Natural-Based Polymers for Biomedical Applications

Natural origin biopolymers are attractive for use in biomedical applications, partly due to their biocompatibility and degradation characteristics. This book comprehensively reviews this important subject in six in-depth sections. Part 1 discusses the sources, properties, modification and processing of natural-based polymers, whilst in the second section surface aspects are reviewed. Parts 3 and 4 cover natural-origin materials for tissue engineering and regenerative medicine, discussing scaffolds, hydrogels and injectable systems. The sustained release of molecules is reviewed in the fifth part of the book, followed by the biocompatibility of natural-based polymers in the final book section.

PART 1 SOURCES, PROPERTIES, MODIFICATION AND PROCESSING OF NATURAL-BASED POLYMERS

Polysaccharides as carriers of bioactive agents for medical applications
P Pawar, W Jadhav, S Bhusare and R Borade, Dnyanopasak College, India, S Farber, D Itzkowitz and A Domb, The Hebrew University, Jerusalem, Israel
Introduction. Starch. Cellulose. Heparinoid (sulfated polysaccharides). Dextran. Pectin. Arabinogalactan. Drug conjugated polysaccharides. Dextrans. Mannan. Pullulan. Polysaccharides macromolecule-protein conjugates. Cationic polysaccharides for gene delivery. Diethylaminoethyl-dextran. Polysaccharide-oligoamine based conjugates. Chitosan. Applicatons of polysaccharides as drug carriers. Applications of dextran conjugates. Site-specific drug delivery. Pectin drug site specific delivery. Liposomal drug delivery. References.

Purification of naturally occurring biomaterials
S Raghava and M Gupta, Indian Institute of Technology Delhi, India
Introduction. Classes of naturally occurring biomaterials. Downstream processing of small molecular weight natural products. Purification strategies for proteins. Purification of lipids. Purification of polysaccharides. Purification of nucleic acids. Purification of complex biomaterials. Future trends. Sources of further information. Acknowledgements. References.

Processing of starch-based blends for biomedical applications
R A de Sousa, V Correlo, S Chung, N Neves, J Mano and M Reis, University of Minho, Portugal
Introduction. Starch. Starch based blends. Conclusions. References.

Controlling the degradation of natural polymers for biomedical applications
H Azevedo, T Santos and R Reis, University of Minho, Portugal
Introduction. The importance of biodegradability of natural polymers in biomedical applications. Degradation mechanisms of natural polymers and metabolic pathways for their disposal in the body. Assessing the in vitro and in vivo biodegradability of natural polymers. Controlling the degradation rate of natural polymers. Concluding remarks. Acknowledgements. References.

Smart systems based on polysaccharides
S Raghava and M Gupta, Indian Institute of Technology Delhi, India
What are smart materials? Chitin and chitosan. Alginates. Carrageenans. Other miscellaneous smart polysaccharides and their applications. Polysaccharide-based composite materials. Future trends. Acknowledgement. Sources of further information and advice. References.

PART 2 SURFACE MODIFICATION AND BIOMIMETIC COATINGS

Surface modification of natural-based biomedical polymers
I Pashkuleva, P López-Pérez and R L Reis, University of Minho, Portugal
Introduction. Some terms and classifications. Wet chemistry in surface modification. Physical methods for surface modification. Grafting. Bio-approaches: mimicking the cell-cell interactions. Future trends. Acknowledgments. References.

New biomineralization strategies for the use of natural-based polymeric materials in bone-tissue engineering
I B Leonor, S Gomes, P C Bessa, J F Mano and R L Reis, University of Minho and M Casal, CBMA - Molecular and Environmental Biology Center, University of Minho, Portugal
Introduction. The structure, development and mineralization of bone. Bone morphogenetic proteins in tissue engineering. Bio-inspired calcium-phosphate mineralization from solution. General remarks and future trends. Acknowledgments. References.

Natural-based multilayer films for biomedical applications
C Picart, Université Montpellier, France
Introduction. Physico-chemical properties. Different types of natural-based multilayer films for different applications. Bioactivity, cell adhesion, and biodegradability properties. Modulation of film mechanical properties. Future trends. Sources of further information and advice. References.

Peptide modification of polysaccharide scaffolds for targeted cell signaling
S Lévesque, R Wylie, Y Aizawa and M Shoichet, University of Toronto, Canada
Introduction. Polysaccharide scaffolds in tissue engineering. Peptide immobilization. Measurement. Challenges associated with peptide immobilization. Tissue engineering approaches targeting cell signalling. References.

