Interactions of corneal cells with transforming growth factor β2‐modified poly dimethyl siloxane surfaces Journal Articles uri icon

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abstract

  • AbstractThe downgrowth of corneal epithelial cells at the interface of an artificial cornea and the host eye tissue poses a significant problem to be overcome in developing a successful implant. As a means of inhibiting the proliferation of corneal epithelial cells on the stromal surface of the implant, we examined the immobilization of transforming growth factor beta‐2 (TGF‐β2) via a bifunctional poly ethylene glycol (PEG) spacer to poly dimethyl siloxane (PDMS) surfaces. Growth factor immobilization was confirmed by modification with 125I‐labeled TGF‐β2. The modified surfaces were also characterized by advancing water contact angles, X‐ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Although the amount of growth factor covalently bound to the surface was difficult to quantify apparently due to strong interactions between the growth factor and the PEG layer and high levels of adsorption, differences in the modified surfaces, suggestive of the presence of a significant amount of TGF‐β2, were found. In vitro interactions of the modified surfaces with human corneal epithelial and stromal cells were examined. Growth factor surface concentrations as well as culture in the absence and presence of serum and other adhesive proteins were examined. Corneal stromal and epithelial cells cultured on the TGF‐β2—modified surfaces consistently gave results opposite to those expected. Likely, the most notable and surprising result was the almost complete lack of adhesion of the stromal cells, with coverages averaging between 3 and 5%. In comparison, corneal epithelial cell growth appeared to be promoted by the presence of the immobilized growth factor, with cell coverages averaging 50–60% at 7 days of culture. A TGF‐β2 concentration effect was noted with both cell types in the absence of serum, with increases in the coverage at higher TGF‐β2 concentrations. The observed cell growth appeared to be the result of interactions between the cells and active growth factor, because the addition of anti‐TGF‐β2 to the culture medium reduced cell coverage to levels similar to those noted on control surfaces. Therefore, although TGF‐β2–modified surfaces may not be suitable as corneal epithelial cell inhibiting surfaces, interactions of surface immobilized growth factor and corneal cells are complex and should be further examined. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 981–993, 2003

publication date

  • December 2003

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