Oxygen Plasma Immersion Ion Implantation Research Articles

AZO work function enhanced by oxygen plasma immersion ion implantation

The surface of aluminum-doped ZnO (AZO) films was modified using the oxygen plasma immersion ion implantation method, which is also called O-PIII. The modified AZO films were analyzed by an X-ray photoelectron spectroscopy system (XPS), X-ray diffraction (XRD), a UV–visible spectrophotometer, atomic force microscopy (AFM), and a Kelvin probe instrument (KP). The results showed that O-PIII modification can further enhance the work function (WF) of AZO based on oxygen plasma (O-ICP) treatment. The optical characteristics of AZO thin films are nearly entirely preserved, and the surface morphology is enhanced. The variation in WF was strongly linked to the surface stoichiometry. The reduction of oxygen vacancies should be attributed to the high WF. The WF of the modified AZO films decreased rapidly with exposure time in the air promptly following O-ICP and O-PIII modification. Nonetheless, the O-PIII treatment had a longer-lasting effect.

Osteogenesis and biofilms formation on titanium surfaces submitted to oxygen plasma immersion ion implantation

The objectives of this study were to characterize titanium (Ti) surfaces treated by ion implantation by immersion in oxygen plasma (O-PIII) at different temperatures, correlating these implanted layers with therapeutic effects and with osteogenesis, as well as the formation of monotypic biofilms microbial. The groups were divided into: a) Ti (pre-treatment) b) Ti O-PIII at 400 ° C. c) Ti O-PIII at 500 ° C. d) Ti O-PIII at 600 ° C. The properties and surface characteristics were evaluated according to the roughness, texture, corrosion resistance, formation of new phases and the identification of chemical compounds present. Cellular analyzes investigated cell interaction, viability, total protein content, alkaline phosphatase and quantification of mineralized nodules using MG-63 cells. The formation of monotypic microbial biofilms, including P. aeruginosa, S. aureus, S. mutans and C. albicans were evaluated. The increase in surface roughness, corrosion resistance and oxygen content, leading to the formation of TiO2-rutile with more intense peaks and in greater numbers according to the increase in the substrate temperature, ionic implanted Ti samples was observed. There was also a significant increase in cell viability, total protein production, alkaline phosphatase activity and formation of mineralization nodules for the group treated with O-PIII at 600ºC compared to other groups, in addition to a reduction of microorganisms in the groups treated with O- PIII. Therefore, treatment with O-PIII at 600ºC in Ti grade IV showed favorable results for its use.

Improving the in vitro cell differentiation and in vivo osseointegration of titanium dental implant through oxygen plasma immersion ion implantation treatment

Titanium (Ti) is widely used in dental implants; however, the bioinert surface has been shown to limit osseointegration, particularly in patients with poor bone quality. This study created a thin bioactive oxide film on Ti dental implants via oxygen plasma immersion ion implantation (OPIII) to improve bone cell differentiation and osseointegration. OPIII treatment was performed using low (1016 ions/cm2) and high (4 × 1017 ions/cm2) doses of oxygen ions. The Ti surfaces were characterized in terms of topography, wettability, chemical composition, and crystal structure. The differentiation of human bone marrow mesenchymal stem cells on OPIII-treated Ti surfaces was evaluated in vitro in terms of alkaline phosphatase (ALP) activity (early stage marker) and von Kossa staining (late stage marker). The osseointegration of OPIII-treated screw-type Ti dental implants in the femur of rabbits was evaluated in vivo using scanning electron microscope/backscattered electron imaging and histological staining at 4 weeks after implantation. OPIII treatment could induce a Ti oxide film on Ti surface without altering the surface topography, roughness or wettability. Higher oxygen ions dose increased the thickness of the surface Ti oxide film as well as the proportion of rutile phase titanium dioxide (TiO2) in the Ti oxide film. The OPIII-treated Ti surfaces presented higher ALP expression level, stronger von Kossa staining signal, and higher bone-to-implant contact. Note that all of these effects were more pronounced on surfaces created using higher oxygen ions dose due to the higher proportion of rutile phase TiO2. Overall, our results indicate that OPIII treatment using higher oxygen ions dose can enhance the in vitro bone cell differentiation and in vivo osseointegration of Ti dental implants.

