18:0 mPEG1000 PE (ammonium) is a PEG-lipid functional end group utilized in the synthesis of liposomes (LPs) and in designing conjugated polymer nanoparticles. These liposome nanoparticles (LNPs), modified with biotin and carboxyl ends, can further couple with other biomolecules. Functionalized nanoparticles are applicable for targeted labeling of specific cellular proteins. With streptavidin as a linker, the biotinylated PEG-lipid conjugated polymer nanoparticles bind to biotinylated antibodies on cell surface receptors, offering utility in fluorescence-based imaging and sensing.