Alginate Fibers and Wound Dressings

Yimin Qin, PhD, is Professor at Jiaxing University, China and is also the director of State Key Laboratory of Bioactive Seaweed Substances at Qingdao Brightmoon Seaweed Group, where his main research interests focused on the extraction, purification, modification and applications of alginate and other novel bioactive seaweed substances.

• Author Biography xiiiPreface xv1 The Extraction of Alginate from Brown Seaweeds 11.1 Introduction 11.2 Global Distribution of Brown Seaweeds 21.3 The Extraction of Alginate from Brown Seaweeds 61.3.1 General Description of the Extraction Process 61.3.2 A Comparison of Alginic Acid Method and Calcium Alginate Method 91.3.3 Process Control 91.3.4 Key Process Parameters 101.3.4.1 Size Reduction of Raw Materials 101.3.4.2 Acid Treatment 101.3.4.3 Formaldehyde Treatment 121.3.4.4 Alkaline Extraction 121.3.4.5 Separation of Alginate from Insoluble Seaweed Residue 121.4 Ultrapure Alginate 141.5 Summary 15References 15Further Reading 172 Chemical, Physical, and Biological Properties of Alginic Materials 192.1 Introduction 192.2 The Chemical Structure of Alginic Acid 192.2.1 Early Studies and Basic Structural Feature 192.2.2 M/G Ratio and Distribution 202.2.3 C-5 Epimerization and Designer Alginate 212.2.4 Molecular Weight and Distribution 222.2.5 Chemical Stability 222.3 Physical Properties of Alginic Materials 242.4 Viscosity of Alginate Solutions 262.4.1 Effect of Molecular Weight on Solution Viscosity 262.4.2 Effect of Concentration on Solution Viscosity 272.4.3 Effect of Temperature on Solution Viscosity 282.4.4 Effect of Shear Rate on Solution Viscosity 282.4.5 Effect of Salt on Solution Viscosity 282.4.6 Effect of pH on Solution Viscosity 292.5 Polyelectrolyte Properties 292.6 The Ion-Exchange Properties of Alginate 292.7 Gelling Properties of Alginate 312.8 Film-Forming Properties 322.9 Fiber-Forming Properties 332.10 Bioactivities of Alginic Materials 332.10.1 Enzyme Inhibition Activities of Alginate 332.10.2 Biocompatibility and Cell Activities of Alginate 342.11 Summary 35References 353 Industrial Applications of Alginic Materials 393.1 Introduction 393.2 Functional Properties of Alginic Material 393.2.1 Alginate as a Thickening Agent 393.2.2 Alginate as a Gelling Agent 403.2.3 Alginate as a Film-Forming Agent 403.2.4 Alginate as a Stabilizer 413.2.5 Alginate for Encapsulation and Immobilization 413.3 Industrial Applications of Alginate 423.3.1 Food Ingredients 423.3.2 Medical and Pharmaceutical Uses 443.3.2.1 Dental Impression 443.3.2.2 Therapeutic Cell Entrapment 453.3.2.3 Controlled Release of Drugs 453.3.2.4 Alginate Oligoelectrolytes as a Mucin Polymer Network Modifier 453.3.2.5 Oligoguluronates as Modifiers of Cystic Fibrosis Mucus 453.3.3 Wound Dressings and Hemostatic Agent 463.3.4 Immobilization of Biocatalysts 463.3.5 Controlled Release of Active Agents 483.3.6 Textile Printing Paste 483.3.7 Sizing Agent for Paper 483.3.8 Coating for Welding Rods 493.3.9 Binders for Fish Feed 503.3.10 Biostimulants 503.4 Summary 50References 514 The Production of Fibers From Alginate 574.1 Introduction 574.2 The Properties of Alginate as a Fiber-Forming Polymer 584.3 Preparation of the Spinning Solutions 604.3.1 Molecular Weight of the Alginate Powder 604.3.2 Concentration of the Spinning Solution 614.3.3 Temperature of the Spinning Solution 614.3.4 pH of the Spinning Solution 614.4 The Production of Calcium Alginate Fibers 614.5 