Effect of copper addition on mechanical properties, corrosion resistance and antibacterial property of 316L stainless steel

Combatting cyanobacteria: unraveling the potency of 316L-Cu stainless steel in inhibiting Microcystis aeruginosa growth

Harmful algal blooms, particularly those of Microcystis aeruginosa, present significant ecological and health risks. To address this issue, this study utilized a custom static algal growth assessment apparatus to investigate the anti-algal performance of a copper-alloyed 316L stainless steel (SS), named 316L-Cu SS. This material was compared with traditional 316L SS, which is widely utilized in freshwater systems for its corrosion resistance. Algal growth dynamics were monitored through optical density (OD) and chlorophyll A concentration measurements. Notably, 316L-Cu SS exhibited superior inhibitory effects on Microcystis aeruginosa growth compared to 316L SS and control groups. Inductively coupled plasma mass spectrometry (ICP-MS) confirmed that the copper ion release from 316L-Cu SS played a critical role in this algal suppression, which interfered with photosynthesis, induced oxidative stress, and damaged algal cell membranes. In contrast, other metal ions (Ni, Cr, Fe) had a negligible impact on algal growth. The study highlights 316L-Cu SS as a promising material for mitigating harmful algal blooms, thereby offering potential benefits for both aquatic ecosystem conservation and public health protection.

Controlled nano Cu precipitation through age treatment: A method to enhance the biodegradation, mechanical, antimicrobial properties and biocompatibility of Fe-20Mn-3Cu alloys

Iron-manganese (Fe-Mn) based degradable biomaterials have been proven as a suitable substitute to permanent internal fracture-fixation devices. However, lower degradation and bacterial infection are still major concerns. To overcome these limitations, in this work, we have incorporated copper (Cu) in Fe-Mn system. The objective is to produce Cu nano-precipitates and refined microstructure through suitable combination of cold-rolling and age-treatment, so that degradation is improved eventually. High resolution transmission electron microscope (TEM) and scanning transmission electron microscope (STEM) confirmed the Cu rich composition of the nano-precipitates. Number of precipitates increased as aging time increased. Three-dimensional visualization of Fe, Mn and Cu atomic distributions using atom probe tomography (APT), indicated that Cu precipitates were in 15-50 nm range. Large number of nano-precipitates along with lower dislocation density led to highest strength (1078 MPa) and ductility (37 %) for the 6 h age-treated sample. On the other hand, nano-precipitates and refined microstructure resulted highest degradation for the 12 h of age treated sample (0.091 mmpy). When E.Coli bacteria was cultured with the sample extract, significantly higher antibacterial efficacy was observed for the sample having higher nano-precipitates. Higher degradation rate did not cause cyto-toxicity, rather promoted statistically higher cell proliferation (1.5 times within 24 h) in in vitro cell-material interaction studies. In vivo biocompatibility of the alloy containing large nano-precipitates was confirmed from higher new bone regeneration (60%) in rabbit femur model. Overall study suggested that the optimization of the thermo-mechanical processes can effectively tailor the Fe-Mn-Cu alloys for successful internal fracture fixation. STATEMENT OF SIGNIFICANCE: In the present work, we have reported a noble thermo-mechanical approach to simultaneously achieve Cu nano-precipitates and grain refinement in Fe-20Mn-3Cu alloy.

Novel Antibacterial Metals as Food Contact Materials: A Review

Food contamination caused by microorganisms is a significant issue in the food field that not only affects the shelf life of food, but also threatens human health, causing huge economic losses. Considering that the materials in direct or indirect contact with food are important carriers and vectors of microorganisms, the development of antibacterial food contact materials is an important coping strategy. However, different antibacterial agents, manufacturing methods, and material characteristics have brought great challenges to the antibacterial effectiveness, durability, and component migration associated with the use security of materials. Therefore, this review focused on the most widely used metal-type food contact materials and comprehensively presents the research progress regarding antibacterial food contact materials, hoping to provide references for exploring novel antibacterial food contact materials.

