Fill in the Blanks: Colloidal Carrier Systems Grafted with ________

Fill in the blanks: Colloidal carrier systems grafted with ________ moieties are considered "smart" carrier systems,which alter and modify their chemical structure or configuration based on a change in the biological environment. Such technology is used to target diseased tissues by using cues specific to the targeted tissue or cell. For example,______,________,_______,_______,or ________ represent some of the currently used triggers to design smart bioresponsive colloidal carrier systems.