Advanced stimuli-responsive polymer nanocapsules with enhanced capabilities for payloads delivery

Stimuli-responsive polymer nanocapsules (PNCs) are smart nanocarriers that encapsulate functional pay-loads and release them on demand upon external triggers. Stimuli-responsive PNCs are of interest in a wide range of disciplines such as pharmaceutics, agriculture, and materials science. Studies on stimuli-responsive PNCs so far are widely reported but are mainly focused on using only one stimulus to release one payload. However, a nanocarrier is efficient if distinct payloads can be selectively released via different stimuli because unwanted and unspecific release can be avoided. Here, the recent progress of stimuli-responsive PNCs that possess enhanced capabilities for payloads delivery is highlighted, including PNCs that respond to multiple stimuli, stimuli-responsive PNCs that co-encapsulate different payloads, and stimuli-responsive PNCs that release the payloads selectively or in a pulsatile way. Finally, the possible future directions in this area are suggested.