Chemoselective modification of CS under mild reaction conditions was developed.

A new derivative of CS – α,β-unsaturated polyaldehyde was synthetized in one pot.

pH-responsive conjugation of α,β-unsaturated aldehyde with various amines was demonstrated.

The crosslinking of α,β-unsaturated aldehyde was performed under physiological conditions and led to well organized and porous structures – hydrogel scaffolds.

α,β-Unsaturated aldehyde of CS is a promising and biocompatible material for drug delivery and tissue engineering.