Response Of Osteoblast-like Cells Research Articles

Polypyrrole zinc-doped film deposited on a plasma-treated surface improves the tribocorrosion behavior of titanium dental implant material

Polypyrrole (PPy) films have shown attractive electrochemical properties and promising implant applications when electrodeposited on plasma electrolytic oxidation (PEO) surfaces. Although the PEO + PPy surface demonstrates excellent mechanical and electrochemical performance, there are no reports on the effects of combined corrosion and mechanical interactions, which simulates the oral environment. In addition, since implant failures may be related to deficiencies in the osseointegration process, the electrodeposition of zinc (Zn) on the coating can promote an osteogenic substrate. Therefore, we aimed to investigate the tribocorrosion behavior of PEO-treated surfaces coated with PPy films with and without Zn and whether such PPy films affect the cellular response of MG-63 human osteoblast-like cells. Titanium discs with machined and PEO-modified surfaces were considered as controls. The experimental groups used PEO surfaces followed by electrodeposition of PPy (PEO + PPy) and PPy and Zn (PEO + PPy/Zn). The surfaces' physical-chemical properties were assessed. The tribocorrosion tests were run under free potential and potentiostatic (anodic and cathodic potentials) conditions using a pin-on-disk tribosystem simulating the oral environment (load = 1 N, stroke = 2 mm, number of cycles = 2000). Electrochemical impedance spectroscopy was performed before and after tribocorrosion to analyze the changes in corrosion kinetics. Worn areas were observed using white-light-interferometry and scanning electron microscopy. For in vitro cell experiments, the viability, number of live/dead cells, adhesion ability, and mineralization property of cells were evaluated. Our outcomes revealed that PPy films improved tribocorrosion performance by exhibiting more positive OCP values and slight fluctuation and variation of the current value during the sliding phases. In general, due to the films' morphology and “cushion effect”, PPy films enhanced the surface resistance against corrosion and wear, indicating a low total weight loss (Kwc) and wear-corrosion degradation mechanism. The PEO + PPy/Zn surface was cytocompatible, enhancing the cell adhesion and proliferation on the surface. Overall, PPy films represent a promising coating to improve the stability and lifetime of biomedical implants.

Exploring the effects of micro-nano surface topography on MG63 osteoblast-like cell responses: An in vitro study

The osseointegration property of dental and bone implants is a crucial factor for proper healing, and is entirely influenced by the surface characteristics, including surface chemistry and roughness. However, the molecular mechanisms for osteoconductivity remain unclear. This study aimed to investigate the effective cellular interactions and stimulatory effect of surface topology on the differentiation of osteoblast-like cells using in-vitro cell culture. Three different substrates, including micro (MS), nano (NS), and combined micro-nano structures (MNS), were used to evaluate the interaction between cells and surface topography. The fabricated membranes were characterized with FESEM for pore study and XRD analysis to identify the Aluminum oxide. The cell count significantly decreased for electropolished (EP) and microstructure (MS) substrates. The expression level of osteogenesis-related genes during differentiation, including Runt-related transcription factor 2 (Runx2), type I Collagen (Col-I), and Osteocalcin (OC) was determined by real-time PCR. The results showed that MG63 osteoblast-like cells cultured on the MNS and NS substrates had significantly higher expression levels of these genes than those cultured on the MS. Additionally, flow cytometry results showed that F-actin levels were higher in MG63 cells cultured on NS and MNS substrates than those cultured on MS. The desirable biological response of MG63 cells to MNS substrates suggests that electrochemical anodization after acid etch and powder blasting treatments is a possible process for high-grade osseointegration in-vivo.

Functionalization of zirconia ceramic with fibronectin proteins enhanced bioactivity and osteogenic response of osteoblast-like cells.

