| 摘要 |
<p>Polymeric hollow particles for delivery of an agent are provided that change permeability in response to a change in an external stimulus such as pH, temperature, light, ionic strength, electric field, magnetic field and/or solvent composition. The particles can have a shell formed of an amphiphilic triblock ABA or BAB copolymer, where A is a hydrophilic block and B is a hydrophobic block. Low permeability particles with a reversibly permeable shell expand and increase permeability in response to a stimulus so that an active agent such as a therapeutic, prophylactic or diagnostic agent can be introduced. Removing the stimulus allows the particles to return to a low permeability state to form particles loaded with the active agent. Surfaces of the particles can be modified with specific ligands that allow the particles to be directed to a specific target via molecular recognition.</p> |
