The present invention provides a nanocomplex comprising at least one agent and a nanocarrier. The agent is bound to the nanocarrier. The nanocarrier comprises at least one cationic polymer responsive to a stimulus, at least one anionic polymer and at least one lipid. The agent is capable of being released from the nanocarrier upon exposure to the stimulus. The released agent is active. The nanocomplex may be used to deliver the agent into cells, in which the agent may be released from the nanocarrier upon exposure of the cells to the stimulus.
