Sr-substituted Hydroxyapatite Research Articles

Injectable mineralized Sr-hydroxyapatite nanoparticles-loaded ɛ-polylysine-hyaluronic acid composite hydrogels for bone regeneration

In this study, multifunctional injectable mineralized antibacterial nanocomposite hydrogels were prepared by a homogenous distribution of high content of (up to 60 wt%) Sr-substituted hydroxyapatite (Sr-HAp) nanoparticles into covalently cross-linked ɛ-polylysine (ɛ-PL) and hyaluronic acid (HA) hydrogel network. The developed bone-targeted nanocomposite hydrogels were to synergistically combine the functional properties of bioactive Sr-HAp nanoparticles and antibacterial ɛ-PL-HA hydrogels for bone tissue regeneration. Viscoelasticity, injectability, structural parameters, degradation, antibacterial activity, and in vitro biocompatibility of the fabricated nanocomposite hydrogels were characterized. Physical performances of the ɛ-PL-HA hydrogels can be tailored by altering the mass ratio of Sr-HAp. The nanocomposite hydrogels revealed good stability against enzymatic degradation, which increased from 5 to 19 weeks with increasing the mass ratio of Sr-HAp from 40 % to 60 %. The loading of the Sr-HAp at relatively high mass ratios did not suppress the fast-acting and long-term antibacterial activity of the ɛ-PL-HA hydrogels against S. aureus and E. coli. The cell studies confirmed the cytocompatibility and pre-collagen I synthesis-promoting activity of the fabricated nanocomposite hydrogels.

On the Ion Implantation Synthesis of Ag-Embedded Over Sr-Substituted Hydroxyapatite on a Nano-Topography Patterned Ti for Application in Acetabular Fracture Sites.

There is an ongoing need for improved healing response and expedited osseointegration on the Ti implants in acetabular fracture sites. To achieve adequate bonding and mechanical stability between the implant surface and the acetabular fracture, a new coating technology must be developed to promote bone integration and prevent bacterial growth. A cylindrical Ti substrate mounted on a rotating specimen holder was used to implant Ca2+, P2+, and Sr2+ ions at energies of 100 KeV, 75 KeV and 180 KeV, respectively, using a low-energy accelerator to synthesize strontium-substituted hydroxyapatite at varying conditions. Ag2+ ions of energy 100 KeV were subsequently implanted on the as-formed surface at the near-surface region to provide anti-bacterial properties to the as-formed specimen. The properties of the as-formed ion-implanted specimen were compared with the SrHA-Ag synthesized specimens by cathodic deposition and low-temperature high-speed collision technique. The adhesion strength of the ion-implanted specimen was 43 ± 2.3 MPa, which is well above the ASTM standard for Ca-P coating on Ti. Live/dead cell analysis showed higher osteoblast activity on the ion-implanted specimen than the other two. Ag in the SrHA implanted Ti by ion implantation process showed superior antibacterial activity. In the ion implantation technique, nano-topography patterned surfaces are not concealed after implantation, and their efficacy in interacting with the osteoblasts is retained. Although all three studies examined the antibacterial effects of Ag2+ ions and the ability to promote bone tissue formation by MC3T3-E1 cells on SrHA-Ag/Ti surfaces, ion implantation techniques demonstrated superior ability. The synthesized specimen can be used as an effective implant in acetabular fracture sites based on their mechanical and biological properties.

Incorporation/Enrichment of 3D Bioprinted Constructs by Biomimetic Nanoparticles: Tuning Printability and Cell Behavior in Bone Models.

Reproducing in vitro a model of the bone microenvironment is a current need. Preclinical in vitro screening, drug discovery, as well as pathophysiology studies may benefit from in vitro three-dimensional (3D) bone models, which permit high-throughput screening, low costs, and high reproducibility, overcoming the limitations of the conventional two-dimensional cell cultures. In order to obtain these models, 3D bioprinting offers new perspectives by allowing a combination of advanced techniques and inks. In this context, we propose the use of hydroxyapatite nanoparticles, assimilated to the mineral component of bone, as a route to tune the printability and the characteristics of the scaffold and to guide cell behavior. To this aim, both stoichiometric and Sr-substituted hydroxyapatite nanocrystals are used, so as to obtain different particle shapes and solubility. Our findings show that the nanoparticles have the desired shape and composition and that they can be embedded in the inks without loss of cell viability. Both Sr-containing and stoichiometric hydroxyapatite crystals permit enhancing the printing fidelity of the scaffolds in a particle-dependent fashion and control the swelling behavior and ion release of the scaffolds. Once Saos-2 cells are encapsulated in the scaffolds, high cell viability is detected until late time points, with a good cellular distribution throughout the material. We also show that even minor modifications in the hydroxyapatite particle characteristics result in a significantly different behavior of the scaffolds. This indicates that the use of calcium phosphate nanocrystals and structural ion-substitution is a promising approach to tune the behavior of 3D bioprinted constructs.

