Alginates: Applications in the Biomedical and Food Industries

Alginate is a hydrophilic, biocompatible, biodegradable, and relatively economical polymer generally found in marine brown algae. The modification in the alginate molecule after polymerization has shown strong potential in biomedical, pharmaceutical and biotechnology applications such as wound dressing, drug delivery, dental treatment, in cell culture and tissue engineering. Besides this, alginates have industrial applications too in the paper and food industries as plasticizers and additives. The few books that have been published on alginates focus more on their biology. This current book focuses on the exploration of alginates and their modification, characterization, derivatives, composites, hydrogels as well as the new and emerging applications.

Table of Contents:
Preface xv Part 1: Alginates—Introduction, Characterization and Properties 1 1 Alginates: General Introduction and Properties 3 Rutika Sehgal, Akshita Mehta and Reena Gupta 1.1 Introduction 4 1.2 History 4 1.3 Structure 4 1.4 Alginates and Their Properties 6 1.4.1 Gel Formation 6 1.4.1.1 Ionic Alginate Gels 6 1.4.1.2 Alginic Acid Gels 8 1.4.2 Molecular Weight 8 1.4.3 Solubility and Viscosity 8 1.4.4 Ionic Cross-Linking 9 1.4.5 Chemical Properties 9 1.5 Sources 11 1.6 Biosynthesis of Bacterial Alginate 11 1.6.1 Precursor Synthesis 12 1.6.2 Polymerization and Cytoplasmic Membrane Transfer 13 1.6.3 Periplasmic Transfer and Modification 15 1.6.3.1 Transacetylases 15 1.6.3.2 Mannuronan C 5-Epimerases 16 1.6.3.3 Lyases 16 1.6.5 Export through the Outer Membrane 16 1.7 Conclusion 16 Acknowledgment 17 Conflict of Interests 17 References 17 2 Alginates Production, Characterization and Modification 21 Pintu Pandit, T. N. Gayatri and Baburaj Regubalan 2.1 Introduction 22 2.2 Alginate: Production 24 2.2.1 Screening of Alginate-Producing Microbes 24 2.2.2 Production of Alginate by Bacteria 25 2.2.3 Production of Alginate by Pseudomonas 26 2.2.4 Production of Alginate by Azotobacter spp. 26 2.2.5 Influence of Medium Components 26 2.2.5.1 Effect of Nutrients on Bacterial Alginate Production 26 2.2.5.2 Effect of Phosphate on Bacterial Alginate Production 27 2.2.5.3 Effect of Dissolved Oxygen on Bacterial Alginate Production 27 2.2.5.4 Effect of Agitation in the Medium for the Production of Alginate 27 2.2.6 Commercial Production of Alginate 28 2.3 Characterization of Physicochemical Properties of Alginate 28 2.3.1 Composition of Alginate Polymer Chains 29 2.3.2 XRD, FTIR, and NMR Spectroscopy for Alginate Structure Analysis 31 2.3.3 Rheology and Mechanical Characterization of Alginate Gels and Solutions 32 2.4 Modification of Alginates 33 2.4.1 Chemical Modification 33 2.4.2 Oxidation 34 2.4.3 Sulfation 34 2.4.4 Phosphorylation 35 2.4.5 Graft Copolymerization 35 2.4.6 Esterification 35 2.4.7 Carbodiimide Coupling 36 2.4.8 Covalent Cross-Linking 36 2.5 Future Perspectives 38 2.6 Conclusions 39 References 39 3 Alginate: Recent Progress and Technological Prospects 45 Tanvir Arfin and Kamini Sonawane 3.1 Introduction 45 3.2 Structure 46 3.3 Sources 47 3.4 Characteristics of Alginate Salts 48 3.5 Properties 48 3.6 Applications 50 3.7 Future Perspectives 53 3.8 Advantages 54 3.9 Disadvantages 54 3.10 Conclusion 54 Acknowledgments 55 References 55 4 Alginate Hydrogel and Aerogel 59 Ajith James Jose, Kavya Mohan and Alice Vavachan 4.1 Introduction 59 4.2 Alginate Hydrogel 60 4.2.1 Preparation of Alginate Hydrogels 61 4.2.1.1 Ionic Cross-Linking 62 4.2.1.2 Covalent Cross-Linking 62 4.2.1.3 Thermal Gelation 62 4.2.1.4 Cell Cross-Linking 63 4.2.2 Biomedical Applications 63 4.2.2.1 Pharmaceutical Applications 63 4.2.3 Tissue Regeneration with Protein and Cell Delivery 68 4.2.3.1 Blood Vessels 68 4.2.3.2 Bones 