Rapidly crosslinkerable bio-inspired adhesives for biomedical applications

A new three component bio-inspired adhesive was synthesized. The new adhesive is a terpolymer composed of water sol. segment, interfacial segment and crosslinking segment. Strong wet adhesion properties are obtained utilizing 3,4-dihydroxy-L-phenylalanine (DOPA) moiety as the interfacial segment. Polyacrylic acid provides high water soly., thanks to strong ionic interactions with water. Acrylic acid N-hydroxysuccinimide ester (NHS) was included in the adhesive polymer to allow rapid crosslinking with thiol terminated, 3-armed polyethylene glycol crosslinking agents. Thiol terminal PEG was designed to have bulky vol. to avoid possible penetration of mols. to the cell and tissue. NHS and thiol group react very rapidly within 30 s to form covalent bonds. This rapid NHS-thiol group reaction formed mech. stable crosslinked adhesives which have strong wet adhesion properties. Lap shear strength test on wet porcine skin demonstrated a 190 % increased value in adhesion strength for adhesives having the DOPA moiety. After crosslinking, adhesion enhanced by 450 % over poly(acrylic acid-co-acrylic acid NHS) and 240 % higher than uncrosslinked poly(acrylic acid-co-acrylic acid NHS-co-DOPA)