Biomaterials (Unit 4) PDF

UNIT 4: Types of Biomaterials Biocompatibility Surface Properties of Biomaterials Applications of Metallic Biomaterials Biocompatible materials Ceramic biomaterials Bioactive ceramics Polymeric Biomaterials Diamond like carbon films  BIOMATERIALS What ? What...

UNIT 4: Types of Biomaterials Biocompatibility Surface Properties of Biomaterials Applications of Metallic Biomaterials Biocompatible materials Ceramic biomaterials Bioactive ceramics Polymeric Biomaterials Diamond like carbon films  BIOMATERIALS What ? What are Biomaterials? Why ? Why do we need Biomaterials? How ? Where ? How do we use Biomaterials? Where do we use Biomaterials?  Biomaterials Biomaterials are substances that can interact with biological systems for medical purposes. Biomaterials can be derived from nature or synthesized in the laboratory using a variety of chemical approaches. Characteristics of Biomaterials i) Biocompatible ii) Nontoxic iii) Noncarcinogen iv) Good physical mechanical properties v) Low cost vi) It must be readily available vii) Should be moulded into different shape viii) Resistant to degradation ix) Acceptable strength x) Resistant to wear https://www.youtube.com/shorts/7D27OHiNCGs https://www.youtube.com/shorts/7D27OHiNCGs  NEED OF BIOMATERIALS Sometimes fail to perform their regular actions that Human tissues may be due to the genetic defects, age, illness, trauma, degeneration and injuries Some of these conditions can be handled Medications through regular medication If cannot Requirement of unique materials and repaired/rectified through devices arises medication Require surgical repairs that involve anatomical sections like knee joints, elbow joints, vertebrae, teeth or even more crucial organs like heart, kidney , skin etc The number of medical devices used annually by humans is significant, estimated at 1.5 million by the World Health Organization, with around 10,000 forms of standardized device classes available worldwide. https://www.youtube.com/shorts/5JoaSfvCSak BIOMATERIALS The unique materials (other than drugs) or combinations of materials that are primarily expected to be used inside a mammal or Definition 1 human to treat, repair, augment or replace any tissue is referred to as biomaterials. Any material that comes into contact with humans or animals to fulfil their intended function without causing any toxic reaction. Definition 2 This is the single most crucial aspect that differentiates a biomaterial from any other material, i.e., its capacity to be in contact with human body tissues without instigating an undesirable degree of response A material designed to take a form Definition 3 that can direct, through interactions with living systems, the course of any therapeutic or diagnostic procedure.”  1. Load bearing implants like orthopaedic, dental surgery Metals Applications 2. Stent and stent graft in cardiovascular surgeries 3. Screws and plates for external fixation  CLASSIFICATION OF BIOMATERIALS Diagnostics (Gene array and biosensors) On the basis Natural Medical Equipment (Blood bags and of Origin surgical tools) Synthetic Therapeutic Medication (Medical implants and devices) On the basis Emerging Regeneration materials (Tissue of engineering skin and cartilage) applications Skeletal system (joint replacement, bone fracture, tendons, ligands) Cardiovascular system (blood vessels, heart valves) Organs (Artificial heart, skin repair) Metallic On the basis of materials Polymers used Ceramics Composites  On the basis of materials used Depending on the chemical bonding, materials can be categorized into three broad groups. These are (i) polymers, (ii) ceramics, and (iii) metals. Because these material structures vary by their nature of bonding (covalent, ionic or metallic), they have different properties, and hence different uses in the different kinds of biomaterials and chemical bonds associated with it Metals and ceramics are differentiated in the field of materials engineering, although they are both inorganic compounds. Each material has its own benefits and drawbacks, and its biomedical applications are decided according to its individual properties and intended place substitution On the basis of materials used  Types of Biomaterials https://www.youtube.com/shorts/Vbhc20wwb9c  On the basis of materials used Polymers Largest class of Biomaterials