AbstractThe development of artificial vesicles into responsive architectures capable of sensing the biological environment and simultaneously signaling the presence of a specific target molecule is a key challenge in a range of biomedical applications from drug delivery to diagnostic tools. Herein, the rational design of biomimetic DNA‐grafted quatsome (QS) nanovesicles capable of translating the binding of a target molecule to amphiphilic DNA probes into an optical output is presented. QSs are synthetic lipid‐based nanovesicles able to confine multiple organic dyes at the nanoscale, resulting in ultra‐bright soft materials with attractiveness for sensing applications. Dye‐loaded QS nanovesicles of different composition and surface charge are grafted with fluorescent amphiphilic nucleic acid‐based probes to produce programmable FRET‐active nanovesicles that operate as highly sensitive signal transducers. The photophysical properties of the DNA‐grafted nanovesicles are characterized and the highly selective, ratiometric detection of clinically relevant microRNAs with sensitivity in the low nanomolar range are demonstrated. The potential applications of responsive QS nanovesicles for biosensing applications but also as functional nanodevices for targeted biomedical applications is envisaged.