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Correlation of magnetic and magnetoresistive properties of nanoporous Co/Pd thin multilayers fabricated on anodized TiO 2 templates. Sci Rep 2020; 10:10838. [PMID: 32616749 PMCID: PMC7331621 DOI: 10.1038/s41598-020-67677-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 06/04/2020] [Indexed: 11/14/2022] Open
Abstract
In this study, we consider a technological approach to obtain a high perpendicular magnetic anisotropy of the Co/Pd multilayers deposited on nanoporous TiO2 templates of different types of surface morphology. It is found that the use of templates with homogeneous and smoothed surface relief, formed on silicon wafers, ensures conservation of perpendicular anisotropy of the deposited films inherent in the continuous multilayers. Also, their magnetic hardening with doubling of the coercive field is observed. However, inhomogeneous magnetic ordering is revealed in the porous films due to the occurrence of magnetically soft regions near the pore edges and/or inside the pores. Modeling of the field dependences of magnetization and electrical resistance indicates that coherent rotation is the dominant mechanism of magnetization reversal in the porous system instead of the domain-wall motion typical of the continuous multilayers, while their magnetoresistance is determined by electron-magnon scattering, similarly to the continuous counterpart. The preservation of spin waves in the porous films indicates a high uniformity of the magnetic ordering in the fabricated porous systems due to a sufficiently regular pores array introduced into the films, despite the existence of soft-magnetic regions. The results are promising for the design and fabrication of future spintronic devices.
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Wu WB, Kasiuk J, Nguyen TNA, Fedotova J, Przewoźnik J, Kapusta C, Kupreeva O, Lazarouk S, Do KT, Nguyen TH, Vu HK, Vu DL, Åkerman J. Complex magnetic ordering in nanoporous [Co/Pd] 5-IrMn multilayers with perpendicular magnetic anisotropy and its impact on magnetization reversal and magnetoresistance. Phys Chem Chem Phys 2020; 22:3661-3674. [PMID: 32002524 DOI: 10.1039/c9cp05947d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We have systematically investigated the magnetization reversal characteristics and magnetoresistance of continuous and nanoporous [Co/Pd]5-IrMn multilayered thin films with perpendicular magnetic anisotropy at different temperatures (4-300 K). For their nanostructuring, porosity was induced by means of deposition onto templates of anodized titania with small (∼30 nm in diameter) homogeneously distributed pores. The magnetization reversal and magnetoresistance of the porous films were found to be closely related to the splitting of the ferromagnetic material into regions with different magnetic properties, in correlation with the complex morphology of the porous system. Independent magnetization reversal is detected for these regions, and is accompanied by its strong impact on the magnetic order in the capping IrMn layer. Electron-magnon scattering is found to be a dominant mechanism of magnetoresistance, determining its almost linear field dependence in a high magnetic field and contributing to its magnetoresistance behavior, similar to magnetization reversal, in a low magnetic field. Partial rotation of IrMn magnetic moments, consistent with the magnetization reversal of the ferromagnet, is proposed as an explanation for the two-state resistance behavior observed in switching between high-resistive and low-resistive values at the magnetization reversal of the porous system studied.
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Affiliation(s)
- Wen-Bin Wu
- Institute for Nuclear Problems, Belarusian State University, 220006 Minsk, Belarus.
| | - Julia Kasiuk
- Institute for Nuclear Problems, Belarusian State University, 220006 Minsk, Belarus.
| | - Thi Ngoc Anh Nguyen
- Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam
| | - Julia Fedotova
- Institute for Nuclear Problems, Belarusian State University, 220006 Minsk, Belarus.