Antibacterial Property and Biocompatibility of Polypyrrole Films Treated by Oxygen Plasma Immersion Ion Implantation

AbstractPolypyrrole (PPy) films obtained by oxidative polymerization have positive charges in its main chains and therefore exhibit antibacterial properties to some extent. However, antibacterial activities of PPy films for biomedical applications are still insufficient. Here, to endow PPy films with excellent antibacterial properties and biocompatibility, oxygen plasma immersion ion implantation (O‐PIII) is performed to regulate their physicochemical properties, including but not limited to wettability and surface charge. Escherichia coli, Staphylococcus aureus, and MC3T3‐E1 cells are utilized to investigate the antibacterial properties and cytocompatibility, respectively. Results show that antibacterial property of PPy films against E. coli is enhanced after O‐PIII treatment, and it becomes more outstanding with the increase of implantation time, which may be ascribed to the improved hydrophilicity and change of sample surfaces from negatively charged to positively charged. The similar results cannot be found from S. aureus due to different cell membrane structure. Meanwhile, O‐PIII can significantly improve the biocompatibility of PPy films.

Phase transformation from rutile to anatase with oxygen ion dose in the TiO2 layer formed on a Ti substrate

The oxygen plasma immersion ion implantation (O-PIII) method was used to form a TiO2 layer on a Ti substrate. The content of the anatase polycrystalline phase increased from 5.1% to 22.3% of the total TiO2 amount with a higher O+ ion dose. The oxygen ion doses were 3.6 × 1016 ions, 8.1 × 1016 ions, 1.26 × 1017 ions, for 1, 2, and 3 h, respectively, with ion energies of E ≈ 0.8 keV. The polycrystalline phases and morphology of the obtained films were characterized by XRD, FESEM, AFM, and Raman spectroscopy. The chemical bond analysis and layer-by-layer measurements for TiO2 layer thickness evaluation were performed by XPS. The photocatalytic decomposition reaction constants of a methylene blue solution increased from 3.2 × 10−3 min−1 to 4.2 × 10−3 min−1 under UV-A irradiation and the liquid free surface energy increased from 39.0 mJ/m2 to 49.5 mJ/m2 with a higher O-PIII treatment doses. These results were explained by the partial phase transition of the TiO2 layer from rutile to anatase. Thus, the increase in the O+ ions implantation dose into the Ti substrate invoked the reduction of material density from Ti (ρ = 4.506 g/cm3) through TiO2 rutile (4.23 g/cm3) to TiO2 anatase (3.78 g/cm3) phase.

Surface modification of L605 by oxygen plasma immersion ion implantation for biomedical applications

Abstract

Enhancing the blood response and antibacterial adhesion of titanium surface through oxygen plasma immersion ion implantation treatment

Titanium (Ti) is a biocompatible alloy widely used in dental implants, thanks to the protective Ti oxide film that forms spontaneously on the surface. Unfortunately, the film is bioinert and prone to the release of metal ions. In a previous study, we applied oxygen plasma immersion ion implantation (O-PIII) treatment to Ti surface to enhance the corrosion resistance and cell response of Ti. In this study, we examined the surface characteristics of the treated alloy, including roughness, hydrophilicity, and chemical composition. We investigated the blood response to the O-PIII-treated Ti surfaces, including the blood-clotting ability and platelet adhesion. We also investigated resistance of the treated alloy to the adhesion of oral bacteria, Streptococcus mutans, in terms of bacterial attachment and morphology. Our results demonstrate that O-PIII treatment did not have a significant effect on surface roughness or hydrophilicity. This treatment resulted in the formation of a Ti oxide film containing mainly TiO2, Ti2O3, and TiO. The presence of surface Ti oxides (particularly TiO2) positively influenced blood-clotting ability and platelet adhesion as well as resistance to bacterial adhesion. These effects were particularly evident when O-PIII treatment was applied at a higher voltage. Our results demonstrate that the proposed O-PIII treatment promotes blood-clotting and resistance to bacterial adhesion in dental implant applications.

