Biomimetic Calcium Phosphate Coatings Research Articles

Macrophage Polarization Related to Biomimetic Calcium Phosphate Coatings: A Preliminary Study

Biomimetic calcium phosphate (BioCaP) coatings were used to deliver bone morphogenetic protein 2 (BMP2), and enhance osteogenesis. However, the mechanism for BioCaP coatings interacting with the immune response during bone regeneration remains unclear. In this preliminary study, the effect of BioCaP coatings on macrophage polarization without (BioCaP group) or with BMP2 (BioCaP+Inc.BMP2 group) was investigated. RAW 264.7 cells were cultured on the rough and platelike surfaces of coatings in BioCaP and BioCaP+Inc.BMP2 groups, while cultured on smooth surfaces in the group without material for 5 days. The BioCaP coatings per se modulated the switch of M1 to M2 phenotype from day 3, which promoted the expressions of Arg1 and CD 206 but reduced the expression of TNF-α compared with No material group. To detect the microenvironmental changes, the concentrations of calcium ion (Ca2+) and inorganic phosphate (Pi), pH values, as well as calcium phosphate crystal pattern were examined. The trends of ionic environmental changes were closely related with macrophage phenotype switch. These results suggest that BioCaP coating itself may affect the macrophage polarization through surface topography, surrounding ionic environment and calcium phosphate crystal pattern.

Biomimetic Calcium Phosphate Coatings for Bioactivation of Titanium Implant Surfaces: Methodological Approach and In Vitro Evaluation of Biocompatibility.

Ti6Al4V as a common implant material features good mechanical properties and corrosion resistance. However, untreated, it lacks bioactivity. In contrast, coatings with calcium phosphates (CaP) were shown to improve cell–material interactions in bone tissue engineering. Therefore, this work aimed to investigate how to tailor biomimetic CaP coatings on Ti6Al4V substrates using modified biomimetic calcium phosphate (BCP) coating solutions. Furthermore, the impact of substrate immersion in a 1 M alkaline CaCl2 solution (pH = 10) on subsequent CaP coating formation was examined. CaP coatings were characterized via scanning electron microscopy, x-ray diffraction, energy-dispersive x-ray spectroscopy, and laser-scanning microscope. Biocompatibility of coatings was carried out with primary human osteoblasts analyzing cell morphology, proliferation, collagen type 1, and interleukin 6 and 8 release. Results indicate a successful formation of low crystalline hydroxyapatite (HA) on top of every sample after immersion in each BCP coating solution after 14 days. Furthermore, HA coating promoted cell proliferation and reduced the concentration of interleukins compared to the uncoated surface, assuming increased biocompatibility.

Human mesenchymal stromal cells response to biomimetic octacalcium phosphate containing strontium.

The incorporation of bioinorganics into synthetic biomaterials is a promising approach to improve the biological performance of bone graft substitutes, while still retaining their synthetic nature. Among these bioinorganics, strontium ions (Sr(2+) ) have reported enhanced bone formation, and a reduced risk of bone fractures. While previous results have been encouraging, more detailed studies are needed to further develop specific applications. This study demonstrates the effects of Sr(2+) on the osteogenic differentiation of human mesenchymal stromal cells (hMSCs) when introduced as either a dissolved salt, or incorporated into biomimetic calcium phosphate (CaP) coatings. Upon attachment, hMSCs seeded in the presence of higher Sr(2+) concentrations presented with a more elongated shape as compared to the controls without Sr(2+) . Both Sr(2+) as a dissolved salt in the medium, or incorporated into CaP coatings, positively influenced hMSC alkaline phosphatase (ALP) activity in a dose-dependent manner. At the mRNA level, the expression of osteogenic markers ALP, bone sialoprotein, bone morphogenetic protein 2, osteopontin, and osteoclacin were increased in the presence of Sr(2+) , independent of the delivery method. Overall, this study demonstrates the positive effects of strontium on the osteogenic differentiation of human MSCs, and supports the use of strontium-incorporated CaPs for bone regeneration applications. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1946-1960, 2016.

