Compositional Effects on Phase Transition Behaviors of Myelin - - PowerPoint PPT Presentation

Compositional Effects on Phase Transition Behaviors of Myelin Monolayers

Antonio Ortiz, Ventura College Chemical Engineering Graduate Mentor: Younjin Min Faculty Advisor: J. Israelachvili & J. Zasadzinski UCSB Chemical Engineering Department

• Cause remains unknown
• Treatments not fully effective
• Structure, composition, &

interactions of healthy myelin not fully understood

• Studying these characteristics

should lead to the advancem ent of finding cure…

Myelin Sheath & Multiple Sclerosis (MS)

Healthy Myelin Diseased Myelin

Research Goals

Mechanism by which MS develops not understood therefore research will be fundamental in nature:

• Myelin composed of 7 constituents
• Pick two of those components and study the

stability/ instability of lipid mixtures of various mole ratios:

• Isotherm Experiments (In Progress)
• Confocal Microscopy (Coming Soon!!!)

Lipids studied this Summer: 1) Cholesterol (CHOL), Bovine 2) Phosphatidylethanolamine (PE), Porcine

Why CHOL & PE ?

• CHOL most abundant component
• PE known to show adhesive forces

in myelin multilayer

• Ultimately few Research Studies

done with CHOL and PE

Cholesterol PE MW 386.66 MW 746.06

Isotherm Experiments

Employs Langmuir

Trough

MOPS Buffer pH 7.2

imitates physiological environments

Place sample… and

compress

Computer collects

data

Pressure Sensor Movable Barrier MOPS Buffer Solution

Phase Transitions

COLLAPSE!!!

Data

CHOL:PE

• 10

10 20 30 40 50 60 20 40 60 80 100 120 Molecular Area(A^2 /mol) Surface Pressure (mN/m)

CHOL:PE 1:0 CHOL:PE 0:1 CHOL:PE 0.50:0.50 CHOL:PE 0.85:0.15 CHOL:PE 0.15:0.85

Data (Con’t)

Pure CHOL collapses much quicker

than pure PE

Lipid Mixtures take on

characteristics of BOTH pure lipids

Data gives us something to

compare to REAL myelin composition

Summary of Achievements

• Identified a lipid that potentially

could reinforce integrity of myelin

• Different Mole Ratios than

Previously Studied Tested all nine lipid mixtures

• Adds to the foundation on which we

can build on.

Future Plans

• Conduct many isotherms to be able

to compare to real myelin lipid compositions

• Different Temperatures (+ / -

Body Temperature)

• Confocal Microscopy

Acknowledgements

• Jens & Dr. Nick, INSET
• Younjin Min, Mentor
• Prajna Dhar, Step-Mentor
• “Joe’s Group”

THANK YOU!!!