The Production of Calcium Sodium Alginate Fibers 654.6 The Production of Sodium Alginate Fibers 664.7 The Production of Alginic Acid Fibers 684.8 The Production of Zinc Alginate Fibers 694.9 The Production of Alginate Fibers Containing Pectin and Carboxymethyl Cellulose 694.10 The Production of Silver-Containing Alginate Fibers 714.11 The Production of Other Novel Alginate Fibers 734.12 Historical Development of Alginate Fibers 764.13 Summary 78References 785 Ion-Exchange and Gel-Forming Properties of Alginate Fibers 835.1 Introduction 835.2 Characterization Methods for Ion Exchange and Gel Forming Properties 835.3 Ion-Exchange Properties of Alginate Fibers 865.3.1 Ion-Exchange Between Calcium Alginate Fibers and Sodium Ions 865.3.2 Ion-Exchange Between Alginate Fibers and Zinc Ions 875.3.3 Ion-Exchange Between Alginate Fibers and Copper Ions 915.4 Gelling Properties of Alginate Fibers 945.5 Summary 98References 996 Applications of Alginate Fibers as Smart Woundcare Materials 1016.1 Introduction 1016.2 Functional Requirements of the Wound Dressings 1036.3 Modern Advanced Wound Dressings 1066.3.1 Chitin and Chitosan Fibers and Wound Dressings 1076.3.2 Superabsorbent Cellulosic Fibers 1086.3.3 Polyurethane Film and Foam 1096.3.4 Hydrogels 1106.3.5 Hydrocolloids 1116.3.6 Activated Carbon 1126.3.7 Low Adherent Dressings 1136.3.8 Composite Wound Care Products 1146.3.9 Antimicrobial Wound Dressings 1166.3.10 Interactive Dressings 1176.3.11 Tissue-Engineered “Skin Equivalents” 1176.3.12 Cell-Containing Matrices 1176.4 Applications of Alginate Fibers in Functional Wound Dressings 1186.5 Development of Alginate Wound Dressings 1196.6 Summary 121References 123Further Reading 1247 Absorption and Interactive Properties of Alginate Wound Dressings 1257.1 Introduction 1257.2 Characterization Methods 1267.2.1 Test on Absorbency 1267.2.2 Fiber Calcium and Sodium Contents 1277.2.3 Gel Swelling 1277.2.4 Wet Integrity 1277.2.5 Wicking Behavior 1277.2.6 Dry and Wet Strength 1287.3 Absorption of Wound Fluid by Alginate-Based Wound Dressings 1287.3.1 Absorption Mechanism of Alginate Wound Dressings 1287.3.2 Absorbency of the Various Types of Alginate Wound Dressings 1297.3.3 Fluid Retention Between Fibers and Inside Fibers 1307.3.4 A Comparison of Absorption Properties Between Alginate Felt and Rope 1317.3.5 Effect of Sterilization on the Absorption Properties of Alginate Dressings 1317.3.6 Effect of Guluronate and Mannuronate Contents 1327.3.7 Effect of Calcium and Sodium Contents 1337.3.8 Effect of Nonwoven Structures 1337.3.9 Effect of Adding CMC Into the Alginate Fibers 1347.3.10 Wicking of Fluid 1357.3.11 Dry and Wet Strength 1377.4 Interactive Properties of Alginate Wound Dressings 1387.4.1 Interactive Moisture Handling Properties of Alginate Wound Dressings 1387.4.2 Biologically Interactive Properties of Alginate Wound Dressings 1387.4.3 Enzyme Inhibition Properties of Alginate Wound Dressings 1397.5 Summary 142References 1438 Clinical Applications of Alginate Wound Dressings 1458.1 Introduction 1458.2 Biocompatibility and Bioactivities of Alginate Wound Dressings 1458.3 Wound Healing Mechanisms of Alginate Wound Dressings 1478.4 Clinical Applications of Alginate Wound Dressings 1488.4.1 Applications of Alginate Wound Dressings in Pressure Ulcers 1498.4.2 Applications of Alginate Wound Dressings in Leg Ulcers 1498.4.3 Applications of Alginate Wound Dressings in Diabetic Foot Ulcers 1518.4.4 Applications of