Titanium-coated Surfaces Research Articles

Surface Characteristics, Properties and Wear Resistance OF TIB2 BASED Hard-Alloy Coatings Obtained by Electrospark Deposition at Negative Polarity on Ti6Al4V Alloy

In the present work, the possibilities of improving the surface properties of titanium alloy Ti6Al4V by electrospark deposition (ESD) at negative polarity were investigated. The coatings were deposited with a TiB2-TiAl-based hard-alloy electrode with nano-sized additives of NbC and ZrO2. The effect of polarity in ESD at low pulse energy (0.01-0.07 J) on the surface roughness, thickness, composition and structure of coatings was studied by profilometric, metallographic, XRD, SEM and EDS methods. In both polarities, dense and uniform coatings were obtained with roughness and thickness, which could be varied by changing the ESD modes within the range Ra=1.5÷4.5 µm, d= 6÷20 µm and microhardness from 9 to 12 GPa, respectively. It was found that the negative polarity coatings obtained are denser and uniform with higher thickness, lower roughness, finer structure, and lower coefficient of friction, and can be successfully used to reduce the surface roughness and defects of 3D printed titanium alloy. Abrasion and erosion wear tests showed that the wear resistance of coated titanium surfaces at both polarities was 2.2 to 3.5 times higher than that of the substrate. Coatings deposited in positive polarity demonstrated higher resistance to abrasive wear, while those in negative polarity are more resistant to erosive wear.

Comparison of the Antibacterial Effect of Silver Nanoparticles and a Multifunctional Antimicrobial Peptide on Titanium Surface.

Titanium implantation success may be compromised by Staphylococcus aureus surface colonization and posterior infection. To avoid this issue, different strategies have been investigated to promote an antibacterial character to titanium. In this work, two antibacterial agents (silver nanoparticles and a multifunctional antimicrobial peptide) were used to coat titanium surfaces. The modulation of the nanoparticle (≈32.1 ± 9.4 nm) density on titanium could be optimized, and a sequential functionalization with both agents was achieved through a two-step functionalization method by means of surface silanization. The antibacterial character of the coating agents was assessed individually as well as combined. The results have shown that a reduction in bacteria after 4 h of incubation can be achieved on all the coated surfaces. After 24 h of incubation, however, the individual antimicrobial peptide coating was more effective than the silver nanoparticles or their combination against Staphylococcus aureus. All tested coatings were non-cytotoxic for eukaryotic cells.

Diamond-like carbon (DLC)-coated titanium surface inhibits bacterial growth and modulates human alveolar bone cell responses in vitro

Modifying the titanium alloy (Ti-6Al-4V) surface plays a key role in improving biological responses. The present work aimed to determine the response of human alveolar bone cells to the diamond-like carbon (DLC) film and to evaluate the antibacterial effect of DLC-coated titanium. The alloys were deposited with different compositions, including C2H2 (DLC), carbon tetrafluoride (CF4:C2H2; F-DLC), and tetramethylsilane (Si(CH3)4:C2H2; Si-DLC). The surface morphology and wettability were measured using an atomic force microscopy (AFM) and a contact angle measurement. Titanium coated with DLC, F-DLC, or Si-DLC increased surface roughness and hydrophobicity. The ratio of spreading cells to initial rounded attaching cells at 20 min of all modified surfaces was higher than that of the control surfaces. F-DLC showed better cell spreading at 20 min compared to other conditions, as observed by scanning electron microscopy (SEM). The DLC, F-DLC, and Si-DLC coating significantly promoted cell proliferation compared to the Ti-6Al-4V control surfaces. ALP mRNA expression was significantly reduced on DLC surfaces compared to the control on day 14. Additionally, ALP and BMP2 mRNA expression increased on F-DLC-coated surfaces, but there were no statistically significant differences. However, DLC surfaces promoted higher mineral deposition than the control. The lower Staphylococcus aureus colony was observed on the surface of the DLC and F-DLC. In conclusion, the DLC-modified Ti-4Al-6V surface modulates cell attachment, proliferation, osteogenic marker gene expression, and bacterial growth. Herein, DLC-coated titanium alloys are still needed for continued development as an alternative biomaterial in dental applications.

