The　development　of　biocompatible　drug　delivery　systems　with　targeted　recognition　and　controlled　release　has　experienced　a　number　of　design　challenges,　including,　for　example,　complicated　preparation　steps　and　premature　drug　release.　Herein,　we　address　these　problems　through　an　in　situ　self-polymerization　method　that　synthesizes　biodegradable　polyphenol-coated　porous　nanomaterials　for　targeted　and　controlled　drug　delivery.　As　a　proof　of　concept,　we　synthesized　polyphenol-coated　mesoporous　silica　nanoparticles,　termed　MSN@polyphenol.　The　polyphenol　coatings　not　only　improved　colloidal　stability　and　prevented　premature　drug　leakage,　but　also　provided　a　scaffold　for　immobilization　of　targeting　moieties,　such　as　aptamers.　Both　immobilization　of　targeting　aptamers　and　synthesis　of　polyphenol　coating　are　easily　accomplished　without　the　aid　of　any　other　organic　reagents.　Importantly,　the　polyphenol　coating　(EGCg)　used　in　this　study　could　be　biodegraded　by　acidic　pH　and　intracellular　glutathione,　resulting　in　the　release　of　trapped　anticancer　drugs.　Based　on　confocal　fluorescence　microscopy　and　cytotoxicity　experiments,　drug-loaded　and　polyphenol-coated　MSNs　were　shown　to　possess　highly　efficient　internalization　and　an　apparent　cytotoxic　effect　on　target　cancer,　but　not　control,　cells.　Our　results　suggest　that　these　highly　biocompatible　and　biodegradable　polyphenol-coated　MSNs　are　promising　vectors　for　controlled-release　biomedical　applications　and　cancer　therapy.