Introduction: To overcome the genuine bioinert properties of zirconia ceramic, functionalization of the surface with the bioactive protein fibronectin was conducted. Methods: Glow discharge plasma (GDP)-Argon was first used to clean the zirconia surface. Then allylamine was treated at three different powers of 50W, 75W, and 85W and immersed into 2 different fibronectin concentrations (5µg/ml and 10µg/ml). Results and Discussion: After surface treatment, irregularly folded protein-like substances were attached on the fibronectin coated disks, and a granular pattern was observed for allylamine grafted samples. Infrared spectroscopy detected C-O, N-O, N-H, C-H, and O-H functional groups for fibronectin treated samples. Surface roughness rose and hydrophilicity improved after the surface modification, with MTT assay showing the highest level of cell viability for the A50F10 group. Cell differentiation markers also showed that fibronectin grafted disks with A50F10 and A85F10 were the most active, which in turn encouraged late-stage mineralization activity on 21d. Up-regulation of osteogenic related mRNA expression from 1d to 10d can be observed in RT-qPCR data for ALP, OC, DLX5, SP7, OPG and RANK biomarkers. These physical and biological properties clearly indicate that an allylamine and fibronectin composite grafted surface significantly stimulated the bioactivity of osteoblast-like cells, and can be utilized for future dental implant applications.

Modulation of MG-63 Osteogenic Response on Mechano-Bactericidal Micronanostructured Titanium Surfaces.

Despite recent advances in the development of orthopedic devices, implant-related failures that occur as a result of poor osseointegration and nosocomial infection are frequent. In this study, we developed a multiscale titanium (Ti) surface topography that promotes both osteogenic and mechano-bactericidal activity using a simple two-step fabrication approach. The response of MG-63 osteoblast-like cells and antibacterial activity toward Pseudomonas aeruginosa and Staphylococcus aureus bacteria was compared for two distinct micronanoarchitectures of differing surface roughness created by acid etching, using either hydrochloric acid (HCl) or sulfuric acid (H2SO4), followed by hydrothermal treatment, henceforth referred to as either MN-HCl or MN-H2SO4. The MN-HCl surfaces were characterized by an average surface microroughness (Sa) of 0.8 ± 0.1 μm covered by blade-like nanosheets of 10 ± 2.1 nm thickness, whereas the MN-H2SO4 surfaces exhibited a greater Sa value of 5.8 ± 0.6 μm, with a network of nanosheets of 20 ± 2.6 nm thickness. Both micronanostructured surfaces promoted enhanced MG-63 attachment and differentiation; however, cell proliferation was only significantly increased on MN-HCl surfaces. In addition, the MN-HCl surface exhibited increased levels of bactericidal activity, with only 0.6% of the P. aeruginosa cells and approximately 5% S. aureus cells remaining viable after 24 h when compared to control surfaces. Thus, we propose the modulation of surface roughness and architecture on the micro- and nanoscale to achieve efficient manipulation of osteogenic cell response combined with mechanical antibacterial activity. The outcomes of this study provide significant insight into the further development of advanced multifunctional orthopedic implant surfaces.

Effects of Titanium Implant Surface Topology on Bone Cell Attachment and Proliferation in vitro.

PurposeTitanium is commonly used for implants because of its corrosion resistance and osseointegration capability. It is well known that surface topology affects the response of bone tissue towards implants. In vivo studies have shown that in weeks or months, bone tissue bonds more efficiently to titanium implants with rough surfaces compared to smooth surfaces. In addition, stimulating early endosseous integration increases the long-term stability of bone-implants and hence their clinical outcome. Here, we evaluated the response of human MG-63 osteoblast-like cells to flat and solid, compared to rough and porous surface topologies in vitro 1–6 days post seeding. We compared the morphology, proliferation, and attachment of cells onto three smooth surfaces: tissue culture (TC) plastic or microscope cover glasses, machined polyether-ether-ketone (PEEK), and machined solid titanium, to cells on a highly porous (average Ra 22.94 μm) plasma-sprayed titanium surface (composite Ti-PEEK spine implants).MethodsWe used immuno-fluorescence (IF) and scanning electron microscopy (SEM), as well as Live/Dead and WST-1 cell proliferation assays.ResultsSEM analyses confirmed the rough topology of the titanium implant surface, compared to the smooth surface of PEEK, solid titanium, TC plastic and cover glasses. In addition, SEM analyses revealed that MG-63 cells seeded onto smooth surfaces (solid titanium, PEEK) adopted a flat, planar morphology, while cells on the rough titanium surface adopted an elongated morphology with numerous filopodial and lamellipodial extensions interacting with the substrate. Finally, IF analyses of focal adhesions (vinculin, focal adhesion kinase), as well as proliferation assays indicate that MG-63 cells adhere less and proliferate at a slower rate on the rough than on a smooth titanium surface.ConclusionThese observations suggest that bone-forming osteoblasts adhere less strongly and proliferate slower on rough compared to smooth titanium surfaces, likely promoting cell differentiation, which is in agreement with other porous implant materials.

