Cell Adhesion Tests Research Articles

Prokaryotic Expression and Purification of the Notch Ligand and Its Effect on Hematopoiesis after Carbon Tetrachloride Damage

To express and purify the mouse endothelial cell-targeted recombinant Notch ligand protein mD1R, and to investigate its effect on hematopoiesis after carbon tetrachloride damage. PCR was performed to clone and construct the expression vector pET22b(+)-mD1R. The mD1R successfully transformed into E. coli was induced by IPTG, and purified with Ni2+-beads affinity chromatography. The target protein was detected by SDS-PAGE. The fluorescence-activated cell sorting analysis (FACS), cell adhesion test, immunofluorescence staining and quantitative real-time PCR were employed to detect the endothelial cell-targeted and Notch signaling-activated biological characteristics of mD1R. The carbon tetrachloride mouse model was established to observe the effects of mD1R on the hematopoietic stem cell (HSC), myeloid cells and lymphoid cells by flow cytometry. The Lin-Scal-1+c-Kit+ cells were sorted by magnetic bead, FACS was performed to analyze the cell cycle, and RT-PCR was employed to observe the expression of interleukin (IL)-10. The prokaryotic expression vector was successfully cloned and constructed. The purity and the activity were confirmed in mD1R recombinant protein. The purified mD1R activated the Notch signaling pathway of hematopoietic stem cells in carbon tetrachloride damaged mouse, and internally elevated the number of HSC and long-term HSC to 2.96-fold and 6.18-fold. In addition, mD1R improved the amplification of the myeloid progenitor cells and the myeloid-derived suppressor cells, particularly the granulocyte/monocyte into blood. Mechanistically, the further analyses suggested that Notch pathway could increase the proliferation of HSC and enhance expression of IL-10 after stress injury. A new and activated recombinant Notch ligand protein has been obtained successfully to communicate hematopoietic stem cells and hematopoietic microenvironment. The Notch- mediated intrinsic hematopoiesis has been regulated by the anti-inflammatory factor after stress injury.

Natural polymer-based hydrogels for cartilage regeneration

Purpose: Cartilage is a tough, flexible tissue found throughout the body. It can become damaged because of a sudden injury, such as a sports injury, or gradual wear and tear (osteoarthritis). Injured articular cartilage has a poor regenerative capability, for this reason, tissue engineering may provide a fundamental therapeutic solution to repair cartilage injury. Human articular cartilages are composed of dense extracellular matrix and chondrocytes. One of the major components in the extracellular matrix is hyaluronic acid. The combination of hyaluronic acid with other natural polymers to prepare hydrogel scaffolds may be potentially useful in many tissue engineering applications, including cartilage regeneration. We propose the synthesis of hydrogels based on hyaluronic acid and chitosan by a new strategy of synthesis using di-isocyanates to obtain an interpenetrated network of chitosan and hyaluronic acid. Methods: Different kinds of hydrogels were synthesized using hyaluronic acid (Bioibérica, Spain), natural polymers (gelatine, chitosan) and stabilized with diisocianates. The hydrogels were charged with chondroitin sulfate (Bioibérica, Spain). Morphological Characterization: The hydrogels were characterized by scanning electron microscopy and energy dispersive X-ray microscopy in order to study the morphology and the composition of the hydrogels. Hydrogel Swelling: Dynamic swelling experiments were performed by placing discs of stabilized hydrogels in PBS at 37.0 °C, and measuring their weight gain as a function of time. Biocompatibility: Cytotoxicity in vitro assays (MTT) and cell adhesion tests (Alamar Blue) were performed on the hydrogels using different cell lines to corroborate the biocompatibility of the hydrogels. Results: All the synthesized hydrogels present a high interconnected porosity. The studied hydrogels swell around 200%. Aaround five hours equilibrium is reached and this equilibrium depend on the ratio hyaluronic acid/natural polymer increasing with the amount of hyaluronic acid present on the hydrogel. MTT assay indicated that the extracts collected at different times from the hydrogels are not cytotoxic and could be considered biocompatible. Cell adhesion assay indicates that the hydrogels support cell adhesion and proliferation, and this behaviour is better on SC-loaded hydrogels. Conclusions: Hydrogels based on hyaluronic acid and natural polymers are proposed as scaffolds for tissue engineering. The presence of interconnected porous and the good swelling properties and biocompatibility represent a great advantage for application in cartilage regeneration. The addition of drugs or glycosaminoglycan is being studied to improve the cartilage regeneration.