Mechanochemical synthesis of strontium- and magnesium-substituted and cosubstituted hydroxyapatite powders for a variety of biomedical applications

Hydroxyapatite (HA) is a biocompatible material widely used in various biomedical applications. Stoichiometric HA has low bioactivity and does not possess antibacterial properties. One way to modify HA properties is to substitute some ions in stoichiometric HA, i.e., to dope HA, for attaining desired properties, e.g., improved bioactivity or an antibacterial effect. This work shows that a soft mechanochemical method of HA synthesis allows to obtain bioactive HA containing strontium ions, magnesium ions, or both. Substituted HAs with substitution degree x(Mg) = 0.5 mol or x(Sr) = 1.5 mol were synthesized, as was cosubstituted HAs contained both magnesium and strontium ions with x(Mg) = 0.5 mol or x(Sr) = 1.5 mol. The resulting materials were investigated by simultaneous thermal analysis, scanning electron microscopy, granulometry, powder X-ray diffraction, Fourier transform infrared, Raman spectroscopy, and X-ray photoelectron spectroscopy. Thermal stability of the obtained materials was studied too. The partial calcium substitution with strontium and/or magnesium changed both HA crystal lattice parameters and positions of absorption bands of phosphate groups in Fourier transform infrared and Raman spectra. X-ray photoelectron spectra of the synthesized materials contain peaks of all elements with binding energies corresponding to substituted HA. The strontium substitution, unlike the magnesium substitution, did not reduce HA thermal stability. The crystal lattice of Sr-substituted HA is stable up to 1300 °C, just as stoichiometric HA. Magnesium cations left HA at 800 °C, forming Mg-substituted β-Ca3(PO4)2. At the cosubstitution, thermal stability of HA became slightly lower. Partial decomposition of the material began already at 700 °C. Accordingly, during manufacturing of medical devices from the proposed materials, their low thermal stability should be taken into account. To preserve the structure of Mg-Sr-cosubstituted HA, heat treatment conditions should not exceed 700 °C.

Synthesis and characterization of Nd3+-Yb3+ doped hydroxyapatite nanoparticles

The present work focuses on Nd3+-Yb3+ co-doping of bare and Sr-substituted hydroxyapatite nanoparticles and their chemical, structural and optical characterization. An energy transfer between Nd3+ and Yb3+ centers was found, generating an efficient down-shifting process, where Nd3+ absorbs at a low near-infrared wavelength and Yb3+ emits at its characteristic 2F7/2 → 2F5/2 transition. The energy transfer was found to be more efficient in Sr-substituted than in bare hydroxyapatite nanoparticles. The synthesized Nd3+-Yb3+ doped hydroxyapatite nanoparticles can potentially find applications not only as diagnostic near-infrared down-shifting agent but also as nanosystem for near-infrared photoactivated treatment.

New Sintered Porous Scaffolds of Mg,Sr Co-Substituted Hydroxyapatite Support Growth and Differentiation of Primary Human Osteoblasts In Vitro

Strontium (Sr) and Magnesium (Mg) are bioactive ions that have been proven to exert a beneficial effect on bone; therefore, their incorporation into bone substitutes has long been viewed as a possible approach to improve tissue integration. However, the thermal instability of Mg-substituted hydroxyapatites has hitherto limited development. We previously described the creation of thermally consolidated porous constructs of Mg,Sr co-substituted apatites with adequate mechanical properties for their clinical use. The present paper describes the biocompatibility of Mg,Sr co-substituted granules using an alveolar-bone-derived primary model of human osteoblasts. Cells were cultured in the presence of different amounts of hydroxyapatite (HA), Sr-substituted HA, or MgSrHA porous macrogranules (with a size of 400–600 microns, obtained by grinding and sieving the sintered scaffolds) for three and seven days, and their viability was measured by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Protein content was measured using the Lowry assay at the same time points. Cell viability was not impaired by any of the tested compounds. Indirect and direct biocompatibility of these macrogranules was assessed by culturing cells in a previously conditioned medium with HA, SrHA, or MgSrHA, or in the presence of material granules. Osteoblasts formed larger and more numerous nodules around SrHA or MgSrHA granules. Furthermore, cell differentiation was evaluated by alkaline phosphatase staining of primary cells cultured in the presence of HA, SrHA, or MgSrHA granules, confirming the increased osteoconductivity of the doped materials.

