylation, or other similar passivating treatment (Pon, 1993;Tang and Tang, 1997). This is because residual groups, such as amino, hydroxyl, or silanol groups, can also react with phosphoramidite derivatives.…”

“…The first insoluble supports developed were polystyrene-divinylbenzene polymers with only a small amount (1% to 5%) of cross-linking (Pon, 1993). These supports could swell up to five times their dry volume in nonpolar solvents, such as dichloromethane, to provide a large surface area and loading capacity (0.1 to 1.5 mmol/g).…”

“…Long-chain alkylamine (LCAA) derivatized CPG supports with 500-Å pores and amino loadings of ∼100 µmol/g are the most commonly used. These supports are usually derivatized with 30 to 40 µmol/g of nucleoside (Pon, 1993) and are suitable for the synthesis of oligonucleotides of up to 50 to 60 bases. The 500-Å pore size begins to restrict the coupling efficiency of longer oligonucleotides because of steric factors; however, much longer oligonucleotides (100 to 150 bases) can be prepared on 1000-Å CPG supports (Efcavitch et al, 1986).…”