Nanofibrillated chitosan/polycaprolactone bionanocomposite scaffold with improved tensile strength and cellular behavior

Objective(s): Fabrication of scaffolds with improved mechanical properties and favorable cellular compatibility is crucial for many tissue engineering applications. This study was aimed to improve mechanical and biological properties of polycaprolactone (PCL), which is a common biocompatible and biodegradable synthetic polymer in tissue engineering. Nanofibrillated chitosan (NC) was used as a natural nanofiller to produced PCL nanobiocomposite scaffold with both enhanced mechanical properties and appropriate biological properties. Materials and Methods: Surface morphology and orientation of chitosan nanofibrils was investigated via atomic force microscopy (AFM). PCL/NC suspension solutions with various content of NC were prepared using dimethylformamide as a dipolar solvent to obtain homogenous solutions. The scaffolds were produced through a solvent casting procedure at room temperature. The prepared scaffolds was characterized using scanning electron microscopy (SEM), attenuated total reflection- fourier transform infrared (ATR-IR) spectroscopy, X-Ray diffraction (XRD), uniaxial mechanical testing, contact angle (CA) measurements and swelling and weight loss analysis. In vitro studies were also exceeded to evaluate the cellular compatibility of the prepared scaffolds. Results: The average diameter of chitosan nanofibrils was measured 88±10 nm. The existence of NC in nanocomposite was proven by ATR-FTIR and XRD results. Interestingly, incorporation of 10% of NC into PCL, improved the tensile strength of scaffolds from 2.7 to 6.5 MPa while reduced the elasticity. What is more, water contact angel of the membranes was decreased from 133° to 88˚ which imply more surface wettability of nanocomposite scaffolds in comparison to PCL. Furthermore, the swelling ratio and weight loss rate of bionanocomposites were increased 30% and 2.5%, respectively. MTT biocompatibility assay and cell adhesion test demonstrated superior cellular behavior of the fibroblasts on nanocomposite scaffolds in comparison to pure PCL scaffold.Conclusion: The acquired results expressed that the PCL/NC bionanocomposite can be a reliable candidate for tissue engineering applications.

Development for Wound Dressing Based on Blended Chitosan and Gelatin Hydrogels

Chitosan and gelatin are potential wound dressing materials. However, chitosan takes too much time to degrade and gelatin degrades too fast. As a result, chitosan and gelatin are blended to adjust their degradation rate. The degree of degradation test by means of weight loss and thermogravimetric analyzer after being incubated with lysozyme, which is a common enzyme in body fluid. Optical microscopy was used to observe the materials morphology after immersed in water. Finally, fibroblast cells were cultured with various material extracts to examine cell adhesion In Vitro. Cell adhesion tests showed there are no negative effect on cells. Therefore, there is no cell toxicity of chitosan on cells. Chitosan and gelatin can be promising wound dressing raw materials in future.

Characterization of Porous Hyaluronan/β-TCP Scaffolds Prepared through Heterogeneous Crosslinking

Porous Hyaluronan/β-tricalcium phosphate composite scaffolds were synthesized through lyophilizing and subsequent heterogeneous crosslinking method. The morphology of the composite scaffolds were investigated by scanning electron microscopy (SEM). The swelling behavior, mechanical property, degradation behavior and cell adhesion ability of samples were also studied. The results revealed that hyaluronan mainly contributed to the polymer matrix and water adsorption, whereas β-TCP acted as a reinforcement to strengthen the porous structure, while too much β-TCP would make the structure collapse. The pose size of obtained scaffolds ranges from100μm to 200μm and the porosity decreased with the increase of β-TCP content. The degradation behavior and cell adhesion test indicated that increasing hyaluronan concentration can effectively improve the degradability of scaffolds and the incorporation of β-TCP improved the cell adhesion performance. Thus a simple way to prepare hyaluronan-based composite scaffolds was provided, which could be potentially used as an tissue engineering material.

