Metallic Biomaterials
Beschreibung
The text is systematically structured, with the information organized according to different material systems, and concentrates on various advanced materials, such as anti-bacterial functionalized stainless steel, biodegradable metals with bioactivity, and novel structured metallic biomaterials. Authors from well-known academic institutes and with many years of clinical experience discuss all important aspects, including design strategies, fabrication and modification techniques, and biocompatibility.
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Personen
Xiaoxue Xu is Macquarie University Research Fellow in the Department of Chemistry and Biomolecular Sciences at Macquarie University, Australia. After she received her PhD in Materials Science and Engineering from the University of Western Australia, she worked there as Research Assistant Professor in the School of Chemical and Mechanical Engineering. She joined Macquarie University in 2014 and her research is focused on nanostructured biomaterials.
Zhigang Xu is Senior Research Scientist in Department of Mechanical Engineering at North Carolina A&T State University, USA. He is also affiliated to NSF Engineering Research Center for Revolutionizing Metallic Biomaterials, USA. He received his PhD in Mechanical Engineering from North Carolina A&T State University and then continued his research there as a faculty. He leads a Mg-alloy processing research group and Mg-based alloy design and processing project.
Jun-Qiang Wang is Professor in Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences. He got his PhD in Condensed Matter Physics from Institute of Physics, Chinese Academy of Sciences. From 2010 to 2014 he worked as Research Associate in Tohoku University, Japan and University of Wisconsin-Madison, USA. He joined the Ningbo Institute of Materials Technology & Engineering in 2014 and was awarded the support of One Hundred Talents Program of Chinese Academy of Science. His research focused on fabrication and applications of metallic glasses.
Hong Cai is Associate Professor in Department of Orthopedics at Peking University Third Hospital, China. He worked over 10 years as Attending in orthopedics. During that time he also worked sometime as Clinical Fellow at Seoul University, Korea, University of Western Ontario, Canada and Rush University Medical Center, USA. His research interest is design and development of new implants and 3D printing in orthopedics.
Inhalt
1.1. Traditional metallic biomaterials
1.2. Revolutionizing metallic biomaterials and their new biofunctions
1.2.1. What are the revolutionizing metallic biomaterials?
1.2.2. Antibacterial function
1.2.3. Promotion of osteogenesis
1.2.4. Reduction of in-stent restenosis
1.2.5. MRI compatibility
1.2.6. Radiopacity
1.2.7. Self-adjustment of Young's modulus for spinal fixation applications
1.3. Technical consideration on alloying design of revolutionizing metallic biomaterials
1.3.1. Evolution of mechanical properties with implantation time
1.3.2. Biocorrosion or biodegradation behavior and control on ion release
1.3.3. Safety and effectiveness of biofunctions
1.4. Novel process technologies for revolutionizing metallic biomaterials
1.4.1. 3-D printing
1.4.2. Severe plastic deformation
Chapter 2. Introduction of the biofunctions into the traditional metallic biomaterials
2.1. Antibacterial metallic biomaterials
2.1.1. Antibacterial metals
2.1.2. Antibacterial stainless steels
2.1.2.1. Ag-bearing antibacterial stainless steels
2.1.2.2. Cu-bearing antibacterial stainless steels
2.1.2.3. Other antibacterial stainless steels
2.1.3. Antibacterial Ti alloys
2.1.3.1. Antibacterial Ti-Ag alloys
2.1.3.2. Antibacterial Ti-Cu alloys
2.1.3.3. Antibacterial TiNi-based shape memory alloys
2.1.3.4. Surface modified Ti alloys with antibacterial property
2.1.4 Antibacterial Mg alloys
2.1.5 Antibacterial bulk metallic glasses
2.2. MRI compatibility of metallic biomaterials
2.2.1. MRI compatibility of traditional metallic biomaterials
2.2.2. MRI compatible Zr alloys
2.2.3. MRI compatible Nb alloys
2.2.4. Other MRI compatible alloys
2.3. Radiopacity of metallic biomaterials
2.3.1. Stainless steel stents
2.3.2. Co-Cr stents
2.3.3. Nitinol stents
2.3.4. Ta stents
2.3.5. Other metallic stents
Chapter 3. Development of Mg-based degradable metallic biomaterials
3.1. Background
3.2. Mg-based alloy design and selection considerations
3.2.1. Bio-degradation
3.2.2. Bio-compatibility
3.2.3. Considerations in Mg-based alloy design
3.2.3.1. Mechanical property requirements
3.2.3.2. Material compositional design
3.2.3.3. Toxicity and degradation consideration
3.2.4. Methods to improve mechanical property
3.2.4.1. in-situ strengthening
3.2.4.2. Post processing
3.3. State-of-the-art of the Mg-based alloy material research
3.3.1. Pure Mg
3.3.2. Mg-based alloys with essential elements
3.3.2.1. Mg-Ca based alloys
