where clearly a drastic decrease of E. coli colonies is observed using the amphiphilic drug release system under visible light irradiation ( Figure 5C ) if compared with the results obtained in dark ( Figure 5D ) . The result demonstrates the hydrophobic cap can efficiently prevent the leaching of the AMP or the influx of the aqueous surrounding media in dark . I.e. , the drug delivery system is comparably stable against drug leakage if stored in dark . XPS data in Figure S3 and Figure S8 also confirm the photocatalytic scission of the hydrophobic chain and the alkyl chain that connects the drug to wall by visible light irradiation . Moreover , if the Au decorated top layer is removed before visible light irradiation ( Figure S9 ) , the drug molecules can not be released .