Characterization Of Biomaterials

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

This brief introductory chapter provides a broad overview of materials, biomaterials and the need to understand different techniques to characterize biomaterials. From this chapter, the reader can gain a perspective on how the rest of the topics in different chapters are divided to fully comprehend this inherently multidisciplinary field. Application of appropriate characterization tools can not only save time to fully evaluate different biomaterials, it can also make commercial biomedical devices safer. In the long run, safer biomedical devices can only reduce the pain and suffering of mankind, a dream that resonates with every biomedical researcher.

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

The physicochemical properties of biomaterials exert a major influence over their interaction with cells and subsequently play an important role on the materials' in vivo performance . Physical characteristics involve internal microstructural features, shape and size of particles, porosity, density, and surface area. Characterization in terms of the chemistry involves determination of the chemical composition and distribution of the elements within the biomaterial. The last decade has seen several innovations in the armory of tools to image and analyze materials, as well as advancement in the collection and processing of those results. In this chapter, the most commonly used methods, which are available for the microstructural characterization of biomaterials, are explained with suitable examples. This chapter starts with microstructural characterization using different types of microscopic techniques including optical and electron microscopy. These techniques can provide information from atomic-scale to microscale to macroscale information. Specific examples are also used for specialized microscopic techniques such as scanning probe microscopy and atomic force microscopy. Some discussions were also used in -related surface characterization using microscopic techniques. Followed by microscopic techniques, phase analysis techniques are discussed based on X-ray diffraction. Short discussion is also placed on infrared (IR)-based spectroscopic characterization for chemical analysis. Further discussion on IR spectroscopy can be found in for surface analysis. The last part of this chapter deals with size, shape, porosity, surface area and surface energy characterization. Particle size analysis by dynamic light scattering (DLS) is discussed in detail followed by IR spectroscopic analysis. Contact angle measurement for surface energy, mercury intrusion porosimetry for analysis of pore structures and gas adsorption measurements for surface area analysis are presented in detail with relevant examples. Throughout this chapter, specific discussions are focused on examples based on applications as well as advantages, disadvantages, and challenges.

Oceans are an abundant source of diverse biomaterials with potential for an array of uses. Marine Biomaterials: Characterization, Isolation and Applications brings together the wide range of research in this important area, including the latest developments and applications, from preliminary research to clinical trials. The book is divided into four parts, with chapters written by experts from around the world. Biomaterials described come from a variety of marine sources, such as fish, algae, microorganisms, crustaceans, and mollusks. Part I covers the isolation and characterization of marine biomaterials—bioceramics, biopolymers, fatty acids, toxins and pigments, nanoparticles, and adhesive materials. It also describes problems that may be encountered in the process as well as possible solutions. Part II looks at biological activities of marine biomaterials, including polysaccharides, biotoxins, and peptides. Chapters examine health benefits of the biomaterials, such as antiviral activity, antidiabetic properties, anticoagulant and anti-allergic effects, and more. Part III discusses biomedical applications of marine biomaterials, including nanocomposites, and describes applications of various materials in tissue engineering and drug delivery. Part IV explores commercialization of marine-derived biomaterials—marine polysaccharides and marine enzymes—and examines industry perspectives and applications. This book covers the key aspects of available marine biomaterials for biological and biomedical applications, and presents techniques that can be used for future isolation of novel materials from marine sources.

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.

Characterisation and Design of Tissue Scaffolds offers scientists a useful guide on the characterization of tissue scaffolds, detailing what needs to be measured and why, how such measurements can be made, and addressing industrially important issues. Part one provides readers with information on the fundamental considerations in the characterization of tissue scaffolds, while other sections detail how to prepare tissue scaffolds, discuss techniques in characterization, and present practical considerations for manufacturers. Summarizes concepts and current practice in the characterization and design of tissue scaffolds Discusses design and preparation of scaffolds Details how to prepare tissue scaffolds, discusses techniques in characterization, and presents practical considerations for manufacturers