Fabrication of a porous hydroxyapatite scaffold with enhanced human osteoblast-like cell response via digital light processing system and biomimetic mineralization

In this study, we developed a photocurable hydroxyapatite (HA) slurry with 43 vol% HA content for a digital light processing (DLP) printing system. We assumed that the biomimetic mineralization coated on the surface of the DLP-printed porous HA scaffold could improve the in vitro cell response of the DLP-printed scaffold, such as in regards to cell adhesion or proliferation. Therefore, to verify the influence of biomimetic mineralization coated on the DLP-printed scaffold, the characteristics of the biomimetic mineralized HA scaffold (S-HA scaffold) were compared with those of HA bulk and HA scaffolds. It was found that the influences of the biomimetic mineralization on the structural characteristics of the HA scaffold were negligible, such as those on the apparent pore size, porosity, and compressive strength. However, the biomimetic mineralization coated on the surface of the HA scaffold improved the cell adhesion, proliferation, ALP activity, and gene expressions (runx2 and osteopontin) relative to the HA bulk and HA scaffolds, owing to the interconnected pores and increased nano-topology from the biomimetic mineralization. Therefore, we revealed that the in vitro cell response of a DLP-printed HA scaffold could be enhanced by biomimetic mineralization.

Comprehensive in vitro studies of novel sol gel-derived Zr4+/Zn2+ co-substituted bioactive glass with enhanced biological properties for bone healing

The synergetic osteogenic effects of zirconium (Zr) and zinc (Zn) along with bioactive glasses (BGs) have been proposed for bone implantation. We incorporated Zn into Zr-modified 58S-BG (Zr content: 5 mol. %) and characterized the structural, morphological, biological, and antibacterial properties of the proposed composite using various methods. Energy-dispersive X-ray spectroscopy analysis showed the calcium to phosphate ratio of ~1.68, after one week of conditioning in SBF. Biological assays also revealed a higher stimulating effect of the biomaterial composite on the proliferation and osteogenic response of osteoblast-like cells compared to only BGs. Antibacterial studies showed ~ 5-10% reduction in resistivity of methicillin-resistant Staphylococcus Aureus (MRSA) bacteria against the biomaterial composite in comparison to the control specimen. The incorporation of Zn led to potential outlooks for implantations instead of Zn-free specimens since they promoted the cell proliferation of MC3T3 cells as well as resistivity toward MRSA bacteria.

Effect of Cobalt Addition on the Cytotoxicity and Cell Attachment of Titanium Alloys

