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Week Topic Instructor

1 Biomedical Engineering World Dr. S. Takaç

2 Biomed. Instrumentation and Signals Dr. Ö. Birgül

3 Medical Imaging Dr. Ö. Birgül

4 Biomechanics Dr. C. Evrensel

5 Biomaterials Dr. P. Yılgör Huri

6 Diagnosis Dr. D. Özel Demiralp

7 Nanomedicine Dr. A. Yılmazer Aktuna

8 Midterm Exam Selection of Project Topics

Rules for writing and presenting a project

9 Special topics in BME 1 Bioinformatics

10 Special topics in BME 2 BME in Orthopedic Surgery

11 Special topics in BME 3 Sağlık Sektöründe Tıbbi Cihaz Teknolojileri

12 Special topics in BME 4 TBA

13 Student Project Presentations Poster and Oral Presentations

14 Student Project Presentations Poster and Oral Presentations

YOU

ARE

HERE

Attention!

Info on Term Projects

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Form groups of 3

Give names to Dr. Huri by next Wednesday, November 2nd, 17:30

Midterm week: Term Project topics will be assigned to each group

You will prepare a poster and a short presentation

You will present in the last 2 weeks of the semester

Your posters will be displayed on the first floor for the rest of the year

Best poster award

BIOMATERIALS

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Doç. Dr. Pınar Yılgör Huri

phuri@ankara.edu.tr

Ankara University

Department of Biomedical Engineering

BME101 Introduction to Biomedical Engineering

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When does a material become a

biomaterial?

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Anything in contact with human

body?A biomaterial is any substance that has been engineered to interact with biological systemsfor a medical purpose

- either therapeutic

�Treat�Augment�Repair�Replace

- or diagnostic use6

a tissue OR function of the body

What is a Biomaterial?

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Biomaterials are used for a variety of

purposes within the body

Annual biomaterial use;

http://www.uweb.engr.washington.edu/research/tutorials/introbiomat.html 10

Expenses associated with biomaterial use;

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Multidisciplinary: Biomaterials research and development have been stimulated and guided by advances in:

� Materials science � Cell and molecular biology � Medicine� Chemistry � Physics � Engineering

Biomaterials ScienceHistory of Biomaterials

• Gold, ivory and wood in dentistry and prosthesis >3000 years ago

First prosthesis in history (Egypt)

Nacre from sea shells by Mayans

.. with no knowledge of sterilization,

toxicology, inflammation, corrosion,

biodegradation, etc.First sutures on mummies using animal tendons

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� 1860: Aseptic surgery

� 1900: Bone plate, 1930: Artificial joints

� Synthetic plastics in use- It was observed during the 2WW that shards of plastic

from shaddered canopies found in war pilots’ eyes were compatible with the body (no reaction)

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History of Biomaterials

�Ridley (ophthalmologist) examined the pieces and found that it is PMMA

�This material was used to fabricate intraocular lenses (and first hard contact lenses)

�> 7million IOL applications today worldwide

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� 1961: PE and stainless steel hip prosthesis

History of Biomaterials

� 1st generation biomaterials (>1950)

Aim: Bioinertness (silicon, PE, PU, PP, PMMA)

� 2nd generation biomaterials (>1980)

Aim: Bioactivity (PLA, PGA, PLGA, PHEMA)

� 3rd generation biomaterials (>2000)

Aim: Functional tissue regeneration

� Gene and cell activation

� Biodegradable polymers designed at

the molecular level

Structural

support

Biodegradable implants

integrating w/

body

Tissue

engineered products

Evolution of Biomaterials • The success of a biomaterial is related to several factors including;

– Material related properties

– General condition of the patient

– Surgical technique and proper follow up

Biomaterial should:

�Retain physical properties

�Be non-toxic

�Be non-carcinogenic

�Be anti-allergic

�Have long service time

�Retain functionality during use

�Be easily sterilized

�Be biocompatible

� Bulk properties: Chemical composition and structure, Purity, leachables

� Surface properties: Porosity, Geometry, Hydrophilicity, Surface charge

� Mechanical properties: Toughness, Elasticity, Stability

�Long term structural integrity: Load, Fatigue performance,

Abrasion and corrosion resistance

Biocompatibilityability of a material to perform with an appropriate

host response in a specific application

Host Response / Foreign Body Reaction

�Thrombosis

�Hemolysis

�Inflammation

�Infection

�Carcinogenesis

�Irritation

Patient

Design

Material Synthesis

Material Testing(in vitro and in vivo)

Production

Sterilization / Packaging

Material Tests Shelf life, stability

Regulation

Clinical application and further tests

Idea Identification of the problem

Biomaterials: From Bench to Bedside

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What are the necessary characteristics of a bone plate material?

Things to ask:

�Does it have sufficient mechanical stability?

�Is it chemically stable? Is it changing over time?

�Is engineering design appropriate?

�Is the density and weight compatible with bone?

�Is the fatigue time acceptable?

�Is the plate accepted by the tissue?

�Is it acceptable pharmacologically?

�What is the cost?

�Is it reproducable? Is it possible to produce at large scale?

Example: Evaluation of the success of a biomaterial Types of Biomaterials

Co-Cr alloys Heart valve, dental prosthesis, ortopedic fixation devices, stents

Au and Pt Dental filling

Silver-tin-copper alloy Dental amalgam

Stainless Steel Dental prosthesis, ortopedic fixation devices, stents

Titanium alloys Heart valve, dental prosthesis, joint prosthesis, screws

Metals

Metals: Generally used in hard tissue repair and blood contacting devices

Aluminium oxides Joint prosthesis, orthopedic load-bearing implants, implant coating, dental implants

Bioactive glass Ortopedic and dental implant coatings, dental implants, bone and facial implants

Calcium phosphates Ortopedic and dental implant coatings, dental implants, bone implants and bone fillers

Ceramics

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Ceramics: Generally used in bone and dental-related applications due to compositional similarity – Have similar chemistry and mechanical properties with natural bone

– More often used as a part of orthopedic implant (coating material) due to highwear resistance

– As dental materials (crowns, dentures)

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Poly(HEMA) Contact lensPDMS Brest prosthesis, contact lensPE Ortopedic joint implantsPEG Wound dressingPET Vascular graft, suturePCL Drug release, biodegradable suturePLGA Biodegradable suturePMMA Bone fillerPTFE Vascular graft, suturePP Suture

Alginate Wound dressingChitosan Wound dressing Collagen Tissue engineering scaffoldElastin Skin regeneration matrixFibrin Tissue adhesiveHA and GAG Orhopedic regeneration matrix

Polymers

Sutures

PGA, Vicryl® Nylon

Polymers: Versatile; used for different applications

Surgical Tapes

Artificial Skin

IOL

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Tissue Engineering

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� Isolate cells from the patient

� Produce the scaffold to guide the tissue production

� Seed the cells onto the scaffolds and grow the tissues in bioreactors

� Transplant the tissue engineered graft back to the patient

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CAD/CAM can be used to produce scaffold of the human ear (auricular cartilage) seeded with chondrocytes and cultured in vitro (cell culture) and in vivo (in the animal model)

Biomaterials Related Courses in Our Curriculum

• BME 341 Biomaterials

• BME332 Biomaterials and Biomechanics Lab

• BME441 Cell and Tissue Engineering

• BME447 Introduction to Polymer Engineering

• BME444 Controlled Release Systems and Drug Targeting

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• Group information by next Wednesday!

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