Fig. 2. Nanogel formulation strategies. (A) Hydrophilic monomers and crosslinkers in a water-in-oil emulsion, stabilized by surfactants. Upon the addition of a catalyst, polymerization occurs within the emulsion droplets, forming nanogels. (B) Hydrophilic polymer modified with functional groups that allow physical/chemical crosslinking to form nanogels. (C) Polymer modified with hydrophobic moieties for self-assembly into nanogels. (D) Positively and negatively charged polymer self-assembly through electrostatic interaction. (E) Polymerization of monomers and crosslinkers shell or self-assembly of polymer modified with hydrophobic moieties in presence of nucleation sites.