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Published December 25, 2012 | Published + Supplemental Material
Journal Article Open

Rapidly Cross-Linkable DOPA Containing Terpolymer Adhesives and PEG-Based Cross-Linkers for Biomedical Applications


A new three-component bio-inspired adhesive was synthesized that is a terpolymer composed of a water-soluble segment, an interfacial adhesion segment, and a cross-linking segment. Strong wet adhesion properties are obtained utilizing a 3,4-dihydroxy-l-phenylalanine (DOPA) moiety. Poly(acrylic acid) provides high water solubility due to strong ionic interactions with water. An acrylic acid N-hydroxysuccinimide ester (NHS) was included in the adhesive polymer to allow rapid cross-linking with thiol-terminated, 3-armed poly(ethylene glycol) cross-linking agents. The thiol terminal poly(ethylene glycol) was designed to be bulky to avoid possible penetration of molecules to the cell and tissue. The NHS and thiol groups react within 30 s to form covalent bonds. This design allows for rapid optimization of properties for specific applications. Lap shear strength tests on wet porcine skin demonstrated a 190% increased value in adhesion strength for adhesives having the DOPA moiety. After cross-linking, adhesion was enhanced by 450% over poly(acrylic acid-co-acrylic acid NHS) and was 240% higher than un-cross-linked poly(acrylic acid-co-acrylic acid NHS-co-N-methacryloyl-3,4-dihydroxyl-l-phenylalanine). Rheology studies show adhesive viscosity drops significantly at high shear rates, demonstrating its potential to be injected via syringe. The cross-linked adhesive displayed much stronger mechanical properties and higher elastic and viscous moduli than an un-cross-linked adhesive model. Furthermore, the cross-linked adhesive has enhanced moduli near body temperature (38 °C) as compared to room temperature (23 °C), increasing the applications as a biomedical adhesive.

Additional Information

© 2012 American Chemical Society. Received: August 27, 2012. Revised: October 23, 2012. Published: December 10, 2012. This work was supported by the provost office at the California Institute of Technology as part of the UCSF/Caltech consortium. We thank Prof. Chiara Daraio, Prof. Pellegrino, and Prof. Julia A. Kornfield for allowing us to use the Instron and rheometer. The authors thank Dr. Michael R. Harrison, Dr. Payam Saadai, and Dillon Kwiat for helpful discussions in designing the adhesives and cross-linkers.

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Published - ma3017986.pdf

Supplemental Material - ma3017986_si_001.pdf


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