69 4.2.3.3 Cartilage 69 4.2.3.4 Muscle, Nerve, Pancreas, and Liver 70 4.3 Alginate Aerogel 70 4.3.1 Properties of Alginate Aerogels 71 4.3.1.1 Bulk Density and Pore Volume 71 4.3.1.2 Specific Surface Area 71 4.3.1.3 Compressibility 71 4.3.1.4 Thermal Conductivity and Absorption 72 4.3.2 Preparative Methods 72 4.4 Future Perspectives 73 References 73 Part 2: Alginates in Biomedical Applications 79 5 Alginate in Biomedical Applications 81 Luiz Pereira da Costa 5.1 Introduction 81 5.2 Chemical Structure and Properties of Alginate 83 5.3 Types of Interaction of Alginate 84 5.4 Biomedical Application of Alginates 87 5.5 Future Perspective of the Use and Biomedical Applications 90 References 90 6 Alginates in Pharmaceutical and Biomedical Application: A Critique 95 Vivek Dave, Kajal Tak, Chavi Gupta, Kanika Verma and Swapnil Sharma 6.1 Introduction 95 6.2 Structure of Alginate 96 6.3 Different Types of Alginates Used in Pharmaceutical Industries 97 6.4 Properties of Alginate 98 6.5 Pathway for the Biosynthesis of Alginate 98 6.6 Regulatory Consideration of Alginate 100 6.7 Applications 100 6.7.1 Other Applications 113 6.8 Conclusion 114 References 115 7 Alginates in Evolution of Restorative Dentistry 125 S.C. Onwubu, P.S. Mdluli, S. Singh and Y. Ngombane 7.1 Introduction 125 7.2 Method of Alginate Extraction 126 7.3 Evolution of Alginate in Restorative Dentistry 128 7.3.1 Problems with Conventional Alginate 129 7.3.2 Current Trends and Modification of Alginate 129 7.3.2.1 Extended Pour Time Alginate 130 7.3.2.2 Dust-Free Alginates 130 7.3.2.3 Infection-Free Alginates 132 7.3.2.4 High Viscosity Alginates 132 7.3.2.5 Alginates in Two Pastes Form 133 7.3.2.6 Tray Adhesive Alginates 133 7.4 The Art of Impression Taking Using Alginates 133 7.4.1 Selection of Impression Trays 134 7.4.2 Mixing and Loading Alginates 135 7.4.3 Preparation of the Oral Cavity before Impression Taking 135 7.4.4 Impression Taking Using Alginate Material 136 7.4.5 Removal and Inspection of Alginate Material 137 7.4.6 Effects of Cast Production Techniques 137 7.5 Conclusions 138 References 138 8 Alginates in Drug Delivery 141 Srijita Basumallick 8.1 Introduction 141 8.2 Chemistry of Alginates 142 8.2.1 Hydrogel Formation by Alginates 143 8.2.1.1 Preparation of Hydrogel 143 8.3 Pharmaceutical and Biomedical Chemistry of Alginates 144 8.3.1 Factors Governing Drug Encapsulation and Drug Delivery Processes 145 8.3.1.1 Delivery and Encapsulation of Small Drugs 145 8.3.1.2 Macromolecular Drug Delivery by Alginates 148 8.4 Conclusions 149 Acknowledgments 149 References 149 9 Alginate in Wound Care 153 Satyaranjan Bairagi and S. Wazed Ali 9.1 Introduction 154 9.2 Sources and Synthesis of Alginate 154 9.3 Physicochemical Properties of the Alginate Biopolymer 156 9.4 Biomedical Applications of Alginate 157 9.4.1 Alginate in Wound Care 158 9.4.1.1 Pure Alginate Polymer-Based Wound Dressing 160 9.4.1.2 Intercellular Mediators Incorporated Alginate Polymer-Based Wound Dressing 160 9.4.1.3 Zinc/Alginate- and Silver/Alginate-Based Wound Dressing 161 9.4.1.4 Chitosan/Alginate- and Collagen/Alginate-Based Wound Dressing 163 9.4.1.5 Alginate Fiber-Based Wound Dressing 163 9.4.1.6 Alginate Hydrogel-Based Wound Dressing 167 9.5 Opportunities and Future Thrust 172 References 173 10 Alginate-Based Biomaterials for Bio-Medical Applications 179 Reena Antil, Ritu Hooda, Minakshi Sharm and Pushpa Dahiya 10.1 Introduction 180 10.2 Alginate: General Properties 180 10.2.1 Chemical Properties, Structure, and Characterization 181 10.3 Extraction and Preparation 182 10.3.1 Gelation and Cross-Linking of Alginate 183 10.3.2 Ionic Cross-Linking 184 10.3.3 External Gelation 184 10.3.4 Internal Gelation 185 10.3.5 Covalent Cross-Linking 185 10.3.6 Large Bead Preparation 186 10.3.7 