Marine Adhesive Containing Nanocomposite Hydrogel with Enhanced Materials and Bioadhesive Properties
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Marine Adhesive Containing Nanocomposite Hydrogel with Enhanced Materials and Bioadhesive Properties Yuan Liu, Hao Zhan, Sarah Skelton and Bruce P. Lee* Department of Biomedical Engineering, Michigan Technological University, Houghton, MI 49931, U. S. A. ABSTRACT 4-arm poly(ethylene glycol) end-capped with mimics of adhesive moiety found in mussel adhesive protein, dopamine, was combined with a biocompatible nano-silicate, Laponite, in creating a nanocomposite hydrogel with improved materials and adhesive properties. Dopamine’s ability to form both irreversible covalent (cohesive and interfacial) and reversible physical (with Laponite) crosslinks was exploited in creating an injectable tissue adhesive. Incorporation of Laponite did not interfere with the curing of the adhesive. In some instances, increasing Laponite content reduced gelation time as dopamine-Laponite bond reduced the required number of covalent bonds needed for network formation. Incorporation of Laponite also increased compressive materials properties (e.g., max strength, energy to failure, etc.) of the nanocomposite without compromising its compliance as strain at failure was also increased. From lap shear adhesion test using wetted pericardium as the substrate, incorporating Laponite increased work of adhesion by 5 fold over that of control. Strong, physical bonds formed between dopamine and Laponite increased bulk materials properties, which contributed to the enhanced adhesive properties. INTRODUCTION Rapid and effective wound closure remains an important goal of virtually all modern endoscopic and conventional surgical procedures and is essential for restoration of the structure and function of injured tissues. While the discontinuity in soft tissues is traditionally secured with mechanical perforating devices (e.g., sutures, tacks, and staples), these devices are also a source of tissue trauma, neural irritation and persistent pain [1, 2]. They are also not suitable for complicated procedures, such as stopping leaks of bodily fluids and air in blood vessels and tissues with rather low cohesive properties (e.g., lung, spleen, and kidney). Tissue adhesives can potentially simplify complex procedures, reduce surgery time, and minimize trauma. However, existing tissue adhesives are hampered by poor adhesive strength and poor biocompatibility [3].
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A biologically inspired approach is described here in developing tissue adhesive with improved materials and adhesive properties. 3,4-Dihydroxyphenylalanine (DOPA), an amino acid found in large abundance in mussel adhesive proteins, is responsible for adhesion and rapid curing of these proteins [4]. DOPA is a unique and versatile adhesive molecule capable of binding to both organic and inorganic surfaces through either irreversible covalent or strong reversible bonds [5]. DOPA-modified PEG hydrogel have previously demonstrated improved adhesive strength over fibrin glue [6]. Hydrogels are considered a good candidate for adhesive biomaterials because of their excellent biocompatibility and ease in ta
