Hydrogels (eBook)

Preface 5
Table of Contents 
6 
List of Contributors 8
Hydrogels and Tissue Engineering 11
1 Introduction 11
2 Materials 12
2.1 Synthetic materials 13
2.2 Naturally derived materials 13
3 Scaffold design 14
4 Degradation 15
5 Diffusion 16
6 Biological properties 16
References 18
Structure-Property Relationships in Hydrogels 19
1 Hydrogel classification and basic structure 19
1.1 Structural parameters 21
2 Hydrogel mechanical properties 21
2.1 Dynamical mechanical analysis 21
2.2 Hydrogel viscoelastic properties 23
2.3 Stress-strain behavior 24
3 Hydrogel swelling properties 25
References 28
Water and Surfaces: a Linkage Unexpectedly Profound 31
References 33
Polysaccharide Based Hydrogels for Biomedical Applications 
35 
1 Hydrogels for soft tissue regeneration 36
1.1 Hydrogel for cartilage regeneration 36
1.2 Amidic Carboxymethylcellulose hydrogel 36
1.2.1 Hydrogels for nucleus pulposus replacement 43
1.3 Amidic alginate hydrogel 43
1.4 Hydrogels for delivery of biologically active substances 48
1.4.1 Hydrogels as vehicles for bioactive substances for regeneration of bone tissue 
48 
1.4.2 Guar gum based Hydrogel enriched with HA 48
2 Conclusions 50
References 50
Hydrogels for Healing 52
1 Introduction 52
2 Sphere templated polymers 54
3 A biodegradable pHEMA hydrogel 55
4 Degradation studies 56
5 Conclusions 59
References 59
Stereocomplexed PEG-PLA Hydrogels 61
1 Introduction 61
2 Hydrogels 62
2.1 General requirements 62
2.2 Synthetic polymers used for hydrogel preparation 62
2.3 In situ forming hydrogels 63
2.4 Physical crosslinking 63
2.5 Thermosensitive hydrogels 64
2.6 Stereocomplexation 64
2.7 Chemical crosslinking by photopolymerization 65
2.8 Synthesis 65
2.9 Solubility 67
2.10 Gelation behavior 67
2.11 Rheology 69
2.12 In situ monitoring of mechanical properties during photopolymerization 70
3 Conclusions 70
References 71
Hybrid Hydrogels Based on Poly (vinylalcohol) Chitosan Blends and Relevant CNT Composites 
74 
1 Introduction 74
2 Experimental procedures 76
2.1 Materials 76
2.2 Processing 76
2.3 Characterization 77
3 Results and discussion 78
4 Conclusions 83
References 85
Poloxamine Hydrogels: from low Cell Adhesion Substrates to Matrices with Improved Cytocompatibility for Tissue Engineering Applications 
86 
1 Introduction 86
2 Poloxamers (Pluronicf®) 
87 
3 Poloxamines (Tetronic®) 
88 
3.1 Poloxamine/collagen hybrids 88
3.1.1 Design of semi-interpenetrating networks and their characterization 88
3.1.2 Cellembedding 90
3.1.3 Cellattachment on poloxamine/collagen hydrogels 90
3.2 Positively-charged matrices 93
3.2.1 Copolymerization of reactive poloxamine with quaternary ammonium methacrylates 
93 
3.2.2 Methylation of poloxamine central block (quatemized poloxamine) 94
3.3 The combined approach 95
3.4 The degradable strategy 96
4 Summary and perspectives 99
References 100
Biohydrogels for the In Vitro Re-construction and In Situ Regeneration of Human Skin 
104 
1 Biohydrogels as scaffolds for in vitro produced skin equivalents 104
2 Biohydrogels for in situ human skin regeneration 107
3 Biohydrogels as carriers of topical drugs facilitating wound healing and attenuating cutaneous inflammation 
109 
4 Anti-oxidant properties of biohydrogels loaded with plant polyphenols 
110 
5 Biohydrogels for drug delivery through the cutaneous barrier 112
6 Perspectives of biohydrogels for dermatological and cosmetological applications 
113 
References 113
Chitosan-Based Beads for Controlled Release of Proteins 
117 
1 Introduction 117
2 Materials and methods 118
2.1 Materials 118
2.2 Preparation of crosslinked Chitosan beads 118
2.3 Preparation of protein loaded Chitosan beads 118
2.4 Morphological characterization 119
2.5 Swelling of Chitosan-TPP beads 119
2.6 Degradation of Chitosan-TPP beads 119
2.7 Evaluation of protein encapsulation efficiency 119
2.8 Protein release studies 120
3 Results and discussion 120
