Branched poly(ethylene glycol) (PEG) 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 significantly increased work of adhesion when compared to Laponite-free gels. Strong, physical bonds formed between dopamine and Laponite increased bulk materials properties, which contributed to the enhanced adhesive properties. The addition of Laponite did not alter the degradation rate and cytocompatibility of PEG adhesive. Based on subcutaneous implantation in rat, the nanocomposite hydrogels elicited minimal inflammatory response and exhibited an enhanced level of cellular infiltration as compared to Laponite-free samples. The addition of Laponite is potentially a simple and effective method to promote bioactivity in a bioinert, synthetic PEG-based adhesive while simultaneously enhance its mechanical and adhesive properties.

Related Publications:

Y Liu, H Meng, Z Qian, N Fan, W Choi, F Zhao, and BP Lee* “A moldable nanocomposite hydrogel composed of a mussel-inspired polymer and a nanosilicate as a fit-to-shape tissue sealant”.  Angewandte Chemie International Edition, 56, 4224-4228, 2017. [Link]

Y Liu and BP Lee* “Recovery property of double-network hydrogel containing mussel-inspired adhesive moiety and nano-silicate”. Journal of Materials Chemistry B, 4, 6534-6540, 2016. [Link]

Y Li, H Meng, Y Liu, A Narkar, and BP Lee* “Gelatin microgel incorporated poly(ethylene glycol)-based bioadhesive with enhanced adhesive property and bioactivity “. ACS Applied Materials & Interfaces, 8 (19), 11980-11989, 2016. [Link]

Y Liu,‡ H Meng,‡ S Konst, R Sarmiento, R Rajachar, and BP Lee.* “Injectable dopamine-modified poly(ethylene glycol) nanocomposite hydrogel with enhanced adhesive property and bioactivity”. ACS Applied Materials & Interfaces, 6 (19), 16982–16992, 2014. ‡ Contributed equally [Link]

Y Liu, H Zhang, S Skelton, BP Lee.* “Marine adhesive containing nanocomposite hydrogel with enhanced materials and bioadhesive properties”. Materials Research Society Proceedings, 1569, 33-38, 2013. [Link]