Influence of the Processes Parameters on the Properties of The ...

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Chapter 1. Polylactide Based Bio-Materials role for transplantation in <strong>the</strong> coming era. Polylactides are currently used in a number <strong>of</strong> biomedical applications, such as sutures, stents, dialysis media and drug delivery devices. Also polylactides are used for tissue, cartilage and bone regeneration. Hyaluronic acid is hydrophilic in nature and using it with polylactide will enhance <strong>the</strong> surface adhesion property <strong>of</strong> <strong>the</strong> scaffold produced. As a result it will augment <strong>the</strong> adhesion, differentiation and proliferation <strong>of</strong> human cell on <strong>the</strong> scaffold to be transplanted. Tri-calcium phosphate is added as mineral in <strong>the</strong> polymer matrix to increase <strong>the</strong> mechanical properties <strong>of</strong> <strong>the</strong> scaffold. The percentage <strong>of</strong> TCP added depends upon <strong>the</strong> nature and mechanical property <strong>of</strong> scaffold required to be transplanted. - 26 -
Chapter 2 Chapter 2 <strong>Processes</strong> to Manufacture Foams and to Functionalize <strong>the</strong> Surface Tissue engineering <strong>of</strong>fers an alternative technique to tissue transplantation for diseased or malfunctioned organs. Adequate porosity and equivalent pore size as well as interconnected pore structure are crucial to allow for easy dispersion <strong>of</strong> cells throughout <strong>the</strong> scaffold structure. Scaffold structure is directly related to fabrication methods, which are presented in this chapter one by one. We adopted <strong>the</strong> technique using supercritical CO 2 in our experiments. This process is a green technology which provides adequate porosity and pore size with no loss <strong>of</strong> bioactive mass in <strong>the</strong> scaffold matrix. The surface and mechanical properties <strong>of</strong> <strong>the</strong> scaffold will be enhanceed by adapting <strong>the</strong> mixing and co-grinding <strong>of</strong> polymer matrix with surface modifier and filler. Hyaluronic acid (HA) has a number <strong>of</strong> potential biomedical applications in drug delivery and tissue engineering. By co-grinding, it coats <strong>the</strong> surface <strong>of</strong> polylactide and being hydrophilic in nature thus improves <strong>the</strong> adhesion energy <strong>of</strong> <strong>the</strong> polymer matrix. Similarly filler having higher mecahnical properties than polymer enhance <strong>the</strong> modulus and strength <strong>of</strong> matrix. 1 Generalities on Polymer Foams The production <strong>of</strong> polymeric-foam materials can be carried out by ei<strong>the</strong>r mechanical, chemical, or physical means. Some <strong>of</strong> <strong>the</strong> most commonly used methods are <strong>the</strong> following [Landrock, 1995]: Thermal decomposition <strong>of</strong> chemical blowing agents generating ei<strong>the</strong>r nitrogen or carbon dioxide, or both, by application <strong>of</strong> heat, or as <strong>the</strong> result <strong>of</strong> <strong>the</strong> exo<strong>the</strong>rmic heat <strong>of</strong> reaction during polymerization. Mechanical whipping <strong>of</strong> gases (frothing) into a polymer system (melt, solution or suspension) which hardens, ei<strong>the</strong>r by catalytic action or heat, or both, thus entrapping <strong>the</strong> gas bubbles in <strong>the</strong> polymer matrix. Volatilization <strong>of</strong> low-boiling liquids such as fluorocarbons or methylene chloride within <strong>the</strong> polymer mass as <strong>the</strong> result <strong>of</strong> <strong>the</strong> exo<strong>the</strong>rmic heat <strong>of</strong> reaction, or by application <strong>of</strong> heat. Volatilization <strong>of</strong> gases produced by <strong>the</strong> exo<strong>the</strong>rmic heat <strong>of</strong> reaction during polymerization such as occurs in <strong>the</strong> reaction <strong>of</strong> isocyanate with water to form carbon dioxide. - 27 -
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Institut National Polytechnique de
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iii Dedicated to My Fathe</
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pleased I was to work with all memb
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Publications and Conferences The wo
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