ABCs of Biomaterials Dr. Alagiriswamy A A, (M.Sc, PhD, PDF) Asst. Professor (Sr. Grade), Dept. of Physics, SRM-University, Kattankulathur campus, Chennai ABCs of Biomaterials UNIT III Lecture 1 September 9, 2018

before i proceed September 9, 2018 I refer you to read out this handbook Available in our SRM library Totally three copies Out of three, only one is reference type Author Information By Dr. Buddy D. Ratner,; School of Dentistry and Medicine, University of Alabama, Birmingham, U.S.A. "The most thorough textbook available, covering most aspects of biomaterials science … provides the most up-to-date and in-depth information on biomaterial developments." --MRS Bulletin, January 2006 September 9, 2018

More than a multi-disciplinary Field Bioengineers Material Scientists Immunologists Chemists Biologists Surgeons others September 9, 2018

A Little History on Biomaterials Romans, Chinese, and Aztecs used gold in dentistry over 2000 years ago, Cu not good. Ivory & wood teeth Aseptic surgery 1860 (Lister) Bone plates 1900, joints 1930 Turn of the century, synthetic plastics came into use WWII, shards of PMMA unintentionally got lodged into eyes of aviators Parachute cloth used for vascular prosthesis 1960- Polyethylene and stainless steel being used for hip implants September 9, 2018

Why Biomaterials ???? September 9, 2018

Background During the last two decades, significant advances have been made in the development of biocompatible and biodegradable materials for medical applications. In the biomedical field, the goal is to develop and characterize artificial materials or, in otherwords, “spare parts” for use in the human body to MEASURE, RESTORE and IMPROVE physical functions and enhance survival and quality of life September 9, 2018

CLASSIFICATION OF BIOMATERIALS First generation: INERT Do not trigger any reaction in the host: neither rejected nor recognition “do not bring any good result” Second generation: BIOACTIVE Ensure a more stable performance in a long time or for the period you want Third generation: BIODEGRADABLE It can be chemically degraded or decomposed by natural effectors (weather, soil, bacteria, plants, animals) September 9, 2018

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Restoration artificial implantation surgery using silicone technology September 9, 2018

What do you mean by the term "Most" ? BIOMATERIALS Biomaterials science may be the MOST multidisciplinary of all the sciences which encompasses aspects of medicine, biology, chemistry, engineering and materials science. Biomaterials are : “Non-viable materials used in a medical devices intended to interact with biological systems” [D.F. Williams, 1987] Non-viable : - incapable of growing and developing independently What do you mean by the term "Most" ? September 9, 2018

What is the definition of a Biomaterial ? Casual definition: A BIOMATERIAL is a synthetic material used to replace part of a living system or to function in intimate contact with living tissue. Formal definition by Clemson University Advisory Board for Biomaterials: A BIOMATERIAL is a systemically and pharmacologically inert substance designed for implantation within or incorporation with living systems. September 9, 2018

Success of biomaterials: Dependent on factors engineers/scientists can control: Choice of material Geometric design Synthesis or manufacturing of biomaterial Dependent on factors engineers/scientists cannot control: Surgical technique Health and condition of patient Post-surgical activities by patient September 9, 2018

Is it derogating ?? September 9, 2018

Some interesting physical measurables September 9, 2018

Variable Pore Size in Bone Is it interesting ???? 4µm 220µm September 9, 2018

Micro-evaluation of biomaterials Define reliability (r) & probability of biomaterial failure (f): r = 1 – f May have multiple modes of failure based on: Body infection Implant toxicity Inflammation of immune response Mechanical failure (strength, stiffness, and fatigue) Optical/Electrical properties Diffusion properties Manufacturability Density Geometric design Thus, total reliability (rt) is given by product of individual reliabilities [r1 = (1-f1)] : rt = r1r2 • • • • rn September 9, 2018

Biomaterials may be considered as metals, ceramics, polymers, or composites: September 9, 2018

Bio-technical terms September 9, 2018 BIOFUNCTIONALITY Playing a specific function in physical and mechanical terms BIOCOMPATIBILITY Concept that refers to a set of properties that a material must have to be used safely in a biological organism Synthetic or natural material used in intimate contact with living tissue (it can be implanted, partially implanted or totally external). Biocompatible materials are intended to interface with biological system to EVALUATE, TREAT, AUGMENT or REPLACE any tissue, organ or function of the body Biocompatible material features Absence of carcinogenicity (the ability or tendency to produce cancer) Absence of immunogenic (absence of a recognition of an external factor which could create rejection) Absence of teratogenicity (ability to cause birth defects) Absence of toxicity September 9, 2018

Testing specimens Biocompatibility is primarily a surface phenomenon … Rabbits – ear, skin, pyrogen Guinea Pigs – skin, esp C@ Mice – genotoxicity Horseshoe Crab – endotoxins Pig – implant Bacteria - genotoxicity Test actual & elutants & extracts… People – long term September 9, 2018

Some more BIO-TECHNICAL terms Bioactivity - Evolving concept: The characteristic that allows the material to form a bond with living tissue (Hench, 1971) The ability of a material to stimulate healing and trick the tissue system into responding as if it were a natural tissue (Hench 2002). Advantages: Bone tissue – implant interface, enhanced healing response, extends implant life Biodegradability: Breakdown of implant due to chemical or cellular actions If timed to rate of tissue healing transforms implant to scaffold for tissue regeneration Negates issues of stress shielding, implant loosening, long term stability what about biodurability, bioavailability, bioinert ????????????? September 9, 2018

Some examples of biomaterials Where is chitra Triunal (trivandrum)?? September 9, 2018

Understanding the ideas of each lecture REQUIRES the knowledge of the previous lectures. In the past, people who have skipped a lot of classes have received very bad grades. Conversely, people who’ve come to most or all of the classes nearly always receive A’s and B’s. Find out the secrets of how to become a rich or a fast learner ????????? If you keep up, you won’t end up looking like this hour before the commencement of the classes. September 9, 2018

Are you compatible with this class?? September 9, 2018