BIOMATERIALS- INTRODUCTION.ppt

1、LECTURE 1,BIOMATERIALS,1,BIOMATERIALS- INTRODUCTION,Bio material- It is a non viable material used in a medical device, intended to interact with biological system.,A biomaterial is defined as any systemically, pharmacologically inert substance or combination of substances utilized for implantation

2、within or incorporation with a living system to supplement or replace functions of living tissues or organs.,LECTURE 1,BIOMATERIALS,2,BIOMATERIALS- INTRODUCTION,The ability to replace or augment damaged organs, or blood vessels or tissues in part or as a whole has improved the scope of human life.In

3、 addition, a variety of extracorporeal devices, such as the heart, lung and blood dialysis machines are used commonly in medical technology. The availability of human organs is difficult which has paved the way for the use of synthetic materials .,LECTURE 1,BIOMATERIALS,3,FUNCTIONS OF BIOMATERIALS,T

4、he functions of implants fall in to one of the categories:Load bearing or transmissionThe control of fluid flow in order to stimulate normal physiological function or situationPassive space filling either for cosmetic reasons or functional reasons or functional reasons or functional reasonsGeneratio

5、n of electric stimuli and transmission of light and sound.,LECTURE 1,BIOMATERIALS,4,BIOMATERIALS-INTRODUCTION,The only alternate to artificial implants is transplantation of organs such as heart, kidney etc., but this effort has been hindered due to social, ethical and immunological problems.,Biocom

6、patibility is the ability of material to perform within an appropriate host response in a specific application.Biocompatibility in other words is the quality of not having toxic or injurious effects on biological systems.,LECTURE 1,BIOMATERIALS,5,BIOMATERIALS-INTRODUCTION,Each biomaterial has a part

7、icular lifespan in the human body.Examples of specific applications include a hemodialysis membrane, a urinary catheter or hip-joint prosthesis.Hemodialysis membrane might be in contact with the patients blood for 3 hours.The catheter may be inserted for a week after which it starts infecting.,LECTU

8、RE 1,BIOMATERIALS,6,BIOMATERIALS FOR APPLICATIONS,Skeletal system Joint replacements -Titanium, stainless steel, polyethylenePlate for fracture fixation - Stainless steel, cobalt-chromium alloyBone cement - Poly(methyl methacrylate) Artificial tendon and ligament-Teflon, DacronDental Implants-Titani

9、um,alumina,calcium phosphate,LECTURE 1,BIOMATERIALS,7,BIOMATERIALS FOR APPLICATIONS,Cardiovascular system Blood vessel prosthesis - Teflon, Dacron, PolyurethaneHeart valve -Reprocessed tissue, Stainless steel, carbonCatheter - Silicone rubber, Teflon, polyurethane,LECTURE 1,BIOMATERIALS,8,BIOMATERIA

10、LS FOR APPLICATIONS,Organs Artificial Heart - PolyurethaneArtificial Kidney - Cellulose, polyacrylonitrileHeart Lung Machine - Silicone rubber,LECTURE 1,BIOMATERIALS,9,BIOMATERIALS FOR APPLICATIONS,Senses Cochlear replacement -Platinum electrodesIntraocular lens - Poly(methyl methacrylate) ,hydro ge

11、lContact Lens - Silicone-acrylate,hydrogelCorneal bandage Collagen,hydrogel,LECTURE 1,BIOMATERIALS,10,TYPICAL BIOMATERIAL APPLICATION,LECTURE 1,BIOMATERIALS,11,TYPICAL BIOMATERIAL APPLICATION,LECTURE 1,BIOMATERIALS,12,GLASS CERAMIC COCHLEAR IMPLANTS,LECTURE 1,BIOMATERIALS,13,SUBJECTS INTEGRAL TO BIO

12、MATERIALS,ToxicologyHealingMechanical and Performance requirements,LECTURE 1,BIOMATERIALS,14,HEALING,Special processes are invoked when a material or device heals in the body.Injury to tissue will stimulate the well-defined inflammatory reaction sequence that leads to healing.Where a foreign body (e

13、.g., an implant) is present in the wound site (surgical incision), the reaction sequence is referred to as the “foreign body reaction.Furthermore, this reaction will differ in intensity and duration depending upon the anatomical site involved.,LECTURE 1,BIOMATERIALS,15,TOXICOLOGY,A biomaterial shoul

14、d not be toxic, unless it is specifically engineered for such requirements.Since the nontoxic requirement is the norm, toxicology for biomaterials has evolved into a sophisticated science. It deals with the substances that migrate out of biomaterials.It is reasonable to say that a biomaterial should

15、 not give off anything from its mass unless it is specifically designed to do so.,LECTURE 1,BIOMATERIALS,16,MECHANICAL AND PERFORMANCE REQUIREMENTS,Biomaterials that have a mechanical operation must perform to certain standards and be able to cope with pressures.It is therefore essential that all bi