A polydopamine-assisted strontium-substituted apatite coating for titanium promotes osteogenesis and angiogenesis via FAK/MAPK and PI3K/AKT signaling pathways

Early osteointegration is essential for biomedical implants. Surface modifications can significantly compensate for an implant's lack of biocompatibility and osteo-differentiation. They can also be designed to promote angiogenesis in order to assist osteogenesis and ultimately facilitate bone regeneration. In this study, a polydopamine-assisted strontium-substituted apatite coating (Ti@PDA + SrHA) was fabricated on a multifunctional titanium implant to induce both angiogenic and osteogenic abilities for rapid osseointegration. Polydopamine and Sr-substituted hydroxyapatite were coated on the implant through biomineralization. The in vitro results showed that Ti@PDA + SrHA improved cell adhesion and increased the proliferation of rat bone marrow-derived mesenchymal stem cells (rBMSCs) and human umbilical vein endothelial cells (HUVECs). Ti@PDA + SrHA upregulated the expression of ALP activity and osteogenic genes in rBMSCs and elevated angiogenic genes in both rBMSCs and HUVECs. Mechanically, the FAK/MAPK signaling pathway was activated in rBMSCs, and the PI3K/AKT signaling pathway was activated in both rBMSCs and HUVECs. Consistent with these findings, Ti@PDA + SrHA accelerated new bone formation and rapid osseointegration in the femoral condyle implantation study with good stability. Overall, we fabricated a multifunctional biocompatible implant with better angiogenic and osteogenic performance compared to the non-coated implant.

Role of Sr2+ concentration on the microstructure of Sr-substituted hydroxyapatite single-crystal microtubes with hexagonal cross-section

Strontium (Sr) can be introduced into hydroxyapatite (HA) crystals and stimulate new bone formation. In this study, the single-crystalline Sr-substituted HA microtubes with hexagonal cross-sections are synthesized under the regulation of Sr2+via the oleic acid-assisted solvothermal method. The morphology of the as-prepared products changes from ultralong flexible nanofibers to hexagonal microtubes with the increasing Sr/(Sr + Ca) ratio. Microtubes can be formed when a small amount of Sr is doped into HA, with the optimal substitution ratio of Sr2+ being ~6%. The inner and outer diameters of the synthetic Sr-substituted HA microtubes are about 1.6 and 2.3 μm, respectively. Moreover, the effects of Sr2+ dopping on the formation process and mechanism of microtubes were discussed.

Influence of magnesium and strontium substitutions in the structure of hydroxyapatite lattice on the deposition rate and properties of the CaP coatings formed via RF-sputtering of the powder targets

This work is dedicated to studying of the properties of the calcium phosphate (CaP) coatings deposited on Ti substrates by radio-frequency magnetron sputtering (RFMS) of three hydroxyapatite-based powder targets: pure hydroxyapatite (HA), Mg-substituted HA (Mg-HA, Mg = 0.93 ± 0.13 at.%) and Sr-substituted HA (Sr-HA, Sr ∼ 0.47 at.%). The influence of ionic substitutions in the structure of the sputtered targets on the surface morphology, physicochemical properties of the coatings and their wettability were studied. It is revealed that Mg and Sr ionic substitutions in the crystal lattice of HA at these concentrations don’t affect deposition rate, however, it influences morphology, wettability and elemental and phase composition of deposited coatings.

