Fn Adsorption: Multilayer versus Monolayer

1
Fn Adsorption Multilayer versus Monolayer
Fn / PLL multilayer (5 layers)
Fn / PLL monolayer
Fn / DS monolayer
Fn / DS multilayer (6 layers)

• Fn adsorption kinetics similar on multilayer
  and monolayer PLL terminated film
  
  
  lower on multilayer than
  monolayer DS terminated film
• suggests Fn to remain at film surface
• suggests DS terminated multilayer to be more
  resistant to Fn adsorption
• after approach of Saloum and Schlenoff,
  Biomacromolecules (2004)

2
Cell Response
Questions How do cells respond to various
multilayer films? How does Fn influence this
response?
3
Cell Spreading Assay

• Cells human umbilical vein endothelial cells
  (HUVECs)
• Seeding Time 3 hours
• Imaging phase contrast microscopy
• Measure extent of cell spreading (projected
  area)
• symmetry of cell spreading (circularity)

1 lt 1 0
Circularity 4p area / perimeter2
Favorable cell-surface interaction characterized
by symmetric spreading.
4
Cell Spreading Assay
Systems to be considered
(PLL-DS)3
PLL-DS
(PLL-DS)2-PLL
ST
PLL
silica-titania
fibronectin
(PLL-DS)3-Fn
PLL-DS-Fn
(PLL-DS)2-PLL-Fn
ST-Fn
PLL-Fn
5
Multilayer Film on Cell Spreading in Absence of
Fn
ST
PLL
PLL-DS
(PLL-DS)3
(PLL-DS)2-PLL
Area Circularity
100 5 0.78 0.02
98 6 0.60 0.02
91 7 0.49 0.02
85 4 0.48 0.02
77 5 0.30 0.02

• Bare ST best cell contact surface (highest
  spreading, circularity)
• Single PLL layer best among polymer films

6
Multilayer Film on Cell Spreading Influence of
Fn
PLL terminated systems
ST
ST-Fn
PLL
PLL-Fn
(PLL-DS)2- PLL-Fn
(PLL-DS)2- PLL
Area Circularity
120 7 0.59 0.02
91 6 0.49 0.02
100 5 0.78 0.01
124 7 0.60 0.02
98 6 0.60 0.02
135 7 0.55 0.02
10 mm

• Cell spreading enhanced by Fn
• Cell circularity enhanced by Fn on multilayer

7
Multilayer Film on Cell Spreading Influence of
Fn
DS terminated systems
(PLL-DS)3-Fn
(PLL-DS)3
PLL-DS
PLL-DS-Fn
ST
ST-Fn
Area Circularity
100 6 0.78 0.01
93 9 0.63 0.03
135 7 0.55 0.02
85 4 0.48 0.02
126 7 0.65 0.03
77 5 0.30 0.01
10 mm

• Cell spreading enhanced by Fn (bilayer gt
  multilayer )
• Cell circularity enhanced by Fn (multilayer gt
  bilayer )

8
Multilayer Film on Cell Spreading in Presence of
Fn
ST
(PLL-DS)3-Fn
ST-Fn
(PLL-DS)2-PLL-Fn
PLL-DS-Fn
PLL-Fn
Area Circularity
100 6 0.78 0.01
93 9 0.63 0.03
126 7 0.65 0.03
124 7 0.60 0.02
120 7 0.59 0.02
135 7 0.55 0.02
Compared to ST-Fn control . cell spreading
slightly diminished on Fn coated polymer films
(greatly diminished on DS terminated
multilayer!) . cell circularity slightly
enhanced on Fn coated polymer films
9
Conclusions

• We investigate
• Fn adsorption to biocompatible multilayer films
• Influence of Fn on cell response to multilayer
  films
• Fn adsorption faster, greater, more irreversible
  to PLL terminated films
• Fn adsorbs to top of multilayer film, not within
  film
• All polymer films exhibit diminished cell
  contacting properties w/o Fn
• Fn coated polymer films exhibit cell contacting
  properties comparable to those of Fn coated bare
  substrate
• Fn coatings important when using multilayer films
  in cell contacting applications

10
Acknowledgements

• Funding
• NIH R01 - EB00258
• QCMD experiments
• Jennifer Phelps, Yale University