This book serves as a guide for practicing engineers, researchers and students interested in MEMS devices and biomaterials and biomedical applications. It is also suitable for engineers and researchers interested in MEMS and its applications but who do not have the necessary background in biomaterials. The book highlights important features and issues of biomaterials that have been used in MEMS and biomedical areas, including the fabrication of devices using biomaterials, biocompatible coatings and issues, thin-film biomaterials and MEMS for tissue engineering, and applications involving MEMS and biomaterials.

The design of biomedical devices almost always involves some form of mechanical characterization of biomaterials. This chapter provides a broad overview of experimental methods and important considerations for mechanical characterization of biomaterials, with special attention to the practical needs of engineers and scientists who encounter a need to characterize the mechanical properties of a biomaterial but may not know where to begin or what the key considerations should be. Many details are necessarily omitted from this broad overview, but numerous references are provided for greater technical depth on a particular topic, standardized methodologies, and exemplary studies. Fundamental concepts are introduced, beginning with stress and strain versus force and displacement. The mechanical properties measured from a stress–strain curve, different types of stress–strain curves, and corresponding constitutive models are reviewed, including differences in material classes and anisotropy. Three primary methods of analysis for fracture mechanics are introduced, including stress concentrations, energy criteria for crack initiation and propagation (fracture toughness), and statistical methods for the probability of fracture. The mechanical characterization of biomaterials begins with selection and preparation of standardized test specimens, which are critical to obtaining accurate and reproducible measurements of material properties. Practical considerations are outlined for selection and preparation of the specimen size, geometry, surface finish, and precracking. The mechanical characterization of biomaterial test specimens always involves the application and measurement of load and deformation. Practical considerations are outlined for the selection and use of load frames, load cells, load fixtures, extensometers, and strain gauges. A number of common loading modes are introduced and compared: uniaxial tension, uniaxial compression, biaxial tension, torsion, diametral compression, three-point bending, four-point bending, and in-plane shear (including biomaterial-tissue interfacial shear strength). Strain-rate sensitivity or time-dependent behavior can profoundly influence stress–strain behavior and thus measured mechanical properties. The effects of high strain rates may be characterized by impact testing using a pendulum, drop tower, or split Hopkinson pressure bar. The effects of low strain rates may be characterized by creep deformation or creep rupture tests. The time-dependent behavior of viscoelastic materials is introduced, including creep, stress relaxation, common constitutive models, and practical considerations for testing. The frequency of loading, or cyclic loading, is another aspect of time-dependent behavior, which is critical for mechanical characterization of biomaterials, leading to fatigue deformation and failure or viscoelastic creep and stress relaxation. Practical considerations are described for selecting the waveform, frequency, cyclic stress/strain levels, loading mode, and test duration. Common methods are introduced for fatigue lifetime testing (including S-N curves, notch factors, and fatigue damage), fatigue crack propagation, and dynamic mechanical analysis (DMA). Nondestructive tests are particularly useful for sampling small volumes of a biomaterial (e.g., implant retrieval or biopsy) or characterizing spatial heterogeneity in mechanical properties. Various indentation tests and indenter geometries are introduced and compared, including classic hardness (Brinell and Rockwell), microhardness (Knoop and Vickers), and instrumented nanoindentation (Berkovich, cube corner, etc.). Methods and limitations are described for characterizing the reduced modulus, viscoelasticity, and fracture toughness using indentation. Ultrasonic wave-propagation methods are also introduced with an emphasis on methods for characterizing anisotropic elastic constants. Biomaterials are typically subjected to various sterilization methods prior to service and an aqueous physiological environment in service. Therefore, the effects of temperature, pressure, various aqueous media (water, phosphate buffered saline (PBS), media, foetal bovine serum (FBS), lipids, etc.), and irradiation on mechanical characterization of biomaterials are considered, including the degradation of mechanical properties by various mechanisms involving water uptake, hydrolysis, and oxidation. Finally, methods and guidelines are provided for data acquisition from transducers and data analysis, including an introduction to some basic statistical methods.

Characterization of Polymeric Biomaterials presents a comprehensive introduction on the topic before discussing the morphology and surface characterization of biomedical polymers. The structural, mechanical, and biological characterization is described in detail, followed by invaluable case studies of polymer biomaterial implants. With comprehensive coverage of both theoretical and experimental information, this title will provide scientists with an essential guide on the topic of these materials which are regularly used for clinical applications, such as implants and drug delivery devices. However, a range of novel polymers and the development and modification of existing medical polymers means that there is an ongoing need to satisfy particular design requirements. This book explains the critical and fundamentals methods to characterize polymer materials for biomedical applications. Presents a self-contained reference on the characterization of polymeric biomaterials Provides comprehensive information on how to characterize biomedical polymers in order to improve design and synthesis Includes useful case studies that demonstrate the characterization of biomaterial implants

One of the key challenges current biomaterials researchers face is identifying which of the dizzying number of highly specialized characterization tools can be gainfully applied to different materials and biomedical devices. Since this diverse marketplace of tools and techniques can be used for numerous applications, choosing the proper characterization tool is highly important, saving both time and resources.Characterization of Biomaterials is a detailed and multidisciplinary discussion of the physical, chemical, mechanical, surface, in vitro and in vivo characterization tools and techniques of increasing importance to fundamental biomaterials research.Characterization of Biomaterials will serve as a comprehensive resource for biomaterials researchers requiring detailed information on physical, chemical, mechanical, surface, and in vitro or in vivo characterization. The book is designed for materials scientists, bioengineers, biologists, clinicians and biomedical device researchers seeking input on planning on how to test their novel materials, structures or biomedical devices to a specific application. Chapters are developed considering the need for industrial researchers as well as academics. Biomaterials researchers come from a wide variety of disciplines: this book will help them to analyze their materials and devices taking advantage of the multiple experiences on offer Coverage encompasses a cross-section of the physical sciences, biological sciences, engineering and applied sciences characterization community, providing gainful and cross-cutting insight into this highly multi-disciplinary field Detailed coverage of important test protocols presents specific examples and standards for applied characterization