mPEG-CHO (MW 550) is involved in the formation of three-dimensional porous scaffolds and acts as a delivery carrier for active substances. The -CHO functional group interacts with the -NH2 functional group of chitosan chains to form a glutaraldehyde-type adduct, functionalizing the mPEG. This functionalization and cross-linking can affect the rigidity of the delivery system, enabling the cross-linked conjugate system to possess slow-release capabilities.