3.3.2.2. Mg-Si- and Mg-Sr-based alloys
3.3.3. Mg-based alloys with high strength
3.3.3.1. Mg-Zn-based alloys
3.3.3.2. Mg-RE-based alloys
3.3.4. Mg-based alloys with special biofunctions
3.3.5. Mg-based alloys with improved corrosion resistance
3.3.6. Mg-based alloys with bio-activated surfaces
3.3.6.1. Drug-releasing coatings
3.3.6.2. Biomimetic coatings
3.4. State-of-the-art of the Mg-based alloy device research
3.4.1. Cardiovascular devices
3.4.2. Orthopedic devices
3.5. Challenges and opportunities for Mg-based biomedical materials and devices
Chapter 4. Development of bulk metallic glasses for biomedical application
4.1. Background
4.1.1. Oxide glasses as biomaterials
4.1.2. Bulk metallic glasses
4.1.3. Fabrication of bulk metallic glasses
4.1.4 properties of bulk metallic glasses
4.2. Non-biodegradable bulk metallic glasses
4.2.1. Ti-based bulk metallic glasses
4.2.2. Zr-based bulk metallic glasses
4.2.3. Fe-based bulk metallic glasses
4.3. Biodegradable bulk metallic glasses
4.3.1. Mg-based bulk metallic glasses
4.3.2. Ca-based bulk metallic glasses
4.3.3. Zn-based bulk metallic glasses
4.3.4. Sr-based bulk metallic glasses
4.4. Perspectives on future R&D of bulk metallic glass for biomedical application
4.4.1. How to design better bulk metallic glasses?
4.4.1.1. Functional minor alloying elements
4.4.1.2. The glass forming ability
4.4.2. Surface modification of bulk metallic glasses
4.4.3. How to manufacture medical devices using bulk metallic glasses?
4.4.4. Future biomedical application areas of bulk metallic glass
Chapter 5.
Chapter 1
Introduction
1.1 Traditional Metallic Biomaterials
Traditional metallic materials have been typically used in medical applications such as orthopedic implants, dental applications, intravascular stents, and prosthetic heart valves. Compared with nonmetallic biomaterials, metallic biomaterials possess superior mechanical properties such as yield strength, ductility, fatigue strength, and fracture toughness [1], which are more suitable for load-bearing without large and/or permanent deformation. Application of metallic biomaterials goes back 100 years; in fact it is reported that a gold (Au) plate was used in the repair of cleft-palate defects as early as in 1565 [2]. Since then, a large number of metals and alloys, such as silver (Ag), platinum (Pt), palladium (Pd), tantalum (Ta), copper (Cu), nickel (Ni), zinc (Zn), aluminum (Al), magnesium (Mg), iron (Fe), carbon steels, stainless steels, cobalt-chromium (Co-Cr) alloys, titanium (Ti) and its alloys, and Nitinol (NiTi alloys), have been introduced into human body [3]. However, practice has shown that most of them are not perfect for implants in the human body due to various factors, such as insufficient mechanical properties, inferior corrosion resistance, and/or inadequate biocompatibility.
More recently, metallic biomaterials with better balance between good mechanical properties, a good corrosion resistance, and an excellent biocompatibility were developed. The common examples of these metallic biomaterials are type 316L stainless steel (316L SS), Co-Cr alloys, and Ti and its alloys [4]. These alloys have been approved for medical devices and surgical implants by the American Society for Testing and Materials (ASTM), and their mechanical properties are listed in Table 1.1. The 316L SS contains 0.03 wt% C, 17-19 wt% Cr, 13-15 wt% Ni, and 2-3 wt% Mo; the high Cr content gives it good resistance to a wide range of corrosive solutions. Due to its relatively low cost, availability, and easy processing, 316L SS has been employed successfully in the human body in contact with tissues and bones for several decades [6]. However, the wear resistance of 316L SS is poor, which makes it less suitable to be used as an artificial joint, because the excessive wear will lead to a rapid loosening. Compared with 316L SS, Co-Cr alloys exhibit a better wear resistance and an excellent corrosion resistance, even in chloride environments [7, 8]. Table 1.1 shows that their mechanical properties are also superior. The range of Co-Cr alloys used in clinical applications includes wrought and cast alloys. However, the elastic modulus of Co-Cr alloys (220-230 GPa) is similar to that of 316L SS (210 GPa), and both of them are much higher than that of cortical bone (20-30 GPa), leading to stress shielding in the adjacent bone and resulting in a final failure of implantation [3, 4]. Compared with 316L SS and Co-Cr alloys, Ti and its alloys exhibit lower modulus of 55-110 GPa, which is close to the bone. In addition, the passive film of TiO2 on the surface of Ti and Ti alloys gives them excellent corrosion resistance. Therefore, Ti and its alloys have been selected as the best among the aforementioned traditional metallic biomaterials for its excellent combination of mechanical properties, corrosion resistance, and biocompatibility [9].
