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Bioactive heparin surfaces from derivatization of polyacrylamide-grafted LLDPE
A Wirsén1, M Ohrlander, A C Albertsson
1Department of Polymer Technology, Royal Institute of Technology, Stockholm, Sweden.
Biomaterials
|October 1, 1996
Summary
Primary amine groups were grafted onto polyacrylamide-LLDPE films and functionalized with heparin. The resulting heparinized surfaces effectively bind antithrombin (AT) without activating coagulation factor XII (FXIIa).
Area of Science:
- Biomaterials Science
- Polymer Chemistry
- Surface Modification
Background:
- Polyacrylamide-LLDPE films are a potential substrate for biomedical applications.
- Introducing primary amine groups is crucial for subsequent surface functionalization.
- Heparinization of surfaces can impart anticoagulant properties.
Purpose of the Study:
- To introduce primary amine groups onto polyacrylamide-LLDPE films using Hofmann degradation.
- To covalently bind heparin to the modified films.
- To evaluate the biological activity of the heparinized surfaces.
Main Methods:
- Hofmann degradation synthesis at room temperature with varying sodium hypochlorite and sodium hydroxide concentrations.
- Covalent binding of diazotized heparin to amine-grafted films.
- Surface analysis using ESCA, ATR-IR, chloride titration, and Toluidine Blue.
- Biological evaluation through antithrombin (AT) binding capacity and inhibition of activated coagulation factor XII (FXIIa).
Main Results:
- Successful introduction of primary amine groups onto polyacrylamide-LLDPE films.
- Effective covalent immobilization of heparin onto the modified surfaces.
- Heparinized surfaces demonstrated significant AT binding capacity (up to 3 pmol cm-2).
- No activation of adsorbed FXIIa was observed on the heparinized surfaces.
Conclusions:
- The Hofmann degradation method is effective for preparing amine-functionalized polyacrylamide-LLDPE films.
- The developed heparinized surfaces exhibit favorable antithrombotic properties by binding AT and not activating FXIIa.
- These findings suggest potential applications in blood-contacting medical devices.