Figure 1. Models of different material forms. a: Nanoparticles include inorganic and organic carriers. As shown in the figure, these are mesoporous nanoparticles. b: Hydrogels are usually made from 3D polymers and can be loaded with drugs or nanoparticles. c: Nanofibers are fibers of approximately 100 nm in diameter which can carry drugs. d: Films are often used for oral mucosal drug delivery. e: Scaffolds are loaded with growth factors and usually used in tissue regeneration.