Yongsheng Han

A new container composed of an inner gel core and an outer protein shell has been prepared by sonicating oil in an aqueous protein solution. Hydrophobic drugs can be loaded into the containers and released by thermal trigger. In this paper, we attempted to discover the release mechanism of the protein containers by means of individual carrier characterization and release data analysis. The mechanical and thermal properties of the containers were first investigated and associated with the release mechanism. At room temperature, the protein container was robust and elastic. Plastic deformation did not happen until the container was compressed above 70% deformation. Stirring the protein containers in a buffer solution could only release 15% of the encapsulated drug. The drug release was mainly from diffusion of the drug located in the outer layer of the gel core. When the temperature increases above the gel transition temperature, the gel core was liquefied and the protein container shrunk, which resulted in a squeezing-controlled quick release. Annealing the protein container at the increased temperature led to a complete release of encapsulated drug via a diffusion-controlled release mechanism.

We designed a biocompatible carrier for controlled release of hydrophobic drugs. The designed carrier was prepared by sonicating oil in a protein aqueous solution forming a protein nanocontainer composed of an inner gel core and an outer protein shell. Two model drugs were loaded into the designed nanocontainers by dissolving drugs in the oil phase before sonication. The loading capacity was up to 0.9 mg/mL for the amphiphilic drug rifampicin, while it reached to 19 mg/mL for the hydrophobic drug indomethacin. The encapsulated drugs were released at different temperatures. At 37 °C, only less than 20% of the drug was released due to the protection by the gel core. Increasing temperature to 40 °C led to a completely release of the remaining drug. The drug release showed drastic temperature dependence. The biocompatibility of the protein nanocontainers was evaluated by incubating the nanocontainers in the 3T3 cell and B-LCL cell lines. Both experiments indicated an excellent biocompatibility of the designed nanocontainers.

A new targeted delivery system was developed in this paper by depositing magnetic NPs on protein containers which were prepared by sonicating oil in a protein solution. The deposition was conducted by layer‐by‐layer technique and monitored by zeta potential measurement. Such prepared samples can be targeted delivery in an external magnetic field. The hydrophobic dye TPP, as a model of drug, was loaded in the containers by dissolution in the oil phase before sonication. The containers loaded with dye are stable and can sustain the deposition treatment without loss of dye due to the protection of protein nanoshells. magnified image

Back Cover: Magnetic protein carriers have been prepared by coating magnetic nanoparticles on protein microspheres which were produced by sonicating oil in a protein solution. Drugs can be easily loaded in such carriers by dissolution in oil phase before sonication. The loaded drugs can be targeted delivery in an external magnetic field. Further details can be found in the article by Y. Han,^* D. Radziuk, D. Shchukin, and H. Moehwald on page 1203.