Công nghệ vật liệu trong y sinh học biom aterials chapter 2 classes of materials used in medicine

Part 1: Material Science & Engineering Chap Properties of materials - The structure of solids - Mechanical properties of materials - Surface properties of materials - Role of water in biomaterials Chap Classes of materials used in medicine c om - Polymer - Silicone - Medical fibers & biotextiles - Hydrogels - Applications of “Smart Polymers” as biomaterials co ng - Bioresorbable and bioerodible materials Advanced Program Biomedical Engineering – HUST, Vietnam ng th an du o Part 1: Material Science & Engineering cu u Chap 2.(cont.) - Natural materials - Metals - Ceramics, glasses, and glass-ceramics - Composite - Nonfouling (Anti-fouling) surfaces - Surface modification of materials used in medicine - Textured and porous materials - Surface-immobilized Biomolecules CuuDuongThanCong.com Advanced Program Biomedical Engineering – HUST, Vietnam https://fb.com/tailieudientucntt Chap.2 Classes of materials used in medicine- Polymer Chapter co ng c om Classes of materials used in medicine Advanced Program Biomedical Engineering – HUST, Vietnam ng th an du o Chap.2 Classes of materials used in medicine- Polymer cu u Classes of biomaterials -Polymers -Metals -Ceramics -Natural materials What is polymer? -Long-chain, consists of many repeating units (monomeric monomeric units) units -Small molecule (repeating units) link together by primary covalent bonding - Monomer: Monomer initial substance to form polymer (ethylene, methyl methacrylate, amide…) - n (number of repeating units, degree of polymerization): polymerization over 1,000 to form strong solids Small n: oligomer (M about 500- 6,000) Great n: high polymer (104-106) Mer and chain structure of (a) polytetraflouroethylene; (b) polyvinylchloride; (c) polypropylene CuuDuongThanCong.com Advanced Program Biomedical Engineering – HUST, Vietnam https://fb.com/tailieudientucntt ng c om Chap.2 Classes of materials used in medicine- Polymer co Polyethylene: (a) mer and chain structure; (b) Zigzac backbone structure of molecule Advanced Program Biomedical Engineering – HUST, Vietnam ng th an du o Chap.2 Classes of materials used in medicine- Polymer - The main backbone chain (polymeric polymeric chain) chain can be made up of different atoms such as silicone rubber-SR or same atoms such as polyethylene-PE u - Homopolymer: Homopolymer polymer containing one type of repeating units (PMMA, SR, PVC, PE) cu - Copolymer: Copolymer two or more type of repeating units (styrene-butadiene rubber, polylactide polyglycolic acid - Very different from molecule structure - Can be synthetic (PE,PP, PMMA) or natural (cellulose, natural rubber, collagen, DNA…) - Wide range of characteristics (biodegradable or not, hydrophilic or hydrophobic, nonwater absorbing or water swelling, saturated or not saturated) - Properties depend on chemical structure, geological structure, polymerization degree (molecular weight - Classification: thermoplastics, thermosetting, elastomer Nomenclature of polymer - Usually: adding prefix poly to name of monomer (ethylene- polyethylene; methyl methacrylate- polymethyl-methacrylate) - Name of monomers (phenol and formaldehyde- phenolformadehyde CuuDuongThanCong.com Advanced Program Biomedical Engineering – HUST, Vietnam https://fb.com/tailieudientucntt Chap.2 Classes of materials used in medicine- Polymer Molecular weight (size) Average molecular weight Mn: Number average molecular weight Mw: Weight average molecular weight Ni: number of mole of species I c om Mi: molecular weight of species I Molecular weight distribution PI: Mw/Mn: Polydispersity index (indicates the breadth of molecular weight distribution -Average molecular weight is very important for mechanical properties, adsorption and processing co ng -Molecular weight distribution shows the homogenity of the properties Advanced Program Biomedical Engineering – HUST, Vietnam ng th an du o Chap.2 Classes of materials used in medicine- Polymer Synthesis (Polymerization) 3.1 Addition polymerization (chain reaction) u - Simple addition of monomer molecules to each other cu - Without the lost of any atoms (no side products) - Monomers should contain un-saturated bonding such as double bonds, triple bonds, dien (ethylene, acetylene, butadiene…) - Initiators (can be free radicals, cations, anions or stereospecific catalyst) :usually needed to open double bonds to cause activate site - Polymerization mechanism: initiation (form activated site for reaction), propagation (additional reaction for rapid chain growth) and termination - Can result in homo-polymer or copolymer - Examples: PE, PP, PMMA, PVC 3.2 Condensation polymerization (stepwise growth) - Two different monomers react to from a covalent bond - Usually produces small molecules condensed out as side products (water, salt, HCl…) - Examples: polyester, polyamide, polysiloxane, poly(ethylene terephtalate) CuuDuongThanCong.com Advanced Program Biomedical Engineering – HUST, Vietnam https://fb.com/tailieudientucntt Chap.2 Classes of materials used in medicine- Polymer co ng c om Example for polymerization Advanced Program Biomedical Engineering – HUST, Vietnam ng th an Example for polymerization cu u du o Chap.2 Classes of materials used in medicine- Polymer 10 CuuDuongThanCong.com Advanced Program Biomedical Engineering – HUST, Vietnam https://fb.com/tailieudientucntt Chap.2 Classes of materials used in medicine- Polymer co ng c om Example for polymerization Advanced Program Biomedical Engineering – HUST, Vietnam ng th an 11 du o Chap.2 Classes of materials used in medicine- Polymer Molecule structure cu u 4.1 Polymer structure (a): Linear (b) (a) (b): Branched (c): Crosslinked (d): Netwok (threedimensional) (c) 12 CuuDuongThanCong.com (d) Advanced Program Biomedical Engineering – HUST, Vietnam https://fb.com/tailieudientucntt Chap.2 Classes of materials used in medicine- Polymer 4.2 Molecule structure of copolymer (a): Random (a) (b): Alternating (c): Block (d): Graft c om (b) ng (c) co (d) Advanced Program Biomedical Engineering – HUST, Vietnam ng th an 13 du o Chap.2 Classes of materials used in medicine- Polymer cu u 4.4 Polymer chain arrangement 14 CuuDuongThanCong.com Advanced Program Biomedical Engineering – HUST, Vietnam https://fb.com/tailieudientucntt Chap.2 Classes of materials used in medicine- Polymer Configuration (Tacticity or Stereoisomerism) (For linear and branched polymer) - Tacticity refers to the arrangement of substituent groups around extended polymer chain - Atactic configuration: substituent groups at random on other side of extended chain backbone; can not crystalize (amorphous polymer) - Syndiotactic: Syndiotactic substituents alternating from side to side of the backbone, may crystallize co ng c om - Isotactic: Isotactic substituents located on the same side of the zigzac plane of chain backbone, may crystallize Advanced Program Biomedical Engineering – HUST, Vietnam ng th an 15 Relationship Structure- Characteristics cu u du o Chap.2 Classes of materials used in medicine- Polymer 16 CuuDuongThanCong.com Advanced Program Biomedical Engineering – HUST, Vietnam https://fb.com/tailieudientucntt Chap.2 Classes of materials used in medicine- Polymer co ng c om Important polymeric implant materials Advanced Program Biomedical Engineering – HUST, Vietnam ng th an 17 du o Chap.2 Classes of materials used in medicine- Polymer 7.1 Polyamide (Nylons) -Polymerize by step-reaction & ring-scission cu u -Have interchain hydrogen bonding and high degree of crystallinity, lead to excellent fiber-forming ability, used for surgical sutures - Basic chemical structure repeating units: different, lead to very different polyamides - Nylons are hydroscopic & lose their strength in vivo when implanted (water molecules serve as plasticizers - Proteolytic enzymes also attack amides groups 17 CuuDuongThanCong.com Advanced Program Biomedical Engineering – HUST, Vietnam https://fb.com/tailieudientucntt Chap.2 Classes of materials used in medicine- Polymer Basic chemical structure of PA from diamine + diacidsNylon ; Nylon type 66 or 610 c om Nylon type co ng Aromatic polyamides, named Aramide Advanced Program Biomedical Engineering – HUST, Vietnam ng th an du o Chap.2 Classes of materials used in medicine- Polymer 7.2 Polyethylene - Can crystallize cu u - Can polymerized at high pressure with radical catalyst (low density PE), or at low pressure with Ziegler catalyst (high-density PE- not contain branches) - Crystallinity: very vary - can be used in solid or porous form - HDPE: used as tubing for drains and catheters - Ultra-molecular weight PE (UHMWPE): extensively used in orthopedic implant fabrications (joint implants) - Biocompatibility: poor 7.2 Polypropylene -Usually crystallize (except atactic) - Have exceptional high flexural fatigue life, used to make intergrally molded hinges for finger joint prostheses -Have excellent environmental stress-cracking resistance, used for sutures and hernia repair CuuDuongThanCong.com Advanced Program Biomedical Engineering – HUST, Vietnam https://fb.com/tailieudientucntt co ng c om Chap.2 Classes of materials used in medicine- Polymer Advanced Program Biomedical Engineering – HUST, Vietnam ng th an cu u du o Chap.2 Classes of materials used in medicine- Polymer CuuDuongThanCong.com Advanced Program Biomedical Engineering – HUST, Vietnam https://fb.com/tailieudientucntt Chap.2 Classes of materials used in medicine- Polymer 7.3 Polyacrylates -Have excellent physical and coloring properties, easy to fabricate -Extensively used for detal cement (polyacrylic acid), hard contact lenses, bone cement * Polymethyl metacrylate (PMMA) -Hydrophobic, amorphous, transparent, glassy at room temperature, tough, stable, excellent light transmittance -Used as major ingredient for bone cement, good for intraocular and hard contact lenses •Poly HEMA: soft contact lenses c om 7.4.PVC -Tubing (blood transfusion, feeding, dialysis) and blood storage bags -Plasticizer problem 7.5 PDMS or SR ng -For finger joint, hart valves, breath implant, for chin, ear, nose reconstruction -Oxygenator membranes co 7.6 PEG: drug delivery, modify polymer surface to form non-fouling surface Advanced Program Biomedical Engineering – HUST, Vietnam ng th an cu u du o Chap.2 Classes of materials used in medicine- Polymer CuuDuongThanCong.com Advanced Program Biomedical Engineering – HUST, Vietnam https://fb.com/tailieudientucntt ...Chap .2 Classes of materials used in medicine- Polymer Chapter co ng c om Classes of materials used in medicine Advanced Program Biomedical Engineering – HUST, Vietnam ng th an du o Chap .2 Classes. .. c om Chap .2 Classes of materials used in medicine- Polymer Advanced Program Biomedical Engineering – HUST, Vietnam ng th an cu u du o Chap .2 Classes of materials used in medicine- Polymer CuuDuongThanCong.com... Chap .2 Classes of materials used in medicine- Polymer cu u Classes of biomaterials -Polymers -Metals -Ceramics -Natural materials What is polymer? -Long-chain, consists of many repeating units (monomeric