2-arm Methoxypoly(ethylene glycol) thiol (PT02) is a PEG derivative mostly used as a biochemical reagent in pharmaceutical research. Its derivative 4-Arm PEG is a multi-arm PEG reagent with 4 reactive groups, which can be used for polyethylene glycolisation, hydrogels, cross-linking, encapsulation, nanoparticles, and polymeric drug couplers. Applications include tissue engineering, drug delivery formulations, diagnostic assays, and pharmaceutical and cosmetic development.