Protein-Based Nanocarriers

Protein-based nanoencapsulation possesses a higher compound/drug loading capacity than other nanostructures. It improves the absorption and bioavailability of the encapsulated compounds (Abaee et al. 2017; Chen et al. 2006). These nanostructures are prepared by the hydrophobic/hydrophilic interaction of bioactive compounds with the encapsulation matrices. Protein-based nanostructures are responsive to changes in the environment, such as pH change, temperature, enzymatic conditions, and ionic strength, making them suitable candidates for the targeted delivery of bioactive compounds to specified sites (Fang et al. 2014). Several types of proteins, such as whey, zein, and collagens, are used to form these nanocarriers. The release of these encapsulated compounds depends on their interaction with the encapsulation matrix; hydrophilic compounds are dispersed by diffusion, whereas hydrophobic compounds are released through enzymatic degradation of the protein matrix in the gastrointestinal tract (GIT). Additionally, these structures possess several limitations, such as disruption by the presence of protease enzymes in the GIT, making it a challenge to deliver bioactive compounds encapsulated with protein matrices (Bourbon et al. 2011; Donato-Capel et al. 2014). Nevertheless, there are different types of protein-based nanostructures, such as nanoparticles, nanohydrogels, nanotubes, hollow nanoparticles, nanofibrillar aggregates, electrospun nanofibers, and native state proteins as natural nanocarriers cited in the literature (Fig. 3.1) (Mohammadian et al. 2020).