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Implantation of a biomaterial provides an adhesion substratum both to host cell integration and to contaminating bacteria. We studied simultaneous competitive adhesion of Staphylococcus aureus in serial 1:10 dilutions of 108 colony forming units (CFU)/mL and human osteogenic sarcoma (SaOS-2) or primary osteoblast (hOB) cells, both 1x105cells/mL, to the surfaces of titanium, polydimethylsiloxane and polystyrene. The bacterial adherence and human cell proliferation, cytotoxicity and production of reactive oxygen species (ROS) were studied using fluorometric (fluorescent microscopy and flow cytometry) and colorimetric methods (MTT, LDH and crystal violet). The bacterial cell viability was also evaluated using the drop plate method. The presence of bacteria resulted in reduced adherence of human cells to the surface of the biomaterials, increased production of ROS, and into increased apoptosis. On the other hand, the presence of either type of human cells was associated with a reduction of bacterial colonization of the biomaterial with Staphylococcus aureus. These results suggest that increasing colonization of the biomaterial surface in vitro by one negatively affects colonization by the other. Host cell integration to an implant surface reduces bacterial contamination, which opens novel opportunities for the design of infection-resistant biomaterials in current implantology and future regenerative medicine. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 62-72, 2017. [ABSTRACT FROM AUTHOR]

The hypothesis was that anti-fouling diamond-like carbon polydimethylsiloxane hybrid (DLC-PDMS-h) surface impairs early and late cellular adhesion and matrix-cell interactions. The effect of hybrid surface on cellular adhesion and cytoskeletal organization, important for osteogenesis of human mesenchymal stromal cells (hMSC), where therefore compared with plain DLC and titanium (Ti). hMSCs were induced to osteogenesis and followed over time using scanning electron microscopy (SEM), time-of-flight secondary ion mass spectrometry (ToF-SIMS), immunofluorescence staining, quantitative real-time polymerase chain reaction (qRT-PCR), and hydroxyapatite (HA) staining. SEM at 7.5 hours showed that initial adherence and spreading of hMSC was poor on DLC-PDMS-h. At 5 days some hMSC were undergoing condensation and apoptotic fragmentation, whereas cells on DLC and Ti grew well. DAPI-actin-vinculin triple staining disclosed dwarfed cells with poorly organized actin cytoskeleton-focal complex/adhesion- growth substrate attachments on hybrid coating, whereas spread cells, organized microfilament bundles, and focal adhesions were seen on DLC and in particular on Ti. Accordingly, at day one ToF-SIMS mass peaks showed poor protein adhesion to DLC-PDMS-h compared with DLC and Ti. COL1A1, ALP, OP mRNA levels at days 0, 7, 14, 21, and/or 28 and lack of HA deposition at day 28 demonstrated delayed or failed osteogenesis on DLC-PDMS-h. Anti-fouling DLC-PDMS-h is a poor cell adhesion substrate during the early protein adsorption-dependent phase and extracellular matrix-dependent late phase. Accordingly, some hMSCs underwent anoikis-type apoptosis and failed to complete osteogenesis, due to few focal adhesions and poor cell-to-ECM contacts. DLC-PDMS-h seems to be a suitable coating for non-integrating implants/devices designed for temporary use. [ABSTRACT FROM AUTHOR]

We hypothesized that when compared with conventional two-dimensional (2D) cultures, substrates containing 3D micropillars would allow cells to grow at levels, activating their cytoskeleton to promote osteogenesis. Fibroblasts, osteoblast-like cells, and mesenchymal stem cells (MSCs) were studied. Planar substrates were compared with 200-nm-, 5-μm-, and 20-μm-high pillars of Ormocomp®, Si, diamond-like carbon, or TiO2. Scanning electron microscopy and staining of actin cytoskeleton showed 7.5-h adhesion to pillar edges and 5-day stretching between adhesion contacts > 100-μm distances of fibroblast and MSC in 3D networks, whereas SaOS-2 cells adhered flatly and individually on horizontal and vertical surfaces. ERK and ROCK immunostaining at 14 and 21 days confirmed activation of the cytoskeleton. In contrast to expectations, success to induce osteogenesis was dominated by the cytocompatibility of the substrate over the 3D structure. This was shown using early alkaline phosphatase, intermediate osteopontin, and late mineralization markers, together with bone nodule formation, which were seen in planar substrates and low-profile TiO2 pillars, but were poor in the 20-μm landscape. The lack of intercellular contacts seems to halt the osteogenesis-promoting effects of cytoskeletal organization and tension described earlier. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 101A: 842-852, 2013. [ABSTRACT FROM AUTHOR]

Recent studies suggest that diamond‐like carbon (DLC) coatings are suitable candidates for application on biomedical devices and implants, due to their high hardness, low friction, high wear and corrosion resistance, chemical inertness, smoothness, and tissue and blood compatibility. However, most studies have neglected the potential susceptibility of DLC coatings to bacterial adhesion, which is the first step in the development of implant‐related infections. This study compares adhesion of seven bacterial strains, commonly implicated in implant‐related infections, to tetrahedral amorphous carbon, with their adhesion to AISI 316L surgical steel. The results show that bacterial adhesion to DLC was similar to the adhesion to commonly used stainless steel. This suggests that DLC coating can be advantageously used on implants made of AISI 316L or other materials without increasing the risk to implant‐related infections. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009 [ABSTRACT FROM AUTHOR]