Supramolecular assembled nanogel made of mannan

► Nanogel synthesis: Michael addition of hexadecanethiol to vinyl methacrylated mannan. ► Nanogel was designed with a versatile, easy, reproducible and low-cost method. ► Nanogel is near neutral, polydisperse with 50-140 nm mean hydrodynamic diameter. ► Nanogel size is stable over storage and at pH 3-8, salt or urea solutions. ► Nanogel is non-toxic to mouse fibroblast 3T3 but toxic to mouse macrophage-like J774.