Details of the cross-linking strategy are schematically shown in Figure . After the cross-linking reaction, the resulting polymer nanogels were analysed by DLS, both above and below the LCST, which is shown in Figure . A small difference in the hydrodynamic diameter was observed between the cross-linked (93 ± 2 nm) and selfassembled 5a4 nanogels (74  7 nm, before cross-linking) above the LCST. In contrast, DLS measurements at 25 °C (below the LCST) revealed successful cross-linking had taken place.