N-Hexadecyl-pSar25 is a polypeptide derived from polysarcosine (pSar), featuring a hexadecyl head group and a 25-unit polysarcosine tail. Sarcosine, an amino acid derivative, is being explored as a PEG substitute for in vivo applications due to its biodegradability and significantly reduced antigenicity. This N-Hexadecyl-pSar25 can be utilized in the development of lipid nanoparticles.