Macro-Microporous Surface with Sulfonic Acid Groups and Micro-Nano Structures of PEEK/Nano Magnesium Silicate Composite Exhibiting Antibacterial Activity and Inducing Cell Responses.

PURPOSE: To improve the surface bio-properties of polyetheretherketone (PEEK)/nano magnesium silicate (n-MS) composite (PC). MATERIALS AND METHODS: The surface of PC was firstly treated by particle impact (PCP) and subsequently modified by concentrated sulfuric acid (PCPS). RESULTS: PCPS surface exhibited not only macropores with sizes of about 150 µm (fabricated by particle impact) but also micropores with sizes of about 2 µm (created by sulfonation of PEEK) on the macroporous walls, and sulfonic acid (-SO3H) groups were introduced on PCPS surface. In addition, many n-MS nanoparticles were exposed on the microporous walls, which formed micro-nano structures. Moreover, the surface roughness and hydrophilicity of PCPS were obviously enhanced as compared with PC and PCP. Moreover, the apatite mineralization of PCPS in simulated body fluid (SBF) was obviously improved as compared with PC. Furthermore, compared with PC and PCP, PCPS exhibited antibacterial performances due to the presence of -SO3H groups. In addition, the responses (eg, adhesion and proliferation as well as differentiation) of bone marrow mesenchymal stem cell of rat to PCPS were significantly promoted as compared with PC and PCP. CONCLUSION: PCPS with macro-microporous surface containing -SO3H groups and micro-nano structures exhibited antibacterial activity and induced cell responses, which might possess large potential for bone substitute and repair.

One-Step Preparation of an AgNP-nHA@RGO Three-Dimensional Porous Scaffold and Its Application in Infected Bone Defect Treatment.

BACKGROUND: Bactericidal capacity, durable inhibition of biofilm formation, and a three-dimensional (3D) porous structure are the emphases of infected bone defect (IBD) treatment via local scaffold implantation strategy. PURPOSE: In this study, silver nanoparticle (AgNP)-loaded nano-hydroxyapatite (nHA)@ reduced graphene oxide (RGO) 3D scaffolds (AHRG scaffolds) were designed to alleviate bone infection, inhibit biofilm formation, and promote bone repair through the synergistic effects of AgNPs, RGO, and nHA. MATERIALS AND METHODS: AHRGs were prepared using a one-step preparation method, to create a 3D porous scaffold to facilitate a uniform distribution of AgNPs and nHA. Methicillin-resistant Staphylococcus aureus (MRSA) was used as a model-resistant bacterium, and the effects of different silver loadings on the antimicrobial activity and cytocompatibility of materials were evaluated. Finally, a rabbit IBD model was used to evaluate the therapeutic effect of the AHRG scaffold in vivo. RESULTS: The results showed successful synthesis of the AHRG scaffold. The ideal 3D porous structure was verified using scanning electron microscopy and transmission electron microscopy, and X-ray photoelectron spectroscopy and selected area electron diffraction measurements revealed uniform distributions of AgNP and nHA. In vitro antibacterial and cytocompatibility indicated that the 4% AHRG scaffolds possessed the most favorable balance of bactericidal properties and cytocompatibility. In vivo evaluation of the IBD model showed promising treatment efficacy of AHRG scaffolds. CONCLUSION: The as-fabricated AHRG scaffolds effectively eliminated infection and inhibited biofilm formation. IBD repair was facilitated by the bactericidal properties and 3D porous structure of the AHRG scaffold, suggesting its potential in the treatment of IBDs.

Promotion of in vivo degradability, vascularization and osteogenesis of calcium sulfate-based bone cements containing nanoporous lithium doping magnesium silicate.

Nanoporous lithium doping magnesium silicate (nl-MS) was introduced into calcium sulfate hemihydrate to prepare calcium sulfate composite (nl-MSC) bone cements. The introduction of nl-MS improved the in vitro degradability of nl-MSC cements, which could neutralize acidic degradable products of calcium sulfate and prevented the pH from dropping. The cements were implanted into the bone defects of femur bone of rabbits, and the results of histological and immunohistochemical analysis revealed that massive new bone tissue formed in the defects while the cements were degradable, indicating that the osteogenesis and degradability of the nl-MSC cements were much better than the control calcium sulfate dihydrate (CSD) cements. Furthermore, the positive expression of vascular endothelial growth factor and collagen type I for nl-MSC cements was higher than CSD, indicating that addition of nl-MS into the cements enhanced vascularization and osteogenic differentiation. The results suggested that the nl-MSC cements with good biocompatibility and degradability could promote vascularization and osteogenesis, and had great potential to treat bone defects.