Preparation, biocompatibility, and biotribological properties of TiN-incorporated graphite-like amorphous carbon bio-ceramic composite films

In this work, TiN-incorporated graphite-like amorphous carbon (a-GLC) bioceramic films were successfully fabricated on Ti alloy (Ti6Al4V) using the magnetron sputtering technique. The biocompatibility and biotribological properties of the TiN/a-GLC-coated Ti alloy were evaluated. Based on the clinical application, the microstructure, biocompatibility, histomorphological observation, and mechanical properties were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, nanoindentation test, and in vitro and in vivo tests including MTT, cell adhesion test, and slice observation of hard tissues. These techniques confirmed that there was strong bonding between the Ti alloy and the TiN/a-GLC film. In addition, face-centered cubic TiN and hexagonal close-packed Ti were clearly detected in the TiN/a-GLC films. A partial nanocomposite structure, comprised of homogeneous nanoclusters and crystalline particles, was detected in the amorphous matrix. Cell adhesion and MTT test results indicated that the TiN/a-GLC film could promote cell attachment and proliferation. Phase composition and the film morphology were determined to be the crucial factors that contributed to the improved biocompatibility. The biotribological property test showed that the TiN/a-GLC film with a Ti content of 7.8at% had the lowest coefficient of friction (COF) of 0.076 and the lowest wear rate of 1.76 × 10–6mm3(Nm)–1. The low COF was attributed to the superior mechanical properties of the TiN/a-GLC composite film. The TiN/a-GLC-coated Ti alloy implants were placed subcutaneously into rabbits for different time periods, and the tissue response decreased significantly as compared to that of the pure a-GLC film. The excellent biocompatibility and function reliability of the TiN/a-GLC bioceramic films showed that they are potential candidates for bone tissue implants.

Porous Titanium Associated with CaP Coating: In Vivo and In Vitro Osteogenic Performance

This in vitro and in vivo study compared different topographies of Ti samples (dense, porosity of 30% and 40%) with or not CaP coating, prepared by powder metallurgy. Osteogenic cells from newborn rat calvaria were plated onto the samples and cell adhesion (24 hours), alkaline phosphatase activity (7 and 10 days) and mineralization nodules (14 days) were assessed. Sixteen rabbits were used for in vivo study. Each animal received three non-treated and three treated implants in the right or left tibia, respectively. Histometric evaluation of bone-implant contact (BIC) were assessed at 1, 2, 4 and 8 weeks. Metallographic analysis revealed porosities of 30% and 40%, with pore size ranging from 250 to 350 µm. Cell adhesion test and ALP revealed similar cell behavior, independently of topography and CaP coating (P > 0.05%). However, CaP coating combined with porosity of 40% influenced positively the mineralized matrix formation (P < 0.05%). CaP-coated implants showed higher BIC than non-CaP implants and BIC was different between the short (1 and 2 weeks) and long (4 and 8 weeks) healing periods (P < 0.05%). The results suggest that CaP coating combined with 40% porosity implants allowed greater osteogenesis in vitro and increased BIC in vivo.

Development of phosphonated alginate derivatives as coating material on titanium surface for medical application

Alginate derivative was prepared to be coated on titanium surface for improving osseointegration. It was modified by reaction of alginate and 3-aminopropylphosphonic acid. The phosphonate group of P-alginate was identified by 31P NMR. There was a specific peak derived from phosphonate group at about 24 ppm form external standard. X-Ray photoelectron spectroscopy (XPS) and water contact angle measurement were carried out for characterization of titanium surface treated with P-alginate. To confirm toxicity, cytotoxicity test was performed. Cell-adhesion test was demonstrated to improve cell adhesion on titanium surface.

Composite fibrous glaucoma drainage implant

Glaucoma is a frequent reason of loss vision. It is usually caused by increased intraocular pressure leading to damage of optic nerve head. This work deals with the development of fibrous structure suitable for glaucoma drainage implants (GDI). Commercially produced metallic glaucoma implants are very effective in lowering intraocular pressure. However, these implants may cause adverse events such as damage to adjacent tissue, fibrosis, hypotony or many others [1]. The aim of this study is to reduce undesirable properties of currently produced drains and improve their properties by creating of the composite fibrous drain for achieve a normal intraocular pressure. Two types of electrospinning technologies were used for the production of very small tubular implants. First type was focused for production of outer part of tubular drain and the second type of electrospinning method made the inner part of shape follows the connections of both parts. Complete implant had a special properties suitable for drainage of fluid. Morphological parameters, liquid transport tests and in-vitro cell adhesion tests were detected.

Quantitating ADCC against adherent cells: Impedance-based detection is superior to release, membrane permeability, or caspase activation assays in resolving antibody dose response.