PART 3 BIODEGRADABLE SCAFFOLDS FOR TISSUE REGENERATION

Scaffolds based on hyaluronan derivatives in biomedical applications
E Tognana, Fidia Advanced Biopolymers s.r.l., Italy
Introduction. Hyaluronan. Hyaluronan-based scaffolds for biomedical applications. Clinical applications. Future trends. Sources of further information and advice. References.

Electrospun elastin and collagen nanofibers and their application as biomaterials
R Sallach and E Chaikof, Emory University/Georgia Institute of Technology, USA
Introduction. Electrospinning as a biomedical fabrication technology. Generation of nanofibers with controlled structures and morphology. Generation of collagen and elastin small-diameter fibers and fiber networks. Biological role of elastin. Generation of crosslinked fibers and fiber networks. Multicomponent electrospun assemblies. Future trends. References.

Starch based scaffold for bone tissue engineering
M Gomes, J T Oliveira, M Rodrigues, M Santos, K Tuzlakoglu, C Viegas, I Diaz and R Reis, University of Minho, Portugal
Introduction. Starch+e-polycaprolactone (SPCL) fiber meshes. SPCL-based scaffold architecture, stem cell proliferation and differentiation. In vivo functionality of SPCL fiber-mesh scaffolds. Cartilage tissue engineering using SPCL fiber-mesh scaffolds. Advanced scaffold design for bone tissue engineering. Nano/micro fiber combined scaffold - innovative architecture. Conclusions. References.

Chitosan-based scaffolds in orthopaedic applications
K Tuzlakoglu and R L Reis, University of Minho, Portugal
Introduction: Chemical and physical structure of chitosan and its derivatives. Production methods for scaffolds based on chitosan and its composites or blends. Orthopaedic applications. Conclusions and future trends. Acknowledgements. References.

Elastin-like systems for tissue engineering
J Rodriguez-Cabello, A Ribeiro, J reguera, A Girotti and A Testera, Universidad de Valladolid, Spain
Introduction. Genetic engineering of protein-based polymers. Genetic strategies for synthesis of protein based polymers. State-of-the-art in genetically-engineered protein-based polymers (GEBPs). Elastin-like polymers. Self-assembly behaviour of peptides and proteins. Self-assembly of elastin-like polymers (ELPs). Biocompatibility of ELPs. Biomedical applications. ELPs for drug delivery. Tissue engineering. Self-assembling properties of ELPs for tissue engineering. Processability of ELPs for tissue engineering. Future trends. References.

Collagen-based scaffolds
G Chen, N Kawazoe and T Tateishi, National Institute for Materials Science, Japan
Introduction. Structure and property of collagen. Collagen sponge. Collagen gel. Collagen–GAG scaffolds. Acellularized scaffolds. Hybrid scaffolds. Future trends. References.

Polyhydroxyalkanoate and its potential for biomedical applications
P Furrer and M Zinn, EMPA and S Panke, Swiss Federal Institute of Technology (ETH), Switzerland
Introduction. Biosynthesis. Chemical digestion of PHA-biomass. Purification of PHA. Potential applications of PHA in medicine and pharmacy. Conclusions and future trends. References.

Electrospinning of natural proteins for tissue engineering scaffolding
P Lelkes, M Li, A Perets, L Lin, J Han and D Woerdeman, Drexel University, USA
Introduction. The electrospinning process. Electrospinning natural animal polymers. Electrospinning blends of synthetic and natural polymers. Electrospinning novel natural ‘green’ plant polymers for tissue engineering. Soy proteins. Corn zein. Wheat gluten. Blends of synthetic and plant proteins. Cellular responses to electrospun scaffolds: does fiber diameter matter? Conclusions and future trends. Sources of further information and advice. References.

PART 4 NATURALLY-DERIVED HYDROGENS: FUNDAMENTALS, CHALLENGES AND APPLICATIONS IN TISSUE ENGINEERING AND REGENERATIVE MEDICINE

Hydrogels from polysaccharide-based materials: fundamentals and applications in regenerative medicine
J T Oliveira and R Reis, University of Minho, Portugal
Introduction: definitions and properties of hydrogels. Applications of hydrogels produced from different polysaccharides in tissue engineering and regenerative medicine. Agarose. Alginate. Carrageenan. Cellulose. Chitin/chitosan. Chondroitin sulphate. Dextran. Gellan. Hyaluronic acid. Starch. Xanthan. Conclusions. References.