Alginate Wound Dressings in Burn Wounds and Donor Sites 1518.4.5 Applications of Alginate Wound Dressings as a Hemostatic Agent for Bleeding Wounds 1548.4.6 Applications of Alginate Wound Dressings in Surgical Wounds 1568.4.7 Applications of Alginate Wound Dressings in Nose Surgery 1588.4.8 Applications of Alginate Wound Dressings in Anal Fistula Surgery 1598.4.9 Applications of Alginate Wound Dressings in Cavity Wounds 1608.4.10 Applications of Alginate-Based Composite Wound Dressings 1608.5 Main Properties of Alginate Wound Dressings 1608.5.1 Wound-Healing Promotion 1618.5.2 The Hemostatic Properties of Alginate Wound Dressing 1628.5.3 Pain Relief Properties of Alginate Wound Dressing 1628.5.4 The Antimicrobial Properties of Alginate Wound Dressing 1638.5.5 Alginate Wound Dressings as Cavity Filler 1638.5.6 Cost-Effectiveness of Alginate Wound Dressings 1638.6 Summary 163References 1639 Functional Modifications of Alginate Fibers and Wound Dressings 1699.1 Introduction 1699.2 Chemical Modification of Alginic Acid 1699.2.1 Chemical Modification of the Hydroxyl Groups 1709.2.1.1 Oxidation 1709.2.1.2 Reductive-Amination of Oxidized Alginate 1719.2.1.3 Sulfation 1729.2.1.4 Cyclodextrin-Linked Alginate 1729.2.1.5 Acetylation of Alginate 1729.2.1.6 Phosphorylation of Alginates 1739.2.2 Chemical Modification of the Carboxyl Groups 1739.2.2.1 Esterification 1739.2.2.2 Amidation 1749.2.3 Other Chemical Modifications 1759.2.3.1 Organic Soluble Derivative of Alginate 1759.2.3.2 Attachment of Cell Signaling Molecules 1759.2.3.3 Covalent Cross-linking of Alginates 1769.2.3.4 Graft Copolymerization of Alginates 1779.3 Innovations in the Fiber-Making Process 1789.3.1 The Production of Alginate Fibers Containing Metal Ions and Inorganic Compounds 1799.3.2 The Production of Polyblend Fibers of Alginate and Other Polymers 1809.3.3 The Production of Alginate Fibers Through Electrospinning 1809.3.4 The Production of Alginate Fibers Containing Drugs 1829.3.5 The Production of Alginate and Chitosan Composite Fibers 1839.4 Summary 185References 18610 Silver-Containing Alginate Fibers and Wound Dressings 19310.1 Introduction 19310.2 Antimicrobial Efficacy of Silver 19410.3 Development of Silver-Containing Wound Dressings 19510.4 Applications of Silver in Alginate Fibers and Wound Dressings 19710.4.1 Types of Silver Compounds Used in Wound Dressings 19710.4.2 Methods for Adding Silver to Wound Dressings 19810.4.3 Examples of Silver-Containing Wound Dressings 19910.4.3.1 Acticoat from Smith & Nephew 19910.4.3.2 Silvercel from Johnson & Johnson 19910.4.3.3 Aquacel Ag from ConvaTec 20010.4.3.4 Contreet Foam from Coloplast 20010.4.3.5 Silverlon from Argentum Medical 20010.4.3.6 SilvaSorb from Medline 20010.4.3.7 Urgotul SSD from Laboratoires URGO 20010.4.3.8 Actisorb Silver 220 from Johnson & Johnson 20010.4.3.9 Microbisan from Lendell Manufacturing Inc. 20110.4.4 Differences Between Silver-Containing Wound Dressings 20110.4.4.1 Different Silver Compounds 20110.4.4.2 Different Contact Areas 20210.4.4.3 Different Absorption Capacities 20210.5 Preparation of Silver-Containing Alginate Fibers and Wound Dressings 20310.5.1 The Addition of Silver Into Alginate Fibers Through Chemical Reaction 20310.5.2 The Addition of Silver Into Alginate Fibers Through Blending 20310.6 Release of Silver Ions from Silver-Containing Alginate Fibers 20410.7 The Antimicrobial Effect of Silver-Containing Alginate Fibers and Wound Dressings 20510.8 