Formation of hybrid materials based on calcium phosphate deposit on carbon fiber scaffold

Event Abstract Back to Event Formation of hybrid materials based on calcium phosphate deposit on carbon fiber scaffold Quentin Picard1, Lise Guichaoua1, Sandrine Delpeux-Ouldriane1, Nathalie Rochet2, Jérôme Chancolon1, Franck Fayon3, Fabienne Warmont1 and Sylvie Bonnamy1 1 CNRS / University of Orleans, ICMN, France 2 INSERM/BIPOA, IBV, France 3 CNRS, CEMHTI, France Introduction: Due to their breathability, specific mechanical properties and biocompatibility, activated carbon clothes (ACC) have previously been considered for hard and soft tissue implanting. However, their poor biological activity restricts their extensive use in medical applications and therefore needs to be enhanced[1]-[3]. Carbon fiber-reinforced calcium phosphate (CaP) composites, combining the highly biocompatible, osteoconductive and bioactive CaP matrix with the properties of carbon fibers, are promising bioceramic material, which could be particularly useful in the reconstruction of bone defects[3]. Experimental Methods: CaP coated ACC are obtained by sono-electrodeposition process using cathodic polarization. Ca(NO3)2, 4H2O and NH4H2PO4 are used as electrolyte. The influence of electrochemical parameters is connected to the amount, microtexture, structure and chemical composition of CaP phases. The materials biocompatibility was determined by culturing primary human osteoblast-cells (HOST) in contact with CaP/ACC hybrid materials. Results and Discussion: The mass uptake tends to a limit corresponding to the decrease of nucleation sites. The current density gouverns the CaP characteristics: amount, morphology and chemical composition. Indeed, the quantity of deposit is proportional to the applied current density (thickness ranging from 10 nm to 1 µm). During CaP deposition, water electrolysis regime gouverns the pH decrease at the carbon electrode surface and consequently leads to CaP precipitation. This process gives biomimetic and uniform CaP coated fibers. Their CaP chemical compositions can be modulated to get similar ones to natural bones. SEM, HRTEM and FTIR characterizations show that the coating consists in a mixture of octacalcium phosphate and plate-like carbonated HA phases at low current densities and needle-like carbonated HA with calcium carbonate phases at high current densities. 1H and 31P MAS NMR of deposits confirm the presence of carbonated HA with a minority of disordered CaP phase. First biological results through in vitro osteoblast culture have evidenced the cell viability on hybrid materials (Fig. 1). Figure 1: SEM image of human osteoblasts cultured at 7 days in the presence of CaP/ACC hybrid material obtained at low current density. Conclusion: The sono-electrodeposition process allows to tailor the thickness, morphology (platelets or needles), chemical composition and to get biomimetic CaP coatings consisting mainly in carbonated HA with minor disordered CaP phases. Close to natural bone chemical composition, the CaP/ACC hybrid materials show a good interaction with primary HOST and therefore could be used as bioactive scaffold for bone regeneration. European Program PF7_IRSES « ABREM »; Region Centre Val-de-Loire project: Hybrid bio-actives materials for bone reconstruction

A review paper on biomimetic calcium phosphate coatings.

Biomimetic calcium phosphate coatings have been developed for bone regeneration and repair because of their biocompatibility, osteoconductivity, and easy preparation. They can be rendered osteoinductive by incorporating an osteogenic agent, such as bone morphogenetic protein 2 (BMP-2), into the crystalline lattice work in physiological situations. The biomimetic calcium phosphate coating enables a controlled, slow and local release of BMP-2 when it undergoes cell mediated coating degradation induced by multinuclear cells, such as osteoclasts and foreign body giant cells, which mimics a physiologically similar release mode, to achieve sustained ectopic or orthotopic bone formation. Therefore, biomimetic calcium phosphate coatings are considered to be a promising delivery vehicle for osteogenic agents. In this review, we present an overview of biomimetic calcium phosphate coatings including their preparation techniques, physico-chemical properties, potential as drug carrier, and their pre-clinical application both in ectopic and orthotopic animal models. We briefly review some features of hydroxyapatite coatings and their clinical applications to gain insight into the clinical applications of biomimetic calcium phosphate coatings in the near future.

Biomineralization of marine-patterned C-scaffolds

Patterned surfaces of marine-derived carbon scaffolds were subjected to a biomimetic approach to be covered with a calcium phosphate thin film. The process was based on Dulbecco’s phosphate-buffered saline solution and investigated in different periods of immersion (from hours to days). A complete physicochemical characterization was performed to demonstrate the optimal calcium/phosphorus ratio, thickness and adherence to the substrate of these biomimetic calcium phosphate coatings, which still retained the naturally derived patterning. A chemical mechanism to explain the coating formation has been proposed and documented, based mainly on the presence of carboxylic groups on the C-scaffold surface, what promoted the anchorage of calcium ions at the first stage and the later binding of phosphate groups to calcium ions. The biological response of MC3T3-E1 preosteoblasts on the calcium phosphate–coated scaffolds was investigated to demonstrate the non-cytotoxicity, adequate morphology and spreading of cells after 7 d of culture, being this proliferation aligned, promoted by the patterning of the scaffold.

