Architectural hydrogels: scaffolds
for vascular and neural progenitor
cell constructs for the nervous
system
Joseph A Madri* and Erin Lavik**
and
Millie Ford, Qi Li, Jennifer Long & Michael Michaud
Departments of Pathology* and Biomedical Engineering**
Yale University, New Haven, CT
Investigating NSC-EC interactions in 3D
Shen et al
Brain endothelial
Song et al
Neural Stem
Cells (NSCs)
Lu et al. Brain Res. 943: 292-300,
2002
Gage et al
Modified from Wurmser et al. Science 304:1338-40, 2004
cells (bECs)
Graesser
et al. J. Clin. Invest. 109: 382-392,
2002
scaffold
Culture: 5 days
Tunable Hydrogel
Polylysine and PEG
Molecular weight of the
components may be
varied as well as the ratio
of the two
Macroporous Hydrogels
isotropic
macroporous
Macroporous hydrogel seeded with bECs
(3 days in culture)
DiI labeled ECs
3 days post
seeding
In vitro tubes: 3 days in culture
In Vivo Experiment
2,4, or 6 weeks post
implantation
NSC Hydrogel
Subcutaneous
implantation
Intravital imaging
(Segal lab)
bEC Hydrogel
NSC:bEC Hydrogel
Fixation for histology
and
immunocytochemistry
NSC
NSC:bEC
In Vivo Microvessels
bEC
Host Red Blood Cells in Tissue
Engineered Blood Vessels
4 wk bEC
4 wk
NSC:bEC
6 wk bEC
6 wk
NSC:bEC
Conclusions
The PLL/PEG hydrogel can be made with a wide
range of properties and supports cell attachment
The PLL/PEG hydrogel can be made with
macroporous networks by casting the gel around a
PLGA scaffold that is subsequently degraded
Macroporous hydrogels lead to the efficient
formation of vessel-like networks in vitro (5 days)
The addition of NSCs does not affect the diameter
or length of vessels in vitro or in vivo
The addition of NSCs leads to stabilization of
microvessels in the polymer at long times (6
weeks)
The vessels are functional (red blood cells)
Neurovascular Interactions
Steven Segal
Potential Spinal Cord Implant
Millicent Ford
Acknowledgements
Madri lab
Joe Madri
Michael Michaud
Qi Li
Segal lab
Steven Segal
Lavik lab
Millicent Ford
Sara Royce Hynes
James Bertram
Justin Roh
Rebecca Royce
Funding
Richard and Gail Siegal
NSF GK-12 Teaching Fellowship, DGE-0231832 (Hynes)
NIH Neuroengineering Training Grant, NIH T90-DK070068 (Ford and Bertram)