Effects of Ageing in Disinfectant Solution on the Corrosion Resistance and Antimicrobial Behavior of Copper Alloys

This work studies two copper-based alloys as potential antimicrobial weapons for sectors where surface hygiene is essential. Effects of different alloying elements addition at the same Cu content (92.5% by weight) on the corrosion resistance and the antibacterial performance of two copper alloys were studied in an aerated disinfectant solution (0.25% v/v Aniosurf Premium (D)) by electrochemical corrosion, X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectroscopy (ToF-SIMS) and antibacterial tests. Results showed that the nature of the alloying elements had a clear influence on the corrosion resistance and antibacterial performance. Electrochemical impedance results and surface analyses demonstrate the presence of organic compounds bound on the substrate and that a film covers part of the total active surface and may act as a protective barrier by preventing the interaction between metal and solution, decreasing the antimicrobial performance of copper-based materials. Low zinc and silicon contents in copper alloys allows for better aging behavior in D solution while maintaining good antibacterial performance. The XPS and ToF-SIMS results indicated that artificial aging in disinfectant enhanced Cu enrichment in the organic film formed, which could effectively stimulate the release of Cu ions from the surface.

Nanostructured Cu-doped TiO2 with photothermal effect for prevention of implant-associated infection

Bacterial infection of titanium (Ti) dental implants is still a major clinical complication. In this study, a combination of copper (Cu) ions and photothermal therapy is used to combat implant-associated infection. Cu doped TiO₂ (TiO₂-Cu) films were prepared on Ti by magnetron sputtering and subsequently annealing. TiO₂-Cu films had efficient photothermal conversion ability due to the generated nanostructure during the annealing process. Under the irradiation of 808 near infrared light, the combined actions of hyperthermia and Cu ions gave rise to excellent antibacterial activity against Streptococcus mutans on Ti as demonstrated by the experiments conducted in vitro and in vivo. The TiO₂-Cu films also exhibited excellent biocompatibility. In addition, the surface hardness and corrosion resistance of TiO₂-Cu films were greatly improved.

Femtosecond Laser Treatment for Improving the Corrosion Resistance of Selective Laser Melted 17-4PH Stainless Steel

Currently, laser surface treatment (LST) is considered the most promising method available within the industry. It delivers precise control over surface topography, morphology, wettability, and chemistry, making the technique suitable for regulating the corrosion behavior of alloys. In this paper, femtosecond laser texturing with different parameters and atmosphere environments was adopted to clarify the effect of surface treatment on the corrosion resistance of selective laser melted (SLM-ed) 17-4PH stainless steel (SS) in a NaCl solution. The experimental results show that, after the heat treatment, the corrosion resistance of the laser-treated samples was enhanced. With the further laser treatment in an argon atmosphere, the oxidation of nanostructural surfaces was avoided. The Cr, Cu, and other alloying elements precipitated on the laser-ablated surface were beneficial to the formation of a passivation film, leading to an improved corrosion resistance performance.

Electrochemical and Optical Behavior of ZrN-Ag Coatings Deposited by Means of DC Reactive Magnetron Sputtering Technique

The formation of nanostructured transition metal nitride coatings by introducing a small amount of silver (Ag) content has been proven to be a good strategy for enhancing the physical properties of these materials. In this investigation, ZrN coatings with different Ag contents were deposited on an AISI 316L substrate using the DC reactive magnetron sputtering technique. The influence of the silver on the chemical composition, morphology, and microstructure was investigated using energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The functional properties, specifically the corrosion resistance and the optical reflectance of the deposited coatings, were investigated using electrochemical impedance spectroscopy (EIS) and UV-Visible-NIR, respectively. The results showed the formation of two nanocrystalline phases, fcc-ZrN and metallic fcc-Ag. On the surface of the deposited coatings, homogeneously distributed silver nanoparticles were observed, and they increased with the Ag atomic content. The chemical composition on the surface showed evidence of the formation of oxides, such as Zr-O and Zr-O-N, before and after the corrosion tests. The corrosion resistance of the AISI 316L substrate and the coatings was improved with the incorporation of Ag, and the optical reflectance increased with increasing the Ag content. Finally, this work investigated the effect of the incorporation of silver into a ZrN matrix for potential use as optical protective coatings.