Keratin coated titanium as an aid to osseointegration: Physicochemical and mechanical properties

Wool-extracted keratin has been shown to promote bone formation in vivo and may therefore be a potential novel bioactive coating material for osseous implants. This study examined the physicochemical and mechanical properties of keratin-coated titanium, to assess its potential for use in bone-implant applications. Keratin was covalently coupled to silane and glutaraldehyde treated titanium by either (a) molecular grafting or (b), solvent casting. The coated titanium surfaces physicochemical properties including contact angle, roughness, degradation, and swelling characteristics, were subsequently characterized using attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). Mechanical properties including the coating adhesion strength and tensile strength were also examined. ATR-FTIR, XPS, XRD, and SEM-EDS all confirmed the presence of keratin on both coated titanium surfaces. SEM imaging showed that solvent casting produced a thick coating which completely covered the titanium surface, while molecular grafting produced a discontinuous thinner coating. The surface roughness increased similarly using either coating methodology while molecular grafting only, increased surface wettability. Both keratin-modified titanium surfaces were stable in solution over 28 days demonstrating suitability for in vivo applications, while the solvent cast titanium also showed good adhesion and tensile bond strength of the coated keratin. These results show a stable keratin coating on the titanium surface was successfully obtained which has both the physiochemical and mechanical properties required for potential dental and or orthopaedic implant applications.

Application of Lyophilized Gene-Delivery Formulations to Dental Implant Surfaces: Non-Cariogenic Lyoprotectant Preserves Transfection Activity of Polyplexes Long-Term

Titanium is the metal of choice for dental implants because of its biocompatibility and ability to merge with human bone tissue. Despite the great success rate of dental implants, early and late complications occur. Coating titanium dental implant surfaces with polyethyleneimine (PEI)-plasmid DNA (pDNA) polyplexes improve osseointegration by generating therapeutic protein expression at the implantation site. Lyophilization is an approach for stabilizing polyplexes and extending their shelf life; however, most lyoprotectants are sugars that can aid bacterial growth in the peri-implant environment. In our research, we coated titanium surfaces with polyplex solutions containing varying amounts of lyoprotectants. We used two common lyoprotectants (sucrose and polyvinylpyrrolidone K30) and showed for the first time that sucralose (a sucrose derivative used as an artificial sweetener) might act as a lyoprotectant for polyplex solutions. Human embryonic kidney (HEK) 293T cells were used to quantify the transfection efficiency and cytotoxicity of the polyplex/lyoprotectant formulations coating titanium surfaces. Polyplexes that were lyophilized in the presence of a lyoprotectant displayed both preserved particle size and high transfection efficiencies. Polyplexes lyophilized in 2% sucralose have maintained transfection efficacy for three years. These findings suggest that modifying dental implants with lyophilized polyplexes might improve their success rate in the clinic.

Multifractal Analysis to Determine the Effect of Surface Topography on the Distribution, Density, Dispersion and Clustering of Differently Organised Coccal-Shaped Bacteria.

The topographic features of surfaces are known to affect bacterial retention on a surface, but the precise mechanisms of this phenomenon are little understood. Four coccal-shaped bacteria, Staphylococcus sciuri, Streptococcus pyogenes, Micrococcus luteus, and Staphylococcus aureus, that organise in different cellular groupings (grape-like clusters, tetrad-arranging clusters, short chains, and diploid arrangement, respectively) were used. These differently grouped cells were used to determine how surface topography affected their distribution, density, dispersion, and clustering when retained on titanium surfaces with defined topographies. Titanium-coated surfaces that were smooth and had grooved features of 1.02 µm-wide, 0.21 µm-deep grooves, and 0.59 µm-wide, 0.17 µm-deep grooves were used. The average contact angle of the surfaces was 91°. All bacterial species were overall of a hydrophobic nature, although M. luteus was the least hydrophobic. It was demonstrated that the 1.02 µm-wide featured surface most affected Strep. pyogenes and S. sciuri, and hence the surfaces with the larger surface features most affected the cells with smaller dimensions. The 0.59 µm featured surface only affected the density of the bacteria, and it may be suggested that the surfaces with the smaller features reduced bacterial retention. These results demonstrate that the size of the topographical surface features affect the distribution, density, dispersion, and clustering of bacteria across surfaces, and this is related to the cellular organisation of the bacterial species. The results from this work inform how surface topographical and bacterial properties affect the distribution, density, dispersion, and clustering of bacterial retention.

