BME 220_Unit 1.pdf

BME – 220 Biomaterials Dr. Abeer Syed Department of Biomedical Engineering King Faisal University Introduction to Biomaterials Unit 1  “A nonviable material used in a medical device, intended to interact with biological systems.”* Any material of natural or of synthetic...

BME – 220 Biomaterials Dr. Abeer Syed Department of Biomedical Engineering King Faisal University Introduction to Biomaterials Unit 1  “A nonviable material used in a medical device, intended to interact with biological systems.”* Any material of natural or of synthetic origin that comes in contact with tissue, blood or biological fluids, and intended for use in prosthetic, diagnostic, therapeutic or storage application. What are “biomaterials”? Biomaterials Science: An Introduction to Materials in Medicine, 4th ed., Wagner et al., eds., Elsevier, NY 2020 Sec 1.1  Biomaterials is a field which is continuing to expand. Scientists, engineers, surgeons and clinicians work together to develop ways of repairing and replacing broken or worn out body parts. As people live to older ages and want to retain the same quality of life worn bits need replacing. We sometimes need to repair damaged or broken body parts following disease or accident. Why – The Need for Biomaterials?  Biomaterials are a small and special group of metals, polymers, ceramics and composites that are safe to use alongside and inside the human body. Types of Biomaterials  Biomaterials cover all classes of materials – metals, ceramics, polymers Biomaterials are defined by their application, NOT chemical make-up Ex. Intraocular lenses Types of Biomaterials Biomaterials must fulfil a range of criteria: Similar mechanical properties to the tissue it is replacing in terms of strength, stiffness and fatigue resistance. Similar values of electrical and thermal conductivity to the tissue it is replacing. Not allow unwanted diffusion between the implant and surrounding tissue. Not absorb water from the surrounding tissue. Stable within the environment of the human body so it does not react chemically with surrounding tissues or fluids – BIOSTABLE/BIOINERT Compatible with the surrounding tissue, that is it should not be toxic or rejected by human tissues - BIOCOMPATIBLE Choosing a Biomaterial The material must have the right mechanical properties. Ideally these should be about the same as the tissue that the implant is replacing, and the implant should be able to cope with the large number of cycles (i.e. loading and unloading) required. In the case of joints or bone plates the implant must not carry more load than the surrounding tissue; if this is the case bone tissue can degrade and eventually be lost (this is a phenomenon known as weight shielding). This can be achieved by choosing a material with a similar stiffness to bone. Choosing a Biomaterial  Replace diseased/damaged part – heart vales, dialysis, amalgam, skin Assist in healing – sutures Improve function – contact lenses Correct function – spinal rods Cosmetic reasons – nose, hips, breast Aid diagnostics – probe Aid therapeutics – catheter Applications Applications https://www.mskcc.org/cancer-care/patient-education/caring-your- urinary-foley-catheter Heart Valve Prostheses Biomaterials Science: An Introduction to Materials in Medicine, 4th ed., Wagner et al., eds., Elsevier, NY 2020 Sec 1.1 Total Hip Replacement Prostheses Biomaterials Science: An Introduction to Materials in Medicine, 4th ed., Wagner et al., eds., Elsevier, NY 2020 Sec 1.1 Dental Implants Biomaterials Science: An Introduction to Materials in Medicine, 4th ed., Wagner et al., eds., Elsevier, NY 2020 Sec 1.1 Intraocular Lenses Biomaterials Science: An Introduction to Materials in Medicine, 4th ed., Wagner et al., eds., Elsevier, NY 2020 Sec 1.1 Ventricular Assist Device https://www.northshore.org/healthresources/encyclopedia/encyclopedia.aspx?Documen tHwid=zm2415 Key Applications of Biomaterials in Medicine Biomaterials Science: An Introduction to Materials in Medicine, 4th ed., Wagner et al., eds., Elsevier, NY 2020 Sec 1.1 Key Applications of Biomaterials in Medicine Biomaterials Science: An Introduction to Materials in Medicine, 4th ed., Wagner et al., eds., Elsevier, NY 2020 Sec 1.1 Key Applications of Biomaterials in Medicine Biomaterials Science: An Introduction to Materials in Medicine, 4th ed., Wagner et al., eds., Elsevier, NY 2020 Sec 1.1 Biomaterial Evolution Need Identification to Product Development Biomaterials Science: An Introduction to Materials in Medicine, 4th ed., Wagner et al., eds., Elsevier, NY 2020 Sec 1.1 Need Identification to Product Development Biomaterials Science: An Introduction to Materials in Medicine, 4th ed., Wagner et al., eds., Elsevier, NY 2020 Sec 1.1 Based on the duration of the device use, invasiveness and risk to the user. Class I: crutches, bedpans, tongue depressors, adhesive bandages etc. minimal invasiveness, does not contact the user internally. Class II: hearing aids, blood pumps, catheters, contact lens, electrodes etc. higher degree of invasiveness and risk, but relatively short duration. Class III: cardiac pacemakers, intrauterine devices, intraocular lenses, heart valves, orthopedic implants, etc. considerably more invasive and can pose immense risk to the user- implantables. Biomedical Devices Classification Material Attributes for Biomedical Applications  To More closely replicate complex tissue architecture and arrangement in vitro To develop novel materials and processing techniques that are compatible with biological interfaces To find better strategies for immune response. Challenges  Animals Is the animal model relevant to human physiology? Specifically, is the experiment well designed and the outcome sufficiently important so that the data obtained will justify the suffering and sacrifice of the life of a living creature? Human Subjects How should human subject research be conducted to minimize negative outcomes to the patient and offer a reasonable risk/benefit ratio? How can we best ensure informed consent? Industrial Involvement Companies fund much biomaterials research and also own proprietary biomaterials. How can the needs of the patient be best balanced with the financial goals of a company? Consider that someone must manufacture devices—these would not be available if a company did not choose to manufacture them. Researchers Since researchers often stand to benefit financially from a successful biomedical device, and sometimes even have devices named after them, how can investigator bias be minimized in biomaterials research? Patients For life-sustaining devices, what is the trade-off between sustaining life and the quality of life with the device for the patient? Should the patient be permitted to “pull the plug” if the quality of life is not satisfactory? Regulatory Agencies With so many unanswered questions about the basic science of biomaterials, do government regulatory agencies have sufficient information to define adequate tests for materials and devices and to properly regulate biomaterials? Ethical Concerns Biomaterials Science: An Introduction to Materials in Medicine, 4th ed., Wagner et al., eds., Elsevier, NY 2020 Sec 1.1 The characteristics of biomaterials science: multidisciplinary multibiomaterial clinical need driven substantial world market, and risk/benefit issues Field of Biomaterials Science Biomaterials Science: An Introduction to Materials in Medicine, 4th ed., Wagner et al., eds., Elsevier, NY 2020 Sec 1.1  Biomaterials Science: An Introduction to Materials in Medicine, 4th ed., Wagner et al., eds., Elsevier, NY 2020 This unit – Section 1.1.1 Textbook Reference