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In the past few years, research and the development of biomedical polymers and processing technologies for biomedical applications have received growing attention. Among the most attractive technologies, additive manufacturing (commonly known as three-dimensional printing) is highly suitable for producing sophisticated and tailor-made scaffolds for biomedical applications due its inherent advantages of customizability and the ability to create complex shapes with precision. Moreover, this is a time-saving approach, being far more reproducible than conventional techniques to obtain scaffolds. Additive manufacturing (AM) includes a wide variety of manufacturing techniques and it is being used in personalized prosthetic/implant devices for otorhinolaryngology, dentistry, orthopedics, and craniofacial reconstruction, among others. Tissue engineering and controlled drug-release systems are also important research fields which use AM as a tool for designing accurate, structured, and tailored functional structures. However, there are some limitations for processing new materials using AM techniques. Furthermore, there is an increasing need for new biocompatible and/or bioresorbable materials with different mechanical properties, degradation rates, and surface requirements to be processed for a broad range of applications. In the past years, biocompatible and biodegradable segmented polyurethanes (SPUs) have been investigated for their applications in tissue engineering, controlled drug-release systems, wound dressings, and many biomedical devices. SPU and their composites with poly(ethylene glycol), cellulose, starch, gelatin, alginate, fibrinogen, and collagen, among others, have been explored through different AM techniques for biomedical applications. This chapter aims to review the use of novel AM as microfabrication tools for bioresorbable SPU elastomers and SPU composites. Current advances in 3D printing of SPU are described and commented on. Advantages and shortcomings of the current approaches, as well as future perspectives are outlined. Finally, a vision for future research on this topic is presented.

Polymeric materials are widely used in orthopedics and traumatology where they have an irreplaceable role in the construction of implants. Unlike metals and ceramics, polymers have a low elastic modulus close to that of cortical bone. Bulk properties together with surface, chemical, and biological properties play a crucial role with regards to the biomedical polymers. However, due to the variability of the polymeric implant applications, the large amount of different polymer types, the variability of their properties and chemistry and, last but not least, many possible methods of their treatment to reach or improve the demanded properties, the polymers used in implant applications are a complex and complicated topic. Plasma surface treatment methods provide independent modification possibilities to the surface and biological properties without any alteration or degradation to the bulk (mechanical) properties. The required biological, chemical, and surface properties of the polymer-based implants will be briefly described including an overview of the plasma methods for the surface treatment of polymeric materials. Afterwards, we will also focus on plasma-modified polymer implants used in various medical applications.

Biomedical polymers have and still continue to play an important role in how we support and treat patients with various diseases through their use in tissue and blood interacting medical devices and drug delivery systems. Today, a wide variety of blood-contacting devices provide the means for the diagnosis, treatment, and support of life until organ transplantation. Their usage warrants their interaction with cells, bacteria, blood, tissue, and sometimes a combination of these complex living systems and the fates of such interactions are critical for applications including biomimetic surfaces, regenerative medicine, immunomodulation, smart biomaterials for drug delivery, and many more. For blood-contacting devices, their surface interactions with blood mostly lead to blood coagulation, inflammation, device failure, and patient complications. Their lifetimes are thus limited to hours and days due to clot formation. Use on the order of months is however needed for many of these devices including vascular grafts, catheters, artificial lungs, extracorporeal circulation circuits, and dialysis membranes, which rely on the free flow of blood over their surfaces. Clots, however halts this flow and causes the devices to fail. This chapter describes prominent challenges and new directions of hemocompatibility and specifically anticlotting biomaterials research.

The usage of biopolymers in medical and biotechnology fields has become a very promising research area due to the cleaner, safer, and renewable technologies. The biopolymers possess unique properties of biodegradability and biocompatibility which seek the attention of researchers to use these biostable polymers in medical application and has enabled us to develop mechanically stable functional implants with a controlled drug- release surface leading to a great deal of positive health outcomes. These biocompatible biopolymers have a great deal of applications in various medical fields such as gene therapy, stem cell research, scaffold engineering, organ regeneration, regenerative medicine, cancer therapy, heart disease, dental treatments, and so on. Biocompatibilty testing helps us to determine the biological reactions of a human body/animal to a product/device that comes into contact with it for a particular duration of time. Various in vivo polymer biocompatibility testing procedures have been developed which entail the development and extraction of various biopolymers from biological samples and help us in determining the rejection, degradation mechanism of these materials inside the human body. Hence, in this chapter, a detailed description regarding the application of various biopolymers in the medical field and also the various in vivo testing methodologies has been elaborated.

