One of the challenges in nanomedicine is to engineer nanostructures and materials that can efficiently encapsulate cargo, for example, drugs, at high concentration, cross the cell membrane, and controllably release the drugs at the target site over a prescribed period of time. Recently, inorganic nanoparticles have emerged as a new generation of drug or therapy delivery vehicles in nanomedicine. More recently, gating methods that employ coumarin, azobenzene, rotaxane, polymers, or nanoparticles have been developed to seal a cargo within a particle and allow a triggered release according to an optical or electrochemical stimulus.
While liposomes have been widely used in drug delivery due to their low immunogenicity and low toxicity, they still need to be improved in several aspects. First, the loading of cargo can only be achieved under the condition in which liposomes are prepared. Therefore, the concentration and category of cargo may be limited. Second, the stability of liposomes is relatively low. The lipid bilayer of the liposomes often tends to age and fuse, which changes their size and size distribution. Third, the release of cargo in liposomes is instantaneous upon rupture of the liposome which makes it difficult to control the release.
Thus, there is a need to overcome these and other problems of the prior art and to provide a nanostructure including a porous core and methods for forming and using the nanostructure.