High-strength, strong-adhesion, and antibacterial polyelectrolyte complex hydrogel films from natural polysaccharides

Naturally occurring polysaccharide-based polyelectrolyte complex (PEC) physical hydrogels have broad applications in biomedicine. Yet, obtaining high-strength, strong-adhesion, and antibacterial PEC hydrogels via physically crosslinking of natural polysaccharides still remains a challenge. In this work, a chitosan (CS)/sodium alginate (SA) PEC physical hydrogel film was developed by using two oppositely charged natural polysaccharides, CS and SA, of equivalently high molecular weight ( M w , approx. 10 5 Da), the tensile stress of which was achieved as high as 12.3 MPa due to CS-CS intermolecular hydrogen bonding and CS-SA electrostatic interaction. In addition, the hydrogel films, upon protonation at acidic conditions (e.g. pH 2.6), exhibited excellent antibacterial activity against Escherichia coli ( E. coli ) and the CS/SA hydrogel films also demonstrated strong adhesion to biological tissue. The high M w -matching, two-component natural polysaccharide approach presented in this work to preparing high-strength, strong-adhesion, and antibacterial PEC hydrogels may shed some lights on converting renewable biomass to value-added biomaterials.