Bio-based polymer hybrid composites hold a unique position in the fast-growing and active multidisciplinary world of biomaterials where engineers, scientists, and biologists combine their knowledge. It is well known that advances in science and engineering of biomaterials are crucial to solve complex medical and biomedical problems involving replacement, repair, and regeneration of tissues. This chapter covers the definition, importance, categorization, and application of polymer hybrid composites in the biomedical field. It is presented into two main parts. The first part includes the categorization of biomedical polymer hybrid composites, with information about the compositions and specifications of nanocomposites on the basis of hybridization of polymers with natural polymers, biopolymers, minerals, and metals. The second covers biomedical uses of polymer hybrid composites, considering their applications (i.e., drug delivery, tissue engineering, bioadhesion, etc.), and composition.

Poly (glycerol adipate) (PGA) can be produced from divinyl adipate and unprotected glycerol by an enzymatic route to generate a polymer with relatively low molar mass (12 kDa). PGA bears a pendant hydroxyl group which imparts a hydrophilic character to this water insoluble polymer. We have examined the effect of synthesis temperature on polymer characteristics through various techniques including FT-IR, 1H and 13C NMR, surface and thermal analysis, both to expand the data already present in the literature about this material and to understand better its properties for potential pharmaceutical applications. The use of a lipase (Novozym 435) as a catalyst suppresses cross-linking at the pendant glyceryl hydroxyl through steric hindrance at the active site, thus producing polymers with low degrees of branching (5–30%), and removes the need for any pre- or post-polymerization protection/deprotection reactions. Careful temperature control during synthesis can give polymers with reproducible molecular weights and reduced amounts of polymer branching compared to synthesis at higher temperatures. Due to the ability of the synthetic route to produce a range of structures, PGA generated by enzymatic routes may emerge as a useful biodegradable polymer platform to engineer solid dispersions or nanoparticles for healthcare applications.

Significant advances in the field of polymer science over the past century have resulted in synthetic polymers becoming the basis for many new approaches to medical therapies and in particular development of new medical devices. While natural polymers have long been used in medicine and surgery, their application in medical devices has experienced a renaissance with advances in understanding of polymer synthesis and processing. In this chapter, natural polymers are discussed in detail, with a focus on proteins and polysaccharides. The major advantages and disadvantages in relation to use of natural polymers are considered with an emphasis on the key factors impacting their biological performance in tissue contacting devices. Approaches to developing hybrid materials that combine the advantages of both natural and synthetic polymers are becoming increasingly topical and hold much promise for the future of medical devices that can integrate with and drive regeneration of tissues.

The poly(α-ester)s are perhaps the most well known biomedical polymers and include polylactides, polyglycolides, poly(lactide-co-glycolides), polycaprolactones, and bacterial and other recombinant polyesters. Interestingly, these degradable polymers are tunable and have application beyond medicine. The polylactides and polyglycolides have the most extensive breadth of use, spanning research to the clinic, the polycaprolactones the next extensive, while the bacterial and recombinant polyesters are found in research and have not yet gained clinical traction. This chapter provides background regarding formulation and processing of these unique materials. A brief look is given to current and future biomedical applications.

Therapeutic embolisation of blood vessels is a procedure commonly performed to treat a variety of conditions including bleeding problems, arterio-venous malformations (AVM), and benign and malignant hypervascular tumours. A range of degradable and permanent embolisation devices composed of natural and synthetic polymers may be used for such applications. Beads composed of a sulfonate-modified poly(vinyl alcohol) (PVA) hydrogel (DC Bead®) are finding wide-spread use for the occlusion and subsequent local, controlled and sustained delivery of chemotherapeutic agents directly within the vasculature of liver tumours. These so-called drug-eluting beads (DEB) are available in a series of calibrated size ranges for matching vessel size; have appropriate physico-mechanical properties to enable them to be delivered with ease through narrow gauge microcatheters; and have the ability to actively sequester and release positively charged anticancer drugs by an ion-exchange mechanism. This product has become one of the standards of care in the Western World for the treatment of intermediate primary liver cancer.