Alginate hydrogels as matrices for tissue engineering
H Park and K Lee, Hanyang University, South Korea
Introduction. Properties of alginate. Methods of gelling. Application of alginate hydrogels in tissue engineering. Summary and future trends. References.

Fibrin matrices in tissue engineering
B Tawil, Baxter BioScience, H Duong and B Wu, University of California, USA
Introduction. Fibrin formation. Fibrin use in surgery. Fibrin matrices to deliver bioactive molecules. Fibrin - cell constructs. Mechanical characteristics of fibrin scaffolds. Future trends. Conclusions. References.

Natural based polymers for encapsulation of living cells: fundamentals, applications and challenges
P De Vos, University Hospital of Groningen, The Netherlands
Introduction. Approaches to encapsulation; materials and biocompatibility issues. Physico-chemistry of microcapsules and their biocompatibility. Immunological considerations. Conclusions and future trends. Sources of further information and advice. References.

Hydrogels for neuronal regeneration
A Salgado, N Silva, N Neves, R Reis and N Sousa, University of Minho, Portugal
Introduction. Brief insights on central nervous system biology. Current approaches for SCI repair. Hydrogel based systems in SCI regenerative medicine. Conclusions and future trends. Acknowledgments. References.

PART 5 SYSTEMS FOR THE SUSTAINED RELEASE OF MOLECULES

Particles for controlled drug delivery
E T Baran and R Reis, University of Minho, Portugal
Introduction. Novel particle processing methods. Hiding particles: the stealth principle. Finding the target. Delivery of bioactive agents at the target site and novel deliveries. Viral delivery systems. Conclusions. Acknowledgements. References.

Thiolated chitosans in non-invasive drug delivery
A Bernkop-Schnürch, Leopold-Franzens-University, Austria
Introduction. Thiolated chitosans. Properties of thiolated chitosans. Drug delivery systems. In vivo performance. Conclusions. References.

Chitosan-polysaccharide blended nanoparticles for controlled drug delivery
J M Alonoso and F M Goycoolea, Universidad de Santiago de Compostela, Spain and I Higuera-Ciapara, Centro de Investigación en Alimentación y Desarrallo, Mexico
Introduction. Polysaccharides in nanoparticle formation. Nanoparticles constituted from chitosan. Drug delivery properties and biopharmaceutical applications. Hybrid nanoparticles consisting of chitosan and other polysaccharides. Future trends. Sources of further information and advice. Acknowledgements. References.

PART 6 BIOCOMPATIBILITY OF NATURAL-BASED POLYMERS

In vivo tissue response to natural-origin biomaterials
T Santos, A Marques and R Reis, University of Minho, Portugal
Introduction. Inflammation and foreign-body reactions to biomaterials. Role of host tissues in biomaterials implantation. Assessing the in vivo tissue responses to natural-origin biomaterials. Controlling the in vivo tissue reactions to natural-origin biomaterials. Final Remarks. Acknowledgements. References.

Immunological issues in tissue engineering
N Rotter, University Hospital of Schleswig-Holstein, Germany
Introduction. Immune reactions to biomaterials. Host reactions related to the implant site. Immune reactions to different types of cells. Immune reactions to in vitro engineered tissues. Immune protection of engineered constructs. Strategies directed towards reactions to biomaterials. Strategies directed towards reactions to implanted cells. Future trends. Sources of further information and advice.

Biocompatibility of hyaluronic acid: from cell recognition to therapeutic applications
K Ghosh, Children’s Hospital and Harvard Medical School, USA
Introduction. Native hyaluronan. Therapeutic implications of native hyaluronan. Engineered hyaluronan. Implications for regenerative medicine. Conclusions. Future trends. References.

Biocompatibility of starch-based polymers
A Marques, R Pirraco and R Reis, University of Minho, Portugal
Introduction. Starch-based polymers in the biomedical field. Cytocompatibility of starch-based polymers. Immunocompatibility of starch-based polymers. Conclusions. Acknowledgments. References.

Vascularisation strategies in tissue engineering
M Santos, University of Minho, Portugal
Introduction. Biology of vascular networks - angiogenesis versus vasculogenesis. Vascularization: the hurdle of tissue engineering. Neovascularization of engineered bone. Strategies to enhance vascularization in engineered grafts. In vivo models to evaluate angiogenesis in tissue engineered products. Future trends. Sources of further information and advice. References.