Properties and Applications of Silver-Containing Alginate Wound Dressings 20610.8.1 Wound Healing Properties of Silver 20610.8.2 The Release of Silver from Silver-Containing Wound Dressings 20610.9 Test Methods for Assessing the Antimicrobial Properties of the Silver Dressing 20810.9.1 Zone of Inhibition 20810.9.2 Challenge Testing 20810.9.3 Microbial Transmission Test 20910.10 In Vitro and In Vivo Findings of the Clinical Benefits of Silver in Wound Healing 21010.11 Local and Systemic Toxicity of Silver in Wound Healing 21110.12 Clinical Efficacy of the Silver-Containing Dressings 21210.13 Summary 213References 213A Appendix A: List of Silver Containing Wound Dressings 217B Appendix B: Answers to Commonly Asked Questions About Alginate Wound Dressings 221B. 1 What Are Alginic Acid, Sodium Alginate, and Calcium Alginate? 221B. 2 What Do M and G Mean With Alginate Fibers and Wound Dressings? 221B. 3 What Are the Differences Between Alginate Wound Dressing and Calcium Alginate Wound Dressing? 222B. 4 How Can Calcium Alginate Dressing Form Hydrogel on Contact With Wound Exudate? 223B. 5 What Role Does Alginate Wound Dressings Play in “Moist Healing”? 223B. 6 What Are the Main Applications of Alginate Wound Dressings? 223B. 7 What Is the Absorption Mechanism of Alginate Wound Dressing? 226B. 8 What Is the Reason That Calcium Alginate Fibers Do Not Gel in Pure Water? 226B. 9 What Are the Differences Between the Absorption of Wound Exudate by Cotton Gauze and Alginate Wound Dressings? 227B. 10 What Are the Differences Between High G and High M Alginate Fibers When They Are Applied on Exuding Wounds? 227B. 11 Can Sodium Alginate Be Absorbed by the Body When Calcium Alginate Fibers Are Converted Into Sodium Alginate Upon Contact With Wound Exudate? 228B. 12 Alginate Wound Dressings Are Divided Into Wet Integral and Wet Dispersible, What Does These Two Types Mean? 228B. 13 How Can Alginate Wound Dressings Reduce Pain? 229B. 14 Are There Any Inappropriate Consequences for the Residue Alginate Fibers Left on the Wound Surface? 229B. 15 Are There Any Differences Between the Alginate Wound Dressings Under Different Brands? 229B. 16 In the Manufacturing Processes, What Do Nip Rolling, Needle Punching, and Freeze Drying Mean? 230B. 17 Can Alginate Wound Dressings Be Used in Combination With Topical Medicines Such as Anti-inflammatory Drugs Like Iodine? 230B.18 Can Alginate Wound Dressings Be Used on Infected Wounds? 230B.19 Can Alginate Wound Dressings Be Cut Into Pieces Before Being Applied to Wounds? 231B.20 What Should Be Done When Alginate Wound Dressings Adhere to the Wound Surface? 231B.21 Some Patients Experience Granulation Edema When Applied With Alginate Wound Dressings, Is This Related to the Release of Calcium Ions by the Dressing? 231B.22 What Are the Clinical Efficacy of Alginate Wound Dressings When Used for Pressure Sore Wounds? 231B.23 What Are the Clinical Efficacy of Alginate Wound Dressings When Used for Leg Ulcer Wounds? 231B.24 What Are the Clinical Efficacy of Alginate Wound Dressings When Used for Diabetic Foot Ulcer Wounds? 232B.25 What Are the Clinical Efficacy of Alginate Wound Dressings When Used for Burn Wounds? 232B.26 What Are the Clinical Efficacy of Alginate Wound Dressings When Used for Anal Fistula Wounds? 232B.27 Does Alginate Wound Dressing Possess Hemostatic Properties? 232B.28 Where Are the Seaweeds Used in the Production of Alginate Wound Dressings Come From? 233Index 235