Biomimetic Coating of Titanium Surface Using Bioactive Glass Nanoparticles.

The aim of this study was to coat titanium substrate with bioactive glass nanoparticles and characterize the deposited surface coat. Amorphous bioglass nanoparticles < 20 nm in diameter were prepared using a modified sol-gel technique followed by a ball-milling process. The prepared nanoparticles were used to coat airborne particle-abraded titanium disks. The in vitro bioactivity of the bioglass nanopowder was confirmed using simulated body fluid. Coated surfaces were characterized in terms of microstructure, composition, thickness, phase structure, surface roughness, wettability, and tissue behavior in a rabbit model. Bioglass nanoparticles showed apatite formation under a scanning electron microscope (SEM) after 5 days, confirming that bioactivity was enhanced with increasing degradation rate for up to 2 weeks. An optimized deposition technique and heat-treatment process produced a homogenous coating with a uniform thickness of 32 to 39 μm. Chemical analysis confirmed the presence of silicon and calcium on the coated disks. Amorphous coated surfaces exhibited porous nano/microroughness with microcracks and super-hydrophilicity. The interface of the coated disks with subcutaneous tissue revealed good tissue adhesion, high cellular activity, and rich vascularization, with multinucleated cells in the microenvironment surrounding the coat, as confirmed using histomorphometric analysis. The results of this study show that it is feasible to coat titanium surfaces with bioactive glass nanoparticles with super-hydrophilicity and high biologic activity. These particles may promote the regenerative environment around dental implants.

Distinct Concentration-Dependent Molecular Pathways Regulate Bone Cell Responses to Cobalt and Chromium Exposure from Joint Replacement Prostheses.

Systemic cobalt (Co) and chromium (Cr) concentrations may be elevated in patients with metal joint replacement prostheses. Several studies have highlighted the detrimental effects of this exposure on bone cells in vitro, but the underlying mechanisms remain unclear. In this study, we use whole-genome microarrays to comprehensively assess gene expression in primary human osteoblasts, osteoclast precursors and mature resorbing osteoclasts following exposure to clinically relevant circulating versus local periprosthetic tissue concentrations of Co2+ and Cr3+ ions and CoCr nanoparticles. We also describe the gene expression response in osteoblasts on routinely used prosthesis surfaces in the presence of metal exposure. Our results suggest that systemic levels of metal exposure have no effect on osteoblasts, and primarily inhibit osteoclast differentiation and function via altering the focal adhesion and extracellular matrix interaction pathways. In contrast, periprosthetic levels of metal exposure inhibit both osteoblast and osteoclast activity by altering HIF-1α signaling and endocytic/cytoskeletal genes respectively, as well as increasing inflammatory signaling with mechanistic implications for adverse reactions to metal debris. Furthermore, we identify gene clusters and KEGG pathways for which the expression correlates with increasing Co2+:Cr3+ concentrations, and has the potential to serve as early markers of metal toxicity. Finally, our study provides a molecular basis for the improved clinical outcomes for hydroxyapatite-coated prostheses that elicit a pro-survival osteogenic gene signature compared to grit-blasted and plasma-sprayed titanium-coated surfaces in the presence of metal exposure.

Improvisation and Evaluation of Laterosporulin Coated Titanium Surfaces for dental Applications: An In Vitro Investigation.

Despite recent improvement in implant survival rates, there remains a significant demand for enhancing the long-term clinical efficacy of titanium (Ti) implants, particularly for the prevention of peri-implantitis. Bioactive substances such as antimicrobial peptides are emerging as effective alternatives for contemporary antimicrobial agents used in dental health care. Current research work was focused to use laterosporulins that are non-haemolytic cationic antimicrobial peptides from Brevibacillus spp. for coating commercially available Ti discs. The coated Ti surfaces were evaluated in vitro for biofilm formation by two dental plaque isolates Streptococcus gordonii strain DIGK25 and S. mutans strain DIGK119 as representatives of commensal and pathogenic streptococci respectively. The biofilm inhibition was ascertained with replicated experiments on hydroxyapatite discs and confirmed by florescence microscopy. The laterosporulin coated Ti discs showed significantly reduced biofilm formation by oral streptococci and displayed promising potential to enhance the antibacterial surface properties. Such improvised Ti surfaces may curb the menace of oral streptococcal biofilm formation on dental implants and the associated implant failures.

