Micro/Nanoporous Micro/Nanoporous Scaffolds for Tissue Scaffolds for Tissue
Engineering Engineering ApplicationsApplications
Department of Chemical Engineering and Department of Chemical Engineering and Materials ScienceMaterials Science
Amrita School of EngineeringAmrita School of Engineering
Coimbatore – 641 105Coimbatore – 641 105
October 2008October 2008
Zeroth ReviewZeroth Review
ByBy
Divya Haridas (CB105PE012)Divya Haridas (CB105PE012)
Karthikeyan G (CB105PE023)Karthikeyan G (CB105PE023)
Krishna Priya C (CB105PE025)Krishna Priya C (CB105PE025)
Premika G (CB105PE028)Premika G (CB105PE028)
GuideGuide
Dr. Murali Rangarajan. Ph.DDr. Murali Rangarajan. Ph.D
Co-GuideCo-Guide
Dr. Nikhil K Kothurkar. Ph.DDr. Nikhil K Kothurkar. Ph.D
Motivation of Tissue Motivation of Tissue EngineeringEngineering
… … Today around 80000 Indians are waiting for Today around 80000 Indians are waiting for Organ / Tissue TransplantationOrgan / Tissue Transplantation
Many children suffer from crippling diseases and Many children suffer from crippling diseases and deformities deformities
Current therapies like bone grafting has many Current therapies like bone grafting has many limitations limitations additional cost of the harvesting procedureadditional cost of the harvesting procedure pain and infection at the harvesting sitepain and infection at the harvesting site
Concept of Tissue EngineeringConcept of Tissue Engineering
Life science and Life science and Engineering dealing Engineering dealing with the with the development of development of biological biological substitutes that substitutes that restore, maintain restore, maintain and improve tissue and improve tissue functions or a whole functions or a whole organorgan
Polymeric ScaffoldsPolymeric Scaffolds Three dimensional Three dimensional
scaffolds play important scaffolds play important roles as extracellular roles as extracellular matrices onto which matrices onto which cells can attach, grow, cells can attach, grow, and form new tissuesand form new tissues
Modeling, design and Modeling, design and fabrication of scaffolds fabrication of scaffolds are always a difficult are always a difficult task in the regenerative task in the regenerative tissue engineeringtissue engineering
Scaffolds – Bone FormationScaffolds – Bone Formation
Scaffold ConsiderationsScaffold Considerations
Matrix Material CharacteristicsMatrix Material Characteristics Bioactive and Biocompatible Bioactive and Biocompatible
Slow degradabilitySlow degradability For stable scaffold morphologyFor stable scaffold morphology For homogeneity of new tissuesFor homogeneity of new tissues
High Porosity & interconnectivityHigh Porosity & interconnectivity To minimize the amount of implanted polymer To minimize the amount of implanted polymer To increase specific surface area for cell attachment & To increase specific surface area for cell attachment &
tissue in growthtissue in growth
Scaffold ConsiderationsScaffold Considerations
Pore Size Pore Size 150 – 500 150 – 500 µµm for bones, < 50 m for bones, < 50 µµm for organsm for organs
3D Pore architecture3D Pore architecture Allows for cell attachment , proliferation and Allows for cell attachment , proliferation and
differentiationdifferentiation Provides pathways for bio-fluids Provides pathways for bio-fluids Pore architecture influences mechanical strengthPore architecture influences mechanical strength
Tailoring possibilities Tailoring possibilities Controllable pore size, porosityControllable pore size, porosity Control of matrix designControl of matrix design
Fabrication TechniquesFabrication Techniques
Electrospinning - Electrospinning - High voltage electrostatic field is High voltage electrostatic field is applied to polymer solution to form non-woven scaffold applied to polymer solution to form non-woven scaffold fibersfibers
Solid Freeform Fabrication - Solid Freeform Fabrication - 3D scaffold is constructed 3D scaffold is constructed from 2D layers (CAD/CAM methodologies) using 3D from 2D layers (CAD/CAM methodologies) using 3D positioning system and extrusion headpositioning system and extrusion head
Fiber Bonding - Fiber Bonding - Polymer fibers are immersed in polymer Polymer fibers are immersed in polymer solution. On heating, the fibers weld together and polymer solution. On heating, the fibers weld together and polymer melts and fills the voids. Removal of polymer results in melts and fills the voids. Removal of polymer results in porous scaffoldporous scaffold
Fabrication TechniquesFabrication Techniques
