Due to its similar elastic modulus of human bones, polyetheretherketone (PEEK) has been considered as an excellent cytocompatible material. However, the bioinertness, poor osteoconduction, and weak antibacterial activity of PEEK limit its wide applications in clinics. In this study, a facile strategy is developed to prepare graphene oxide (GO) modified sulfonated polyetheretherketone (SPEEK) (GO-SPEEK) through a simple dip-coating method. After detailed characterization, it is found that the GO closely deposits on the surface of PEEK, which is attributed to the π-π stacking interaction between PEEK and GO. Antibacterial tests reveal that the GO-SPEEK exhibits excellent suppression toward Escherichia coli. In vitro cell attachment, growth, differentiation, alkaline phosphatase activity, quantitative real-time polymerase chain reaction analyses, and calcium mineral deposition all illustrate that the GO-SPEEK substrate can significantly accelerate the proliferation and osteogenic differentiation of osteoblast-like MG-63 cells compared with those on PEEK and SPEEK groups. These results suggest that the GO-SPEEK has an improved antibacterial activity and cytocompatibility in vitro, showing that the developed GO-SPEEK has a great potential as the bioactive implant material in bone tissue engineering.

Polyetheretherketone is attractive for dental and orthopedic applications due to its mechanical attributes close to that of human bone; however, the lack of antibacterial capability and bioactivity of polyetheretherketone has substantially impeded its clinical applications. Here, a dual therapy implant coating is developed on the 3D micro-/nanoporous sulfonated polyetheretherketone via layer-by-layer self-assembly of Ag ions and Zn ions. Material characterization studies have indicated that nanoparticles consisting of elemental Ag and ZnO are uniformly incorporated on the porous sulfonated polyetheretherketone surface. The antibacterial assays demonstrate that Ag-decorated sulfonated polyetheretherketone and Ag/ZnO-codecorated sulfonated polyetheretherketone effectively inhibit the reproduction of Gram-negative and Gram-positive bacteria. Owing to the coordination of micro-/nanoscale topological cues and Zn induction, the Ag/ZnO-codecorated sulfonated polyetheretherketone substrates are found to enhance biocompatibility (cell viability, spreading, and proliferation), and hasten osteodifferentiation and -maturation (alkaline phosphate activity (ALP) production, and osteogenesis-related genetic expression), compared with the Ag-decorated sulfonated polyetheretherketone and the ZnO-decorated sulfonated polyetheretherketone counterparts. The dual therapy Ag/ZnO-codecorated sulfonated polyetheretherketone has an appealing bacteriostatic performance and osteogenic differentiation potential, showing great potential for dental and orthopedic implants.

Biomaterial-enabled regeneration of the infected or contaminated bone defects remains one of the critical challenges in the development of new clinical treatments. Three-dimensional (3D) porous scaffolds, which can synchronously emulate the hierarchy of bone structures and additionally provide bactericidal and osteogenic features, offer a potential solution to tackle this issue. In this work, we construct hierarchical porous polyetheretherketone (PEEK) scaffolds via 3D printing, equipped with a pH-triggered osteopotentiating coating. In the design of the coating, silver nanoparticles (AgNPs) are trapped onto the first polydopamine (pDA) layer, and apatite is further anchored onto the second pDA layer. The unique “pDA–Ag–pDA” sandwich structure imparts bacteria-triggered pH-responsive ion-releasing behavior to the inert PEEK scaffolds, i.e., the liberation of Ag+ ions from the coating is augmented with decreasing pH value, which is associated with the metabolism of bacteria. These bioscaffolds exhibit excellent capability for eradicating bacteria, as well as harness acceptable cytocompatibility and protuberant osteogenetic potential of osteoblastic MC3T3-E1 cells. Importantly, in vivo evaluation indicates that the Ag/apatite codecorated multifunctional bioscaffolds present appealing in vivo antibacterial efficacy and excellent bone ingrowth and osseointegration in an infected critical-sized bone defect. Accordingly, such “smart” pH-triggered osteopromotive PEEK implants demonstrate strong potential in the treatment of the complicated infective bone disorders.

Implantable polyetheretherketone (PEEK) has great biomedical potential as hard tissue substitute in orthopedic application due to its outstanding mechanical properties and excellent biological stability. However, the poor osseointegration and bacteriostatic ability of implantable PEEK become the major barrier for its wide clinic application. In this study, a hierarchically micro/nano-topographic PEEK with specific functional groups (amino and COOH/COOR) has been fabricated using facile sulfonation combined with argon plasma treatment. The new developed hierarchically micro/nano-topographic PEEK have enhanced hydrophilicity, surface roughness, as well as the high ability of apatite-layer forming. Antibacterial assessment shows that as-treated samples exhibit better antibacterial activity. The cellular responses in osteoblast-like MG-63 cells culturing experiment reveal that the micro/nano-topography accompanied with specific functional groups improves the cell adhesion at the initial stage, further ameliorates proliferation and osteogenic differentiation of MG-63. This study proposes a promising approach to increase osteo-differentiation activity and bacteriostasis of PEEK via synergistic effects involving surface topologic structure and chemical modification, which shows great potential in developing advanced implantable materials.

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