| | - Janusz Przewoźnik
- AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Department of Solid State Physics, 30-059 Krakow, Poland
| | - Czesław Kapusta
- AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, Department of Solid State Physics, 30-059 Krakow, Poland
| | - Olga Kupreeva
- Belarusian State University of Informatics and Radioelectronics, 220013 Minsk, Belarus
| | - Serguei Lazarouk
- Belarusian State University of Informatics and Radioelectronics, 220013 Minsk, Belarus
| | - Khanh Tung Do
- Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam
| | - Thanh Huong Nguyen
- Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam
| | - Hong Ky Vu
- Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam
| | - Dinh Lam Vu
- Institute of Materials Science, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi, Vietnam
| | - Johan Åkerman
- Department of Physics, University of Gothenburg, 41296 Göteborg, Sweden
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Dental Implants with Anti-Biofilm Properties: A Pilot Study for Developing a New Sericin-Based Coating. MATERIALS 2019; 12:ma12152429. [PMID: 31366076 PMCID: PMC6695694 DOI: 10.3390/ma12152429] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 07/16/2019] [Accepted: 07/23/2019] [Indexed: 12/16/2022]
Abstract
Aim: several strategies have been tested in recent years to prevent bacterial colonization of dental implants. Sericin, one of the two main silk proteins, possesses relevant biological activities and also literature reports about its potential antibacterial properties, but results are discordant and not yet definitive. The aim of this study was to evaluate the effectiveness of different experimental protocols in order to obtain a sericin-based coating on medical grade titanium (Ti) able to reduce microbial adhesion to the dental implant surface. Materials and Methods: different strategies for covalent bonding of sericin to Ti were pursued throughout a multi-step procedure on Ti-6Al-4V disks. The surface of grade 5 Ti was initially immersed in NaOH solution to obtain the exposure of functional -OH groups. Two different silanization strategies were then tested using aminopropyltriethoxysilane (APTES). Eventually, the bonding between silanized Ti-6Al-4V and sericin was obtained with two different crosslinking processes: glutaraldehyde (GLU) or carbodiimide/N-Hydroxy-succinimide (EDC/NHS). Micro-morphological and compositional analyses were performed on the samples at each intermediate step to assess the most effective coating strategy able to optimize the silanization and bioconjugation processes. Microbiological tests on the coated Ti-6Al-4V disks were conducted in vitro using a standard biofilm producer strain of Staphylococcus aureus (ATCC 6538) to quantify the inhibition of microbial biofilm formation (anti-biofilm efficacy) at 24 hours. Results: both silanization techniques resulted in a significant increase of silicon (Si) on the Ti-6Al-4V surfaces etched with NaOH. Differences were found between GLU and EDC/NHS bioconjugation strategies in terms of composition, surface micro-morphology and anti-biofilm efficacy. Ti-6Al-4V samples coated with GLU-bound sericin after silanization obtained via vapor phase deposition proved that this technique is the most convenient and effective coating strategy, resulting in a bacterial inhibition of about 53% in respect to the uncoated Ti-6Al-4V disks. Conclusions: The coating with glutaraldehyde-bound sericin after silanization in the vapor phase showed promising bacterial inhibition values with a significant reduction of S. aureus biofilm. Further studies including higher number of replicates and more peri-implant-relevant microorganisms are needed to evaluate the applicability of this experimental protocol to dental implants.
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Titanium surface modification to enhance antibacterial and bioactive properties while retaining biocompatibility. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2019; 96:272-279. [DOI: 10.1016/j.msec.2018.11.021] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 05/23/2018] [Accepted: 11/17/2018] [Indexed: 11/18/2022]
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Rodríguez-Contreras A, Marqués-Calvo MS, Gil FJ, Manero JM. Modification of titanium surfaces by adding antibiotic-loaded PHB spheres and PEG for biomedical applications. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2016; 27:124. [PMID: 27318469 DOI: 10.1007/s10856-016-5723-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 05/02/2016] [Indexed: 06/06/2023]
Abstract
Novel researches are focused on the prevention and management of post-operative infections. To avoid this common complication of implant surgery, it is preferable to use new biomaterials with antibacterial properties. Therefore, the aim of this work is to develop a method of combining the antibacterial properties of antibiotic-loaded poly(3-hydroxybutyrate) (PHB) nano- and micro-spheres and poly(ethylene glycol) (PEG) as an antifouling agent, with titanium (Ti), as the base material for implants, in order to obtain surfaces with antibacterial activity. The Ti surfaces were linked to both PHB particles and PEG by a covalent bond. This attachment was carried out by firstly activating the surfaces with either Oxygen plasma or Sodium hydroxide. Further functionalization of the activated surfaces with different alkoxysilanes allows the reaction with PHB particles and PEG. The study confirms that the Ti surfaces achieved the antibacterial properties by combining the antibiotic-loaded PHB spheres, and PEG as an antifouling agent.