Morphology regulation of Sr-substituted hydroxyapatite by l-glutamic acid in a solvent- and initial temperature-dependent manner

A bi-solvent system (ethanol and water) with the presence of l-glutamic acid (L-glu) was developed to achieve the controlled synthesis of whisker-like or urchin-like Sr-substituted HA (SrHA) through hydrothermal treatment. The effects of initial temperature of aqueous solution (ASIT), the presence of Sr, and ethanol proportion on HA morphology were investigated and the underlying mechanisms were illustrated. The results indicate that Sr and ethanol have antagonistic effects on the size of HA whisker, the introduction of Sr tends to reduce the whisker size, while the addition of ethanol tends to increase the nucleation efficiency. Finally, the whisker size and uniformity of SrHA can be regulated via ethanol proportion in the bi-solvent system. ASIT mainly affects the uniformity of solution by affecting Brownian motion in solution, which couples with the different solubility of l-glu and reactant ions in water and ethanol, ultimately determines whether the morphology of HA is whisker-like or urchin-like. Our bi-solvent system simplifies the complex process of template agent screening compared with the ways that introducing several templates agents to achieve the morphology regulation, and enriches the methods of controlled synthesis of different morphological Sr-HA. This feasible method may provide new strategy for simplifying the synthesis of other ions-doping HA with a certain morphology.

Porous CaP Coatings Formed by Combination of Plasma Electrolytic Oxidation and RF-Magnetron Sputtering

The porous CaP subcoating was formed on the Ti6Al4V titanium alloy substrate by plasma electrolytic oxidation (PEO). Then, upper coatings were formed by radio frequency magnetron sputtering (RFMS) over the PEO subcoating by the sputtering of various CaP powder targets: β-tricalcium phosphate (β-TCP), hydroxyapatite (HA), Mg-substituted β-tricalcium phosphate (Mg-β-TCP) and Mg-substituted hydroxyapatite (Mg-HA), Sr-substituted β-tricalcium phosphate (Sr-β-TCP) and Sr-substituted hydroxyapatite (Sr-HA). The coating surface morphology was studied by scanning electron and atomic force microscopy. The chemical composition was determined by X-ray photoelectron spectroscopy. The phase composition of the coatings was studied by X-ray diffraction analysis. The Young’s modulus of the coatings was studied by nanoindentation test. RF-magnetron sputtering treatment of PEO subcoating resulted in multileveled roughness, increased Ca/P ratio and Young’s modulus and enrichment with Sr and Mg. Sputtering of the upper layer also helped to adjust the coating crystallinity.

TOFSIMS and XPS characterisation of strontium in amorphous calcium phosphate sputter deposited coatings

Strontium (Sr) substituted calcium phosphate (CaP) coatings have stimulated a lot of interest as Sr is known to provide osteoconductive properties. Most of the work to date with respect to Sr substituted coatings has focused on the creation of crystalline Sr-substituted hydroxyapatite (HA), as opposed to amorphous coatings. The work reported here utilises radio frequency magnetron sputtering to deposit both amorphous CaP and Sr-containing CaP coatings and their characterisation using X-Ray Photoelectron Spectroscopy (XPS) and Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS). The CaP coating had a high Ca/P atomic ratio at 1.81 ± 0.02. The amorphous Sr containing CaP coating was shown to contain Sr with a Ca/P and (Ca + Sr)/P atomic ratios of 1.18 ± 0.05 and 1.49 ± 0.05, respectively. Peak-fitting of the overlapping Sr3d and P2p region also showed the presence of previously unreported doublets for each element. The ToF-SIMS results also highlighted that Sr was homogeneously distributed across the surface of the Sr containing coating via detailed chemical mapping experiments. This study has shown that sputtering can be used to deposit Sr-containing CaP coatings and that the use of surface analytical techniqes is important for understanding their uppermost surface properties.

Influence of DMSO-Sr on the Synthesis of Hydroxyapatite by Hydrothermal Coupled Microemulsion Method

Hydroxyapatite (denoted as HAP), which is chemically represented as Ca10(PO4)6(OH)2), is an extensively used biocompatible ceramic material for the regeneration of hard tissue because of its crystallographic and chemical similarities with natural bone. In this paper, we report the preparation of strontium (Sr) incorporated nano-HAP powder by hydrothermal coupled microemulsion (HT-ME) method employing DMSO as a primary surfactant. This paper discusses the effect of DMSO as well as Sr in the synthesis of HAP powders. Strontium stimulates the bone formation and prevention of bone resorption while dimethyl sulfoxide (DMSO) aids in the formation of improved morphological features and structure of nano-crystalline hydroxyapatite powders. FTIR, XRD, SEM and TGA techniques were performed to analyse the chemical composition, crystallite structure and uniform morphology. XRD results have shown the presence of hexagonal structure in HAP while the scanning electron microscopic technique reveals that DMSO assisted Sr-substituted hydroxyapatite powders are not agglomerated and the particle nanostructure is homogeneous. The synthesised powder is to be studied further for its biocompatibility.