https://www.youtube.com/watch?v=ptE8dEdSbeY  Polymers & Biomaterials https://www.youtube.com/watch?v=ptE8dEdSbeY Advantages Widely applied in biomedical applications due to their low toxicity in biological fluids easy pre/post-processing easy sterilization better shelf life lightweight nature Remarkable physical and chemical properties. https://www.youtube.com/watch?v=pBxIQulqadM Applications Biomaterials for Medical Devices https://www.youtube.com/watch?v=pBxIQulqadM Applications Applications Applications  On the basis of materials used Metals - Most widely used class of Biomaterials  Metals Properties 1. Mostly crystalline 2. High tensile strength 3. Resistance to fracture toughness 4. Better rigidity 5. Outstanding mechanical reliability  1. Load bearing implants like orthopaedic, dental surgery Metals Applications 2. Stent and stent graft in cardiovascular surgeries 3. Screws and plates for external fixation  4. Ti-Alloy pacemaker case and metallic leads encapsulated in Metals Applications silicone tubing  8. Knee replacement Metals 9. Stent Applications https://www.youtube.com/shorts/llkA2m9n3fw https://www.youtube.com/watch?v=kyFIDt3OJV4&t=1s Knee replacement https://www.youtube.com/shorts/llkA2m9n3fw Knee replacement 00:00 – 2:00 https://www.youtube.com/watch?v=kyFIDt3OJV4&t=1s  On the basis of materials used Ceramics Inorganic solid materials made up of metallic and non metallic elements bound together via ionic bonds May be crystalline or amorphous Ceramics Further classified into 1. Bioinert ceramics: Types Alumina Al2O3 Zirconia Zr2O3 2. Bioresorbable  Ceramics Applications `1. Cosmo-surgery/orthodontics https://www.youtube.com/shorts/tcHLPuYsql4 https://www.youtube.com/shorts/i2EnlibQPQ8  Ceramic biomaterials in dentistry https://www.youtube.com/shorts/tcHLPuYsql4 https://www.youtube.com/shorts/i2EnlibQPQ8  Ceramics 2. Cardiac-surgery Applications Mechanical heart valve with ball shape Mechanical heart valve with disc shape Comparison of typical properties of biomaterials  Biocompatibility Biocompatibility is, by definition, a measurement of how compatible a device is with a biological system i.e. the ability of a material to co-exist and perform its desired function with respect to a medical therapy, without eliciting any undesirable local or systemic effects in the recipient or beneficiary of that therapy, but generating the most appropriate beneficial cellular or tissue response in that specific situation, and optimizing the clinically relevant performance of that therapy”.  Biocompatibility 1. It is often used in reference to materials that do not produce a toxic or immune response within the human body. 2. Materials or devices are considered biocompatible only within their specific location within the human body and in relation to their specific application. 3. The term “Biocompatibility” is typically used to define polymers, meaning plastics, metals, and ceramics, though it can refer to devices that contain several materials. https://www.youtube.com/watch?v=3BvfKU8-smU  Biocompatibility Components of biocompatibility Following components are considered to constitute “biocompatibility”: Beneficial tissue response and the clinically relevant performance Cytotoxicity (Cell damage/death; systemic and local) – local toxicity is the adverse reactions emerging at the application site which is differentiated from systemic toxicity, in which adverse reaction appear in an area distant from the application site. Genotoxicity-an alteration of the base-pair sequence of the genome DNA. Mutagenicity-if theses genetic damages are passed on to the next generation, this effect is called mutagenicity. Carcinogenicity-Carcinogenicity means that alterations in the DNA have caused a cell to grow and divide inappropriately; in other words, alterations of DNA promoted the generation of malignant tumors. Carcinogenicity results from several mutations. It is important to understand that not all mutagenic events lead to carcinogenesis. Immunogenicity-the ability of a substance to provoke an immune response or the degree to which it provokes a response. WHY IS IT IMPORTANT TO USE BIOCOMPATIBLE MATERIALS? The human body’s immune system is designed to protect it from external attacks, including germs such as viruses, parasites, bacteria, and fungi. This sort of response can occur when a healthcare application uses a non-biocompatible