Oxygen-implanted induced formation of oxide layer enhances blood compatibility on titanium for biomedical applications

Titanium dioxide (TiO2) layers were prepared on a Ti substrate by using oxygen plasma immersion ion implantation (oxygen PIII). The surface chemical states, structure, and morphology of the layers were studied using X-ray photoelectron spectroscopy, X-ray diffraction, Raman microscopy, atomic force microscopy and scanning electron microscope. The mechanical properties, such as the Young's modulus and hardness, of the layers were investigated using nanoindentation testing. The Ti4+ chemical state was determined to be present on oxygen-PIII-treated surfaces, which consisted of nanocrystalline TiO2 with a rutile structure. Compared with Ti substrates, the oxygen-PIII-treated surfaces exhibited decreased Young's moduli and hardness. Parameters indicating the blood compatibility of the oxygen-PIII-treated surfaces, including the clotting time and platelet adhesion and activation, were studied in vitro. Clotting time assays indicated that the clotting time of oxygen-PIII-treated surfaces was longer than that of the Ti substrate, which was associated with decreased fibrinogen adsorption. In conclusion, the surface characteristics and the blood compatibility of Ti implants can be modified and improved using oxygen PIII.

Surface modification of L605 by oxygen plasma immersion ion implantation

Event Abstract Back to Event Surface modification of L605 by oxygen plasma immersion ion implantation Carlo Paternoster1, Letícia Marin De Andrade1, Vanessa Montaño-Machado1, Ranna Tolouei1, Stéphane Turgeon1 and Diego Mantovani1 1 Laval University, Lab. for Biomaterials & Bioengineering (CRC-I), Dept. Min-Met-Materials Engineering & CHU de Quebec, Canada Introduction: Co-Cr alloys are currently used in biomedical applications for artificial heart valves, dental prosthesis, vascular stents and orthopedic fixation plates[1],[2]. L605, a Co-Cr alloy shows excellent mechanical properties, suitable for cardiovascular applications, but the presence of high amounts of Ni, Cr and Co is a health concern. A surface treatment creating a stable surface layer can effectively hinder the release of toxic ions and accommodate substrate deformation. For this reason, an electropolished L605 substrate was modified by oxygen plasma immersion ion implantation (PIII), to improve biocompatibility and increase the corrosion resistance, modifying the chemical composition[3],[4]. The effects of implanted oxygen dose (d) and antenna power (P) were investigated; the characterization of the surface condition was performed by different techniques and the interaction of endothelial cells with the modified surfaces was assessed. Materials and Methods: L605 flat samples were electropolished and subsequently oxygen implanted with a pulse duration and frequency respectively in the range of 50-100 µs and 10-40 Hz. Effect of antenna power and implanted doses have been investigated, in terms of surface and proliferation of human endothelial cells. X-Ray photoelectric spectroscopy (XPS) and scanning electron microscopy (SEM) were used to assess surface chemistry and morphology. Roughness and surface energy were studied by atomic force microscopy (AFM) and contact angle measurements. Finally, corrosion resistance was investigated by potentiodynamic test in 0,152 M saline solution. Endothelial cell viability was investigated after 1, 3 and 7 days of culture through resazurin tests. Results and Discussions: After oxygen implantation, the oxidized layer chemical composition is different from the one of the electropolished sample, and it is mainly composed by O and Co (figure 1). The oxygen amount increases for increasing doses (in the range of 17.5 % at. to 54% at.). For increasing antenna power, the oxygen surface amount does not vary in considerable way. XPS analysis attributed O1s peak to the formation of metallic oxides and complex phases including Si. Roughness decreased gradually both with increasing implantation time and with increasing antenna power (figure 2). The implantation process does not affect in a considerable way the surface morphology, as evidenced by SEM micrographs. The potentiodynamic polarization show an increase of Ecorr potential in oxygen implanted samples. Endothelial cell investigations in L605 treated samples show the highest cell viability on A3 condition (d = 400%, P = 300 W) and the lowest on B1 one (d = 400%, P = 150 W). Conclusions: Oxygen PIII can effectively change the chemical composition and surface energy of the substrate alloy. Increasing both implantation doses and antenna power increase the amount of Co oxide on the surface, improving the corrosion resistance and biological response. This work was partially funded by NSERC-Canada, FRQ-NT-Quebec and CFI-Canada. VMM was awarded of a doctoral scholarship from Conacyt – National Council of Science and Technology, Mexico. LMA was awarded of an undergraduate scholarship from CNPq - CAPES Foundation and Ministry of Education of Brazil. CP and DM were recipiendaries of the Linkage Grant from Quebec/Italy sub-commission of the Quebec Ministry of Intl Relations.