Anti-pathogen stainless steel combating COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exhibits strong stability on conventional stainless steel (SS) surface, with infectious virus detected even after two days, posing a high risk of virus transmission via surface touching in public areas. In order to mitigate the surface toughing transmission, the present study develops the first SS with excellent anti-pathogen properties against SARS-COV-2. The stabilities of SARS-CoV-2, H1N1 influenza A virus (H1N1), and Escherichia coli (E.coli) on the surfaces of Cu-contained SS, pure Cu, Ag-contained SS, and pure Ag were investigated. It is discovered that pure Ag and Ag-contained SS surfaces do not display apparent inhibitory effects on SARS-CoV-2 and H1N1. In comparison, both pure Cu and Cu-contained SS with a high Cu content exhibit significant antiviral properties. Significantly, the developed anti-pathogen SS with 20 wt% Cu can distinctly reduce 99.75% and 99.99% of viable SARS-CoV-2 on its surface within 3 and 6 h, respectively. In addition, the present anti-pathogen SS also exhibits an excellent inactivation ability for H1N1 influenza A virus (H1N1), and Escherichia coli (E.coli). Interestingly, the Cu ion concentration released from the anti-pathogen SS with 10 wt% and 20 wt% Cu was notably higher than the Ag ion concentration released from Ag and the Ag-contained SS. Lift buttons made of the present anti-pathogen SS are produced using mature powder metallurgy technique, demonstrating its potential applications in public areas and fighting the transmission of SARS-CoV-2 and other pathogens via surface touching.

The effect of high temperature aging on the corrosion resistance, mechanical property and antibacterial activity of Cu-2205 DSS

The effects of high temperature aging on the corrosion resistance, mechanical property and antibacterial activity of a copper-bearing 2205 duplex stainless steel (Cu-2205 DSS) were investigated. The results from scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM) and EDS analysis showed that after aging the proportion of γ phase in microstructure was increased and new σ phase and copper-rich precipitates were formed. The mechanical properties including hardness and tensile and yield strengths of the aged Cu-2205 DSS were significantly enhanced compared to the solution-treated Cu-2205 DSS as well as the 2205 DSS. Electrochemical measurements including electrochemical impedance spectroscopy, potentiodynamic polarization curves and potentiostatic polarization scan were performed to evaluate the corrosion behavior of the Cu-2205 DSS. It was found that aging increased the uniform corrosion resistance but had slightly adverse effect on the pitting corrosion resistance. Additionally, the antibacterial performance of aged Cu-2205 DSS was significantly improved compared to the solution treated Cu-2205 DSS, which was attributed to the more release of copper ions from the matrix that killed the bacteria cells and inhibited the biofilm formation on the surface. The above results suggest that Cu-2205 DSS after high temperature aging revealed good mechanical property, antibacterial performance, and corrosion resistance, which will further expand the application of duplex stainless steel in marine engineering fields.

Corrosion Resistance of AlxCoCrFeNiM (M = Ti, V, Si, Mn, Cu) High Entropy Alloys in NaCl and H2SO4 Solutions

The electrochemical behavior of as-cast AlxCoCrFeNiM (M = Ti, V, Si, Mn, Cu) high entropy alloys (HEAs) in 1 M NaCl and 0.5 M H2SO4 solutions is studied. Polarization measurements were carried out in a standard three-electrode electrochemical cell with a platinum auxiliary electrode using a P-30J potentiostat device. The potentials were measured relative to a saturated silver chloride reference electrode EVL-1M3 at room temperature (25 °C) with a sweep rate of 5 mV/s. It is shown that despite a wide passivation region, Al0.5CoCrFeNi1.6Ti0.7 HEA undergoes significant corrosion in both sodium chloride and sulfuric acid solutions and exhibits low corrosion potential and current density. Energy-dispersive X-ray spectroscopy (EDS) analysis revealed that Ti-containing eutectic areas are the most susceptible regions to corrosion. Intergranular corrosion was found in Al0.25CoCrFeNiMn and Al0.25CoCrFeNiCu HEAs. Moreover, Al0.25CoCrFeNiCu possesses the smallest passivation interval ΔE among all the investigated HEAs. For samples with Ti, Mn, and Cu, a protective film layer is not formed on the surface of the phases enriched in these elements, or it is brittle and crumbles. For samples with Si and V, a passivating film is formed. Thus, Al0.45CoCrFeNiSi0.45 and Al0.25CoCrFeNiV HEAs exhibited the highest resistance in 1 M NaCl and 0.5 M H2SO4 corrosive environments, respectively.

