Piezoelectric jetting is a common form of additive manufacturing technology. With the development of material science and manufacturing devices, piezoelectric jetting of biomaterials has been applied to various fields including biosensors, tissue engineering, deoxyribonucleic acid (DNA) synthesis, and biorobots. This article discusses the processes involved in piezoelectric jetting of biosensors and biorobots and the applications of piezoelectric jetting for tissue engineering and producing DNA. In addition, it reviews the challenges and perspectives of piezoelectric jetting.

This article describes the corrosion resistance and ion release from main transition metallic bearings used as medical devices. It discusses the main issues associated with the in vivo presence of ions and their biocompatibility during the exposure of patients to different aspects of ion toxicity. These include ion concentration and accumulation in organisms, reactive oxygen species and oxidative stress, and carcinogenicity stimulated by the corrosion process and toxic ions release.

The use of 3D bioprinting techniques has contributed to the development of novel cellular patterns and constructs in vitro, ex vivo, and even in vivo. There are three main bioprinting techniques: inkjet printing, extrusion printing (also known as bioextrusion), laser-induced forward transfer (LIFT) printing, which is also known as modified LIFT printing, matrix-assisted pulsed-laser evaporation direct write, and laser-based printing (laser-assisted bioprinting, or biological laser printing). This article provides an overview of the LIFT process, including the LIFT process introduction, different implementations, jetting dynamics, printability phase diagrams, and printing process simulations. Additionally, materials involved during LIFT are introduced in terms of bioink materials and energy-absorbing layer materials. Also, the printing of single cells and 2D and 3D constructs is introduced, showcasing the current state of the art with the ultimate goal for tissue- and organ-printing applications.

This article discusses the composition of the major components of dental composite resins: organic resin matrix, filler, coupling agents, and initiator-accelerator systems. It describes the properties of composite resins that are related to the amount and type of filler and resin-matrix compositions. The article also discusses the compositions, properties, and clinical applications of polyacid-modified composite resins and resin-modified glass-ionomer cements. It concludes with information on biodegradation and biocompatibility of resin-based restorative materials.

This article discusses several aspects of biocompatibility of polymers, including the selection of a suitable polymer, specific use of a material, contact of polymer on body site, and duration of the contact. It describes the factors influencing the biological response of the polymer from a biocompatibility perspective. These include raw materials, the manufacturing process, cleaning and sterilization processes, and biodegradation and biostability. The article reviews the general testing methods of polymers, such as chemical, mechanical and thermal. It concludes with a section on the guidance, provided by the regulatory authorities, on the biocompatibility testing of polymers and polymer-containing devices that can aid in selecting the right analysis.

Implant debris is known to cause local inflammation, local osteolysis, and, in some cases, local and systemic hypersensitivity. The debris can be stainless steel, cobalt alloy, and titanium alloy, and soluble debris obtained due to wear from all orthopedic implants. This article addresses the biologic aspects of implant debris, both locally and systemically. It describes debris-induced local effects, particle-induced proinflammatory responses, and debris-induced systemic effects. The article concludes with a discussion on the four systemic effects of implant debris, namely, neuropathic effects, hypersensitivity effects, carcinogenicity, and general toxicity.

Polymers offer a wide range of choices for medical applications because of their versatility in properties and processing. This article provides an overview of polymeric materials and the characteristics that make them a unique class of materials. It describes the ways to classify polymers, including the polymerization method, how the material deforms, or molecular origin or stability. The article contains tables that list common medical polymers used in medical devices. It explains the medical polymer selection criteria and regulatory aspects of materials selection failure analysis and prevention. Failure analysis and prevention processes to determine the root cause of failures that arise at different stages of the product life cycle are reviewed. The article describes the mechanisms of plastic product failure analysis. It discusses the trends in the use of medical polymers, such as high-performance polymers for implants, tissue engineering, and bioresorbable polymers.

This article discusses the mechanisms of metal and alloy biocompatibility. It provides information on early testing and experience with metals in medical device applications. The article describes the response of implant and particulate materials to severe corrosion. It provides a description of metal binding and its effects on metabolic processes. Hypersensitive responses to metal ions are also reviewed. The article concludes with a discussion on the possible cancer-causing effects of metallic biomaterials.

This article outlines the selection criteria for choosing an implant material for biomedical devices in orthopedic, dental, soft-tissue, and cardiovascular applications. It details the development of various implants, such as metallic, ceramic, and polymeric implants. The article discusses specific problems associated with implant manufacturing processes and the consequent compromises in the properties of functionally graded implants. It describes the manufacturing of the functionally-graded hip implant by using the LENS process. The article reviews four different types of tissue responses to the biomaterial. It discusses the testing methods of implant failure, such as in vitro and in vivo assessment of tissue compatibility.

Metal contamination of the environment reflects both natural sources and industrial activity, affecting human health. This article begins with a discussion on the level of metal exposure resulting in toxicological effects, the factors influencing toxicity of metals, and carcinogenicity of metal compounds. It discusses some commonly used chelating agents for treating metal intoxication, and clinical effectiveness in treating poisoning by different metals. The metals discussed are grouped into four categories: (1) major toxic metals with multiple effects, including arsenic, beryllium, cadmium, chromium, lead, mercury, and nickel; (2) essential metals with potential for toxicity, including cobalt, copper, iron, manganese, molybdenum, selenium, and zinc; (3) metals with toxicity related to medical therapy, including aluminum, bismuth, gallium, gold, lithium, and platinum; and (4) minor toxic metals, including antimony, barium, indium, magnesium, silver, tellurium, thallium, tin, titanium, uranium, and vanadium. The main factors included in the discussion are their disposition, toxicity, biological factors and treatment.

Additive manufacturing (AM) has been growing as a significant research interest in academic and industry research communities. This article presents flexible and biocompatible energy-harvesting devices using AM technology. First, it discusses material selection for achieving piezoelectricity and triboelectricity. Then, the article highlights the structures of energy harvesters and describes their working mechanisms. Next, it covers the additively manufactured implantable piezoelectric and triboelectric energy harvesters. Further, the article describes the 3D-printed wearable energy harvesters as well as their applications. An overview of additively manufactured self-powered sensors is highlighted. Finally, the article discusses the issues for 3D-printed energy harvesters and their roadmap.

The biocompatibility of a material relates to its immunological response, toxicity profile, and ability to integrate with surrounding tissue without undesirable local or systemic effects on a patient. This article underscores the transformation of the medical device design ecosystem engaged as an integral part of the device ecosystem. It discusses the applications of biomaterials, including orthopedic, cardiovascular, ophthalmic, and dental applications. The article describes four major categories of biomaterials such as metals, polymers, glass and ceramics, and composites. A discussion on natural materials, nanomaterials, and stem cells is also provided. The article concludes with examples of biomaterials applications, such as endovascular devices, knee implants, and neurostimulation.