material. The human body’s immense system is complex, so materials can produce a toxic response in the short term, long term, or when combined with other materials. For that reason, biocompatibility testing is critical for all classes of medical devices. In many cases, a medical device will involve more than one material and several rounds of animal testing and clinical trials. The more complex a medical device, the more important testing is. Testing typically involves three types of tests: Analytical chemistry In vitro testing Animal testing Toxicology: A biomaterial should not be toxic, unless it is specifically engineered for such requirements (for example a "smart" bomb" drug delivery system that targets cancer cells and destroy them). 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. When a foreign body is present in the wound site, the reaction sequence is referred to as the "foreign body reaction". This reaction will differ in intensity and duration depending upon the anatomical site involved. Mechanical and Performance Requirements Biomaterials and devices have mechanical and performance requirements that originate from the physical properties of the materials.  BIOCOMPATIBLE MATERIALS https://www.youtube.com/watch?v=3BvfKU8-smU  Factors affecting Biocompatible WHAT AFFECTS A DEVICE/MATERIAL’S BIOCOMPATIBILITY? There are three critical factors taken into account with biocompatibility testing: The physical and chemical natures of a device’s material(s) The human tissue that will be exposed to the material(s) The length of the tissue’s exposure to the material(s) Medical applications are not thought of as 100% biocompatible because the risk is never zero. It’s a question of how much risk is associated with a material. This is why some medical components are safe for short term use, rather than in long term.  Biocompatible Materials BIOCOMPATIBLE MATERIALS 1. Alumina (a ceramic biomaterial) 2. Bioglass (ceramic biomaterial) 3. Cobalt-chromium alloy (metal) 4. Hydroxyapatite (ceramic biomaterial) 5. Medical-grade silicone (short-term implantable and long-term implantable) 6. Polyvinylchloride (PVC) (polymer) 7. Polyethylene (PE) (polymer) 8. Polypropylene (PP) (polymer) 9. Polytetrafluoroethylene (PTFE) (polymer) 10.Polymethylmethacrylate (PMMA) (polymer) 11.Stainless steel 12.Trimethylcarbonate (polymer) 13.TMC NAD-lactide (polymer) 14.Titanium & titanium alloys (metal) 15.Zirconia (ceramic biomaterial)  titanium bone titanium bone Plane of slip or fracture Low stress Rounded to reduce stress concentration Diamond like carbon films  Diamond like carbon films 1. Diamond-like carbon (DLC) is a non-crystalline or amorphous carbon- based material (lacking a crystalline structure) consisting of sp2- bonded carbon atoms of a graphite structure and sp3-bonded carbon atoms of a diamond structure. 2. Some coatings contain hydrogen at 0–40 atm%, and their properties depend on the ratio between sp2 bonding and sp3 bonding with the hydrogen content. Therefore, DLC coatings are produced under conditions suitable for intended use and the properties on the material surfaces. 3. Owing to its high hardness, low-friction properties, and other features depending on the coating formation methods, DLC coating continues to be developed in industrial applications, such as surface coating of cutting tools and optical parts. 4. In addition, because DLC has properties like chemical stability and biocompatibility, it is attracting attention as a surface modification for medical devices with DLC coated on biomaterials. https://www.youtube.com/watch?v=ToaIx6FVbgE  Diamond like carbon films https://www.youtube.com/watch?v=ToaIx6FVbgE Diamond like carbon films Diamond like carbon films  Diamond like carbon films 1. DLC films with various atomic bond structures and compositions are finding places in orthopedic, cardiovascular, and dental applications. 2. Cells grew on to DLC coating without any cytotoxity and inflammation. 3. DLC coatings in orthopedic applications reduced wear, corrosion, and debris formation. 4. DLC coating also reduced thrombogenicity (the tendency of a material in contact with the blood to produce a thrombus, or clot) by minimizing the platelet adhesion and activation. Diamond like carbon films Diamond like carbon films Diamond like carbon films Diamond like carbon films Diamond like carbon films