Enhanced osteogenic and selective antibacterial activities on micro-/nano-structured carbon fiber reinforced polyetheretherketone.

Carbon fiber reinforced polyetheretherketone (CFRPEEK) possesses a similar elastic modulus to that of human cortical bone and is considered as a promising candidate to replace metallic surgical implants. However, the bioinertness and deficiency of antibacterial activities impedes the application of CFRPEEK as orthopedic and especially oral implants. In this work, dual zinc and oxygen plasma immersion ion implantation (Zn/O-PIII) is applied to modify CFRPEEK, achieving both zinc incorporation and introduction of unique micro-/nano-structures on the surface. Scanning electron microscopy (SEM) observation reveals the formation of micro-pits with the size of around 800 nm on the CFRPEEK surface. X-ray photoelectron spectroscopy (XPS) test results confirm the existence of ZnO on the near surface. In vitro cell adhesion, viability assay, and real-time PCR analyses disclose enhanced adhesion, proliferation, and osteo-differentiation of mouse osteoblasts (MC3T3-E1) and rat bone mesenchymal stem cells (bMSCs) on the structured surface. Furthermore, the multilevel structures on CFRPEEK exhibit great antibacterial activity to biofilm-positive Staphylococcus aureus (ATCC 25923), MRSA (ATCC 43300) and Staphylococcus epidermidis (ATCC 35984) while show no obvious inhibition to Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853) and biofilm-negative Staphylococcus epidermidis (ATCC 12228). The obtained results indicate that the CFRPEEK surface with specific biological properties can be enhanced by zinc incorporation and multilevel structure introduction, through which the application of CFRPEEK to orthopedic and dental implants can be further broadened.

Research of biocompatibility on bioactive films fabricated using oxygen plasma immersion ion implantation

Abstract In the present study, a nanoporous, biocompatible titanium dioxide (TiO2) film was formed on the surface of titanium, using oxygen plasma immersion ion implantation (OPIII), and the influence of this film on the bio-functionalization, including the proliferation and differentiation properties of MG-63 osteoblast-like cells, was analyzed and investigated. The OPIII-treated surface was characterized by X-ray photoelectron, which showed that a TiOx layer was formed on Ti substrates. This TiOx surface exhibited nanoscale surface roughness in the form of nanoporous structures. The results also revealed that MG-63 cells expressed increased proliferation on the OPIII-treated surface as compared with the untreated Ti substrate. The Ti specimens treated with plasma energy of 1 kW revealed better expression of alkaline phosphatase (ALP) activity and showed higher average surface roughness than untreated specimens. Thus, it can be concluded that bioactivity of Ti implants can potentially be improved by OPIII.

Oxygen plasma immersion ion implantation treatment to enhance data retention of tungsten nanocrystal nonvolatile memory

Data retention characteristics of tungsten nanocrystal (W-NC) memory devices using an oxygen plasma immersion ion implantation (PIII) treatment are investigated. With an increase of oxygen PIII bias voltage and treatment time, the capacitance–voltage hysteresis memory window is increased but the data retention characteristics become degraded. High-resolution transmission electron microscopy images show that this poor data retention is a result of plasma damage on the tunneling oxide layer, which can be prevented by lowering the bias voltage to 7 kV. In addition, by using the elevated temperature retention measurement technique, the effective charge trapping level of the WO3 film surrounding the W-NCs can be extracted. This measurement reveals that a higher oxygen PIII bias voltage and treatment time induces more shallow traps within the WO3 film, degrading the retention behavior of the W-NC memory.