Various types of titanium base alloys are utilized as implant materials and as minis crews in orthodontics. The purpose of the current study is to enhancing titanium-based alloys with the additions of Cobalt in different percentage (5%, 10%, and 15%) to enhance primary osteoblast attachment and implant tissue incorporation. the reaction between human MG63 osteoblast-like cells and titanium – cobalt alloy face is substantial in biomaterials and tissue engineering field. The major target was to estimate the proteomic response of MG63 osteoblast-like cells in various cobalt percentages. The samples with and without cobalt addition was produced by using powder technology in order to get an acceptable initial surface roughness. Also sample characterizations includes (scanning electron microscopy (SEM), X-ray diffraction (XRD), vitro test (Biocompatibility MTT assay with MG-63 Cells). Results obtained from XRD and microstructure observations, sample without cobalt addition refer to an alloy with single I± phase, while after the additions of cobalt in different percentage (5%, 10%, 15%) the samples consist of two I±-Ti and intermetallic compound Ti2Co and the amount of Ti2Co phase slightly increase with increasing cobalt content. From MTT assays Proliferation and cells attachment of MG63 were cultured after 2 days Cells grown for the pure titanium alloys possess finer and circular confines compared with the grown cells at (titanium – cobalt) alloys with all cobalt percentages. Rising cobalt percentage makes the MG63 cell sharper and enlarges which means cobalt aid to enhancing both cell proliferation and growth. Cytotoxicity Cell Viability results was kept, exhibition no kind of attack caused by titanium or cobalt materials, The feature, of cobalt additions, in contrast to commercial pure titanium alloys, is the presence of active and non- cytotoxic compound (Ti2Co) which presents several attractive features, make the surface more attractive to the bone . How to Cite this Article Pubmed Style Fatimah J. Al-Hasani. of Cobalt Addition on the Cytotoxicity and Cell Attachment of Titanium Alloys. SRP. 2020; 11(5): 804-813. doi:10.31838/srp.2020.5.119 Web Style Fatimah J. Al-Hasani. of Cobalt Addition on the Cytotoxicity and Cell Attachment of Titanium Alloys. http://www.sysrevpharm.org/?mno=131488 [Access: March 30, 2021]. doi:10.31838/srp.2020.5.119 AMA (American Medical Association) Style Fatimah J. Al-Hasani. of Cobalt Addition on the Cytotoxicity and Cell Attachment of Titanium Alloys. SRP. 2020; 11(5): 804-813. doi:10.31838/srp.2020.5.119 Vancouver/ICMJE Style Fatimah J. Al-Hasani. of Cobalt Addition on the Cytotoxicity and Cell Attachment of Titanium Alloys. SRP. (2020), [cited March 30, 2021]; 11(5): 804-813. doi:10.31838/srp.2020.5.119 Harvard Style Fatimah J. Al-Hasani (2020) of Cobalt Addition on the Cytotoxicity and Cell Attachment of Titanium Alloys. SRP, 11 (5), 804-813. doi:10.31838/srp.2020.5.119 Turabian Style Fatimah J. Al-Hasani. 2020. of Cobalt Addition on the Cytotoxicity and Cell Attachment of Titanium Reviews in Pharmacy, 11 (5), 804-813. doi:10.31838/srp.2020.5.119 Chicago Style Fatimah J. Al-Hasani. Effect of Cobalt Addition on the Cytotoxicity and Cell Attachment of Titanium Alloys. Systematic Reviews in Pharmacy 11 (2020), 804-813. doi:10.31838/srp.2020.5.119 MLA (The Modern Language Association) Style Fatimah J. Al-Hasani. Effect of Cobalt Addition on the Cytotoxicity and Cell Attachment of Titanium Alloys. Systematic Reviews in Pharmacy 11.5 (2020), 804-813. Print. doi:10.31838/srp.2020.5.119 APA (American Psychological Association) Style Fatimah J. Al-Hasani (2020) of Cobalt Addition on the Cytotoxicity and Cell Attachment of Titanium Reviews in Pharmacy, 11 (5), 804-813. doi:10.31838/srp.2020.5.119

Beta-Titanium Alloy Covered by Ferroelectric Coating–Physicochemical Properties and Human Osteoblast-Like Cell Response

Beta-titanium alloys are promising materials for bone implants due to their advantageous mechanical properties. For enhancing the interaction of bone cells with this perspective material, we developed a ferroelectric barium titanate (BaTiO3) coating on a Ti39Nb alloy by hydrothermal synthesis. This coating was analyzed by scanning electron and Raman microscopy, X-ray diffraction, piezoresponse force microscopy, X-ray photoelectron spectroscopy, nanoindentation, and roughness measurement. Leaching experiments in a saline solution revealed that Ba is released from the coating. A progressive decrease of Ba concentration in the material was also found after 1, 3, and 7 days of cultivation of human osteoblast-like Saos-2 cells. On day 1, the Saos-2 cells adhered on the BaTiO3 film in higher initial numbers than on the bare alloy, but they were less spread, and their initial proliferation rate was slower. These cells also contained a lower amount of beta1-integrins and vinculin, i.e., molecules involved in cell adhesion, and produced a lower amount of collagen I. This cell behavior was attributed to a higher surface roughness of BaTiO3 film rather than to its potential cytotoxicity, because the cell viability on this film was very high, reaching almost 99%. The amount of alkaline phosphatase, an enzyme involved in bone matrix mineralization, was similar in cells on the BaTiO3-coated and uncoated alloy, and on day 7, the cells on BaTiO3 film attained a higher final cell population density. These results indicate that after some improvements, particularly in its roughness and stability, the hydrothermal ferroelectric BaTiO3 film could be promising coating for improved osseointegration of bone implants.