Monoclonal antibody-based immunotherapeutics will dominate Pharma's next generation of blockbuster drugs, and Fc-associated functions, including antibody dependent cellular cytotoxicity (ADCC) are among the highly desired activities mediated by these antibodies. Therefore, quantitative evaluation of ADCC is required during drug development. Our objective was to find the most suitable and reliable nonradioactive method for quantitative analysis of in vitro ADCC against adherent cells, which often serve as models for solid tumors. The test system was comprised the HER2 positive JIMT-1 cells targeted by the specific therapeutic antibodies trastuzumab (Herceptin® ) and pertuzumab (Perjeta® ). These cells are resistant to the direct biological effects of these antibodies, and, therefore, allow the isolated assessment of ADCC. We compared fluorescein diacetate (FDA) and carboxyfluorescein diacetate succinimidyl ester (CFSE) release as a fluorescent alternative to 51 Cr release; propidium iodide (PI) uptake revealing increased membrane permeability; the PanToxiLux assay measuring ADCC induced pro-apoptotic protease activity in flow cytometry; and an impedance-based real time cell adhesion test. We found that release assays are compromised by high spontaneous release of the label. PI uptake could not differentiate well between spontaneous NK activity and specific ADCC. The PanToxiLux assay, besides allowing for shorter assay times, offers improvement over the previous approaches in distinguishing spontaneous and antibody mediated NK action, but, probably owed to the prolonged detached state of adherent target cells, only at highly saturating antibody concentrations. In the case of adherent target cells, impedance-based cell analysis attains functional information exclusively on the target cells without having to label them for distinguishing from effectors or assay readout. It also allows continuous monitoring for days, and specifically detects target cell detachment, as the final functional consequence of ADCC. The sensitivity of this method even allows for quantitating the additivity and saturability of ADCC as a function of antibody concentration. We conclude that impedance-based assays are the most sensitive for quantitatively assessing in vitro ADCC on adherent target cells. © 2017 International Society for Advancement of Cytometry.

From waste to high-value product: Jackfruit peel derived pectin/apatite bionanocomposites for bone healing applications

Public requirements encouraged by the current asset framework drive industry to expand its general effectiveness by enhancing existing procedures or finding new uses for waste. Thus, the aim of this study was the isolation, fabrication, and characterization of pectin derived from jackfruit (Artocarpus heterophyllus) peels and the generation of hybrid of pectin (P)/apatite (HA) (P/HA) bionanocomposites. In this process, the natural pectin polymer derived from the peel of jackfruits was used in different concentrations for the fabrication of HA bionanocomposites. Characterization of the isolated pectin and bionanocomposites samples was performed with 1H NMR and 13C NMR, FTIR, XRD, SEM-EDX, and HR-TEM. Cytocompatibility, ALP, fibroblast stem cells, anti-inflammatory and cell adhesion testing of the fabricated bionanocomposites was showed good biocompatibility. Our results signify that the fabricated bionanocomposites might be applicable as bone graft materials.

Biocomposites Based on Biogenous Mineral for Inducing Biomimetic Mineralization

In this work, we focused on the potential of biogenous mineral from Cuttlefish bone for inducing biomimetic mineralization with further biomedical applications. We demonstrate the formation of strong and flexible hydrogels via physical immobilization of cuttlefish bone powder in the presence of bovine gelatin and alginate. The properties of hydrogels loaded with biogenous mineral, with a commercial bone substitute, with commercial nano-hydroxyapatite and in situ generated hydroxyapatite. In vitro cell adhesion tests demonstrated that the new developed hydrogels showed a promising cell adhesion.

Fabrication and Characterization of Polyphosphazene/Calcium Phosphate Scaffolds Containing Chitosan Microspheres for Sustained Release of Bone Morphogenetic Protein 2 in Bone Tissue Engineering.

