Preparation And Application Of Silk Fibroin Microcapsules

Emulsifiers are widely used in food,cosmetic,drug delivery and catalysis because of its superior amphiphilicity.Traditional amphiphilic emulsifiers are used to stabilize emulsions,but they exhibit some disadvantages,such as potential toxicity,inflammation,and inferior stability toward p H,salts,and temperature.Peptides are emerging as promising biocompatible emulsifiers due to their superior versatility through the active design,size,and sequence control of peptide building blocks with diverse chemical functionalities.However,compared to traditional emulsifiers,scalability and costs are key challenges for peptide emulsifiers,restricting their potential applications.How to prepare a kind of emulsion that can adjust,stabilize and satisfy different needs is the hot spot of current emulsion research.Compared with polypeptide emulsifiers,silk protein nanofibers have advantages in cost,purity,mass production,biocompatibility,degradability and stability.Here we demonstrate the utility of silk fibroin nanofibers as emulsifiers.The systems were universal for diverse oil phases with different polarity and versatile where tunable microcapsules(200 nm-30 μm)were prepared through tuning oil phases and W/O ratio.The high modulus of the silk nanofiber microcapsules(27.4 MPa ± 1.7)further confirmed the strong physical interactions of the nanofibers.Furthermore,compared to the more traditional peptide emulsifiers,these emulsions showed superior stability without loss of emulsification at room temperature and 60 °C for 6 months and additional stability to the emulsions formed under high salt concentration and low p H values.For biomedical application,oil soluble quantum dots Cd SSe/Zn S were coated inside silk nanofiber microcapsules efficiently(82%)and facilitated fluorescent stability than water-soluble quantum dots,which resulted in optimized cell imaging when compared to a soluble control.By carbonization treatment of silk protein microcapsules with pores on their surfaces(3-8 nm),partial graphene-doped mesoporous(5-50 nm)materials were prepared and the electrochemical properties and potential applications were investigated.The materials with superior cycle stability is expected to be a breakthrough in the field ofenergy storage materials.In conclusion,stable nanofibers were used directly to stabilize emulsions rather than self-assembled in the emulsifying process,providing better control in emulsion systems,the corresponding functional materials were prepared and further discussed the possible applications for fluorescence imaging and electrochemical applications.