Bio-Inspired Silicon-Based Materials (eBook)

Contents 6
Contributors 8
Chapter-1 10
Silicon in a Biological Environment 10
1.1 Silicon-Based Life: Science-Fiction? 10
1.2 Not Science Fiction After All: Plants, Diatoms, and Sponges 11
1.2.1 Plants 11
1.2.2 Marine Organisms 12
1.2.2.1 Diatoms 12
1.2.2.2 Sponges 13
1.3 Drawing Inspiration from Nature 15
1.3.1 Applications in Agriculture 15
1.3.2 Silicon in Human Health and Medicine 15
1.3.2.1 Silicon in Food and in the Human Body 16
1.3.2.2 Silicon in Medicine 19
1.3.2.2.1 Silicon-Containing Molecules with Medicinal Applications 19
1.3.2.2.2 Biomedical Devices Based on Silicon 21
References 24
Chapter-2 28
The Role of Silicates in the Synthesis of Sugars Under Prebiotic Conditions 28
2.1Sugars and Life 28
2.2The Formose Reaction 28
2.3The Interaction(s) of Carbohydrates with Silicates 30
2.4Summary 33
References 34
Chapter-3 35
Protease-Mediated Hydrolysis and Condensation of Tetra- and Trialkoxysilanes 35
3.1Introduction 35
3.1.1Biosilica Synthesis 35
3.2Enzyme-Mediated Hydrolysis and Condensation of Alkoxysilanes 37
3.3Hydrolysis and Condensation of Organically Modified Alkoxysilanes 39
3.4Active Site Considerations 41
3.5Conclusions 43
References 44
Chapter-4 46
Bioinspired Silica for Enzyme Immobilisation: A Comparison with Traditional Methods 46
4.1 Introduction to Enzymes 46
4.2 Enzyme Immobilisation Overview 47
4.2.1 Outline of Enzyme Immobilisation Techniques 49
4.2.2 Supports 49
4.3 Immobilisation Techniques 51
4.3.1 Evaluation and Comparison of Biocatalyst Performance 51
4.3.2 Lipase 52
4.3.3 Covalent Binding 53
4.3.4 Adsorption 55
4.3.5 Cross-Linking 57
4.3.6 Entrapment/Encapsulation 58
4.4 Bioinspired Silica for Enzyme Immobilisation 62
4.5 Conclusion 65
4.6 Acknowledgments 65
References 66
Chapter-5 70
On The Immobilization of Candida antarctica Lipase B onto Surface Modified Porous Silica Gel Particles 70
5.1 Introduction 70
5.2 Experimental 72
5.2.1 Materials 72
5.2.2 Enzyme Immobilization Protocol 73
5.2.3 Enzyme Activity Assay 73
5.2.4 Instrumental Methods 74
5.2.5 Results and Discussion 74
5.2.6 CALB Immobilization on Surface Modified Porous Silica Gel Particles 74
5.2.7 Thermal Stability of the Immobilized CALB 74
5.2.8 Support Material Swelling 77
5.2.9 Conclusions 78
References 78
Chapter-6 80
Enzymatic Modification and Polymerization of Siloxane-Containing Materials 80
6.1 Introduction 80
6.2 Enzyme-Mediated Catalysis of Siloxane-Containing Materials 81
6.3 Structural Characterization of Siloxane-Containing Polyesters 82
6.4 Elongation Kinetics 84
6.4.1 CPr-TMDS and 3HP-TMDS 84
6.4.2 CPr-TMDS and HA-PDMS 85
6.4.3 A Comparsion of Acyl-Donors 86
6.5 Thermal Properties of Disiloxane Containing Polyesters 88
6.6 A Comparison of the Activation Energy for N435-Mediated Polyesterification Reactions 88
6.7 Residual Activity of Novozyme-435 89
6.8 Thermal Tolerance and Repeated Use of Novozyme-435 90
6.9 Enzymatic Deacylation of 1,3-Bis(3-Acetoxypropyl)-1,1,3,3-Tetramethyldisiloxane 92
6.10 Conclusions 93
References 95
Chapter-7 97
Design and Thermal Properties of Interpenetrating and Intercrosslinked Biosilicate Materials 97
7.1 Introduction 97
7.2 Biohybrid Materials 99
7.3 Biohybrid Material Thermal Properties 103
7.4 Conclusions 107
References 107
Chapter-8 109
Bioactive Amino Acids, Peptides and Peptidomimetics Containing Silicon 109
8.1 Silicon in Amino Acids and Peptides 109
8.2 Where Silicon Can—and Cannot—be Used 109
8.3 Silicon Containing Amino Acids [2] 111
8.3.1 The ?-Silyl Amino Acids 111
8.3.2 The ?-Silyl Amino Acids 112
8.4 Silanediol Protease Inhibitors 115
8.4.1 Design and Activity 115
8.4.2 Silanediol Synthesis 117
8.4.3 An HIV Protease Inhibitor 118
8.4.4 Thermolysin Inhibitor 119
8.4.5 Angiotension-Converting Enzyme Inhibitors 120
8.5 Improved Chemistries for Silanediol Inhibitor Construction 122
8.5.1 ?-Alkyl-?-Silyl Acids 122
8.5.1.1 Asymmetric Hydroboration of 2,5-Dihydrosiloles 122
8.5.1.2 Asymmetric Intramolecular Hydrosilylation 123
8.5.2 ?-Alkyl-?-Amino Silanes 124
8.5.2.1 Asymmetric Reduction of a Silyl Ketone 124
8.5.2.2 Asymmetric Reverse-aza-Brook Rearrangment 125
8.5.2.3 Silyllithium Addition to Sulfinimines 125
8.6 Future Prospects 126
References 127
Index 130