Bi-functionalization of a calcium phosphate-coated titanium surface with slow-release simvastatin and metronidazole to provide antibacterial activities and pro-osteodifferentiation capabilities.

Coating the surface of titanium implants or other bone graft substitute materials with calcium phosphate (Ca-P) crystals is an effective way to enhance the osteoconduction of the implants. Ca-P coating alone cannot confer pro-osteodifferentiation and antibacterial capabilities on implants; however, it can serve as a carrier for biological agents which could improve the performance of implants and bone substitutes. Here, we constructed a novel, bi-functional Ca-P coating with combined pro-osteodifferentiation and antibacterial capabilities. Different concentrations of metronidazole (MNZ) and simvastatin (SIM) were integrated into biomimetic Ca-P coatings on the surface of titanium disks. The biological effects of this bi-functional biomimetic coating on human bone marrow mesenchymal stem cells (hBMMSCs), human adipose derived stromal cells (hASCs), and Porphyromonas gingivalis were assessed in vitro. We observed that Ca-P coatings loaded with both SIM and MNZ display favorable release kinetics without affecting cell proliferation or attachment. In the inhibition zone test, we found that the bi-functional coating showed lasting antibacterial effects when incubated with Porphyromonas gingivalis for 2 and 4 days. Moreover, the osteodifferentiation of hBMMSCs and hASCs were increased when cultured on this bi-functional coating for 7 and 14 days. Both drugs were loaded onto the Ca-P coating at specific concentrations (10−5 M SIM; 10−2 M MNZ) to achieve optimal release kinetics. Considering the safety, stability and low cost of SIM and MNZ, this novel bi-functional Ca-P coating technique represents a promising method to improve the performance of metal implants or other bone substitute materials, and can theoretically be easily translated to clinical applications.

Influence of coating bath chemistry on biomimetic calcium phosphate coatings

Magnesium alloys are an emerging class of biodegradable medical implant materials. However, control of their degradation rate and biocompatibility are key issues that need to be addressed prior to their use in clinical applications. In this article, a two-step method to biomimetically deposit corrosion-resistant calcium phosphate coatings on magnesium alloy AZ31 is described. A decrease in the overall dissolution of the magnesium substrate of up to 99·8% was observed for the coated samples in comparison with non-treated magnesium AZ31. Surface characterization of the coatings was performed by attenuated total reflectance–Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive spectroscopy and X-ray photoelectron spectroscopy. The results indicate that the composition, morphology and corrosion resistance of the biomimetic calcium phosphate coatings depend strongly on the coating bath composition.

Improving in vitro corrosion resistance of biomimetic calcium phosphate coatings for Mg substrates using calcium hydroxide layer

Biomimetic calcium phosphate coatings have been studied to improve the corrosion resistance of biodegradable magnesium alloys. The corrosion resistance of these coatings is often limited by defects during creation. A method for improving the corrosion response of these coatings is therefore needed if biomimetic coatings are to be used for corrosion protection. In this study, a calcium hydroxide underlayer was applied to improve the properties of these biomimetic coatings. The in vitro corrosion response was studied using hydrogen evolution and electrochemical techniques. It was found that the calcium hydroxide layer increased the corrosion resistance of the coatings. The coatings created had fewer defects than the unmodified biomimetic coatings. Over time, the calcium hydroxide layer also prevented the defects in the coating from growing, leading to longer lasting protection. The results of this study suggest that calcium hydroxide coatings can significantly improve the corrosion protection of a biomimetic coating.