Transcript-Activated Coatings on Titanium Mediate Cellular Osteogenesis for Enhanced Osteointegration.

Osteointegration is one of the most important factors for implant success. Several biomolecules have been used as part of drug delivery systems to improve implant integration into the surrounding bone tissue. Chemically modified mRNA (cmRNA) is a new form of therapeutic that has been used to induce bone healing. Combined with biomaterials, cmRNA can be used to develop transcript-activated matrices for local protein production with osteoinductive potential. In this study, we aimed to utilize this technology to create bone morphogenetic protein 2 (BMP2) transcript-activated coatings for titanium (Ti) implants. Therefore, different coating methodologies as well as cmRNA incorporation strategies were evaluated. Three different biocompatible biomaterials were used for the coating of Ti, namely, poly-d,l-lactic acid (PDLLA), fibrin, and fibrinogen. cmRNA-coated Ti disks were assayed for transfection efficiency, cmRNA release, cell viability and proliferation, and osteogenic activity in vitro. We found that cmRNA release was significantly delayed in Ti surfaces previously coated with biomaterials. Consequently, the transfection efficiency was greatly improved. PDLLA coating improved the transfection efficiency in a concentration-dependent manner. Lower PDLLA concentration used for the coating of Ti resulted in higher transfection efficiency. Fibrin and fibrinogen coatings showed even higher transfection efficiencies compared to all PDLLA concentrations. In those disks, not only the expression was up to 24-fold higher but also the peak of maximal expression was delayed from 24 h to 5 days, and the duration of expression was also extended until 7 days post-transfection. For fibrin, higher transfection efficiencies were obtained in the coatings with the lowest thrombin amounts. Accordingly, fibrinogen coatings gave the best results in terms of cmRNA transfection. All biomaterial-coated Ti surfaces showed improved cell viability and proliferation, though this was more noticeable in the fibrinogen-coated disks. The latter was also the only coating to support significant amounts of BMP2 produced by C2C12 cells in vitro. Osteogenesis was confirmed using BMP2 cmRNA fibrinogen-coated Ti disks, and it was dependent of the cmRNA amount present. Alkaline phosphatase (ALP) activity of C2C12 increased when using fibrinogen coatings containing 250 ng of cmRNA or more. Similarly, mineralization was also observed that increased with increasing cmRNA concentration. Overall, our results support fibrinogen as an optimal material to deliver cmRNA from titanium-coated surfaces.

Comparative analysis of titanium coating on cobalt-chrome alloy in vitro and in vivo direct metal fabrication vs. plasma spraying

sBackgroundTitanium surface coating on cobalt-chromium (CoCr) alloy has characteristics desirable for an orthopedic implant as follows: strength, osteointegrative capability, and biocompatibility. Creating such a coated surface takes a challenging process and two dissimilar metals are not easily welded. In our study, we utilized additive manufacturing with a 3D printing called direct metal fabrication (DMF) and compared it to the plasma spraying method (TPS), to coat titanium onto CoCr alloy. We hypothesized that this would yield a coated surface quality as acceptable or better than the already established method of plasma spraying. For this, we compared characteristics of titanium-coated surfaces created by direct metal fabrication method (DMF) and titanium plasma spraying (TPS), both in vitro and in vivo, for (1) cell morphology, (2) confocal microscopy images of immunofluorescent assay of RUNX2 and fibronectin, (3) quantification of cell proliferation rate, (4) push-out biomechanical test, and (5) bone histomorphometry.MethodFor in vitro study, human osteoblast cells were seeded onto the coated surfaces. Cellular morphology was observed with a scanning electron microscope. Cellular proliferation was validated with ELISA, immunofluorescent assay. For in vivo study, coated rods were inserted into the distal femur of the rabbit and then harvested. The rods were biomechanically tested with a push-out test and observed for histomorphometry to evaluate the microscopic bone to implant ratio.ResultFor cell morphology observation, lamellipodia and filopodia, a cytoplasmic projection extending into porous structure, formed on both surfaces created by DMF and TPS. The proliferation of the osteoblasts, the DMF group showed a better result at different optic density levels (p = 0.035, 0.005, 0.001). Expression and distribution of fibronectin and Runx-2 genes showed similar degrees of expressions. The biomechanical push-out test yielded a similar result (p = 0.714). Histomorphometry analysis also showed a similar result (p = 0.657).ConclusionIn conclusion, DMF is a method which can reliably create a proper titanium surface on CoCr alloy. The resulting product of the surface shows a similar quality to that of the plasma spraying method, both in vivo and in vitro, in terms of biological and mechanical property.