Bone morphogenetic protein 2 has a major role in promoting bone regeneration in tissue engineering scaffolds. Growth factor release rate is a remaining crucial problem in these systems. The aim of this study was to fabricate and characterize a novel calcium phosphate/polyphosphazenes porous scaffold for the sustained release of bone morphogenetic protein 2 in bone tissue engineering. Polyphosphazenes were substituted with 2-dimethylaminoethanol and evaluated by GPC, NMR, and in vitro degradation. Calcium phosphate porous samples were prepared from hydroxyapatite nanoparticles and naphthalene using the sintering method at 1250°C before being composited with poly(dimethylaminoethanol)phosphazenes containing chitosan microspheres loaded with bone morphogenetic protein 2. The characteristics and biodegradability of the product were evaluated by SEM, XRD, and in vitro degradation. Moreover, the release rate and mechanical properties of the scaffolds were investigated. The release behavior was found to be sustained since the scaffolds had been fabricated from polyphosphazenes with a low degradation rate. The release rates of the scaffolds were observed to increase with increasing chitosan microspheres content from 10 to 30%. The bioactivity of the scaffolds depended on the release rate of growth factor while bone morphogenetic protein 2 was able to induce an osteoblast proliferation. The results of cell adhesion and cell viability tests showed that scaffolds displayed a non-toxic behavior and western blot analyses confirmed that the scaffolds loaded with growth factor increased the osteogenic differentiation potential of cells when compared with scaffolds alone. These results demonstrate that these scaffolds can be successfully utilized in bone tissue engineering.

Semifluorinated Synergistic Nonfouling/Fouling-Release Surface.

The preparation of a fluorine-containing synergistic nonfouling/fouling-release surface, using a b-PFMA-PEO asymmetric molecular brush possessing both poly(ethylene glycol) (PEO) and poly(2,2,2-trifluoroethyl methacrylate) (PFMA) side chains densely distributed on the same repeat unit along the polymeric backbone, is reported. On the basis of the poly(Br-acrylate-alkyne) macroagent comprising two functionalities (alkynyl and 2-bromopropionate), which is prepared by reversible addition-fragmentation chain transfer homopolymerization of a new trifunctional acrylate monomer of Br-acrylate-alkyne, b-PFMA-PEO asymmetric molecular brushes are obtained by concurrent atom transfer radical polymerization and Cu-catalyzed azide/alkyne cycloaddition "click" reaction in a one-shot system. A spin-cast thin film of the b-PFMA-PEO asymmetric molecular brush exhibits a synergistic antifouling property, in which PEO side chains endow the surface with a nonfouling characteristic, whereas PFMA side chains display the fouling-release functionality because of their low surface energy. Both protein adsorption and cell adhesion tests provided estimates of the antifouling activity of the asymmetric molecular brush surfaces, which was demonstrated to be influenced by the degree of polymerization of the backbone and the length of the PEO and PFMA side chains. With compositional heterogeneities, all asymmetric molecular brush surfaces show considerable antifouling performance with much less protein adsorption (at least 45% off, up to 75% off) and cell adhesion (at least 70% off, up to 90% off) in comparison with a bare surface.

Composites Produced from Natural Rubber and Chrome-Tanned Leather Wastes: Evaluation of their In Vitro Toxicological Effects for Application in Footwear and Textile Industries

A new composite has been developed from natural rubber and chrome-tanned leather waste for use in footwear and textile industries. The contribution of this material to environmental quality and sustained development should be highligh because chrome tanned leather wastes, a major environmental problem, can be recycled. However, the safety of this new material for human use is questionable, as it is already well reported in the literature that chromium, particularly in its hexavalent oxidation state, can be genotoxic and carcinogenic to living beings. Thus, the aim of this study was to evaluate in vitro biocompatibility of this composite material for possible use in the footwear and textile industries, through cytotoxicity, cell adhesion, and genotoxicity tests. Inductively coupled plasma optical emission spectrometry (ICP-OES) was used to measure both concentrations of total and hexavalent chromium. Based on the findings, it was concluded that the composite exhibits low levels of cytotoxicity and genotoxicity, and possesses favorable properties for initial cell adhesion. Furthermore, it was verified that the composites released low concentrations of chromium and that the predominant species released would be trivalent chromium. The results of the present study open the possibility of the incorporation of solid residues of tanned leather into chromium without necessarily the chromium contained in these residues influences the toxicity and genotoxicity of this new material.

Prevention of intra-abdominal adhesion using electrospun PEG/PLGA nanofibrous membranes

The use of physical barriers, such as nanofiber membranes, is a potential method to prevent adhesion formation after surgery. In this study, we fabricated electrospun composite poly(ethylene glycol) (PEG)/poly(lactic-co-glycolic) (PLGA) nanofibrous membrane to prevent abdomen adhesion; this composite acts as a barrier between cecum and the surrounding tissues without interrupting mass transfer and cecum healing. PEG/PLGA nanofibrous membranes consisting of 0% (P0), 5% (P1), 10% (P2), 15% (P3), 20% (P4), and 25% (P5) PEG were prepared, and their physicochemical properties were characterized. The P0 shows the highest thermostability, whereas P1 exhibited the most homogenous morphology, the narrowest diameter distribution, and the largest ultimate stress and strain. In vitro cell adhesion and proliferation tests using fibroblasts indicate that all nanofibrous membranes inhibited cell proliferation, with P1 showing the lowest degree of cell attachment. In vivo application of nanofibrous membranes on the repaired site of rat cecum model demonstrated that all of the membranes prevent adhesion formation to a certain extent. We concluded based on gross observation, histological analysis, and functional assays that P1 served as an effective anti-adhesion membrane after cecum surgery in a clinical setting.