Inhibition efficiency of 304-Cu stainless steel against oral bacterial biofilm

PURPOSE

This study aims to evaluate the antibacterial properties of 304 Cu-bearing stainless steel (SS) with different Cu contents (0, 2.5, 4.5 wt.%) against oral biofilms of Streptococcus mutans (S. mutans), Streptococcus sanguinis (S. sanguinis), and their mixture.

METHODS

Bacterial biofilms on the surface of 304-Cu SS were characterized by plate counting, 4', 6-diamidino-2-phenylindole (DAPI) staining with aid of sanning electron microscopy (SEM) and 2, 3-bis (2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide inner salt (XTT). In addition, the inhibition zone method was also employed to evaluate the antibacterial properties of 304-Cu SS. Cell Counting Kit-8 (CCK-8) and flow cytometry were used to assess the cytotoxicity and apoptosis rate of 304-Cu SS, respectively.

RESULTS

304-4.5Cu SS could effectively inhibit the attachment, formation, activity, and metabolism of bacterial biofilm, possessing the best antibacterial properties exceeding 99.9% of antibacterial rate against S. mutans, S. sanguinis, and their mixture. The diameters of inhibition zones to S. mutans and S. sanguinis on the surface of 304-4.5Cu SS were 21.7 and 14.7 mm, respectively. The results of cell experiments in vitro showed that both 304-2.5Cu SS and 304-4.5Cu SS had no evident cytotoxicity with an identical grade 1. The apoptosis rate exhibited a gradually increased tendency with increase of the Cu content in 304 SS.

CONCLUSIONS

304-4.5Cu SS without cytotoxic effect on NIH3T3 cells has obvious antibacterial activity against S. mutans, S. sanguinis and their mixture.

CLINICAL SIGNIFICANCE

The Cu-bearing stainless steel provides a new solution to be used as oral orthodontic devices for inhibiting oral microflora imbalance and enamel demineralization.

Analysis of the Crystallization Kinetics and Thermal Stability of the Amorphous Mg72Zn24Ca4 Alloy

The aim of this study was to analyze the crystallization of the Mg₇₂Zn₂₄Ca₄ metallic glass alloy. The crystallization process of metallic glass Mg₇₂Zn₂₄Ca₄ was investigated by means of the differential scanning calorimetry. The glass-forming ability and crystallization are both strongly dependent on the heating rate. The crystallization kinetics, during the isothermal annealing, were modelled by the Johnson–Mehl–Avrami equation. Avrami exponents were from 2.7 to 3.51, which indicates diffusion-controlled grain growth. Local exponents of the Johnson–Mehl–Avrami equation were also calculated. In addition, the Mg phase—being the isothermal crystallization product—was found, and the diagram of the time–temperature phase transformation was developed. This diagram enables the reading of the start and end times of the crystallization process, occurring in amorphous ribbons of the Mg₇₂Zn₂₄Ca₄ alloy on the isothermal annealing temperature. The research showed high stability of the amorphous structure of Mg₇₂Zn₂₄Ca₄ alloy at human body temperature.

Antibacterial metals and alloys for potential biomedical implants

Metals and alloys, including stainless steel, titanium and its alloys, cobalt alloys, and other metals and alloys have been widely used clinically as implant materials, but implant-related infection or inflammation is still one of the main causes of implantation failure. The bacterial infection or inflammation that seriously threatens human health has already become a worldwide complaint. Antibacterial metals and alloys recently have attracted wide attention for their long-term stable antibacterial ability, good mechanical properties and good biocompatibility in vitro and in vivo. In this review, common antibacterial alloying elements, antibacterial standards and testing methods were introduced. Recent developments in the design and manufacturing of antibacterial metal alloys containing various antibacterial agents were described in detail, including antibacterial stainless steel, antibacterial titanium alloy, antibacterial zinc and alloy, antibacterial magnesium and alloy, antibacterial cobalt alloy, and other antibacterial metals and alloys. Researches on the antibacterial properties, mechanical properties, corrosion resistance and biocompatibility of antibacterial metals and alloys have been summarized in detail for the first time. It is hoped that this review could help researchers understand the development of antibacterial alloys in a timely manner, thereby could promote the development of antibacterial metal alloys and the clinical application.

