Synthesis and characterization of novel multi-hydroxy polyaspartamide derivative and its crosslinked hydrogels

In this study, a new type of multihydroxy synthetic polymer and its crosslinked gels were prepared. Poly(N-2,3-dihydroxypropyl aspartamide) (PDHPA), a poly(amino acid) composed of a peptide backbone and pendent 1,2-dihydroxy functional groups, was synthesized from polysuccinimide, the precursor polymer, by aminolysis reaction using 3-amino-1,2-propanediol. This polyaspartamide derivative exhibited several valuable properties including biodegradability, high water solubility, excellent biocompatibility, and good adhesion. Because of its unique chemical structure, PDHPA could serve as a useful platform for combination with other materials and preparation of dynamically reversible and self-healing crosslinked hydrogels. PDHPA was reacted with boric acid (H3BO3) to produce a transparent, dynamically reversible, and self-healing hydrogel, whose viscoelastic behavior depended on the chemical composition, water content, and pH condition. Moreover, PDHPA and the crosslinked gel exhibited relatively strong adhesion toward various types of substrates including glass, paper, metal, and plastic. Another hydrogel was prepared using PDHPA and glutaraldehyde in the presence of an acid catalyst; this hydrogel exhibited relatively high gel strength and swelling ratios in the range of 2-5. This new class of hydrophilic water-soluble polymer and its crosslinked gels with excellent hydrolytic degradability, adhesive property, non-cytotoxicity, and biocompatibility have application potential in various biomedical fields.