A photochemical method for immobilization of azidated dextran onto aminated poly(ethylene terephthalate) surfaces

Bhat, Venugopal T. ; James, Nirmala R. ; Jayakrishnan, Athipettah (2008) A photochemical method for immobilization of azidated dextran onto aminated poly(ethylene terephthalate) surfaces Polymer International, 57 (1). pp. 124-132. ISSN 0959-8103

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Official URL: http://onlinelibrary.wiley.com/doi/10.1002/pi.2332...

Related URL: http://dx.doi.org/10.1002/pi.2332


Background: Dextran, a bacterial polysaccharide, has been reported to be as good as poly(ethylene glycol) in its protein-rejecting and cell-repelling abilities. In addition, the multivalent nature of dextran is advantageous for surface grafting of biologically active molecules. We report here a method to photochemically bind dextran hydrogel films to aminated poly(ethylene terephthalate) (PET) surfaces in aqueous media using a heterobifunctional crosslinker, 4-azidobenzoic acid. In order to achieve this, dextran was first functionalized with the crosslinker using carbodiimide chemistry followed by photo-crosslinking and immobilization onto the nucleophile-rich aminated PET surfaces. Results: The presence of the immobilized dextran on PET was verified by attenuated total-reflection Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy and contact angle measurements. The grafted surface was highly hydrophilic due to the heavily hydrated polysaccharide network on the surface as demonstrated by the near zero water contact angle. Conclusion: A photochemical method for surface immobilization of dextran onto aminated PET using aryl azide chemistry is a facile technique to generate highly hydrophilic and more hemocompatible surfaces. The aryl nitrenes generated by photolysis produce a metastable, electron-deficient intermediate, azacycloheptatetraene, which is believed to be responsible for the simultaneous crosslinking of dextran and its immobilization onto the aminated PET surface. The aryl azide chemistry reported here for dextran could be useful as a versatile technique for surface modification of other nucleophile-rich polymers to create dextran- or similar polysaccharide-immobilized surfaces.

Item Type:Article
Source:Copyright of this article belongs to Society of Chemical Industry.
Keywords:Dextran; Hydrophilicity; Photopolymerization; Poly(ethylene Terephthalate); Surface Modification
ID Code:13950
Deposited On:12 Nov 2010 14:25
Last Modified:17 Feb 2011 08:15

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