Comparative Study of the Structure, Properties, and Corrosion Behavior of Sr-Containing Biocoatings on Mg0.8Ca.

A comparative analysis of the structure, properties and the corrosion behavior of the micro-arc coatings based on Sr-substituted hydroxyapatite (Sr-HA) and Sr-substituted tricalcium phosphate (Sr-TCP) deposited on Mg0.8Ca alloy substrates was performed. The current density during the formation of the Sr-HA coatings was higher than that for the Sr-TCP coatings. As a result, the Sr-HA coatings were thicker and had a greater surface roughness Ra than the Sr-TCP coatings. In addition, pore sizes of the Sr-HA were almost two times larger. The ratio (Ca + Sr + Mg)/P were equal 1.64 and 1.47 for Sr-HA and Sr-TCP coatings, respectively. Thus, it can be assumed that the composition of Sr-HA and Sr-TCP coatings was predominantly presented by (Sr,Mg)-substituted hydroxyapatite and (Sr,Mg)-substituted tricalcium phosphate. However, the average content of Sr was approximately the same for both types of the coatings and was equal to 1.8 at.%. The Sr-HA coatings were less soluble and had higher corrosion resistance than the Sr-TCP coatings. Cytotoxic tests in vitro demonstrated a higher cell viability after cultivation with extracts of the Sr-HA coatings.

Preparation of Sr-substituted Hydroxyapatite Nanorods for Liquid Crystal Phase Transition

A citrate-assisted hydrothermal method was utilized for the preparation of Sr-substituted hydroxyapatite (HA) nanoparticles. The influences of Sr-substituting degree on the phase identifications, microstructures and colloidal stability of the resultant products were studied. The experimental results show that the crystalline structures and morphologies of final resultants are significantly changed by controlling the Sr-substituting degree. As the Sr-substituting degree increases, the colloidal stability of samples first increases and then decreases rapidly; the morphology of the product first changes from nanorods to short nanorods rod and then becomes nanowires. Uniform HA hexagonal nanorods with high aspect ratio (>4.0) and excellent aqueous colloidal stability were prepared by 6 h hydrothermal reaction at 180 °C without Sr substitution. The dispersion underwent the phase transition from isotropic to liquid-crystalline state upon the increasing concentration of 25wt% and the complete liquid-crystalline phase was achieved when at the concentration above 31wt%. These novel findings provide new insights into the role of Sr substitution on both the citrate-assisted hydroxyapatite crystallization and tailoring of colloidal stability. Moreover, HA liquid crystal behavior was successfully observed, which lays a foundation for the fabrication of macroscopically assembled hydroxyapatite-based biomimetic materials for biomedical applications.

Electrodeposition of Sr-substituted hydroxyapatite on low modulus beta-type Ti-45Nb and effect on in vitro Sr release and cell response.

Beta-type Ti-based alloys are promising new materials for bone implants owing to their excellent mechanical biofunctionality and biocompatibility. For treatment of fractures in case of systemic diseases like osteoporosis the generation of implant surfaces which actively support the problematic bone healing is a most important aspect. This work aimed at developing suitable approaches for electrodeposition of Sr-substituted hydroxyapatite (Srx-HAp) coatings onto Ti-45Nb. Potentiodynamic polarization measurements in electrolytes with 1.67 mmol/L Ca(NO3)2, which was substituted by 0, 10, 50 and 100% Sr(NO3)2, and 1 mmol/L NH4H2PO4 at 333 K revealed the basic reaction steps for OH- and PO43- formation needed for the chemical precipitation of Srx-HAp. Studies under potentiostatic control confirmed that partial or complete substitution of Ca2+- by Sr2+-ions in solution has a significant effect on the complex reaction process. High Sr2+-ion contents yield intermediate phases and a subsequent growth of more refined Srx-HAp coatings. Upon galvanostatic pulse-deposition higher reaction rates are controlled and in all electrolytes very fine needle-like crystalline coatings are obtained. With XRD the incorporation of Sr-species in the hexagonal HAp lattice is evidenced. Coatings formed in electrolytes with 10 and 50% Sr-nitrate were chemically analyzed with EDX mapping and GD-OES depth profiling. Only a fraction of the Sr-ions in solution is incorporated into the Srx-HAp coatings. Therein, the Sr-distribution is laterally homogeneous but non-homogeneous along the cross-section. Increasing Sr-content retards the coating thickness growth. Most promising coatings formed in the electrolyte with 10% Sr-nitrate were employed for Ca, P and Sr release analysis in Tris-Buffered Saline (150 mM NaCl, pH 7.6) at 310 K. At a sample surface: solution volume ratio of 1:200, after 24 h the amount of released Sr-ions was about 30-35% of that determined in the deposited Srx-HAp coating. In vitro studies with human bone marrow stromal cells (hBMSC) revealed that the released Sr-ions led to a significantly enhanced cell proliferation and osteogenic differentiation and that the Sr-HAp surface supported cell adhesion indicating its excellent cytocompatibility.