Biomimetic Mineralization of Calcium Phosphate on a Functionalized Porous Silicon Carbide Biomaterial

AbstractPorous biomorphic silicon carbide (bioSiC) is a structurally realistic, high‐strength, and biocompatible material which is promising for application in load‐bearing implants. The deposition of an osteoconductive coating is essential for further improvement of its integration with the surrounding tissue. A new strategy towards biomimetic calcium phosphate coatings on bioSiC is described. X‐ray photoelectron spectroscopy (XPS) analysis shows that using 10‐undecenoic acid methyl ester a covalently bound monolayer can be synthesized on the surface of the bioSiC. After hydrolysis it exposes carboxylic acid groups that promote the selective nucleation and growth of a very well‐defined crystalline layer of calcium phosphate. The resulting calcium phosphate coating is characterized by X‐ray diffraction and electron microscopy techniques. Further, ion beam imaging is employed to quantify the mineral deposition meanwhile, three‐dimensional dual‐beam imaging (FIB/SEM) is used to visualize the bioSiC/mineral interface. The monolayer is show to actively induce the nucleation of a well‐defined and highly crystalline mixed octacalcium phosphate/hydroxyapatite (OCP/HAP) coating on implantable bioSiC substrates with complex geometry. The mild biomimetic procedure, in principle, allows for the inclusion of bioactive compounds that aid in tissue regeneration. Moreover, the mixed OCP/HAP phase will have a higher solubility compared to HAP, which, in combination with its porous structure, is expected to render the coating more reabsorbable than standard HAP coatings.

Control of Surface Topography in Biomimetic Calcium Phosphate Coatings

The behavior of cells responsible for bone formation, osseointegration, and bone bonding in vivo are governed by both the surface chemistry and topography of scaffold matrices. Bone-like apatite coatings represent a promising method to improve the osteoconductivity and bonding of synthetic scaffold materials to mineralized tissues for regenerative procedures in orthopedics and dentistry. Polycaprolactone (PCL) films were coated with calcium phosphates (CaP) by incubation in simulated body fluid (SBF). We investigated the effect of SBF ion concentration and soaking time on the surface properties of the resulting apatite coatings. CaP coatings were examined by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), and energy dispersive X-ray spectrometry (EDX). Young's modulus (E(s)) was determined by nanoindentation, and surface roughness was assessed by atomic force microscopy (AFM) and mechanical stylus profilometry. CaP such as carbonate-substituted apatite were deposited onto PCL films. SEM and AFM images of the apatite coatings revealed an increase in topographical complexity and surface roughness with increasing ion concentration of SBF solutions. Young's moduli (E(s)) of various CaP coatings were not significantly different, regardless of the CaP phase or surface roughness. Thus, SBF with high ion concentrations may be used to coat synthetic polymers with CaP layers of different surface topography and roughness to improve the osteoconductivity and bone-bonding ability of the scaffold.

Gradual pore formation in natural origin scaffolds throughout subcutaneous implantation

This study used a rat subcutaneous implantation model to investigate gradual in situ pore formation in a self-regulating degradable chitosan-based material, which comprises lysozyme incorporated into biomimetic calcium phosphate (CaP) coatings at the surface to control the scaffold degradation and subsequent pore formation. Specifically, the in vivo degradation of the scaffolds, the in situ pore formation, and the tissue response were investigated. Chitosan or chitosan/starch scaffolds were studied with and without a CaP coating in the presence or absence of lysozyme for a total of six experimental groups. Twenty-four scaffolds per group were implanted, and eight scaffolds were retrieved at each of three time points (3, 6, and 12 weeks). Harvested samples were analyzed for weight loss, microcomputed tomography, and histological analysis. All scaffolds showed pronounced weight loss and pore formation as a function of time. The highest weight loss was 29.8% ± 1.5%, obtained at week 12 for CaP chitosan/starch scaffolds with lysozyme incorporated. Moreover, all experimental groups showed a significant increase in porosity after 12 weeks. At all time points no adverse tissue reaction was observed, and as degradation increased, histological analysis showed cellular ingrowth throughout the implants. Using this innovative methodology, the ability to gradually generate pores in situ was clearly demonstrated in vivo.

Corrosion resistance of biomimetic calcium phosphate coatings on magnesium due to varying pretreatment time

Calcium phosphate coatings were prepared on magnesium substrates via a biomimetic coating process. The effects of a magnesium hydroxide pretreatment on the formation and the ultimate corrosion protection of the coatings were studied. The pretreatment layer was found to affect the amount of defects present in the coatings. Corrosion resistance of the coatings was studied in vitro using two simulated body fluids, 0.8% NaCl and Hanks solution. In NaCl, the resistance to corrosion of all samples decreases with time as corrosion proceeded through cracks and other defects in the coatings. Samples with no pretreatment displayed the highest corrosion resistance as these samples had the fewest defects in the coating. However, in Hanks solution, corrosion resistance increased with time due to additional nucleation of calcium phosphate from the fluid on to the substrate. In this solution, additional pretreatment time was beneficial to the overall corrosion resistance.