Table 1.1 Mechanical properties of traditional metallic biomaterials.
Materials Elastic modulus (GPa) Yield strength (MPa) Tensile strength (MPa) Elongation (%) ASTM Standard Wrought 316L SS 190 190-690 490-1350 12-40 F138 Cast Co-28Cr-6Mo 210-253 450 655 8 F75 Wrought Co-20Cr-15W-10Ni (L605) 210 310-379 860-896 30-45 F90 Wrought Co-35Ni-20Cr-10Mo (MP 35N) 200-300 241-1586 793-1793 8-50 F562 Wrought Co-20Ni-20Cr-3.5Mo-3.5W-5Fe - 276-1310 600-1586 12-50 F563 CP Ti (grade 1-4) 105 170-483 240-550 15-24 F67 Wrought Ti-6Al-4V ELI 110 760-795 825-860 8-10 F136 Wrought Ti-6Al-4V ELI 110 825-869 895-930 6-10 F1472 Cast Ti-6Al-4V 110 758 860 8 F1108 Wrought Ti-3Al-2.5V - 517-714 621-862 10-15 F2146 Wrought Ti-6Al-7Nb 105 800 900 10 F1295 Wrought Ti-13Nb-13Zr 79-84 345-725 550-860 8-15 F1713 Wrought Ti-12Mo-6Zr-2Fe 74-85 897 931 12 F1813 Wrought Ti-15Mo - 483-552 690-724 12-20 F2066 Wrought Ni-Ti 48 - 551 10 F2063Elastic modulus data from Ref. [4, 5].
1.2 Revolutionizing Metallic Biomaterials and Their New Biofunctions
1.2.1 What are Revolutionizing Metallic Biomaterials?
According to Williams [10], the performance of any biomedical materials is controlled by two characteristics: biofunctionality and biocompatibility. Following this paradigm, many of the metallic materials used in the human body in the past have been extremely limited due to their insufficient biofunctionality and/or inferior biocompatibility [3]. Revolutionizing metallic biomaterials should have not only an excellent biocompatibility but also a specific biofunction in order to match the requirements in a variety of applications. Therefore, the revolutionizing metallic biomaterials researched and developed in recent years have various biofunctions. An interaction between the metallic biomaterials and the host is shown in Figure 1.1.
Figure 1.1 Comparison between the traditional and revolutionalizing metallic biomaterials.
(Reproduced with permission.)
1.2.2 Antibacterial Function
The most serious complication in implantation surgery is bacterial infection. However, the traditional metallic biomaterials usually do not possess antibacterial function. Therefore, in the past few decades, the bacterial colonization and antibacterial activity on metallic implant materials have been reported under in vitro and in vivo tests [11-20]. The antibacterial function of metallic biomaterials is based on the antibacterial effect of the alloying elements, such as Ag, Cu, Zn, Co, Ni, Fe, Al, Sn, and Mg [21]. And in the current research of antibacterial metallic biomaterials, Ag and Cu are the commonly used alloying elements.
The metals Ag and Cu have antibacterial functions against a broad spectrum of microorganisms and their effects depend on their doses [22, 23]. The medical uses of Ag include its incorporation into wound dressing and as an antibacterial coating on medical devices. There is little evidence to support the application of wound dressings containing Ag sulfadiazine or Ag nanoparticles for external infections [24-26]. The use of Ag coatings on urinary catheters and endotracheal breathing tubes has been reported [27, 28], which may reduce the incidence of catheter-related urinary tract infections and ventilator-associated pneumonia, respectively. Ag exhibits low toxicity in the human body, and minimal risk is expected due to clinical exposure by inhalation, ingestion, or dermal application [29]. The antibacterial action of Ag is dependent on the Ag ion, which is bioactive and in sufficient concentration readily kills bacteria in vitro. Ag and Ag nanoparticles are used as an antibacterial agent in a variety of industrial, healthcare, and domestic applications [30]. However, Ag is not an essential mineral in humans. There is no dietary requirement for Ag, and the chronic intake of Ag products can result in an accumulation of Ag or silver sulfide particles in the skin [31].
Unlike Ag, Cu is a trace metal and an essential component of several enzymes; the adult body contains between 1.4 and 2.1 mg of Cu per kg of body weight [32]. More importantly Cu can be metabolized and is much safer for the human body than Ag. As a matter of fact, in a proper range, the Cu can be excreted in the bile [15]. Cu and its alloys can be considered as natural antibacterial materials [33]. Numerous antibacterial efficacy studies indicated that Cu alloy contact surfaces have natural intrinsic properties to destroy a wide range of bacteria, as well as influenza A virus, adenovirus, and fungi [34]....