Growth factors enhanced angiogenesis and osteogenesis on polydopamine coated titanium surface for bone regeneration

Angiogenesis and osteogenesis have been considered as inseparable and critical processes for bone formation and fracture healing. One promising strategy to improve the capability of angiogenesis and osteogenesis on a titanium (Ti) surface involves the fabrication of stable multifunctional release interfaces. This study developed a combined sequential bio-interfacial release system with basic fibroblast growth factor (bFGF) and bone morphogenetic protein 2 (BMP-2) using a polydopamine (PDA) coating on the Ti surface to enhance angiogenesis and osteogenesis. Their surfaces were characterized and their biological properties were evaluated to provide sufficient supporting evidence for successfully fabricating the combined release system. The novel bio-interface demonstrated a significant improvement in surface hydrophilicity; highly effective growth factor adsorption; and moderate, sustained release on the surface of modified Ti substrates. Furthermore, this system surpassingly promoted the initial proliferation, migration and late angiogenic and osteogenic differentiation of HUVECs and MC3T3-E1 in vitro while also augmenting the osseointegration between the implant surface and the surrounding host tissues in vivo. All these results suggest that the fabrication of this novel bio-interface is a practical modification strategy for Ti implants to stimulate angiogenesis and osteogenesis and further optimize its clinical performance.

Sequential release of immunomodulatory cytokines binding on nano-hydroxyapatite coated titanium surface for regulating macrophage polarization and bone regeneration

Inflammation occurs when the material is implanted into the body. As one of the important immune cells in the regulation of inflammation, macrophages are able to remove pathogens and necrotic cells, and polarize to different phenotypes to regulate inflammatory response for tissue regeneration. Therefore, it is known that the sequential release of immunomodulatory cytokines from the surface of titanium (Ti) implants can regulate the polarization of macrophages and promote osseointegration of implants. In order to control the switch of macrophage phenotypes at desired time, we fabricated hydroxyapatite (HAp) nanotube arrays coating on Ti surface, by acid-etching, alkali-heating and HAp coating sequentially. Then we loaded the interleukin-4 (IL-4) encapsulated by poly (lactic-co-glycolic acid) (PLGA) on the bottom of the nanotube and the interferon-γ (IFN-γ) encapsulated by sodium hyaluronate (SH) on the top of the nanotube. Based on the physical and chemical properties of PLGA and SH and the spatial distribution of loaded cytokines, we hypothesized that the programmed release of IFN-γ and IL-4, which made the phenotypic transition of macrophages at a specific time, so as to regulate inflammation and promote osteogenic repair. Our hypothesis created a new type of drug sustained release system, which has high research value for improving the osseointegration of implants.

Koh group influence on titanium surfaces and pure sol-gel silica for enhanced osteogenic activity.

Although, the excellent level of success of titanium surfaces is based on the literature, there are some biological challenges such as unfavorable metabolic conditions or regions of poor bone quality where greater surface bioactivity is desired. Seeking better performance, we hypothesized that silica-based coating via sol-gel route with immersion in potassium hydroxide basic solution induces acceleration of bone mineralization. This in vitro experimental study coated titanium surfaces with bioactive glass synthesized by route sol-gel via hydrolysis and condensation of chemical alkoxide precursor, tetraethylorthosilicate (TEOS) and/or deposition of chemical compound potassium hydroxide (KOH) to accelerate bone apposition. The generated surfaces titanium(T), titanium with potassium hydroxide deposition (T + KOH), titanium with bioactive glass deposition synthesized by sol-gel route via tetraethylorthosilicate hydrolysis (TEOS), titanium with bioactive glass deposition synthesized by sol-gel route via tetraethylorthosilicate hydrolysis with potassium hydroxide deposition (TEOS + KOH) were characterized by 3D optical profilometry, scanning electron microscopy (SEM), transmission electron microscopy (TEM), contact angle by the sessile drop method, x-ray excited photoelectron spectroscopy (XPS) and energy dispersive x-ray spectrometer (EDX). The addition of the KOH group on the pure titanium (T) or bioactive glass (TEOS) surfaces generated a tendency for better results for mineralization. Groups covered with bioactive glass (TEOS, TEOS + KOH) tended to outperform even groups with titanium substrate (T, T + KOH). The addition of both, bioactive glass and KOH, in a single pure titanium substrate yielded the best results for the mineralization process.