16、omaterials are well designed and are tested.Biomaterials that are used with a mechanical application, such as hip implants, are usually designed using CAD (Computer Aided Design),LECTURE 1,BIOMATERIALS,17,HISTORICAL DEVELOPMENT OF BIOMATERIALS,Some of the earliest biomaterial applications were as fa

17、r back as ancient Phoenicia where loose teeth were bound together with gold wires for tying artificial ones to neighboring teeth.In the early 1900s bone plates were successfully implemented to stabilize bone fractures and to accelerate their healing.While by the time of the 1950s to 60s, blood vesse

18、l replacement were in clinical trials and artificial heart valves and hip joints were in development.,LECTURE 1,BIOMATERIALS,18,HISTORICAL DEVELOPMENT OF BIOMATERIALS,600 B.C Samhita Nose construction1893-1912 W.A.Lane Steel screws for fixation1912 W.D.Sherman Use of Vanadium steel plate1938 P.Wiles

19、 First total hip replacement,LECTURE 1,BIOMATERIALS,19,HISTORICAL DEVELOPMENT OF BIOMATERIALS,1952 A.B.Voorhees Blood Vessel1953 A.Kantrowitz Intraortic balloon pumping1960 M.I.Edwards Heart valve1980 W.J.Kolff Artificial Heart,LECTURE 1,BIOMATERIALS,20,HEART VALVE PROSTHESIS,Heart valves open and c

20、lose over 40 million times a year and they can accumulate damage sufficient to require replacement in many individuals. More than 80,000 replacement valves are implanted each year in the United States .There are many types of heart valve prostheses and they are fabricated from carbons, metals, elast

21、omers, plastics, fabrics and animal or human tissues,LECTURE 1,BIOMATERIALS,21,HEART VALVE PROSTHESIS,Generally, almost as soon as the valve is implanted, cardiac function is restored to near normal levels and the patient shows rapid improvement. In spite of the overall success seen with replacement

22、 heart valves, there are problems that may differ with different types of valves; they include induction of blood clots, degeneration of tissue, mechanical failure, and infection.,LECTURE 1,BIOMATERIALS,22,ARTIFICIAL HIP JOINTS,After 50 or more years of cyclic mechanical stress, or because of degene

23、rative or rheumatological disease, the natural joint wears out, leading to considerable loss of mobility and often confinement to a wheel chair. Hip-joint prostheses are fabricated from titanium, stainless steel, special high-strength alloys, ceramics, composites, and ultra high-molecular-weight pol

24、yethylene.,LECTURE 1,BIOMATERIALS,23,ARTIFICIAL HIP JOINTS,With some types of replacement hip joints and surgical procedures that use polymeric cement, ambulatory function is restored within days after surgery.For other types, a healing period is required for integration between bone and the implant

25、 before the joint can bear the full weight of the body.After 10-15 years, the implant may loosen, necessitating another operation.,LECTURE 1,BIOMATERIALS,24,DENTAL IMPLANTS,The widespread introduction of titanium implants has revolutionized dental implantology. These devices form an implanted artifi

26、cial tooth anchor upon which a crown is affixed. One of the primary advantages originally cited for the titanium implant was its osseous integration with the bone of the jaw. Loss of tissue support leading to loosening along with infection remains an issue in the topic of Dental implants.,LECTURE 1,

27、BIOMATERIALS,25,INTRAOCULAR LENSES,A variety of intraocular lenses (IOLs) have been fabricated of poly methyl methacrylate, Silicone elastomer, soft acrylic polymers, or hydro gels and are used to replace a natural lens when it becomes cloudy due to cataract formation.Good vision is generally restor

28、ed almost immediately after the lens is inserted and the success rate with this device is high. IOL surgical procedures are well developed and implantation is often performed on an outpatient basis.,LECTURE 1,BIOMATERIALS,26,STEPS INVOVLED IN THE DEVELOPMENT,The various steps involved in the develop

29、ment of biomaterial devices areIdentifying a needDevice designMaterial SynthesisMaterial Testing,LECTURE 1,BIOMATERIALS,27,STEPS INVOVLED IN THE DEVELOPMENT,Fabrication Sterilization and PackagingDevice TestingClinical Use,LECTURE 1,BIOMATERIALS,28,EXAMPLES,LECTURE 1,BIOMATERIALS,29,EXAMPLES,LECTURE 1,BIOMATERIALS,30,EXAMPLES,LECTURE 1,BIOMATERIALS,31,EXAMPLES,LECTURE 1,BIOMATERIALS,32,EXAMPLES,LECTURE 1,BIOMATERIALS,33,EXAMPLES,