Phase Separation - Phase Separation - A homogeneous multi-component A homogeneous multi-component system phase separates (polymer rich - polymer lean system phase separates (polymer rich - polymer lean phase) under certain conditions. Removal of solvent results phase) under certain conditions. Removal of solvent results in solidification of polymer rich phase which forms porous in solidification of polymer rich phase which forms porous scaffoldscaffold
Solvent Casting and Particulate Leaching - Solvent Casting and Particulate Leaching - Polymer Polymer solution is cast into the particle assembly (salt, paraffin). solution is cast into the particle assembly (salt, paraffin). Vacuum is applied to evaporate the solvent. Particles are Vacuum is applied to evaporate the solvent. Particles are leached using solvent. Pore architecture resembles the leached using solvent. Pore architecture resembles the particles particles
Technique Advantages Disadvantages
ElectrospinningGood mechanical
strength, highly porous structure
Costly process, poor control over internal
architecture
Solid Freeform Fabrication
Good mechanical strength, solvent free
High processing temperature
Fiber Bonding High porosityLimited range of
polymer, Residual solvent, lack mechanical
strength
Phase SeparationHighly porous
structure, permit incorporation of bioactive agents
Poor internal architecture, limited range of pore size
Solvent Casting/Particulate
Leaching
Large range of pore size, good control of
porosity and pore size
Poor control over internal architecture
Focus of the ProjectFocus of the Project
Preparation of Scaffold from the feasible Preparation of Scaffold from the feasible Fabrication TechniqueFabrication Technique
Incorporation of Hydroxyapatite for Bone Tissue Incorporation of Hydroxyapatite for Bone Tissue Engineering ApplicationEngineering Application
Characterization of Fabricated ScaffoldsCharacterization of Fabricated Scaffolds
Modeling and Simulation of HAp incorporated Modeling and Simulation of HAp incorporated ScaffoldsScaffolds
MethodologyMethodology
Step 1Step 1
Identification of Fabrication MethodIdentification of Fabrication Method
The Particulate Leaching method is identified The Particulate Leaching method is identified through Literature Survey during August – through Literature Survey during August – September 2008 by considering the constraints September 2008 by considering the constraints like do-ability in the Institution, with limited like do-ability in the Institution, with limited financial resources, in limited timefinancial resources, in limited time
MethodologyMethodology
Step 2Step 2
Fabrication of Scaffolds by Particulate Leaching Fabrication of Scaffolds by Particulate Leaching TechniqueTechnique
Preparation of Solid Paraffin
Spheres
Ma PX, Ji-Won Choi. Biodegradable Polymer Scaffolds with Well Defined Interconnected Spherical Pore Network. Tissue Engineering 2001;7(1):23-33.
MethodologyMethodology
Step 2Step 2
Fabrication of Scaffolds by Particulate Leaching Fabrication of Scaffolds by Particulate Leaching TechniqueTechnique
Preparation ofPolymer Foam
Ma PX, Ji-Won Choi. Biodegradable Polymer Scaffolds with Well Defined Interconnected Spherical Pore Network. Tissue Engineering 2001;7(1):23-33.
MethodologyMethodology
Step 3Step 3
Incorporation of Hydroxyapatite and fabricating Incorporation of Hydroxyapatite and fabricating ScaffoldsScaffolds
The major mineral phase in the bone is The major mineral phase in the bone is Hydroxyapatite. Incorporating them in Polymer Hydroxyapatite. Incorporating them in Polymer Scaffolds offers bone regeneration potentialScaffolds offers bone regeneration potential
Literature Survey on HAp incorporation in Literature Survey on HAp incorporation in Polymeric Scaffolds and its fabricationPolymeric Scaffolds and its fabrication
MethodologyMethodology
Step 4Step 4
CharacterizationCharacterization
Density Density PorosityPorosity Morphology to be studied using SEMMorphology to be studied using SEM Compressive Modulus using a Mechanical TesterCompressive Modulus using a Mechanical Tester
MethodologyMethodology
Step 5Step 5
Modeling and SimulationModeling and Simulation
To study the kinetics of Hydroxyapatite (HAp) To study the kinetics of Hydroxyapatite (HAp) incorporationincorporation
Physical /chemical absorption of HApPhysical /chemical absorption of HAp
Resulting morphology changes in scaffoldResulting morphology changes in scaffold
Project CalendarProject Calendar
Aug
Sep Oct Nov
Dec Jan Feb Mar
Apr
Literature Survey
Materials Purchase
Experimental Process
HAp Incorporation
Characterization
Modeling and Simulation
Final Report
Thank youThank you