Toward Better Biointegration of Boston KPro

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Toward Better Biointegration of Boston KPro

• Kyung Jae Jeong, Ph.D., Claes H. Dohlman, M.D.,
  Ph.D., and Daniel S. Kohane, M.D., Ph.D.

Harvard-MIT Health Sciences and
Technology, Department of Anesthesiology,
Childrens Hospital Boston, Harvard Medical
School Massachusetts Eye and Ear Infirmary,
Harvard Medical School
The authors have no financial interest in the
subject matter of this poster.
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Boston Kpro and Biointegration

• Cell migration
• Cell proliferation with minimal immune response
• ECM Production
• Adhesion
• Good biointegration will also reduce the danger
  of bacterial/fungal infection.

Khan et al. (2008)
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Advantages of Dopamine-Based Surface Chemistry

• Dopamine (or DOPA) is a major component of mussel
  adhesive protein and has good adhesive
  properties.
• Polydopamine coating can form on virtually all
  surfaces.
• Polydopamine coating can further be used to
  immobilize biological molecules which contain
  either thiol or amine groups at a high density.
• Chemistry is very simple.

Lee et al. Nature (2007)
Lee et al. Adv. Materials (2009)
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Corneal Epithelial Cells on Various Surfaces
PMMA
PMMA-RGD
MTS assay on corneal epithelial cells
Dopa-PMMA-RGD
Dopa-PMMA
Fluorescence micrographs of epithelial cells.
Nucleus (blue) and actin cytoskeleton (red)
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Keratocytes on Various Surfaces
PMMA
PMMA-RGD
MTS assay on keratocytes
Dopa-PMMA
Dopa-PMMA-RGD
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Biological Effect of Polydopamine Coating
Calcium assay. on human aortic smooth muscle
cells (HASMC). Red point corresponds to
polydopamine coating. Higher fluorescence
response corresponds to higher cell contraction.
IL-6 concentration from the cells seeded on
various surfaces after 24 hours. TNF- a was not
detected from neither cell types.

• Polydopamine coating does not release dopamine
  monomer (mass spectrometry)
• Minimal contraction of the aortic smooth muscle
  cells (Calcium Flux Assay).
• Not significantly high level of proinflammatory
  cytokines released from the cells seeded on the
  polydopamine surface (ELISA, IL-6 and TNF-a).

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SEM Images
PMMA-RGD
PMMA
Dopa-PMMA
Dopa-RGD-PMMA
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Adhesion of Polydopamine Coated PMMA to Collagen
Gel
A small PMMA cylinder was pressed onto collagen
gel over night to see if there is any adhesion at
the interface.
PMMA Cylinder
Collagen Gel
PMMA
Dopa-PMMA
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Summary

• Polydopamine coating enhanced the proliferation
  of corneal epithelial cells and keratocytes in
  vitro.
• Polydopamine coating is not proinflammatory and
  is not expected to cause vascular constriction as
  its monomer would do.
• SEM images show ECM secretion from all surfaces.
• Both polydopamine-coated surfaces exhibited firm
  adhesion to collagen gel.
• Polydopamine coating may enhance the
  biointegration of Boston KPro when applied to the
  stem of the device.