In vitro biocompatibility of a ferrimagnetic glass-ceramic for hyperthermia application

Ferrimagnetic glass-ceramics containing magnetite crystals were developed for hyperthermia applications of solid neoplastic tissue. The present work is focused on in vitro evaluation of the biocompatibility of these materials, before and after soaking in a simulated body fluid (SBF). X-ray diffraction, scanning electron microscopy, atomic absorption spectrophotometry, X-ray photoelectron spectrometry and pH measurements were employed in glass-ceramic characterisation. The free-radical mediated reactivity of the glass-ceramic was evaluated by Electron Paramagnetic Resonance (EPR) spin trapping. Cell adhesion and proliferation tests were carried out by using 3T3 murine fibroblasts. Cytotoxicity was performed by qualitative evaluation of human bone osteosarcoma cells U2OS cell line. The results show that almost two times more 3T3 cells proliferated on the samples pre-treated in SBF, compared with the untreated specimens. Moreover a decrease of confluence was observed at 48 and 72h for U2OS cells exposed to the untreated glass-ceramic, while the powder suspensions of glass-ceramic pre-treated in SBF did not influence the cell morphology up to 72h of exposition. The untreated glass-ceramic exhibited Fenton-like reactivity, as well as reactivity towards formate molecule. After pre-treatment with SBF the reactivity towards formate was completely suppressed. The concentration of iron released into the SBF solution was below 0.1ppm at 37°C, during one month of soaking. The different in vitro behaviour of the samples before and after SBF treatment has been correlated to the bioactive glass-ceramic surface modifications as detected by morphological, structural and compositional analyses.

Facile Preparation of Photoactivatable Surfaces with Tuned Substrate Adhesiveness.

This paper describes a facile method for the preparation of photoactivatable substrates with tuned surface density of an extracellular matrix peptide to resolve the impacts of biochemical and mechanical cues on collective cell migration. The controllability of surface ligand density was validated by cell adhesion and migration tests, complemented with fluorescence observation of an alternative ligand. Depending on the surface ligand density, HeLa cells either kept or lost collective characteristics. The present materials will be useful to address mechanobiology of collective cell migration.

Copper incorporated microporous chitosan-polyethylene glycol hydrogels loaded with naproxen for effective drug release and anti-infection wound dressing

Copper ion (Cu2+) incorporated microporous chitosan-polyethylene glycol films were developed as a multipotent wound dressing material. The mechanical properties, swelling behavior and moisture permeability of hydrogel films with varying Cu2+ concentration and the release of Cu2+ from films were evaluated. The results revealed the enhanced mechanical stability of films with increasing Cu2+ concentration without compromising moisture permeability and absorption capability of wound exudates. Microporous surface and swollen micropores in hydrated conditions were confirmed from morphological analysis. Degradation studies in lysozyme and H2O2 demonstrated increasing stability of films with increasing Cu2+ concentration up to 30days. Antibacterial tests revealed superiority in inhibiting biofilm formation in comparison to chitosan films. In vitro drug release, MTT assays and cell adhesion tests demonstrated the efficiency of Cu2+ incorporated hydrogels in sustained drug release and antibacterial activity with excellent keratinocyte cell response.

Direct silanization of zirconia for increased biointegration.

The use of zirconia-based ceramics in biomedical devices is broad and well accepted, especially in dental implants. However, they do not bond naturally to bone, therefore to ensure fixation surgeons typically rely on roughness at different scales, or on cements. Alternatively in this work we present a new perspective of surface modification through chemistry to enhance the interaction between surface and biological environment, without the downsides of roughness. This surface treatment is proposed for zirconia, which allowed a direct silanization of its surface and a higher cell attachment. The results of this research may open the possibility for the next generation of bioinert ceramic implants with more advanced tailored surfaces for increased osseointegration.