Index of /rozprawy2/11138

CONTENTS 3

Contents

1.1.3 Self-organization and lipid structures . . . 9

1.1.4 Phases and phase transitions . . . 11

1.1.5 Mechanical properties of membranes . . . 13

1.2 Carotenoids . . . 15

1.2.1 Chemical structure . . . 15

1.2.2 Functions of carotenoids . . . 16

1.2.3 Interaction with membranes . . . 19

1.3 Motivation and aims of this thesis . . . 22

1.3.1 Motivation . . . 22

1.3.2 Objectives . . . 23

2 Materials and methods 24 2.1 Chemicals . . . 24

2.2 Preparation of samples . . . 24

2.2.1 Preparation of multilamellar liposomes . . . 24

2.2.2 Preparation of samples for AFM measurement . . . 25

2.2.3 Isolation of violaxanthin . . . 25

2.3 Dierential scanning calorimetry . . . 28

2.3.1 Principles and conguration . . . 28

2.3.2 Details of the experiments . . . 30

2.4 Atomic force microscopy . . . 31

2.4.1 Introduction . . . 31

2.4.2 Principles and conguration . . . 31

2.4.3 Interaction forces . . . 33

CONTENTS 4

2.4.5 Force spectroscopy . . . 36

2.4.6 Adhesion . . . 37

2.4.7 Elasticity . . . 38

2.4.8 Details of the experiments . . . 40

3 Results 42 3.1 Phase behaviour of liposomes . . . 42

3.1.1 Pure DPPC liposomes . . . 42

3.1.2 Liposomes enriched in β-carotene . . . 44

3.1.3 Liposomes enriched in zeaxanthin . . . 44

3.2 Structural properties of liposomes . . . 46

3.2.1 Measurements performed in air . . . 46

3.2.2 Measurements performed in water . . . 48

3.3 Temperature dependence of the adhesion forces . . . 51

3.3.1 Measurements performed in air . . . 51

3.3.2 Measurements performed in water . . . 53

3.4 Inuence of loading rate on the adhesion forces . . . 59

3.4.1 Measurements performed in air . . . 59

3.4.2 Measurements performed in water . . . 61

4 Discussion 70 4.1 Phase behaviour of liposomes . . . 70

4.2 Structural properties of liposomes . . . 71

4.3 Temperature dependence of the adhesion forces . . . 72

4.4 Inuence of loading rate on the adhesion forces . . . 75

5 Conclusions 78

Acknowledgements 81

References 82

Abstract 99