document: for TrQβ@b-3WJsiEGFR Let-7g and significantly retained inside tumour tissue for a longer time, and have not been eliminated until 24 h after CED infusion, indicating excellent tumour penetrability. Furthermore, b-3WJsiEGFR Let-7g was taken up in mouse brain tumour cells and was easily monitored without extra tracer labelling after administration of TrQβ@b-3WJsiEGFR Let-7g by CED using a fluorescence microscope. As shown in Figure S17, the green fluorescence accumulated at the injection site in