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Affiliation(s)
- Alejandra Rodríguez-Contreras
- Departament de Ciència dels Materials i Enginyeria Metal·lúrgica, Laboratori de Microscòpia Electrònica, Universitat Politècnica de Catalunya-Barcelona TECH, Avda. Diagonal Pavelló E (Etseib)-Planta 0, 647-08028, Barcelona, Spain.
| | - María Soledad Marqués-Calvo
- Departament d'Òptica i Optometria, Universitat Politècnica de Catalunya-Barcelona TECH, Sant Nebridi 22, 08222, Terrassa Barcelona, Spain
| | - Francisco Javier Gil
- Departament de Ciència dels Materials i Enginyeria Metal·lúrgica, Laboratori de Microscòpia Electrònica, Universitat Politècnica de Catalunya-Barcelona TECH, Avda. Diagonal Pavelló E (Etseib)-Planta 0, 647-08028, Barcelona, Spain
- Departament de Ciència dels Materials i Enginyeria Metal·lúrgica, Biomaterials, Biomechanics and Tissue Engineering Group, Universitat Politècnica de Catalunya-Barcelona TECH, Avda. Diagonal, 647-08028, Barcelona, Spain
- CIBER-BBN, Centro de Investigación Biomédica en Red, Madrid, Spain
| | - José María Manero
- Departament de Ciència dels Materials i Enginyeria Metal·lúrgica, Laboratori de Microscòpia Electrònica, Universitat Politècnica de Catalunya-Barcelona TECH, Avda. Diagonal Pavelló E (Etseib)-Planta 0, 647-08028, Barcelona, Spain
- Departament de Ciència dels Materials i Enginyeria Metal·lúrgica, Biomaterials, Biomechanics and Tissue Engineering Group, Universitat Politècnica de Catalunya-Barcelona TECH, Avda. Diagonal, 647-08028, Barcelona, Spain
- CIBER-BBN, Centro de Investigación Biomédica en Red, Madrid, Spain
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Xiao M, Chen YM, Biao MN, Zhang XD, Yang BC. Bio-functionalization of biomedical metals. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2016; 70:1057-1070. [PMID: 27772705 DOI: 10.1016/j.msec.2016.06.067] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 04/18/2016] [Accepted: 06/22/2016] [Indexed: 12/27/2022]
Abstract
Bio-functionalization means to endow biomaterials with bio-functions so as to make the materials or devices more suitable for biomedical applications. Traditionally, because of the excellent mechanical properties, the biomedical metals have been widely used in clinic. However, the utilized functions are basically supporting or fixation especially for the implantable devices. Nowadays, some new functions, including bioactivity, anti-tumor, anti-microbial, and so on, are introduced to biomedical metals. To realize those bio-functions on the metallic biomedical materials, surface modification is the most commonly used method. Surface modification, including physical and chemical methods, is an effective way to alter the surface morphology and composition of biomaterials. It can endow the biomedical metals with new surface properties while still retain the good mechanical properties of the bulk material. Having analyzed the ways of realizing the bio-functionalization, this article briefly summarized the bio-functionalization concepts of six hot spots in this field. They are bioactivity, bony tissue inducing, anti-microbial, anti-tumor, anticoagulation, and drug loading functions.
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Affiliation(s)
- M Xiao
- Engineering Research Center in Biomaterials, Sichuan University, Chengdu 610064, China; National Engineering Research Center for Biomaterials, Chengdu, 610064, China
| | - Y M Chen
- Engineering Research Center in Biomaterials, Sichuan University, Chengdu 610064, China; National Engineering Research Center for Biomaterials, Chengdu, 610064, China
| | - M N Biao
- Engineering Research Center in Biomaterials, Sichuan University, Chengdu 610064, China; National Engineering Research Center for Biomaterials, Chengdu, 610064, China
| | - X D Zhang
- Engineering Research Center in Biomaterials, Sichuan University, Chengdu 610064, China; National Engineering Research Center for Biomaterials, Chengdu, 610064, China
| | - B C Yang
- Engineering Research Center in Biomaterials, Sichuan University, Chengdu 610064, China; National Engineering Research Center for Biomaterials, Chengdu, 610064, China.
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Thermally oxidized titania nanotubes enhance the corrosion resistance of Ti6Al4V. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2016; 59:677-689. [DOI: 10.1016/j.msec.2015.10.056] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 09/24/2015] [Accepted: 10/20/2015] [Indexed: 12/31/2022]
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