M-PEG7-t-butyl ester is widely used in the field of bioconjugation and drug delivery. Its primary application is as a linker or spacer molecule in the development of prodrugs and targeted therapeutic agents. The PEG (polyethylene glycol) chain enhances solubility and stability, while the t-butyl ester group provides a protective moiety that can be cleaved under specific conditions, allowing controlled release of active compounds. In pharmaceutical research, it is employed to modify peptides, proteins, and small molecules, improving their pharmacokinetic properties and reducing immunogenicity. Additionally, it is utilized in the synthesis of hydrogels and biomaterials for tissue engineering, where its biocompatibility and tunable degradation are advantageous. Its versatility also extends to nanotechnology, where it serves as a surface modifier for nanoparticles, enhancing their circulation time and targeting efficiency in drug delivery systems.