Chemically engineered nanomaterials have been extensively used in early
tumor detection and
cancer therapy. Despite the promise shown, their chemical or exogenous nature hinders their application due to their unknown adverse effects. Herein, using a
cancer cell environment, fluorescent
DNA-
gold nanostructures were bio-self-assembled through simple incubation of
DNA and Au solutions with
cancer cells. In situ, ex vivo, bio-responsive self-assembly of ring-shaped
DNA-Au nanostructures is reported for the first time. Subsequently, the exosomes released by the above-mentioned
cancer cells were found to carry the self-assembled
DNA-Au nanostructures, exhibiting strong in vivo dual fluorescence properties. Interestingly, these exosomes could be immediately taken up in vitro by their parent cells, reaching the nucleus within 10 min after incubation. Taking advantage of the unique endogenous properties of exosomes, and their advanced cargo delivery capacity, we further exploited the
DNA-Au nanostructure loaded exosomes with
mitoxantrone for accurate
cancer theranostics. The in vitro and in vivo results showed that the exosomes could effectively deliver the drug cargo to cancerous cells, hence, displaying an enhanced targeting effect towards parent
cancer cells, and a synergistic
tumor inhibition effect, while showing great biocompatibility towards normal cells and vital organs. Hence, exosomes carrying the in situ bio-self-assembled
DNA-Au nanostructures could be an outstanding delivery system for
dye-free targeted
cancer detection and
therapy.