Creating 3D Angiogenic Growth Factor Gradients in Fibrous Constructs to Guide Fast Angiogenesis
详细信息 查看全文
- 作者：Xiaolei Guo ; Christopher G. Elliott ; Zhenqing Li ; Yanyi Xu ; Douglas W. Hamilton ; Jianjun Guan
- 刊名：Biomacromolecules
- 出版年：2012
- 出版时间：October 8, 2012
- 年：2012
- 卷：13
- 期：10
- 页码：3262-3271
- 全文大小：785K
- 年卷期：v.13,no.10(October 8, 2012)
- ISSN：1526-4602
文摘
Fast angiogenesis in 3D fibrous constructs that mimic the morphology of the extracellular matrix remains challenging due to limited porosity in the densely packed constructs. We investigated whether mimicking the in vivo chemotaxis microenvironment for native blood vessel formation would stimulate angiogenesis in the fibrous constructs. The chemotaxis microenvironment was created by introducing 3D angiogenic growth factor gradients into the constructs. We have developed a technique that can quickly fabricate (40 min) such 3D gradients by simultaneously electrospinning polycaprolactone (PCL) fibers, encapsulating gradient amount of bFGF (stabilized by heparin) into poly(lactide-co-glycolide) (PLGA) microspheres, and electrospraying the microspheres into PCL fibers. Gradient formation was confirmed by fluorescence microscopy. Gradients with different steepnesses were obtained by modulating the initial concentration of the bFGF solution. All of the constructs were able to sustainedly release bioactive bFGF over a 28 day period. The release kinetics was dependent on the bFGF loading and steepness of the gradient. In vitro cell migration study demonstrated that bFGF gradients significantly increased the depth of cell migration. To assess the efficacy of bFGF gradients in inducing angiogenesis, we implanted constructs subcutaneously using mouse model. bFGF gradients significantly promoted cell penetration into the constructs. After 10 days of implantation, a high density of mature blood vessels (positive to both CD31 and 伪-SMA) were formed in the constructs. Vessel density was increased with the increase in steepness of the bFGF gradient. These gradient constructs may have potential to engineer vascularized tissues for various applications.