Fig. 4From: Organic–inorganic hybrid nanoflowers: types, characteristics, and future prospectsSchematic synthesis of chitosan–calcium ion hybrid nanoflower. Chitosan binds to pyrophosphate through ionotropic gelation and generates CS-TPP gel complex which reacts with calcium phosphate crystal to form hybrid nanoflower. Reproduced with permission from Ref. [45]: Copyright 2014, American Chemical SocietyBack to article page