Evidence of Modular Responsiveness of Osteoblast-Like Cells Exposed to Hydroxyapatite-Containing Magnetic Nanostructures.

Simple SummaryCurrent research on nanocomposite materials with tailored physical–chemical properties is increasingly advancing in biomedical applications for bone regeneration. In this study, occurrence of differential responsiveness to dextran-grafted iron oxide (DM) nanoparticles and to their hybrid nano-hydroxyapatite (DM/n-HA) counterpart was investigated in human-derived, osteoblast-like cells. Sensitivity of cells in the presence of DMs or DM/n-HAs was evaluated in terms of cytoskeletal dynamics. Remarkably, it was shown that effects triggered by the DM are no more retained when DM is embedded onto DM/n-HA nanocomposites. In parallel, analyses on the expression of genes involved in (a) intracellular signaling pathways triggered by ligands or cell interactions with elements of the extracellular matrix, (b) modulation of processes such as cell cycle arrest, apoptosis, senescence, DNA repair, metabolism changes, and (c) iron homeostasis and absorption through cell membranes, indicated that the DM/n-HA-treated cells retain tracts of physiological responsiveness unlike DM-treated cells. Overall, a shielding effect by the n-HA was assumed (masking the DM’s cytotoxicity), and a modular biomimicry of the DM/n-HA nanocomposites. On these bases, the biocompatibility of n-HA associated to DM’s magnetic responsiveness offer a combination of structural/functional features of these nano-tools for bone tissue engineering, for finely acting within physiological ranges.The development of nanocomposites with tailored physical–chemical properties, such as nanoparticles containing magnetic iron oxides for manipulating cellular events at distance, implies exciting prospects in biomedical applications for bone tissue regeneration. In this context, this study aims to emphasize the occurrence of differential responsiveness in osteoblast-like cells to different nanocomposites with diverse features: dextran-grafted iron oxide (DM) nanoparticles and their hybrid nano-hydroxyapatite (DM/n-HA) counterpart. Here, responsiveness of cells in the presence of DMs or DM/n-HAs was evaluated in terms of cytoskeletal features. We observed that effects triggered by the DM are no more retained when DM is embedded onto the DM/n-HA nanocomposites. Also, analysis of mRNA level variations of the focal adhesion kinase (FAK), P53 and SLC11A2/DMT1 human genes showed that the DM/n-HA-treated cells retain tracts of physiological responsiveness compared to the DM-treated cells. Overall, a shielding effect by the n-HA component can be assumed, masking the DM’s cytotoxic potential, also hinting a modular biomimicry of the nanocomposites respect to the physiological responses of osteoblast-like cells. In this view, the biocompatibility of n-HA together with the magnetic responsiveness of DMs represent an optimized combination of structural with functional features of the DM/n-HA nano-tools for bone tissue engineering, for finely acting within physiological ranges.

Response of Saos-2 osteoblast-like cells to kilohertz-resonance excitation in porous metallic scaffolds

Post-operative therapy for joint replacement is often performed to optimize bone volume and bone-implant contact. Methods, such as pulsed therapeutic ultrasound, have been shown to be a valuable addition to regular physiotherapy to increase bone regeneration. To evaluate the efficacy of kilohertz-frequency (kHz) resonant stimuli to additively manufactured implant analogues, Saos-2 cells were seeded onto porous stainless steel scaffolds and flat substrates. Resonant frequency modes were mapped in the low kHz range, and cells were subjected to daily stimulus for 10 min at a frequency of 1.278 kHz. kHz-frequency excitation was found to increase normalized alkaline phosphatase production by almost twofold on metallic substrates relative to non-vibrated control scaffolds, while peak velocity influenced alkaline phosphatase production on porous scaffolds but not flat substrates. Total cell proliferation was downregulated by excitation, and all excited samples displayed larger variability. This work indicates that vibration within the range of 0.16–0.48 mm/s may reduce cell proliferation, but favour osteogenic gene expression. This study highlights the potential of using kHz-resonance therapy to mitigate early-onset pore occlusion to achieve uniform osseointegration through porous metallic scaffolds.

