BME 401 Progress Report

1
BME 401 Progress Report

• Creating a Concentration Gradient of NT-3 in a
  Fibrin-Based Gel

Group Members Jennifer Johnson, Katelyn McGary,
Matthew S. Reiter Mentors Philip Johnson, Dr.
Shelly Sakiyama-Elbert
2
Background

• Damaged nerves in neurotrophin gradient
• Show directed outgrowth
• Possible nerve function recovery
• Saneinejad S, et al.

3
Need

• Device will create a concentration gradient of
  cross-linked NT-3
• Within nerve guidance tube
• Filled with polymerized fibrin gel
• To direct nerve growth
• To be applied to CNS or PNS after nerve damage

4
Fabrication of Fibrin Gel

• Final stages of blood coagulation cascade
• What does a cross-linked fibrin gel look like?

http//www.umbi.umd.edu/cbr/payne_files/image006.
jpg
5
Fabrication of Fibrin Gel NT-3

• What happens when concentration gradient of NT-3
  created?

NT-3
NT-3
In Nerve Guidance Conduit
6
Design Requirements

• Must create concentration gradient of NT-3
• Preserve sterility of all reagents for cell
  culture purposes
• Easily maintainable/reusable
• Using Chick Dorsal Root Ganglia (DRG) as a
  regeneration model

7
1) Modified Gradient Maker
Fibrinogen w/ Factor XIII
Calcium Thrombin NT-3
Calcium Thrombin
Fibrinogen w/ Factor XIII
Linear Gradient of NT-3
Kapur TA, et al.
8
2) Microfluidics System
Calcium Thrombin Fibrinogen Factor XIII
NT-3
Calcium Thrombin Fibrinogen Factor XIII
Calcium Thrombin Fibrinogen Factor XIII
Calcium Thrombin Fibrinogen Factor XIII
NT-3
Radial
Jeon NL et al
9
Microfluidics System
10
3) Combination of 1 and 2
NT-3 pre-polymer
pre-polymer solution
pre-polymer solution
pre-polymer solution
11
Combination of 1 and 2
Calcium Thrombin NT-3
Calcium Thrombin
Fibrinogen Factor XIII
Fibrinogen Factor XIII
Conical Concentration Gradient
pre-polymer solution
Kapur TA, et al.
12
Combination System Overhead
A
B
13
Analysis Pugh Chart
14
Combination of 1 and 2
Calcium Thrombin NT-3
Calcium Thrombin
Fibrinogen Factor XIII
Fibrinogen Factor XIII
Radial Concentration Gradient
pre-polymer solution (same, minus NT-3)
Kapur TA, et al.
15
Parameters of Chosen Design

• Nerve growth conduit
• 15 mm long
• 1.4372 mm inner diameter
• .2286 mm wall thickness
• Tube exiting MGM 0.829mm
• Vsystem 0.061mL
• Assumptions use other neurotrophins

16
Analysis - Calculations

• VNGC 5.026E-8 m3
• Flow Rate Calculation Assumptions
• Laminar flow
• Rigid cylinders
• Dissipation due to friction negligible
• Viscosity independent of shear
• Poiseuille-Hagen equation ,
• MATLAB Program to solve kinetic rate constants at
  varying temperatures

17
Inherent Considerations

• Temperature
• Flow Rate
• Maintenance
• Air Bubbles - interface

18
Updated Design Schedule
19
Team Responsibilities

• Jen
• Website, Flow Rate Calculations
• Matt
• Visual Aids, Website, Progress Report
• Katelyn
• MATLAB programming, Final Report
• All
• Design Specifications, Weekly Progress Reports,
  Analyses

20
Literature

• Kapur TA, Shoichet MS. J Biomed Mater Res. Vol
  68A, 2004 235-243.
• Jeon NL, Dertinger SKW, Chiu DT, Choi IS, Stroock
  AD, Whitesides GM. Langmuir. Vol 16, 2000
  8311-8316.

21
Additional Information

• http//userfs.cec.wustl.edu/fibrin/
• MATLAB analysis

22
Acknowledgements

• Philip Johnson
• Dr. Sakiyama-Elbert
• Dr. Elbert

23
Questions?