TABLE 3.
Common preparation methods for nanoparticles of silk fibroin.
| Methods | Advantages | Disadvantages | Particle size | References |
|---|---|---|---|---|
| Desolvation | Mild conditions; simple operation; controllable volume | Particles are easy to polymerize; low drug retention and loading capacity; organic solvents are not easy to elute; cumbersome washing steps | 35–125 nm | Zhang et al. (2007) |
| Electrospraying | No organic solvent; size controllable nanoparticles; high drug loading and encapsulation efficiency; high purity and excellent monodispersity | High cost; complex operation | 59–75 nm | Qu et al. (2014) |
| Spray-freeze-drying or Spray-drying | No organic solvent; size controllable nanoparticles; uniform appearance; high drug loading and encapsulation efficiency | Freeze drying agent is required; high cost | ∼5 μm | Kim et al. (2015) |
| PVA blend film | Mild conditions; simple operation; no organic solvent | Polymer residues; silk II should be induced after post treatment | 300 nm–20 μm | Wang et al. (2010) |
| Supercritical fluid | No organic solvent; size controllable nanoparticles; high drug loading and encapsulation efficiency | High cost; complex operation | ∼50 nm | Zhao et al. (2012) |
| Laminar jet break-up | No organic solvent; mild conditions; high drug loading and encapsulation efficiency | Big particle size; silk II should be induced after post treatment | 30–440 μm | Wenk et al. (2008) |
| Capillary microdot | Nanoparticles are small and controllable | Silk II should be induced after post treatment | 20–130 nm | Gupta et al. (2009) |
| Microemulsion | Nanoparticle size controllable | Residual organic solvent | 167–169 nm | Myung et al. (2020) |
| Ball milling | Simple operation; easy to scale up | Wide size distribution; grinding impurities; May reduce silk II content | 0.2–4 μm | Rajkhowa et al. (2008) |
| Salting out | Simple operation; high yield; no organic solvent; sustainable protein activity | Hydrophobic drugs are not easy to be embedded; salting-out agent residue; complicated washing steps | 486 nm–2 μm | Lammel et al. (2010) |
| Crosslinking reaction | Simple operation; controllable volume | Complex operation; residual organic solvent | 0.3–1 μm | Pham et al. (2019) |