Evaluation of Osteoblast-like Cell Responses to Surfaces Patterned with Hydroxyapatite Nanopowders on Ti Surfaces

Evaluation of Osteoblast-like Cell Responses to Surfaces Patterned with Hydroxyapatite Nanopowders on Ti Surfaces

Baghdadite/Polycaprolactone nanocomposite scaffolds: preparation, characterisation, and in vitro biological responses of human osteoblast-like cells (Saos-2 cell line)

ABSTRACT In the present research, porous composite scaffolds consisting of baghdadite scaffolds with polycaprolactone (PCL) coating, were fabricated via combining polyurethane sponge replication method and dip-coating processes and characterised by x-ray diffraction (XRD), scanning electron microscope (SEM), and porosity and compressive strength measurements. MTT assay and cell attachment were carried out via human osteoblast-like cell culture on the scaffolds. Results showed that the scaffolds possessed porous structures with porosity about 70-83%, and compressive strengths 0.18–1.31 MPa. Polycaprolactone can affect a significant role in improving the mechanical properties of baghdadite scaffold. It could enhance the compressive strength of baghdadite scaffold from 0.18 to 0.41 MPa while its porous structure is maintained. The evaluation of cell viability and attachment, verified no cytotoxicity, and good attachment and proliferation of cells on the scaffolds. To summarise, baghdadite–PCL composite scaffold with a porous structure, great mechanical properties and excellent biological responses is a promising candidate for bone tissue engineering.

Similar inductive effects of enamel and dentin matrix derivatives on osteoblast-like cell response over SLA titanium surface

ObjectivesThe aim of this in vitro study was to investigate the behavior of osteoblasts on titanium discs under different concentrations of enamel matrix derivatives (EMD) and dentin matrix derivative (DMD). Materials and methodsMC3T3-E1 osteoblast-like cells were cultivated on coated titanium SLA discs with EMD or DMD at 100 μg/ml, 1 mg/ml, 10 mg/ml and 30 mg/ml or left uncoated. Cell viability, proliferation, adhesion and migration were assessed respectively with MTT, BrdU, DAPI and scratch wound healing assays. Messenger ribonucleic acid of different genes related to osteoblastic differentiation was quantified by means of real-time quantitative PCR. Data were analyzed using student t-test for adhesion and migration assay and ANOVA for proliferation assay (p < 0.05). ResultsBrdU incorporation was found in proliferative osteoblasts for both test solutions at all concentrations. Osteoblast migrated and covered approximately 70% of the wound area observed at time zero when exposed to EMD and DMD to all concentrations. The increase of gene expression was dependent on the concentration enhancement of EMD and DMD. Higher concentrations showed proliferation augmentation if compared to lower concentrations. ConclusionsRoughness surface of Ti SLA can limit cell adhesion independent of the presence EMD or DMD. DMD enhances cell migration of osteoblasts on SLA titanium implants in a concentration-dependent manner.

Enhancement of hydroxyapatite dissolution through structure modification by Krypton ion irradiation