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This paper focuses the recent development of several antibacterial metals and alloys as biomedical materials.

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The possible antibacterial mechanisms of antibacterial metals and alloys are summarized in this paper.

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This review discusses the feasibility of antibacterial metals and alloys as biomedical implants in the future.

Antibacterial effect of a copper-containing titanium alloy against implant-associated infection induced by methicillin-resistant Staphylococcus aureus

Implant-associated infection (IAI) induced by methicillin-resistant Staphylococcus aureus (MRSA) is a devastating complication in the orthopedic clinic. Traditional implant materials, such as Ti6Al4V, are vulnerable to microbial infection. In this study, we fabricated a copper (Cu)-containing titanium alloy (Ti6Al4V-Cu) for the prevention and treatment of MRSA-induced IAI. The material characteristics, antibacterial activity, and biocompatibility of Ti6Al4V-Cu were systematically investigated and compared with those of Ti6Al4V. Ti6Al4V-Cu provided stable and continuous Cu²⁺ release, at a rate of 0.106 mg/cm²/d. Its antibacterial performance against MRSA in vitro was confirmed by plate counting analysis, crystal violet staining, and scanning electron microscopic observations. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) analysis demonstrated that Ti6Al4V-Cu suppressed biofilm formation, virulence, and antibiotic-resistance of MRSA. The in vivo anti-MRSA effect was investigated in a rat IAI model. Implants were contaminated with MRSA solution, implanted into the femur, and left for 6 weeks. Severe IAI developed in the Ti6Al4V group, with increased radiological score (9.6 ± 1.3) and high histological score (10.1 ± 1.9). However, no sign of infection was found in the Ti6Al4V-Cu group, as indicated by decreased radiological score (1.3 ± 0.4) and low histological score (2.3 ± 0.5). In addition, Ti6Al4V-Cu had favorable biocompatibility both in vitro and in vivo. In summary, Ti6Al4V-Cu is a promising implant material to protect against MRSA-induced IAI.

Effect of Low Copper Addition to As-Forged 304 Stainless Steel for Dental Applications

The aim of this study was to investigate the effect of incorporating low copper (0, 0.5, 1, 1.5, and 2 wt.%) additions into as-forged AISI 304 stainless steel (304SS). The microstructures and mechanical properties of the steel were examined using scanning electron microscopy and a universal testing machine. The antibacterial properties of the Cu-bearing 304SS specimens were investigated using Escherichia coli. Each specimen was soaked in artificial saliva to detect the release of copper ions through inductively coupled plasma atomic emission spectrometry. The addition of copper had no significant effect on the microstructure of the as-forged Cu-bearing 304SS, but it slightly increased its maximum tensile strength. The antibacterial rate of the as-cast and as-forged 304SS with 2 wt.% Cu was over 80%, which corresponded to an increase in the release of copper ions. This study demonstrates that low-Cu-content stainless steel can reduce bacteria and can be a suitable material for the oral environment because of the low release of Cu ions.

Effects of Ag-Rich Nano-Precipitates on the Antibacterial Properties of 2205 Duplex Stainless Steel

The effects of the addition of silver on the microstructural variation and antibacterial performance of 2205 duplex stainless steel after solution and aging treatment were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution TEM, and antibacterial testing. The microstructure showed that 2205Ag is composed of a ferrite (α) + austenite (γ) duplex phase and Ag-rich nano-precipitates (Ag-NPs). The morphology of the Ag-NPs varied from spherical to polygonal after aging treatment at 450 °C for 4 h. These precipitates were identified as face-centered-cubic structures with a lattice parameter of a = 0.354 nm and a mismatch of δ = 0.84% relative to the austenite matrix. Notably, 2205Ag with polygonal Ag-NPs exhibited excellent antibacterial properties that were superior to those of 2205Ag with spherical Ag-NPs.

