Tailoring the mechanoresponsive release from silica nanocapsules

Triggering the release of encapsulated cargos using mechanical stress acting on a nanocarrier is a strategy with potential applications from drug delivery to self-healing coatings. The mechanically triggered release of encapsulated molecules can be controlled by tuning the mechanical properties of the nanocapsules, which are strongly linked to the nanocapsule architecture. Here, silica nanocarriers were designed to tune precisely the release initiated by mechanical stress. We synthesized silica nanocapsules (SiNCs) with a finely tunable diameter and shell thickness and performed AFM nanoindentation experiments to determine the breaking force of single SiNCs. We demonstrated that it is possible to trigger the release of encapsulated payload by the application of an external mechanical force on the SiNCs. Furthermore, we successfully controlled the breaking force and the amount of released payload by tailoring the architecture of the nanocarriers, illustrating how such mechanoresponsive SiNCs could be used as responsive nanocarriers for the delivery of molecular cargos.