Composite coatings of Mg-MOF74 and Sr-substituted hydroxyapatite on titanium substrates for local antibacterial, anti-osteosarcoma and pro-osteogenesis applications

It has been noticed that residual osteosarcoma cells or infective bacteria would greatly hinder the osseointegration between implants and natural bone at the early stage of implant surgeries. Thus, in this work, composite coatings of magnesium-mediated metal-organic frameworks (Mg-MOF74) and strontium-substituted hydroxyapatite (Sr-HA) were constructed on titanium surfaces for improving the local injury treatment even with complications (osteosarcoma or bacterial infection). It was proved that the superficial Mg-MOF74 could rapidly degrade (especially under bacteria- or osteosarcoma-induced acid microenvironment) and effectively kill surrounding Staphylococcus aureus, Escherichia coli and Saos-2 cells, and then the exposed Sr-HA coating had great potential to promote the proliferation and osteogenic differentiation of osteoblasts.

Characterization of Sr-substituted hydroxyapatite synthesized by the mechanochemical method

This paper presents a structural study of Sr-substituted hydroxyapatites carried out by the full profile Rietveld method. A series of samples having different degrees of substitution was prepared by the mechanochemical method, which offers possibilities of the fast synthesis of these compounds. For the first time, it was shown that strontium and calcium cations located in the M2 site do not have the same positions.

Mechanochemical Synthesis of Sr-Substituted Hydroxyapatite

We demonstrate that a nanoparticulate Sr-substituted carbonate hydroxyapatite can be prepared by fast mechanochemical synthesis, without further annealing of the material. The synthesis process takes 30 min and yields single-phase products. We have obtained a series of Ca10–xSrx(PO4)6(OH)2 samples with x = 0–2.

Gradient coatings of strontium hydroxyapatite/zinc β-tricalcium phosphate as a tool to modulate osteoblast/osteoclast response

The chemistry, structure and morphology of the implant surface have a great influence on the integration of an implant material with bone tissue. In this work, we applied Combinatorial Matrix-Assisted Pulsed Laser Evaporation (C-MAPLE) to deposit gradient thin films with variable compositions of Sr-substituted hydroxyapatite (SrHA) and Zn-substituted β-tricalcium phosphate (ZnTCP) on Titanium substrates. Five samples with different SrHA/ZnTCP composition ratios were fabricated by a single step laser procedure. SrHA was synthesized in aqueous medium, whereas ZnTCP was obtained by reaction at high temperature. Both powders were separately suspended in deionized water, frozen at liquid nitrogen temperature and used as targets for C-MAPLE experiments, which proceed via simultaneous laser vaporization of two distinct material targets. X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy analyses confirmed that the coatings contain the same crystalline phases as the as-prepared powder samples, with a homogeneous distribution of the two phosphates along deposited thin films. Human osteoclast precursor 2T-110 and human osteoblast-like cells MG63 were co-cultured on the coatings. The results indicate that osteoblast viability and production of osteocalcin were promoted by the presence of ZnTCP. On the other hand, SrHA inhibited osteoclastogenesis and osteoclast differentiation, as demonstrated by the observed increase of the osteoprotegerin/RANKL ratio and decrease of the number of TRAP-positive multinucleated cells when increasing SrHA amount in the coatings. The results indicate that the possibility to tailor the composition of the coatings provides materials able to modulate bone growth and bone resorption.