The chemical and biochemical degradation and calcification are investigated as processes that alter the physical and mechanical properties of implanted polymers. The principles of oxidative, hydrolytic and enzymatic degradation and calcification of polymers in the body are discussed and the natural ageing of polymers in vivo and in vitro and the accelerated ageing of polymers are examined. The use of accelerated ageng is described as a method to predict changes in the physical and mechanical properties of polymers in vivo .

Publisher Summary This chapter discusses the surface modification for natural-based biomedical polymers. Surface is defined as the outside or top layer of the material. The chapter discusses the tissue-biomaterial interface. The environment inside the body is dynamic and active, and the interface between an implanted biomaterial and the body is the location of a variety of dynamic biochemical processes and reactions. During contact of non-bio surfaces with biological fluids, protein adsorption occurs almost instantaneously. This protein layer would further mediate the key bio/material interactions. Therefore, protein adsorption plays a fundamental role in dictating the cellular response elicited by biomedical systems implanted in the human body. Thus, the ability to control these phenomena at the biomaterial surface largely determines the biological performance of biomedical systems. Prevention of non-specific adhesion of proteins and polymer functionalization with cell-type specific molecules can help to direct control of cell adhesion on biomaterials. The environment and the role which a certain biomaterial is expected to play, call for a specific, unique and resistant enough modification to ensure its good performance. To make this task even more complex, the requirements in the biomedical material research and development field are growing very fast.

14 páginas, 10 figuras, 7 tablas., Non-toxic biodegradable linear poly(ester-urethane-urea)s with different hydrophilic character were synthesized from poly(ε-caprolactone) as macrodiol, l-lysine diisocyanate (LDI) and ethyl ester l-lysine or l-ornithine as chain extenders. Linear segmented polymers were synthesized by the prepolymer method with a tertiary amine playing a critical role in the chain extension in heterogeneous conditions. The prepared segmented polymers were fully chemically and physically characterized, including water uptake and hydrolytic stability measurements. Depending on the poly(ε-caprolactone) length, the segmented polymers were amorphous or semicrystalline. The crystallinity degree strongly affected the mechanical properties and water uptake behaviour., Partial financial support of this work by CICYT (MAT2004- 01654), CSIC and CONICET (2004AR0061), Fundación ANTORCHAS and ANPCyT is gratefully acknowledged. The donation of LDI by Kyowa Hakko Kogyo Co., Ltd (Japan) is acknowledged.

Publisher Summary This chapter focuses on the polymers that are biocompatible, that is, those that are not toxic to the body on implantation, can be classified as being bioinert or bioresorbable. Generally, high molecular weight biocompatible polymers are non-degradable and are classed as bioinert. Toxicity can occur with normally biocompatible polymers due to leaching of low molecular weight plasticizers and additives. It is important to characterize the grade of polymer in use. What is sold as polymer X by one manufacturer may be very different from polymer X sold by another, due to the purity and additives present. Surface reactions and absorption of proteins at the polymer surface can also cause problems. Therefore, the surface texture and the shape of the implant are also important. Bioinert polymers, such as polyethylene and polymethylmethacrylate are used in joint replacements and are designed to remain in place, unchanged for many years. Polyethylene has been used in composites such as HAPEX®;, which has been used as middle ear prostheses. Polyesters, such as polyglycolic and polylactic acids, are used as resorbable polymers in applications, such as dissolving sutures. Resorbable polymers are also being investigated for use as scaffolds for tissue engineering applications.

In this highly complex interdisciplinary area of biomedical polymers, progress is beginning to be made in a variety of implants. Of probable major importance is that of small diameter blood vessel repair. The studies leading to the development of a small diameter vascular graft are discussed to show the interrelationship between polymer surface and bulk morphology, polymer-protein interaction, platelet adhesion, and implant mechanical properties on the performance of the implant in the body.