Effect of bisphosphonate treatment of titanium surfaces on alkaline phosphatase activity in osteoblasts: a systematic review and meta-analysis

BackgroundBisphosphonate coating of dental implants is a promising tool for surface modification aiming to improve the osseointegration process and clinical outcome. The biological effects of bisphosphonates are thought to be mainly associated with osteoclasts inhibition, whereas their effects on osteoblast function are unclear. A potential of bisphosphonate coated surfaces to stimulate osteoblast differentiation was investigated by several in vitro studies with contradictory results. The purpose of this systematic review and meta-analysis was to evaluate the effect of bisphosphonate coated implant surfaces on alkaline phosphatase activity in osteoblasts.MethodsIn vitro studies that assessed alkaline phosphatase activity in osteoblasts following cell culture on bisphosphonate coated titanium surfaces were searched in electronic databases PubMed/MEDLINE, Scopus and ISI Web of Science. Animal studies and clinical trials were excluded. The literature search was restricted to articles written in English and published up to August 2019. Publication bias was assessed by the construction of funnel plots.ResultsEleven studies met the inclusion criteria. Meta-analysis showed that coating of titanium surfaces with bisphosphonates increases alkaline phosphatase activity in osteoblasts after 3 days (n = 1), 7 (n = 7), 14 (n = 6) and 21 (n = 3) days. (7 days beta coefficient = 1.363, p-value = 0.001; 14 days beta coefficient = 1.325, p-value < 0.001; 21 days beta coefficient = 1.152, p-value = 0.159).ConclusionsThe meta-analysis suggests that bisphosphonate coatings of titanium implant surfaces may have beneficial effects on osteogenic behaviour of osteoblasts grown on titanium surfaces in vitro. Further studies are required to assess to which extent bisphosphonates coating might improve osseointegration in clinical situations.

Graphene oxide coated Titanium Surfaces with Osteoimmunomodulatory Role to Enhance Osteogenesis.

Graphene oxide (GO) and its derivatives are currently being explored for the modification of bone biomaterials. However, the effect of GO coatings on immunoregulation and subsequent impacts on osteogenesis are not known. In this study, GO was coated on pure titanium using dopamine. GO-coated titanium (Ti-GO) surfaces exhibited good biocompatibility, with the ability to stimulate the expression of osteogenic genes, and extracellular matrix mineralization in human mesenchymal stromal cells (hMSCs). Interestingly, it was found that GO-coated surfaces could manipulate the polarization of macrophages and expression of inflammatory cytokines via the Toll-like receptor pathway. Under physiological conditions, Ti-GO activated macrophages and induced mild inflammation and a pro-osteogenic environment, characterized by a slight increase in the levels of proinflammatory cytokines, as well as increased expression of the TGF-β1 and oncostatin M genes. In an environment mimicking acute inflammatory conditions, Ti-GO attenuated inflammatory responses, as shown by the downregulation of proinflammatory cytokines. Conditioned medium collected from macrophages stimulated by Ti-GO played a significant stimulatory role in the osteogenic differentiation of hMSCs. In summary, GO-coated surfaces displayed beneficial immunomodulatory effects in osteogenesis, indicating that GO could be a potential substance for the modification of bone scaffolds and implants.

A zwitterionic hydrogel coated titanium surface with high-efficiency endothelial cell selectivity for rapid re-endothelialization.