Oxygen plasma immersion ion implantation treatment enhances the human bone marrow mesenchymal stem cells responses to titanium surface for dental implant application

The present investigation utilized a novel oxygen plasma immersion ion implantation (O-PIII) treatment to create a dense and thin oxide layer on a titanium (Ti) surface for dental implant application. This study evaluated the behavior of human bone marrow mesenchymal stem cells (hMSCs) on O-PIII-treated Ti. The O-PIII treatments were performed using different oxygen ion doses (T(L): 1 × 10(16); T(M): 4 × 10(16); T(H): 1 × 10(17) ions/cm(2)). Analysis using an X-ray photoelectron spectrometer (XPS) and high resolution X-ray diffractometer (HR-XRD) indicated that the O-PIII-treated specimen T(M) had the highest proportion of rutile phase TiO2 component. The O-PIII-treated specimen T(M) had the greatest protein adsorption capability of the test Ti surfaces using XPS analysis and bicinchoninic acid (BCA) protein assay. Immunofluorescent staining revealed that hMSCs had the best cell adhesion on the O-PIII-treated specimen T(M), whereas green fluorescent protein (GFP)-labeled hMSCs experienced the fastest cell migration based on a wound healing assay. Other assays, including MTT assay, Alizarin red S staining and Western blot analysis, demonstrated that the adhered hMSCs exhibited the greatest cell proliferation, mineralization, and differentiation capabilities on the TM specimen. Oxidated Ti (primarily rutile TiO2 ) was produced using a facile and rapid O-PIII treatment procedure, which enhances the biocompatibility of the Ti surface with potential implications for further dental implant application.

Work Function Enhancement of Indium Tin Oxide via Oxygen Plasma Immersion Ion Implantation

Indium tin oxide (ITO) transparent conducting film was treated with oxygen plasma immersion ion implantation (PIII). X-ray photoelectron spectroscopy (XPS) was employed to characterize the effect. The results suggested that the oxygen content in the surface was increased and maintained for more than 50 h compared with traditional plasma-treated samples. Meanwhile, the work function of ITO estimated by comparing the peak shift in the XPS diagram suggested a corresponding increase by more than 1 eV.

Optical characterization of As–S thin films induced by plasma immersion O− ion implantation

In this study, optical constants of different thicknesses of stoichiometric composition As40S60 obtained from transmission spectra were investigated. The effect of exposure to oxygen plasma immersion ion implantation (O−-PIII) on the optical constants of the same samples of different thicknesses was also investigated. It is observed that the O−-PIII treatment can effectively improve the transmission spectra of the samples, particularly in medium and transparent regions; therefore the refractive index decreases. In addition, the optical band gap Egopt was determined before and after PIII from the absorption coefficient values using Tauc's procedure, i.e. from the relationship α hν = K(hν - Egopt )2 where K is a constant. The O−-PIII causes an increase in the energy gap of stoichiometric composition As40S60.

X-ray photoelectron spectroscopy studies of indium-tin-oxide treated via oxygen plasma immersion ion implantation

Surface modification was performed on the indium-tin-oxide (ITO) thin films by oxygen inductive coupling plasma (O-ICP) and oxygen plasma immersion ion implantation (O-PIII). The electronic states of ITO surfaces were characterized by X-ray photoelectron spectroscopy (XPS). The observed peak shifts of O 1 s , In 3 d 5/2 and Sn d 5/2 core levels showed that the work function of ITO can be further enhanced by O-PIII treatment, compared with that of untreated and O-ICP treated surfaces. The deconvolution of O 1 s spectrum and calculation of stoichiometry showed that the work function improvement should be attributed to the increase of effective oxygen content, namely, the elimination of oxygen vacancies. In addition, the measurement of Kelvin probe confirmed that an increment of the ITO work function by 1.1 eV was obtained on O-PIII treated sample and the results sustained our proposal.

