Functional Silver-Coated Colloidosomes as Targeted Carriers for Small Molecules.

Colloidosomes have attracted great interest in recent years because of their capability for storage and delivery of small molecules for medical and pharmaceutical applications. However, traditional polymer shell colloidosomes leak low molecular weight drugs due to their intrinsic shell permeability. Here, we report aqueous core colloidosomes with a silver shell, which seals the core and makes the shell impermeable. The silver-coated colloidosomes were prepared by reacting l-ascorbic acid in the microcapsule core with silver nitrate in the wash solution. The silver shell colloidosomes were then modified by using 4,4'-dithiodibutyric acid and cross-linked with rabbit Immunoglobulin G (IgG). Label-free surface plasmon resonance was used to test the specific targeting of the functional silver shell with rabbit antigen. To break the shells, ultrasound treatment was used. The results demonstrate that a new type of functional silver-coated colloidosome with immunoassay targeting, nonpermeability, and ultrasound sensitivity could be applied to many medical applications.