Coronary stent implantation is an effective procedure for percutaneous coronary intervention treatment. However, its long-term safety and efficacy are still hindered by the in-stent restenosis and late thrombus formation. Herein, an anti-biofouling and endothelial cell selective zwitterionic hydrogel coating was developed to simultaneously enhance the nonspecific resistance and rapid re-endothelialization of the titanium surface. An endothelial cell selective peptide, REDV, could be simply conjugated on the zwitterionic carboxybetaine (CB) hydrogel to prepare the REDV/CB coating. It was found that the REDV/CB hydrogel layer maintained antifouling properties, which could inhibit the protein adsorption, bacterial adhesion, platelet activation and aggregation, and smooth muscle cell proliferation. More importantly, the co-culture study confirmed that the conjugated REVD peptide could specifically capture endothelial cells and promote their migration and proliferation, and simultaneously decrease the adhesion and proliferation of smooth muscle cells. Therefore, the antifouling and endothelial cell selective coating proposed in this work provides a promising strategy to develop an intravascular stent for promoted re-endothelialization and inhibited neointimal hyperplasia in clinical applications.

Effect of Strontium-Coated Titanium Implants on Osseointegration in Animal Models: A Literature Systematic Review.

This study represents a systematic review of the literature to assess the effectiveness of strontium-coated titanium surfaces on osseointegration in experimental assays with healthy, nonosteoporotic and/or nonosteopenic animals. An electronic search was conducted of the databases MEDLINE/PubMed, Wiley Library, and Web of Science through 2018, with the aim of identifying studies on the osseointegration of titanium implants modified with strontium. A total of 255 papers were found, of which 11 were included in this systematic review. The primary result was the percentage of bone-to-implant contact (BIC) around the titanium implants with or without a strontium-coated surface. The different techniques used to coat titanium surfaces with strontium recorded significant results in terms of the improvement in the implant's quality, as they increased its contact with the bone, bone area, and bone formation, as well as enhanced its biomechanical properties. Nine of 11 studies reported that titanium implants coated with strontium showed significantly higher BIC (P < .001 to P < .05). This coating also improved the implants' biomechanical properties.

5-Dodecanolide interferes with biofilm formation and reduces the virulence of Methicillin-resistant Staphylococcus aureus (MRSA) through up regulation of agr system

Methicillin resistant Staphylococcus aureus (MRSA) is a predominant human pathogen with high morbidity that is listed in the WHO high priority pathogen list. Being a primary cause of persistent human infections, biofilm forming ability of S. aureus plays a pivotal role in the development of antibiotic resistance. Hence, targeting biofilm is an alternative strategy to fight bacterial infections. The present study for the first time demonstrates the non-antibacterial biofilm inhibitory efficacy of 5-Dodecanolide (DD) against ATCC strain and clinical isolates of S. aureus. In addition, DD is able to inhibit adherence of MRSA on human plasma coated Titanium surface. Further, treatment with DD significantly reduced the eDNA synthesis, autoaggregation, staphyloxanthin biosynthesis and ring biofilm formation. Reduction in staphyloxanthin in turn increased the susceptibility of MRSA to healthy human blood and H2O2 exposure. Quantitative PCR analysis revealed the induced expression of agrA and agrC upon DD treatment. This resulted down regulation of genes involved in biofilm formation such as fnbA and fnbB and up regulation of RNAIII, hld, psmα and genes involved in biofilm matrix degradation such as aur and nuc. Inefficacy of DD on the biofilm formation of agr mutant further validated the agr mediated antibiofilm potential of DD. Notably, DD was efficient in reducing the in vivo colonization of MRSA in Caenorhabditis elegans. Results of gene expression studies and physiological assays unveiled the agr mediated antibiofilm efficacy of DD.

Investigation of MoS2 on coated titanium surface plasmon resonance side-polished optical fiber sensor

In this paper, we propose a rigorous configuration of 2D-material using MoS2 coated on titanium (Ti) surface plasmon resonance (SPR) optical fiber sensor. The present configuration is included side-polished optical fiber sensor, titanium (Ti) coating, MoS2 and sensing medium. The SPR sensing device uses a standard single-mode optical fiber with locally removed cladding and a thin Ti film supporting a surface plasma wave (SPW). We perform the performance characteristics of the design sensor in terms of sensitivity, detection accuracy and quality factor. Addition of MoS2 layer on the Ti-SPR will increase the overall sensitivity of the device. The polishing region is covered by metallic layer acted as active sensing medium as the interaction between the SPW, fiber mode and consequently the fiber mode attenuation which depends strongly on the refractive index of analytes. Variations of analytes used such as water, 60% alcohol, sodium chloride, glucose and sucrose can be determined by monitoring changes in the wavelength at which the resonant attenuation of the fiber mode occurs.