Surface work function of indium tin oxide treated using plasma immersion ion implantation

Oxygen plasma immersion ion implantation (O-PIII) was introduced to modify the surface of indium tin oxide (ITO) thin films. X-ray photoelectron spectroscopy and Kelvin probe were employed to study the surface work function of the treated ITO films. The results showed that the surface work function of ITO can be further enhanced by O-PIII treatment based on an oxygen inductively coupled plasma (O-ICP). The change in surface work function correlated largely with the surface stoichiometry and the high work function should be attributed to the elimination of oxygen vacancies. The surface work function of the modified ITO films showed a rapid decreasing trend with a time-dependent curve immediately after O-ICP and O-PIII treatments. However, a stabler modification effect was achieved by O-PIII.

SURFACE PROPERTIES OF INDIUM-TIN-OXIDE MODIFIED BY OXYGEN PLASMA IMMERSION ION IMPLANTATION

Indium tin oxide (ITO) was modified by oxygen inductive coupled plasma (O-ICP) and oxygen plasma immersion ion implantation (O-PIII) respectively to compare the effects of both techniques on the surface properties. X-ray photoelectron spectroscopy (XPS) was applied to characterize the electronic state of ITO surface. The oxygen content enhancement and band bending at the surface of ITO were found after treatment by both O-ICP and O-PIII. The surface work function of ITO thin film depends on the oxygen composition at the surface. A surface work function increment of 0.8 eV by O-PIII was estimated from the shift of O1s core levels to low binding energy, which was the double of that by O-ICP. The conductivity increment of ITO films was less than 1% after O-ICP and O-PIII treatment. The transparency of ITO films increased by about 1% resulted from surface texture by O-PIII sputtering.

Surface modification of indium tin oxide by oxygen plasma immersion ion implantation

Organic electroluminescent device, also known as organic light-emitting diode (OLED), is a kind of solid state light emitting device by carrier injection which can directly transform electrical energy into luminous energy. Due to its low operating voltage, low energy consumption, high brightness, flexibility in the choice of materials and easy realization of full color display, OLED is the potential material both in the display and illumination fields. However, there is much scope to improve the efficiency, lifetime, and reduce the cost in mass production before OLEDs can replace traditional technology in some application fields. In this work, we report the oxygen plasma immersion ion implantation (PIII) to improve the surface oxygen ratio of ITO films for further increase of surface work function above the common treatment of O2 inductively coupled plasma (ICP). The ratio of oxygen content at the surface layer was improved to be much higher than by O2 ICP treatment. A further surface work function relative increase of 0.4 eV above OICP sample and 0.4 eV above the as-prepared sample can be estimated by the peak relative shift in the X-ray photoelectron spectroscopy (XPS) diagram. Moreover, the XPS characterization was carried out at least 50 h after the PIII implantation to indicate that the surface modifying effects are stable. The variations of transparency and conductivity of the PIII treated ITO samples can be neglected.

Antimicrobial effects of oxygen plasma modified medical grade Ti–6Al–4V alloy

Biomedical titanium alloy (Ti–6Al–4V) has good mechanical properties and cytocompatibility but post-operative implant-related bacterial infection is a big concern. Therefore, it is very important to suppress adhesion of bacteria on the implants or even kill the bacteria by proper surface modification. In this study, oxygen plasma immersion ion implantation (O-PIII) is employed to produce antibacterial effects on medical grade titanium alloy. The correlation between the surface chemistry and topography on antibacterial behavior is systematically investigated. Colony forming unit (CFU) counting is carried out to evaluate the adhesion of bacteria on the surface and enhanced green fluorescent protein (EGFP) mouse osteoblastic cells are used to study the cytocompatibility after the plasma treatment. Our results suggest that the nanostructured TiO2 layer produced by O-PIII can significantly suppress bacterial adhesion while the original cytocompatibility can be retained. The nanoscale TiO2 layer is promising in the prevention of implant-related bacterial infection on orthopedic implants.