Improving the Biophysical Activity of Dysfunctional Lung Surfactant - - PowerPoint PPT Presentation

Vanessa Sousa

Ventura College Chemistry

Lab Mentor: Ian Shieh Faculty Advisor: Dr. Joseph Zasadzinski

Chemical Engineering Department, UCSB

Improving the Biophysical Activity of Dysfunctional Lung Surfactant

Lung Surfactant & ARDS

• What is Lung Surfactant?

– Lowers Surface Tension in Lungs

• Acute Respiratory Distress

Syndrome (ARDS)

– Surfactant Deactivation – In the U.S., 150,000 cases/year, 40% mortality rate

• Reversal of Surfactant

Deactivation

Notter, R.H., ed. Lung Surfactants: Basic Science and Clinical Applications. 1 ed. Lung Biology in Health and Disease, ed. C. Lenfant. Vol. 149. 2000, Marcel Dekker, Inc.: New York, N.Y. 444. http://www.lawsonresearch.com/v1.0/website/lung/images/lungs_1.jpg http://services.epnet.com/GetImage.aspx/getImage.aspx?ImageIID=2547 http://www.scitech.ac.uk/PandS/Gallery/ISISbeauty/ISISlbf0004.jpg

Air Liquid Surfactant

• Lung Surfactant Meets Albumin

– Main Protein in Blood Serum

• Competitive Adsorption

– Albumin Blocks Lung Surfactant from Interface

Albumin & Competitive Adsorption

Subphase (Liquid)

Surfactant Aggregates Interface

Albumin Albumin Albumin

• Our Model of the Human Lung

– Expansion & Compression of Barriers

Langmuir Trough

Surface Pressure Sensor Metal Barriers Thermometer

• The Healthy Lung

– Survanta (Lung Surfactant) – Rapid Adsorption

• ARDS

– Albumin – Surfactant Inhibition

• Reversing ARDS with

Polyethylene glycol (PEG)

– Hydrophilic Polymer – Shown to enable re‐adsorption

Modeling Lung Behavior

Metal Barriers Saline Solution

• Simultaneous Multiple Imaging

– Fluorescently View & Track Three Molecules at the Same Time

• Optical Sectioning Capability

– Image Slices Taken at Various Depths

Confocal Microscopy

Lung Surfactant Albumin PEG Z (µm) Air Subphase (Liquid) Interface

• Unique Shapes

– Tells Type of Molecule at Interface

• Surface Pressure

– High Surface Pressure = Low Surface Tension – Can Evaluate Effectiveness

• f Surfactant at Interface
• Our Models

– The Healthy Lung – Albumin – Lung Surfactant Inhibition – PEG Reversal of Inhibition

Surface Pressure vs. Area

30 40 50 60 70 80 90 100 10 20 30 40 50 60 70

Surface Pressure (mN/m) Trough Area (%)

Albumin Only

in Saline Soln.

30 40 50 60 70 80 90 100 10 20 30 40 50 60 70

Surface Pressure (mN/m) Trough Area (%)

Albumin Only Albumin & Survanta

30 40 50 60 70 80 90 100 10 20 30 40 50 60 70

Surface Pressure (mN/m) Trough Area (%)

Albumin Only Albumin & Survanta Albumin,Survanta,& PEG

• Fluorescence Intensity

– Peak Occurs at Interface – Indicates Molecule Location (in terms of depth)

• Our Models

– The Healthy Lung – Albumin

Intensity Profiles

• 5

5 10 15 0.0 0.2 0.4 0.6 0.8 1.0

Normalized Fluorescence Intensity Depth (µm)

Survanta

Only

• 5

5 10 15 0.0 0.2 0.4 0.6 0.8 1.0

Normalized Fluorescence Intensity Depth (µm)

Albumin

Only

Air Subphase

Confocal Images

20 µm

Survanta Only Albumin Only Survanta/Albumin with PEG

50 µm 100 µm

Albumin Only

in Saline Soln.

Albumin,Survanta,& PEG

• What I Learned This Summer

– Importance of Lung Surfactant – ARDS/Inhibition Process – Langmuir Trough/Microscopy Techniques

• Continuing Research

– Reversal Process Was Unsuccessful

• New Sample of Survanta

– Use Three Lasers

• We Have Only Used Two

Project Overview & Future Goals

Thank You to:

Ian Shieh, Mentor

• Dr. Joseph Zasadzinski, Faculty Advisor
• Dr. Jens‐Uwe Kuhn, Program Coordinator

“Dr. Nick” Arnold, Faculty Coordinator For Funding Our Project

Polyethylene glycol (PEG)

Excluded Volumes Excluded Volumes Overlap Frees Volume

• PEG Mechanism

– Excluded Volumes Surround Surfactant Aggregates – PEG Helps Aggregates Stick Together & to the Interface – Rise In Entropy

• f System

Ian Shieh, Zasadzinski Lab