Tuning cell adhesion on gradient poly(2-hydroxyethyl methacrylate)-grafted surfaces.
A simple yet versatile method was developed to prepare a low-density polymerization initiator gradient, which was combined with surface-initiated atom transfer radical polymerization (ATRP) to produce a well-defined poly(2-hydroxyethyl methacrylate) (HEMA) gradient substrate. A smooth variation in film thickness was measured across the gradient, ranging from 20 A to over 80 A, but we observed a nonmonotonic variation in water contact angle. Fits of X-ray reflectivity profiles suggested that at the low graft density end, the polymer chain structure was in a "mushroom" regime, while the polymer chains at high graft density were in a "brush" regime. It was found that the "mushroom" region of the gradient could be made adhesive to cells by adsorbing adhesion proteins, and cell adhesion could be tuned by controlling the density of the polymer grafts. Fibroblasts were seeded on gradients precoated with fibronectin to test cellular responses to this novel substrate, but it was found that cell adhesion did not follow the expected trend; instead, saturated cell adhesion and spreading was found at the low grafting density region.
Mei
Ying
Y
Polymers Division and Biotechnology Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
Wu
Tao
T
Xu
Chang
C
Langenbach
Kurt J
KJ
Elliott
John T
JT
Vogt
Bryan D
BD
Beers
Kathryn L
KL
Amis
Eric J
EJ
Washburn
Newell R
NR
D000327:Adsorption; D000818:Animals; D002448:Cell Adhesion; D008689:Methacrylates / Q000737:chemistry*; D051379:Mice; D041681:NIH 3T3 Cells; D011108:Polymers / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry; D013499:Surface Properties
D008689:Methacrylates; D011108:Polymers; D011506:Proteins; C005044:hydroxyethyl methacrylate