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Polyelectrolyte Complex for Heparin Binding Domain Osteogenic Growth Factor Delivery
Published on: August 22, 2016
Covalent surface heparinization potentiates porous polyurethane scaffold vascularization
Deon Bezuidenhout1, Neil Davies, Melanie Black
1Cardiovascular Research Unit, Chris Barnard Division of Cardiothoracic Surgery, Faculty of Health Sciences University of Cape Town, Cape Town, South Africa. deon.bezuidenhout@uct.ac.za
Journal of Biomaterials Applications
|November 27, 2008
Summary
Surface modification of porous scaffolds with heparin significantly enhanced vascularization and arteriolization in vivo. This technique increased blood vessel formation without causing a greater inflammatory response, aiding tissue engineering.
Area of Science:
- Biomaterials Science
- Tissue Engineering
- Regenerative Medicine
Background:
- Porous scaffolds are crucial for tissue engineering, but improving vascularization while minimizing inflammation is key for long-term success.
- Previous work optimized scaffold pore dimensions; this study focused on surface modification to shift the biological response from inflammation to vascularization.
Purpose of the Study:
- To investigate the effect of surface immobilization with heparin on vascularization and inflammation in porous polyurethane scaffolds.
- To determine if heparinization can enhance blood vessel formation without increasing the inflammatory response in a subcutaneous implantation model.
Main Methods:
- Porous polyurethane disks with defined pore sizes (147 ± 2 µm) and interconnecting windows (67 ± 2 µm) were fabricated.
- Scaffolds were surface-modified with heparin via copolymer grafting and amination, achieving a heparin load of 32 µg.
- The modified scaffolds were implanted subcutaneously in rats for 28 days and assessed for vascularization (CD31/actin staining) and inflammation (ED-1 staining).
Main Results:
- Heparinization significantly increased capillary density by 62% (p < 0.03) and capillary area by 56% (p < 0.02).
- Arteriole number increased by 200% (p < 0.03), though normalized arteriole count did not change significantly.
- The inflammatory response, quantified by ED-1 positive macrophages and foreign body giant cells, was not significantly affected by heparinization at 28 days.
Conclusions:
- Surface immobilization of heparin on porous scaffolds effectively enhances in vivo vascularization and arteriolization.
- This simple surface modification technique increases blood vessel formation without a concomitant rise in the inflammatory response.
- Heparinized porous scaffolds represent a promising strategy for tissue engineering applications requiring improved vascular integration.