Hydroxyapatite (HA) synthesized by a wet chemical route was subjected to heavy ion irradiation, using 4 MeV Krypton ion (Kr17+) with ion fluence ranging from 1 × 1013 to 1 × 1015 ions/cm2. Glancing incidence X-ray diffraction (GIXRD) results confirmed the phase purity of irradiated HA with a moderate contraction in lattice parameters, and further indicated the irradiation-induced structural disorder, evidenced by broadening of the diffraction peaks. High-resolution transmission electron microscopy (HRTEM) observations indicated that the applied Kr irradiation induced significant damage in the hydroxyapatite lattice. Specifically, cavities were observed with their diameter and density varying with the irradiation fluences, while a radiation-induced crystalline-to-amorphous transition with increasing ion dose was identified. Raman and X-ray photoelectron spectroscopy (XPS) analysis further indicated the presence of irradiation-induced defects. Ion release from pristine and irradiated materials following immersion in Tris (pH 7.4, 37 ℃) buffer showed that dissolution in vitro was enhanced by irradiation, reaching a peak at 0.1dpa. We examined the effects of irradiation on the early stages of the mouse osteoblast-like cells (MC3T3-E) response. A cell counting kit-8 assay (CCK-8 test) was carried out to investigate the cytotoxicity of samples, and viable cells can be observed on the irradiated materials.

Response of Saos-2 osteoblast-like cells to laser surface texturing, sandblasting and hydroxyapatite coating on CoCrMo alloy surfaces

Cobalt chrome alloys are commonly used in orthopaedic implants where high stiffness and wear resistance are required. This study proposes Laser Surface Texturing (LST) as a cost-effective mean for producing bioinspired surface textures in order to improve the performance of CoCrMo orthopaedic implants. Cobalt-chrome alloy disks were modified using three different LST strategies: i) micro-scale texturing using a nanosecond laser source; (ii) micro-scale texturing with an ultrashort laser source and (iii) bioinspired sub-micron scale texturing with an ultrashort laser source. The modified disks were characterized and compared to blasted, hydroxyapatite coated and polished surface finishes. Saos-2 osteoblast-like cells were seeded on the different surfaces and their proliferation and morphology was assessed. The laser modification increases the surface energy of the CoCrMo alloy disks when compared to their untreated counterparts. The bioinspired sub-micron textured surfaces exhibited the highest cell metabolic activity on day 7 of the MTT assay.

Influence of nanoporous titanium niobium alloy surfaces produced via hydrogen peroxide oxidative etching on the osteogenic differentiation of human mesenchymal stromal cells

Titanium niobium alloys exhibit a lower stiffness compared to Ti6Al4V, the ‘gold standard’ for load-bearing bone implants. Thus, the critical mismatch in stiffness between the implant and adjacent bone tissue could be addressed with TiNb alloys and thereby reduce stress shielding, which can result in bone resorption and subsequent implant loosening; however, the cellular response on the specific material is crucial for sufficient osseointegration. We therefore hypothesize that the response of human mesenchymal stromal cells (hMSC) and osteoblast-like cells on Ti45Nb surfaces can be improved by a novel nanoporous surface structure. For this purpose, an etching technique using hydrogen peroxide electrolyte solution was applied to Ti45Nb. The treated surfaces were characterized using SEM, LSM, AFM, nanoindentation, and contact angle measurements. Cell culture experiments using hMCS and MG-63 were conducted. The H2O2 treatment resulted in surface nanopores, an increase in surface wettability and a reduction in surface hardness. The proliferation of MG-63 was enhanced on TiNb45 compared to Ti6Al4V. MG-63 focal adhesion complexes were detected on all Ti45Nb surfaces, whereas the nanostructures notably increased the cell area and decreased cell solidity, indicating stimulated cell spreading and pseudopodia formation. Alizarin red stainings indicated that the nanoporous surfaces stimulated the osteogenic differentiation of hMSC. It can be concluded that the proposed surface treatment could potentially help to stimulate the osseointegration behaviour of the advantageous low stiff Ti45Nb alloy.

TiO2 doped chitosan/hydroxyapatite/halloysite nanotube membranes with enhanced mechanical properties and osteoblast-like cell response for application in bone tissue engineering.

