title: Mussel-inspired bioceramics with self-assembled Ca-P/polydopamine composite nanolayer: preparation, formation mechanism, improved cellular bioactivity and osteogenic differentiation of bone marrow stromal cells.
abstract: The nanostructured surface of biomaterials plays an important role in improving their in vitro cellular bioactivity as well as stimulating in vivo tissue regeneration. Inspired by the mussel's adhesive versatility, which is thought to be due to the plaque-substrate interface being rich in 3,4-dihydroxy-l-phenylalamine (DOPA) and lysine amino acids, in this study we developed a self-assembly method to prepare a uniform calcium phosphate (Ca-P)/polydopamine composite nanolayer on the surface of β-tricalcium phosphate (β-TCP) bioceramics by soaking β-TCP bioceramics in Tris-dopamine solution. It was found that the addition of dopamine, reaction temperature and reaction time are three key factors inducing the formation of a uniform Ca-P/polydopamine composite nanolayer. The formation mechanism of a Ca-P/polydopamine composite nanolayer involved two important steps: (i) the addition of dopamine to Tris-HCl solution decreases the pH value and accelerates Ca and P ionic dissolution from the crystal boundaries of β-TCP ceramics; (ii) dopamine is polymerized to form self-assembled polydopamine film and, at the same time, nanosized Ca-P particles are mineralized with the assistance of polydopamine, in which the formation of polydopamine occurs simultaneously with Ca-P mineralization (formation of nanosized microparticles composed of calcium phosphate-based materials), and finally a self-assembled Ca-P/polydopamine composite nanolayer forms on the surface of the β-TCP ceramics. Furthermore, the formed self-assembled Ca-P/polydopamine composite nanolayer significantly enhances the surface roughness and hydrophilicity of β-TCP ceramics, and stimulates the attachment, proliferation, alkaline phosphate (ALP) activity and bone-related gene expression (ALP, OCN, COL1 and Runx2) of human bone marrow stromal cells. Our results suggest that the preparation of self-assembled Ca-P/polydopamine composite nanolayers is a viable method to modify the surface of biomaterials by significantly improving their surface physicochemical properties and cellular bioactivity for bone regeneration application.
authors.affiliation: State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, People's Republic of China.
authors.forename: Chengtie
authors.initials: C
authors.lastname: Wu
authors.forename: Pingping
authors.initials: P
authors.lastname: Han
authors.forename: Xiaoguo
authors.initials: X
authors.lastname: Liu
authors.forename: Mengchi
authors.initials: M
authors.lastname: Xu
authors.forename: Tian
authors.initials: T
authors.lastname: Tian
authors.forename: Jiang
authors.initials: J
authors.lastname: Chang
authors.forename: Yin
authors.initials: Y
authors.lastname: Xiao
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D001672:Biocompatible Materials / Q000494:pharmacology*; D049872:Bivalvia / Q000737:chemistry*; D001854:Bone Marrow Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D002130:Calcium Phosphates / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D049109:Cell Proliferation / Q000187:drug effects; D002516:Ceramics / Q000138:chemical synthesis / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D057927:Hydrophobic and Hydrophilic Interactions / Q000187:drug effects; D007211:Indoles / Q000494:pharmacology*; D018625:Microscopy, Atomic Force; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010012:Osteogenesis / Q000187:drug effects* / Q000235:genetics; D011108:Polymers / Q000494:pharmacology*; D017154:Stromal Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D001672:Biocompatible Materials; D002130:Calcium Phosphates; D007211:Indoles; D011108:Polymers; C485817:beta-tricalcium phosphate; C568283:polydopamine; D014867:Water; D000469:Alkaline Phosphatase
keywords: Biomaterials; Ca-P/polydopamine composite; Cellular bioactivity; Self-assemble