Aim: To evaluate the biological function of titanium implants coated with cell-derived mineralized extracellular matrix, which mimics a bony microenvironment. Materials & methods: A biomimetic titanium implant was fabricated primarily by modifying the titanium surface with TiO2 nanotubes or sand-blasted, acid-etched topography, then was coated with mineralized extracellular matrix constructed by culturing bone marrow mesenchymal stromal cells. The osteogenic ability of biomimetic titanium surface in vitro and in vivo were evaluated. Results: In vitro and in vivo studies revealed that the biomimetic titanium implant enhanced and accelerated osteogenesis of bone marrow stromal cells by increasing cell proliferation and calcium deposition. Conclusion: By combining surface topography modification with biological coating, the results provided a valuable method to produce biomimetic titanium implants with excellent osteogenic ability.
Acinetobacter baumannii has emerged as an important cause of healthcare-associated infections causing great morbidity and mortality. Despite its clinical importance, it is still unknown which molecular typing method is the best to determine or confirm institutional outbreaks as well as to identify epidemiologically related isolates from different geographical areas. To determine the most discriminatory molecular typing method, we isolated A. baumannii from perianal swabs collected from intensive care unit (ICU) patients in a cohort study during 2002 and 2008. Strains from each year were analyzed by pulsed-field gel electrophoresis (PFGE), multi-locus sequence typing (MLST), and multi-locus variable-number tandem repeat analysis (MLVA). Genetic relatedness of the isolates was consistent between PFGE and MLST as well as between analyses of loci containing MLVA and MLST. Our data show that PFGE and MLVA are similar when discriminating between isolates and are both good methods to use when questioning whether two isolates are indistinguishable.
A new braided poly lactic-co-glycolic acid (PLGA) (LA : GA = 10 : 90) catheter, consisting of an outside-tube and an inside-scaffold, was designed and fabricated to guide and support peripheral nerve regeneration. According to the process of peripheral nerve regeneration, the functional division of the outside-tube and the inside-scaffold was confirmed as follows: the major function of the outside-tube was support for the space of the nerve regeneration and the needed good compression performance and the major function of the inside-scaffold was simulation of the matrix bridge in the nerve regeneration process. Therefore, the outside-tube was braided for a higher density with PLGA ply yarns and coated with chitosan; the inside-scaffold was braided for a lower density with PLGA single filaments treated by H2O2. The arrangement and number of micro-tubes were designed and theoretically calculated. In this paper, the basic thickness and density performance of the new catheter was tested first. Then, the fibroblast cytocompatibility and the fiber tensile in degradation were assessed as indications of the performance change of the unmodified and modified materials. Finally, the compression performance of the new catheter was compared with two other catheters. The results showed that the new catheter had a uniform and stable structure. The modified inside-scaffold had a higher cytocompatibility and facilitation of fibroblast growth than the unmodified one; meanwhile, it maintained enough mechanical properties to support nerve regeneration in degradation. Furthermore, the elastic recovery and compressive resistance retention respectively reached 84% and 93%, which meant excellent compression performance. In summary, the performance of this new braided PLGA catheter attained the designed targets.
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