The use of biomaterials has become indispensable in modern medicine that includes primarily for the restoration of function as well as drug carriers. Biomaterials developed for bone, cartilage, ligament, tendon, skeletal muscle, dental, and other musculoskeletal applications almost always necessitate mechanical properties characterization to guarantee that they are robust enough for their in vivo functionality. In addition, mechanical conditioning often has a direct consequence on cellular behaviors such as differentiation, extracellular matrix production, migration, and proliferation. There is imperative necessity to get real-time data of tissue development in vivo in response to various biomechanical stimuli such as tension/compression, bending, torsion, and steady or dynamic fluid flow of construct that allows experimental protocol changes to be made early. In vitro characterization is unable to exhibit the tissue response to materials, instead being limited to the response of individual cell lines or primary cells taken from animals. Considering the wide and ever-increasing use of biomaterials in different fields of veterinary and medical sciences with its effective use in emerging fields, the characterization in respect to cellular response in the living system and its effect thereafter for leading a physiologic life, a comprehensive understanding have to be developed in totality. Further, implant safety such as avoidance of adverse tissue reaction and resistance to wear and corrosion are of high clinical significance for implants used in long-term clinical situations. The characterization along with related factors like histological, histomorphological, biochemical, radiological, scanning and transmission electron microscopic, fluorochrome labelling, biomechanical, micro-CT analysis, immunohistochemistry in orthopaedic and soft tissue surgery have been tried to elucidate with emphasis on in vivo applications of biomaterials. Amid various characterization parameters, histology is one of the most important tools to assess cellular reactions in the implant–tissue interface that can be carried out by both undecalcified and decalcified bone specimens. Histomorphometry can directly help in quantitative measurement (percentage) of newly formed bone in the implanted scaffold using semiautomatic image analysis software and also sometimes determines the host's vascularization. Histochemistry can be used to observe connective tissue ingrowth within the scaffold. The morphology and the proliferating cells can be evaluated by immunohistochemical technique. Biochemical markers like serum calcium, phosphorus, alkaline phosphatase, and osteocalcin help in evaluating the progress of healing and tartrate-resistant acid phosphatase for determining the osteoclasts activity. To understand the mechanisms of unusual bone remodelling, a number of different fluorescent stains like calcein green, tetracycline, alizarin red derivatives and xylenol orange have been developed to detect and quantify bone mineralization. Angiogenesis within the scaffold can be observed and quantified by angiography, osteomedullography, micro-CT, immunostaining with von Willebrand factor stain and intravital microscopy. Biomechanical testing is essential for quantitative assessment of implant integration and contact percentage between implant materials with the host tissue and can be performed by pull-out or push-out tests. Surface analysis and the interaction with bone tissue can be best detected by scanning electron microscopy. Non-invasive techniques include radiological, micro-CT analysis, densitometry study and ultrasound elasticity imaging (UEI). Radiological study helps to assess the union at the host bone–implant interfaces during the follow-up period and should be carried out at regular and calculated interval. Micro-CT is also a non-invasive technique and has great potential in characterization of biomaterials in regard to pore size and spatial distribution of newly formed bone together with quantitative information. Densitometric evaluation is helpful for estimating bone mineral content and density. UEI provides more information of scaffold degradation and tissue development. Finally, targeted delivery system needs quantitative measurements of biodistributable materials which can be best accomplished by computed tomography (CT), fluorescence imaging, inductively coupled atomic emission spectroscopy, inductively coupled plasma-mass spectrometry, micro-positron emission tomography, MRI imaging, and radiography. This chapter is primarily on hands-on experience in surgical manipulation of different biomaterials like hydroxyapatite, tricalcium phosphate, bioactive glass, metals, chitosan, as well as natural coralline hydroxyapatite. Different characterization techniques elaborated in this chapter can show a road map to the researchers, scientists, teachers and readers in this field of biomaterials to understand fundamental aspects of materials and related tissue response to the system in vivo. It can also provide clues for further research in the future towards this emerging field.