Rapid development of biomedicine creates a continuous demand for new polymers with tailored properties for the fabrication of various biomaterials. Poly(ethylene glycol) (PEG) is particularly suitable for this purpose due to its biocompatibility and exceptional protein resistance, however introduction of new functional groups as well as the increase of their number per polymer chain is required in order to tune PEG's properties and increase its loading capacity. A general method for the anionic ring-opening polymerization of ethylene oxide and functional epoxides has been developed and utilized for the preparation of a number of multifunctional PEGs and their copolymers with PEG. The obtained polymers were either directly or after post-polymerization modification utilized for the fabrication of biomaterials. Smart hydrogels have been prepared from a multifunctional photoresponsive PEG copolymer and multifunctional hydrazide PEG. Reactive anisotropic particles suitable for either reversible sugar conjugation or dual stimuli (oxidation and UV irradiation) triggered degradation have been fabricated via electrohydrodynamic co-jetting. These new biomaterials have great potential for applications in tissue engineering and targeted drug delivery with controlled release.