The current therapeutic strategies for healing bone defects commonly suffer from the occurrence of bacterial contamination on the graft, resulting in nonunion in the segmental bone defects and the requirement for secondary surgery to remove or sterilize the primary graft. A membrane with enhanced anti-bacterial efficacy, mechanical strength and osteoconductivity would represent an improvement in the therapeutic strategy for guided bone regeneration. The present study aims to optimize the content of halloysite nanotubes (HNTs) and TiO2 in the polymer matrix of chitosan (CTS) with a constant amount of nano-hydroxyapatite (5%) with the objective of mimicking the mechanical and biological microenvironment of the natural bone extracellular matrix with enhanced anti-bacterial efficacy. HNTs are a low-cost alternative to MWNCTs for enhancing the mechanical properties and anti-bacterial efficacy of the composite. From the first stage of the study, it was concluded that the membranes possessed enhanced mechanical properties and optimum biological properties at 7.5% (w/w) loading of HNTs in the composite. In the second stage of this investigation, we studied the effect of the addition of TiO2 nanoparticles (NPs) and TiO2 nanotubes (NTs) in small amounts to the CTS/n-HAP/HNT nanocomposite at 7.5% HNT loading, with an aim to augment the anti-bacterial efficacy and osteoconductivity of this mechanically strong membrane. The study revealed a significant enhancement in the anti-bacterial efficacy, osteoblast-like MG-63 cell proliferation and ALP expression with the addition of TiO2 NTs. The CHH-TiT membrane successfully inhibited the S. aureus and E. coli growth within 16 hours and simultaneously assisted the enhanced proliferation of osteoblast-like cells on its surface. The study supports the potential exploitation of CHH-TiT (7.5% HNT & 0.2% TiO2 NT) membranes as a template for guided bone tissue regeneration.

Initial osteoblast adhesion and subsequent differentiation on zirconia surfaces are regulated by integrins and heparin-sensitive molecule.

PurposeIt is well known that zirconia materials have good biocompatibility; however, little is known regarding the mechanism by which cells attach to these materials. The purpose of this study is to elucidate the mechanism of cell attachment.Materials and methodsIn this study, we examined the surface characteristics of ceria-stabilized zirconia/alumina nanocomposite (NANOZR), yttria-stabilized zirconia (Y-TZP) and commercially pure titanium (CpTi), and we evaluated the initial response of osteoblast-like cells to them with different inhibitors.ResultsUnder the same polishing treatment, the three materials, NANOZR, Y-TZP and CpTi, show similar surface wettability but different surface roughness. Osteoblasts could adhere to the surface of all three materials, and spindle shapes were clearer in serum-containing media compared to PBS and serum-free culture media, suggesting that serum-contained proteins are helpful for the initial cell adhesion and spreading. Cell adhesion and proliferation were disrupted in the presence of EDTA. RGD-peptide interfered with cell proliferation by affecting cell protrusion and stress fibers. Monoclonal antibody against non-RGD type integrin α2β1 enhanced proliferation in Y-TZP, CpTi and culture dish but not in NANOZR. Cell proliferation on NANOZR was specifically inhibited in the presence of heparin. Furthermore, under heparin administration, spindle shape formation was maintained but actin cytoskeleton was disrupted, resulting in loose cellular spreading.ConclusionThese results suggest that RGD type integrins and heparin-sensitive protein in coordination regulate cell morphology and proliferation on NANOZR, through the regulation of cell polarity and stress fiber formation, respectively.

Biological effect of hydrothermally synthesized silica nanoparticles within crystalline hydroxyapatite coatings for titanium implants

Development of functional coatings for artificial bone implants that strengthen the osseointegration and accelerate bone healing processes is urgently needed in the biomedical field. In this study we present biological effect of novel composite coatings with different concentration of silica nanoparticles within crystalline hydroxyapatite matrix (HAp-SiO2) synthesized on titanium under hydrothermal conditions. Samples were analyzed for their elemental composition, structure, bioactivity and in vitro cytotoxicity. The results indicate the formation and homogeneous distribution of silica nanoparticles on the surface of hexagonal hydroxyapatite (HAp) crystals. The coatings show improved bioactivity in comparison with pure HAp after 4 days of immersion in simulated body fluid (SBF). The responses of human osteoblast-like cells (MG-63) cultured onto the synthesized materials provide evidence that HAp-SiO2 composites exhibit good biocompatibility. We propose that this is because HAp-SiO2 composites favor biomineralization process with cell proliferation remaining unaffected, regardless of the amount of silica. Furthermore, SEM and fluorescence measurements demonstrate that HAp-SiO2 had positive effect on cell morphology, favoring cell adhesion.