Effect of two-step functionalization of Ti by chemical processes on protein adsorption

Titanium and its alloys are widely used for orthopedic and dental implants because of their superior mechanical properties, low modulus, excellent corrosion resistance and good biocompatibility. However, it takes several months for titanium implants and bone tissue to reach integration. Hence, there is growing interest in shortening the process of osseointegration and thereby reducing surgical restrictions. Various surface modifications have been applied to form a bioactive titanium oxide layer on the metal surface, which is known to accelerate osseointegration. The present work shows that titanium dioxide (TiO 2) layers formed on titanium substrates by etching in a solution of sodium hydroxide (NaOH) or hydrogen peroxide/phosphoric acid (H 3PO 4/H 2O 2, with a volume ratio of 1:1) are highly suitable pre-treatments for apatite-like coating deposition. Using a two-step procedure (etching in an alkaline or acidic solution followed by soaking in Hanks’ medium), biomimetic calcium phosphate coatings were deposited on porous TiO 2 layers. The combined effects of surface topography and chemistry on the formation of the calcium phosphate layer are presented. The topography of the TiO 2 layers was characterized using HR-SEM and AFM techniques. The nucleation and growth of calcium phosphate (Ca–P) coatings deposited on TiO 2 porous layers from Hanks’ solution was investigated using HR-SEM microscopy. AES, XPS and FTIR surface analytical techniques were used to characterize the titanium dioxide layers before and after deposition of the calcium phosphate coatings, as well as after the process of protein adsorption. To evaluate the potential use of such materials for biomedical applications, the adsorption of serum albumin, the most abundant protein in the blood, was studied on such surfaces.

Biomimetic Calcium Phosphate Growth over Differently Shaped Ti Substrates: Modeling the Effect of Surface Curvature

The growth of biomimetic calcium phosphate (CaP) coatings on flat Ti coupons and rounded pins (wires) immersed in simulated body fluid (SBF) was studied. Depending on the substrate curvature and immersion time, single- or double-layer coatings were obtained, comprised of submicrometer-size hydroxyapatite (HA) and platelike crystals of octacalcium phosphate (OCP). Increasing the curvature was found to delay the growth of OCP, to increase the relative thickness of HA, and to increase the total coating thickness. A computational model of CaP deposition was developed based on the assumption that the nucleation of the kinetically favored OCP phase and its hydrolysis into the more stable HA at high initial supersaturations is superseded by OCP crystal growth due to decreasing local supersaturation on the substrate surface. The model calculations showed good agreement with the experimental results and allowed us to qualitatively predict the coating thickness and OCP/HA sublayer proportion on different diameter wires. In addition, the effect of SBF solution parameters on CaP coating growth was studied experimentally and modeled.

Effect of water aging on the apatite formation of a low-modulus Ti–7.5Mo alloy treated with aqueous NaOH

The objective of this experiment was to develop biomimetic calcium phosphate coatings on low-modulus Ti–7.5Mo substrates treated with NaOH aqueous solutions and subsequent water aging before soaking them in simulated body fluid (SBF). Specimens of commercially pure titanium (c.p. Ti) and Ti–7.5Mo were initially treated with 5 M NaOH at 60 °C for 24 h, resulting in the formation of a porous network structure composed of sodium titanate (Na2Ti5O11). Afterward, the specimens were aged in distilled water at 80 °C for 12, 24, or 48 h, and subsequently immersed in 1.5SBF at 37 °C for either 1 or 13 days. The calcium phosphate-forming abilities of the c.p. Ti and Ti–7.5Mo achieved by a single NaOH treatment were low, but were significantly increased by the water aging. The amount of calcium phosphate deposited on the Ti–7.5Mo after NaOH treatment and subsequent water aging for 12 or 24 h was much greater than other conditions. The calcium phosphate-coated Ti–7.5Mo has strong potential as an artificial bone substitute or in other hard tissue-replacement materials with heavy load-bearing requirements due to a favorable combination of bioactivity, low elastic modulus, and low processing costs.

