Optimization of Vesicle Optimization of Vesicle Adsorption to Form - - PowerPoint PPT Presentation

Optimization of Vesicle Optimization of Vesicle Adsorption to Form Lipid Adsorption to Form Lipid Bilayers Bilayers

Ricardo Garcia, Allan Hancock College Ricardo Garcia, Allan Hancock College Mechanical Engineering Mechanical Engineering Faculty Advisor: Jacob Faculty Advisor: Jacob Israelachvili Israelachvili Lab Mentor: Lab Mentor: Younjin Younjin Min Min Funded by Corning Inc. Funded by Corning Inc.

Lipid Bilayers Lipid Bilayers

A lipid bilayer is the outer A lipid bilayer is the outer structure of a cell membrane or structure of a cell membrane or vesicle consisting of a double vesicle consisting of a double layer of phospholipids layer of phospholipids molecules molecules Hydrophilic polar head Hydrophilic polar head Hydrophobic non Hydrophobic non-

• polar tail

polar tail Adsorption Adsorption

http://homepage.mac.com/huntington.c/Images/lipidbilayer.gif http://img.sparknotes.com/figures/A/a981208a1abd542364d5a13c08702881/phospholipid.gif http://www.uni-leipzig.de/~sfb294/Symposium2002/Vestext.htm

Why are Lipid Bilayers so Important? Why are Lipid Bilayers so Important?

Critical components in biology Critical components in biology

• Outer structure of a cell

Outer structure of a cell

• Main composition of a cell membrane

Main composition of a cell membrane

• Protection

Protection

• Endocytosis

Endocytosis

Models for fundamental biological membranes Models for fundamental biological membranes Application in biosensors, semiconductors, Application in biosensors, semiconductors, protein mobilization protein mobilization

Goals Goals

Help redesign and test the streaming potential Help redesign and test the streaming potential apparatus apparatus Experimentally determine the factors that Experimentally determine the factors that

• ptimize the adsorption of vesicles onto a glass
• ptimize the adsorption of vesicles onto a glass

surface surface

• Concentration of Lipid

Concentration of Lipid

• Concentration of Aqueous Solution

Concentration of Aqueous Solution Understand the interactions between the Understand the interactions between the vesicles and surface as well as between the vesicles and surface as well as between the vesicles themselves vesicles themselves

Streaming Potential Streaming Potential

This device is used to indicate when the glass substrate This device is used to indicate when the glass substrate is completely adsorbed with lipid is completely adsorbed with lipid bilayers bilayers. . Used as a tool to view adsorption of vesicles. Used as a tool to view adsorption of vesicles.

CAD Renderings CAD Renderings

How It Works How It Works

Silica Substrate K+ Cl

_

Flow Flow Flow Accumulation Streaming Current Electric Field Conduction Current ∆V

100 mM KCl with Old Teflon Piece

0.00 0.05 0.10 0.15 0.20 0.25 0.30 500 1000 1500 2000 2500 3000 Pressure (Pa) Streaming potential (mV) Experimental Theoretical

Streaming potentials increased as applied pressures increased and salt concentrations decreased Pressure increased as flow rate increases and channel size decreases

E P k εζ η =

100 mM KCl with New Teflon Piece

0.00 0.05 0.10 0.15 0.20 0.25 2000 4000 6000 8000 10000 12000 Pressure (Pa) Streaming potential (mV) Experimental Theoretical

What Remains to be Done What Remains to be Done

Complete my goals: Complete my goals:

• Test under different concentration

Test under different concentration

• Introduce vesicles

Introduce vesicles

• Experimentally determine the factors that optimize the

Experimentally determine the factors that optimize the adsorption of vesicles onto a glass surface adsorption of vesicles onto a glass surface

• Understand the interactions between the vesicles and

Understand the interactions between the vesicles and surface as well as between the vesicles themselves surface as well as between the vesicles themselves

Acknowledgments Acknowledgments

Jacob Jacob Irealachvilli Irealachvilli INSET INSET UCSB UCSB National Science Foundation (NSF) National Science Foundation (NSF) California California NanoSystem NanoSystem Insitute Insitute (CNSI) (CNSI) Corning Inc. Corning Inc. Special Thanks to: Special Thanks to: Samantha Freeman Samantha Freeman

• Dr. Nick Arnold
• Dr. Nick Arnold

Noshir Noshir Pesika Pesika Ranulfo Ranulfo Morales Morales

Thank You, Thank You,

Questions? Questions?

Three Dimensional Bottom View Three Dimensional Bottom View

Three Dimensional View of Top Three Dimensional View of Top

Skeletal Side View Skeletal Side View

Skeletal View Skeletal View

Endocytosis Endocytosis

Is the cellular Is the cellular procsess of engulfing procsess of engulfing solid or liquid particles solid or liquid particles by the cell membrane by the cell membrane to form an internal to form an internal “ “food vesicle food vesicle” ”

http://www.mansfield.ohio-state.edu/~sabedon/039phago.gif

K+ Cl- Charged Layer Flow Streaming Current Accumulation Electric Field Conducting Current ∆V +

• How it Works

How it Works