Microbead Preparation 186 10.4 Alginate Hydrogels 187 10.5 Photocross-Linking 188 10.6 Shape-Memory Alginate Scaffolds 188 10.7 Biodegradation of Alginate 189 10.8 Biomedical Application of Alginates 190 10.8.1 Controlled Chemical and Protein Drug Delivery 190 10.8.2 Wound/Injury Dressings 193 10.8.3 Cell Culture 194 10.8.4 Tissue Regeneration 195 References 196 Part 3: Alginates in Food Industry 205 11 Alginates for Food Packaging Applications 207 Radhika Theagarajan, Sayantani Dutta, J.A. Moses and C. Anandharamakrishnan 11.1 Introduction 207 11.2 Biopolymer in Food Industry 208 11.3 Alginates in Food Packaging 209 11.4 Biosynthesis of Alginate 213 11.5 Application of Alginate in Formation of Biofilm 215 11.5.1 Preparation of Packaging Films 215 11.5.2 Role of Alginate in Biofilm Formation 215 11.6 Packaging Properties of Alginate 217 11.6.1 Thermostability of Alginate Packaging 218 11.6.2 Water Solubility 218 11.6.3 Water Vapor Permeability 218 11.6.4 Tensile Strength 218 11.6.5 Oxygen Permeability 219 11.6.6 Barrier Property 219 11.6.7 Antimicrobial Activity 219 11.7 Effect of Alginate on the Quality of Food 222 11.8 Interaction between Food and Alginates 223 11.9 Environmental Effects on Alginate Packaging 224 11.10 Market Outlook 224 11.11 Conclusion 225 References 226 12 Potential Application of Alginates in the Beverage Industry 233 S. Vijayalakshmi, S.K. Sivakamasundari, J.A. Moses and C. Anandharamakrishnan 12.1 Introduction 233 12.2 Alginate Source 234 12.3 Extraction of Alginates 235 12.4 Physical, Chemical and Functional Properties of Alginate 236 12.5 Uses as a Food Additive/Ingredient 241 12.6 Alginate as Stabilizer 245 12.7 As Encapsulating Wall Material 247 12.7.1 Immobilization of Biocatalysts 249 12.7.2 Probiotics 250 12.7.3 Improvement of the Alginate Encapsulation: Prebiotics Addition 253 12.8 Conclusion 254 References 254 13 Alginates in Comestibles 263 Ashwini Ravi, S. Vijayanand, Velu Rajeshkannan, S. Aisverya, K. Sangeetha, P.N. Sudha and J. Hemapriya 13.1 Introduction 264 13.2 Alginates in Agricultural Marketing 265 13.3 Use of Alginates in Food Industry 266 13.3.1 Thickeners and Gelling Agents 267 13.3.2 Stabilizers and Emulsifiers 268 13.3.3 Texturizers 269 13.3.4 Encapsulation 269 13.3.5 Food Coating 270 13.4 Use of Alginates for Pets 271 13.5 Effect of Dietary Alginates 271 13.6 Alginate Safety 272 13.7 Conclusion 272 References 272 Part 4: Alginates Future Prospects 281 14 Alginates: Current Uses and Future Perspective 283 Ashwini Ravi, S. Vijayanand, G. Ramya, A. Shyamala, Velu Rajeshkannan, S. Aisverya, P.N. Sudha and J. Hemapriya 14.1 Introduction 284 14.2 Sources of Alginate Synthesis 285 14.2.1 Brown Seaweeds 285 14.2.2 Bacteria 287 14.3 Synthesis of Alginate 288 14.3.1 Alginate Biosynthesis Gene 289 14.4 Properties of Alginates 290 14.4.1 Molecular Weight 290 14.4.2 Solubility 291 14.4.3 Stability 291 14.4.4 Ionic Binding Property 292 14.4.5 Gel Formation Ability 293 14.4.6 Biological Properties 293 14.5 Application of Alginates 294 14.6 Future Perspectives of Alginates 295 14.6.1 3D-Based Cell Culture Systems 295 14.6.2 Impressions 296 14.6.3 Cell-Based Microparticles 296 14.6.4 Alginate Oligosaccharides 298 14.6.5 Drug Targeting 299 14.6.6 Nanoparticulate Systems 300 14.7 Conclusion 300 References 300 Index 313

About the Author :
Shakeel Ahmed is an Assistant Professor at the Department of Chemistry, Government Degree College Mendhar, Jammu and Kashmir, India. He obtained his PhD in the area of biopolymers and bionanocomposites and has published several research publications in the area of green nanomaterials and biopolymers for various applications including biomedical, packaging, sensors, and water treatment. He has edited or co-edited 4 books for Wiley-Scrivener.