DSPE-PEG(2000)-biotin is a biotinylated and PEGylated form of 1,2-distearoyl-sn-glycerol-3-phosphoethanolamine. This compound is extensively used in both in vitro and in vivo for the delivery of small molecule liposomes, as well as for fluorescently labeling nanoparticle lipid carriers (NLCs). Additionally, DSPE-PEG(2000)-biotin is employed to form micelles and serves as a precursor for immobilizing liposomes, utilized in biolayer interferometry binding experiments. Liposomes containing DSPE-PEG(2000)-biotin, encapsulating doxorubicin and quercetin, exhibit cytotoxicity against MCF-7/adr multidrug-resistant breast cancer cells in vitro and slow tumor growth in the MCF-7/adr mouse xenograft model. Fluorescent labeling of NLCs containing DSPE-PEG(2000)-biotin has been successfully achieved using avidin conjugated with FITC-labeled biotin.