Fabrication of polydopamine nanoparticles knotted alginate scaffolds and their properties

Polydopamine (PDA) can greatly affect polymer's properties, due to the chemical and physical interactions between the polymers and PDA. In this study, PDA was demonstrated to adjust the pore structures and increase the mechanical properties of alginate hydrogel-based cartilage tissue scaffolds. Dopamine modified alginate (Alg-DA) was firstly synthesized by modification of Alg with DA. Alg-DA interacted with preprepared PDA nanoparticles and further crosslinked with calcium ions (Ca2+) to form the hydrogel scaffold (Alg-DA/PDA). The Alg-DA/PDA scaffold combined multiple advantageous features, including continuous pore structure, high level of porosity, well mechanical properties, good biocompatibility and appropriate cycle life of degradation. Moreover, it could provide an optimized forming environment for hydroxyapatite (HAp) by mineralization process, thus accelerating cartilage repair. The improved performances were mainly ascribed to physical enhancement of the PDA nanoparticles and crosslinking points among the polymers and catechol groups in DA. These findings might offer a guideline for fabricating robust biocompatible cartilage tissue scaffold. (c) 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 3255-3266, 2018.