Quaternary ouzo droplets provide method for forming porous microstructures made from silk
Quaternary ouzo droplets provide method for forming porous microstructures made from silk lead image
The high biocompatibility and biodegradability of silk fibroin made by the cocoons of the domestic silk moth, or Bombyx mori, have made it an attractive material for biomedical use. Numerous work has laid the groundwork for using the material to construct porous microstructures called supraparticles for drug delivery.
Lamb et al. report the formation of supraparticles made from silk fibroin. Dissolving fibroins into quaternary Ouzo droplets formed an oil ring that facilitated the droplet contraction to create a three-dimensional supraparticle.
The process consistently yielded highly porous structures that could be used for future methods of drug delivery.
“This work provides a new cost-effective, scalable and simple way to create three-dimensional porous particles from biomaterials by simply evaporating ouzo droplets,” said author Hui Zhao. “In particular, considering the solubility of silk fibroin, we extend the evaporation of ouzo droplets or ternary droplets to create silk fibroin-based supraparticles by evaporating a quaternary droplet.”
Ouzo droplets form from spontaneous emulsification from oil-in-water mixtures. Since they require no energy or surfactant and are cost-effective, their use has garnered renewed interest for creating supraparticles.
They also prevent silk fibroin from forming rings of residue when they evaporate, allowing the fibers to nucleate and form the 3D porous supraparticles.
The group, however, modified the standard composition of ouzo droplets.
“Traditional Ouzo droplets or ternary droplets are composed of ultrapure water, ethanol and trans-anethole oil [and] cannot dissolve sufficient silk fibroin to create silk fibroin porous particles,” said author Shengjie Zhai. “Instead, we used a quaternary droplet including formic acid, which can completely dissolve silk fibroin.”
They next look to model supraparticle formation to find the optimal formation parameters.
Source: “Silk fibroin supraparticles created by the evaporation of colloidal ouzo droplets,” by Ashley Lamb, Fengjie He, Shengjie Zhai, and Hui Zhao, AIP Advances (2021). The article can be accessed at https://doi.org/10.1063/5.0057228 .