Biomimetic calcium phosphate coating on Ti wires versus flat substrates: structure and mechanism of formation

Biomimetic calcium phosphate (Ca-P) coatings improve the osteoconductivity of orthopedic implants and show promise as slow delivery systems for growth factors. This paper compares the structure and composition of biomimetic coatings on flat titanium coupons and on Ti wires/thin pins that are often used as model implants in small animal in vivo models. Ca-P coatings were grown on alkali-treated Ti substrates using a two-step deposition procedure. The coatings on wires consisted of a surface layer of octacalcium phosphate (OCP) and a layer of Ca-deficient hydroxyapatite (CDHA) underneath. The coating thickness and the proportion of CDHA decreased with increasing wire diameter. The coatings on flat coupons were the thinnest, and were comprised almost entirely of OCP. A mechanism of successive formation of the CDHA and OCP phases based on the interplay between nucleation, growth and hydrolysis of OCP crystals as a function of changing local supersaturation is proposed.

Natural Stimulus Responsive Scaffolds/Cells for Bone Tissue Engineering: Influence of Lysozyme upon Scaffold Degradation and Osteogenic Differentiation of Cultured Marrow Stromal Cells Induced by CaP Coatings

This work proposes the use of nonporous, smart, and stimulus responsive chitosan-based scaffolds for bone tissue engineering applications. The overall vision is to use biodegradable scaffolds based on chitosan and starch that present properties that will be regulated by bone regeneration, with the capability of gradual in situ pore formation. Biomimetic calcium phosphate (CaP) coatings were used as a strategy to incorporate lysozyme at the surface of chitosan-based materials with the main objective of controlling and tailoring their degradation profile as a function of immersion time. To confirm the concept, degradation tests with a lysozyme concentration similar to that incorporated into CaP chitosan-based scaffolds were used to study the degradation of the scaffolds and the formation of pores as a function of immersion time. Degradation studies with lysozyme (1.5 g/L) showed the formation of pores, indicating an increase of porosity ( approximately 5-55% up to 21 days) resulting in porous three-dimensional structures with interconnected pores. Additional studies investigated the influence of a CaP biomimetic coating on osteogenic differentiation of rat marrow stromal cells (MSCs) and showed enhanced differentiation of rat MSCs seeded on the CaP-coated chitosan-based scaffolds with lysozyme incorporated. At all culture times, CaP-coated chitosan-based scaffolds with incorporated lysozyme demonstrated greater osteogenic differentiation of MSCs, bone matrix production, and mineralization as demonstrated by calcium deposition measurements, compared with controls (uncoated scaffolds). The ability of these CaP-coated chitosan-based scaffolds with incorporated lysozyme to create an interconnected pore network in situ coupled with the demonstrated positive effect of these scaffolds upon osteogenic differentiation of MSCs and mineralized matrix production illustrates the strong potential of these scaffolds for application in bone tissue engineering strategies.

A new evaporation-based method for the preparation of biomimetic calcium phosphate coatings on metals

This study reports a new method to prepare biomimetic calcium phosphate coatings on titanium, stainless steel, CoCrMo, and tantalum. The method does not require surface etching, high supersaturation, or tight control of solution conditions. Metallic samples were dipped into a supersaturated calcium phosphate solution, withdrawn, and left to dry at room temperature. Calcium phosphate crystallites formed on and completely covered the surfaces by repeating the dip-and-dry treatment. The crystallite-covered surfaces readily grew to calcium phosphate coatings when immersed in the supersaturated solution. The mechanism of the treatment was suggested to be an evaporation-induced surface crystallization process.

An effective approach to activate 316L stainless steel for biomimetic coating of calcium phosphate: electrochemical pretreatment

In this paper, an electrochemical (EC) method to activate 316L stainless steel (denoted as 316L) surface for biomimetic calcium phosphate (Ca–P) coatings was reported. After EC treatment, a gel-like Ca–P film with a thickness of 150 nm was generated on the stainless steel surface after treatment, which was composed of amorphous phase of calcium phosphate with a large number of crystal nuclei of octacalcium phosphate (OCP) inside. This Ca–P thin film is the main factor that causes Ca–P formation under biomimetic condition. The effectiveness of EC treatment was also compared with alkali heat (AH) pretreatment in producing biomimetic coating on 316L. A uniform Ca–P coating formed on EC treated samples after samples were immersed in saturated calcium solution (SCS) for several hours, while only some island-like deposits were found on the sample surface with AH treatment followed by immersion in SCS for several days. This work has explored a novel and effective pretreatment method to activate 316L implant surface, which can be expected to be applied to activate other metal implants.