Solid phase peptide synthesis (SPPS) has been extensively developed in the synthesis of biomacromolecules. One key factor for the success of solid-phase methods relates to the options of polymeric support. Low cross-linked polystyrene(PSt) beads were extensively used as SPPS supports, and grafting of PSt core with hydrophilic polymers, such as poly (ethylene glycol) (PEG), has shown that it is superior to conventional PSt supports especially for the solid phase synthesis of hydrophobic peptides. But the resin could give a poor loading capacity in use.

Researchers with Institute of Process Engineering (IPE) proposed an approach to obtain PS–PEG resin with a relatively high loading capacity by grafting poly (ethylene glycol) acrylate (PEGA) monomer, including oligo PEG unit, from Merrifield resins via activators generated by electron transfer atom transfer radical polymerization.

The grafted resins demonstrate well-swellability in both polar and nonpolar solvent such as dichloromethane, dimethylformamide, ethanol, tetrahydrofuran, acetonitrile, methanol and water. Particularly, the swelling ability of the grafted resin has reached two-fold of Merrifield resin in the polar solvent such as acetonitrile, methanol and water, and it enable high functional loadings up to 0.5–1.2 mmol g−1 compared with the conventional polystyrene-grafting-poly (ethylene glycol) (0.15–0.25 mmol g−1).

This kind of resin can be used for the synthesis of hydrophobic peptides in high yield and purity with a high loading capacity of 0.5–1.0 mmol g−1. The results in this study show a potential alternative scale-up production under high substitution.

The paper was published in Reactive and Functional Polymers.