Since Merrifield has developed solid-phase peptide synthesis (SPPS) method, polystyrene (PS) based resins have been utilized mostly in peptide synthesis. For efficient SPPS, we have developed several kinds of core-shell type resins, in which reactive functional groups are mainly located on the shell layer of the resins.The core-shell (CS) structure was designed to overcome the diffusion problem and for easy accessibility of reagents, and washings. Because of this distinctive structural feature, the CS type resins afforded high performance in peptide synthesis and even photolytic cleavage reactions.
These resins were prepared by suspension co-polymerization, two-step polymerization, cross-linking core backbone, partial hydrolysis, and biphasic functionalization methods. Recently, we have developed diffusion-controlled functionalization method to obtain CS type PEGylated PS resin. To evaluate the performance of the resins, various peptide sequences were synthesized, and the results were compared with those of non-CS type PS resin and other PEG-based resins. Those resins gave excellent performance in peptide synthesis as well as screening peptide ligands form peptide libraries. When properly designed, the PEGylated resin could also be used for the synthesis of oligonucleotide, and purification of therapeutic antibodies.
 Kim, H.; Cho, J. K.; Chung, W. J.; Lee, Y. S. Org. Lett. 2004, 6, 3273.  Lee, T. K.; Ryoo, S. J.; Byun, J. W.; Lee, S. M.; Lee, Y. S. J. Comb. Chem. 2005, 7, 170.  Lee, T. K.; Lee, S. M.; Ryoo, S. J.; Byun, J. W.; Lee, Y. S. Tetrahedron Lett. 2005, 46, 7135.
 Cho, H. J.; Lee, T. K.; Kim, J. W.; Lee, S. M.; Lee, Y. S. J. Org. Chem. 2012, 77, 9156.  Kim, J; Kim S.; Shin, D.S.; Lee, Y.S. J. Peptide Science, 2018, 24:e3061.