3.1 Preparation of crosslinked Chitosan beads 120
3.2 Morphological observation 120
3.3 Swelling ratio 122
3.4 Degradation of Chitosan-TPP beads 122
3.5 Protein encapsulation and release studies 123
4 Conclusions 123
References 125
Synthesis of Stimuli-Sensitive Hydrogels in the µm and sub-µm Range by Radiation Techniques and their Application 
126 
1 Stimuli-sensitive hydrogels 126
2 Materials and the swelling process 128
3 Patterning 129
Irradiation through a mask 133
4 Application of gels in MEMS 139
4.1 Microvalves 139
4.2 Microchemostat valves 141
5 Conclusions 142
References 143
Stimuli-Sensitive Composite Microgels 146
1 Introduction 146
2 The representative thermosensitive polymer, poly(N-isopropylacrylamide) 
147 
3 Design and synthesis of smart particles 149
3.1 PNIPAM microgel 149
3.2 Hard core I PNIPAM gel shell particles 150
3.3 Hairy particles 151
3.3.1 Molecular assemby method 151
3.3.2 Grafting-to method 151
4 Colloid chemistry of thermo-sensitive microgels 153
5 Products of living radical graft polymerization 154
6 Smart composite microgels 156
6.1 Chymotrypsin-carrying thermo-sensitive microgels [19] 156
6.2 Magnetite nanoparticle-carrying thermo-sensitive particles 156
6.3 Gold nanoparticle-carrying thermo-sensitive particles [23,24] 158
6.4 Titania nanoparticle-carrying thermo-sensitive particles [25] 158
7 Conclusions 160
References 160
Novel pH/Temperature-Sensitive Hydrogels Based on Poly(ß-Amino Ester) for Controlled Protein Delivery 
162 
1 Introduction 162
2 Experimental details 164
2.1 Materials 164
2.2 Synthesis of copolymers 164
2.2.1 Synthesis of temperature sensitive PCL-PEG-PCL triblock copolymers 164
2.2.2 Synthesis of acrylated triblock copolymers 165
2.2.3 Synthesis of pWtemperature-sensitive pentablock copolymers 165
2.3 Characterization 167
2.3.1 Polymer characterization 167
2.3.2 Sol-gel phase transition measurement 168
2.3.3 Cytotoxicity evaluation of pentablock copolymer 168
2.3.4 Insulin loading process 168
2.3.5 Degradability evaluation of block copolymers and complex gel in vitro 168
2.3.6 Insulin release in vitro 169
2.3.7 Insulin release in vivo in SD rats 169
3 Results and discussion 170
3.1 Polymer characterization 170
3.2 Sol-gel transition of block copolymer solutions 170
3.3 Cytotoxicity evaluation of pentablock copolymers 172
3.4 Insulin loading and release in vitro 173
3.4.1 Effect of insulin on sol-gel transition diagram of pentablock copolymer 173
3.4.2 Mechanism of insulin loading and release 174
3.5 Comparison between PAE-PCL-PEG-PCL-PAE and PAE-PCLA-PEG-PCLA-PAE 
176 
3.5.1 Degradability evaluation of block copolymer and complex gel in vitro 176
3.5.2 Effect of the copolymer's degradation on the release of insulin 177
3.6 Insulin release from triblock and complex gel in SD rats 178
3.7 Storage stability of pentablock copolymers 179
4 Conclusions 180
References 180
On-Off Switching Properties of ultra thin Intelligent Temperature-Responsive Polymer Modified Surface 
183 
1 Introduction 183
2 Poly(N-isopropylacrylamide) grafted surfaces 
184 
3 Green chromatography utilizing PIPAAm modified surfaces 186
4 Modulation of cell adhesion and detachment properties using intelligent temperature-responsive surfaces 
188 
5 Accelerated cell sheet recovery from various types of PIPAAm grafted surfaces 
193 
5.1 PIPAAm grafted porous membrane for rapid cell sheet recovery 193
5.2 Further rapid cell sheet recovery utilizing hydrophilic unit 194
6 Functionalization of temperature-responsive cell culture surfaces 
195 
6.1 Thermal control of cell adhesion and detachment using temperature-responsive copolymer grafted surfaces 
195 
6.2 Patterned dual temperature-responsive surfaces for recovery of continuous co-cul tured cell sheets 
196 
6.3 Affinity control between cell integrins and RGDS ligands immobilized onto temperature-responsive cell culture surfaces 
197 
7 Conclusions 199
References 199