The Intergranular Corrosion Susceptibility of Metastable Austenitic Cr⁻Mn⁻Ni⁻N⁻Cu High-Strength Stainless Steel under Various Heat Treatments

The intergranular corrosion (IGC) behavior of a new metastable austenitic Cr-Mn-Ni-N-Cu high-strength stainless steel under various heat treatments was studied. The samples were solution treated at 1050 °C for 30 min and then aged at 600 to 900 °C for 10 to 300 min, respectively. The IGC susceptibility of aged samples was investigated using a double-loop electrochemical potentiokinetic reactivation (DL-EPR) test in a solution of 0.1 M H₂SO₄ and 0.002 M KSCN and the 10% oxalic acid etch. The surface morphologies of samples were characterized using optical microscopy and the scanning electron microscopy after electrochemical tests. Two time-temperature-sensitization diagrams were plotted based on the DL-EPR test and oxalic acid etching. No IGC and precipitate were observed for samples aged at 600 °C and 900 °C. For samples aged at 650 °C to 750 °C, the IGC susceptibility and the amount of precipitate both increased with the extended aging time. For samples aged at 800 °C and 850 °C, the amount of precipitate increased as the aging time was prolonged. However, only the sample aged at 800 °C for 60 min showed slight intergranular corrosion in the DL-EPR test. The IGC of the Cr-Mn-Ni-N-Cu austenitic stainless steel originated from the precipitation of Cr₂₃C₆ and Cr₂N at the grain boundaries. The chromium-depleted zones near grain boundaries stood as the corrosion nucleation sites, but the dissolution of the weak area followed a consistent crystallographic orientation along each grain boundary.

Antibacterial durability and biocompatibility of antibacterial-passivated 316L stainless steel in simulated physiological environment

Stainless steel (SS) has been widely applied as one of the most efficient implant metal materials, although corrosion and infection in body environment are still challenging. Herein, an antibacterial passivation method was employed to enhance the antibacterial performance and corrosion resistance of the medical 316L SS. The result proved that the antibacterial-passivated 316L SS exhibited stable antibacterial activity and effectively inhibited the formation of bacterial biofilm. Electrochemical measurements combined with X-ray photoelectron spectroscopy technique were used to study the corrosion resistance and semiconductor behavior of passivated 316L SS immersed in simulated physiological environment. The results indicated that the 316L SS after antibacterial passivation treatment for 1 h, soaking in the medium for 10 days, showed satisfactory corrosion resistance attributing to proper Cu deposition in the passive film. The anodic stripping voltammetry measurement further confirmed that the Cu-bearing passive film could continuously release Cu ions into medium. The zebrafish test demonstrated an excellent in vivo biocompatibility for the 316L SS with antibacterial passivation for 0.5 and 1 h, respectively. In addition, changes of surface roughness, contact angle and chemical composition after antibacterial passivation played an important role in explaining the antibacterial mechanism, which could be clearly divided into contact killing and ionic release killing. Hence, the antibacterial passivation treatment was preliminarily proved as a potential way for enhancing the persistent antibacterial activity and corrosion resistance of 316L SS.

Evaluation of promoting effect of a novel Cu-bearing metal stent on endothelialization process from in vitro and in vivo studies

Drug eluting stents (DES) have been extensively applied nowadays and reduce the incidence of in-stent restenosis (ISR) greatly as compared with bare metal stents (BMS). However, the development of DES is hindered by the risk of late stent thrombosis (LST) due to delayed re-endothelialization, while endothelialization is an important process related to ISR and LST after implantation. 316L is a traditional stent material without bioactivity and have a high risk of ISR. Cu is recognized for angiogenesis stimulation in these years. Hence a copper bearing 316L stainless steel (316L-Cu) was prepared and evaluated about its effect on endothelialization in this paper. Compared with traditional 316L, it was proved that 316L-Cu increased the proliferation of co-cultured human umbilical vein endothelial cells (HUVECs) at first day. Moreover, HUVECs stretched better on the surface of 316L-Cu. It also improved the expression of angiogenesis related genes and tube formation ability in vitro. 316L-Cu-BMS, DES and 316L-BMS were implanted in swine to evaluate the re-endothelialization ability in vivo. And 316L-Cu-BMS showed the best effect on endothelialization with good biosafety. Consequently, 316L-Cu is a kind of promising BMS material for coronary field.