Biological Properties ISSUES TO ADDRESS... Biomaterials definition Different types of interaction between body and foreign material What are main characteristics of a biomaterial Types of biomaterials Applications of biomaterials

Biomaterials Definition A multidisciplinary knowledge of studying materials behavior in the body environment Any material, natural or synthetic, that comprises whole or part of a living structure or a biomedical device which performs, enhances, or replace a function that has been lost through disease or injury

Different types of interaction between body and foreign material ExampleResultType of foreign material Most of the MetalsTissues deathToxic Most of the Ceramics like Alumina and Zirconia Fibrous tissue formationNearly Inert Hydroxyapatite, BioglassSurface-tissue interaction at the interface Bioactive Tricalcium phosphate, Collagen Substitution of material whit tissue Degradable

What are main characteristics of a biomaterial? Biocompatibility Mechanical properties Properties regarding to application

Different types of biomaterials

CeramicPolymerMetalProperty High Mostly bioactive and non-toxic Intermediate Can be toxic Low Toxic productsBiocompatibility LowintermediateHighMechanical LowHighintermediateProcessability

Classification of application of materials in Biomedical Engineering Implants and tissue replacement Tissue Engineering Drug delivery systems Biosensors and medical diagnosis

Implants and tissue replacement Body Biomaterial  Fibrosis encapsulation  Protein attachment  Coagulation  Mechanical degradation and erosion  Undesirable immunological response Biomaterial rejection

Biocompatibility Biocompatibility is the ability of the materials to perform in the presence of an appropriate host for a specific application. Titanium and titanium alloys (Thin surface oxide) Relatively inert good corrosion resistance

Cardiovascular substitutes: Artificial heart valves Heart Function : pumping blood to all parts of body Entrance and outgoing of blood into ventricle heart is occurring in heart valves -Tricuspid valve - Pulmonary valve - Mitral valve - Aortic valve

Types of Artificial Heart Valves  Natural substitutes (Bioprosthetic Heart Valves) -High biocompatibility and blood compability -Shorter life-time -Grafting problems like out break of disease  Artificial substitutes (Mechanical Heart Valves) -Longer life-time -Stronger mechanical properties -Can be lead to coagulation

Skin Tissue Engineering

Nerve repair

Injectable Scaffolds (Insitu forming)

Cell Source 1.Autologous cells 2.Allogenic cells Primary cells Cell-Lines Stem cells

Drug Delivery Systems Delivering drug or any other biological agent to a specific part of patients body with the control of the dosage Advantages: – Increasing drugs effectiveness – Preventing from toxic dosages – Decreasing side effects – Preventing drug loss – Controlling drug behavior – Probability of targeted and prolonged release

Biosensors The term ‘‘biosensor’’ is used to cover sensor devices in order to determine the concentration of substances and other analytes of biological interest, in some cases even where they do not utilize a biological system directly

Biosensors Physical sensors Optical sensors Pressure sensors Temperature sensors Magnetic sensors Acoustic sensors Chemical sensors Gas sensors Humidity sensors Ionic sensors Biochemical sensors Biosensors

Sensors compared with sense organs of man: - Optical sensors- eyesight - Gas sensors- olfaction - Sensors for pressure, temperature-touch - Acoustic sensors- hearing - Chemical sensors- taste

Materials for biosensors Synthetic polymers Hydrogels Natural polymers Biological materials CeramicsMetals Biological tissues

Piezoelectric Sensors

Bioceramics Calcium phosphates: hydroxyapatite, tricalcium phosphate Alumina Zirconia Glass-Ceramics Bioglass Clays and LDHs( Layered Double Hydroxide) Ferromagnetic bioceramics Carbons

Types of bioceramics applicationStructureForms Filler, tissue regeneration and repair Polycrystalline Amorphous Powder and granules Tissue bonding, anti- coagulation, anti-corrosion Polycrystalline Amorphous Semi-Crystal Coat Tissue regeneration and replacement Single crystal Polycrystalline Amorphous Composite Body

Bioceramics advantages over other materials Consisting of elements similar to body physiological environment like: Ca, K, P, Na and Mg Products of mechanical degradation and chemical dissolution are inert and can be adsorbed through body metabolism Strong ionic and covalent bonds and lack of free electrons prevent formation of electrochemical cell

Types of Bioceramics Nearly Inert Bioactive Resorbable Porous

Bioceramics applications Orthopedic implants Dental implants Grafts and substitutes Hypodermic devices Ear implants Contact lens Artificial heart valves