Applications of Polymerized Vesicles

1. Applications of Polymerized Vesicles Seung-Woo Son, Complex System and Statistical Physics Lab.

2. Motivation : Nature and Membranes What is a membrane structure ? Simply lipid bilayers or vesicles !

3. Introduction : Glossaries of Soft Matters • What is Vesicles? • Spherical closed bilayer structures • Surfactants comprising two alkyl chains and a cationic polar head (ammonium, phosphate or zwitterion) cf.) micelles, microemulsions, bilayers • Liposomes ( a special case of vesicles ) • Vesicles formed from naturally occurring lipid molecules. • Lipid : 비극성 유기용매의 추출에 의해 세포나 조직으로부터 분리되는 자연계에 존재하는 유기분자 ( 종류: 지방, 왁스, 콜레스테롤, 스테로이드 ) * Other useful expression… • In vivo : 생체에서… • In vitro : 시험관에서…

4. Physics of Soft Matters • Micelles, bilayers, vesicles and biological membranes • Self-assembly of certain amphiphilic molecules • Association colloids or complex fluids • Soft, flexible (fluid-like) unlike solid particles, rigid macromolecules(ex.DNA) • Van der Waals force, hydrophobic, hydrogen-bond, screened electrostatic interactions etc.(not covalent bond or ionic bond) • Solution conditions(electrolyte concentration, pH, temperature, etc.) change the size and shape of molecule aggregates. • Ref. Jacob N. Israelachvili, “Intermolecular and Surface Forces” Ch 16, 17

5. Special Character of Vesicles • Diameter ~ 10nm, thickness 4~5nm spherical water-filled pockets • Several weeks lifetime • Great kinetic stability • Lower surfactant exchange rate • Higher number of surfactant molecules

6. Polymerization of Vesicles • The aim of polymerization is to fix the structure • To observe the shape of vesicle, to measure the size • Control the size, rigidity, permeability • Actually unlimited lifetime(several month) : greater stability • To clarify the mechanism of vesicle fusion

7. Polymerization Strategies

8. Applications of Polymerized Vesicles (1) : DDS • Active molecule transport • Pharmacology : selectively carry a compoundto a preselected site in the organism. • pH, temperature, photochemical isomerisation,enzymes, etc.

9. Applications of Polymerized Vesicles (2) : catalysts • Ideal medium for the formation of small and uniform colloidal particles of metals or oxides. • Potassium tetrachloroplatinatr ( K2PtCl4) + polymerisable surfactants : extremely efficient colloidal platinum catalyst. • Artificial photosynthesis • Photochemical solar-energy conversion using colloidal semiconductor • Decomposing water

10. Summaries • Vesicles의 모양와 성질에 대해서 • Polymerization을 연구해야 하는 이유 • Polymerization 방법들 • Polymerized vesicles의 응용

14. Motivation :

15. Applications of Polymerized Vesicles (2) : photosynthesis