# Poly(lactic acid)-Based Electrospun Fibrous Structures for Biomedical Applications
## 8 Biomedical Applications of PLA-Based Nanofibrous Structures
### Tissue Engineering
#### 8.3.3 PLA Scaffolds for Cardiovascular Tissue Engineering  
The development of novel tissue engineering strategies to replace cardiovascular tissues is very important since cardiovascular disease is the leading cause of death worldwide [154]. Like in nerve conduit scaffolds, a biocompatible and biodegradable tube with hollow lumen is required for designing vascular scaffolds that mechanically match with the graft site. The application of PLA nanofibrous scaffolds would aid the large-scale requirement of heart and blood vessels regeneration. Conduits for vascular tissue engineering are often limited by the tendency for the lumen to clot, especially in small diameter vessels, preventing blood flow from occurring; however, [PERSON] et al. [147]. Constructed tissue-engineered vascular graft (TEVG) composed of PLA tubular nanofiber scaffolds and successfully implanted these grafts in mice as aortic interposition conduits without any graft stenosis or aneurysmal dilatation (Figure 17). [PERSON] et al. [148] developed a bilayered electrospun scaffold containing PLA nanofibers mesh outer layer and silk fibroin-gelatin nanofibrous inner layer to improve scaffold biomimicry for blood vessel application. In another study, the potential of PLA/gelatin scaffold with aligned fibers was investigated for vascular tissue engineering application (Figure 18).  
Figure 17: **(a) Structure of TEVG. Implanted TEVG was composed of biodegradable electrospun PLA nanofibers with a length of approximately 3 mm and an inner luminal diameter of 500–600 μm. Scanning electron microscopy (SEM) demonstrates macro- and micro-arrangement of graft. (b) TEVG after surgical implantation (IVC: inferior vena cava; Ao: aorta). (c,d) High-resolution post-mortem microCT angiography at 12 months post-implantation. The results indicated a smooth endoluminal surface and absence of aneurys dilatation or stenosis. Yellow bar indicates the approximate location of the vascular graft. TEVG resembles native aorta on microCT throughout the 12 month-experiment; (\(n=5\) in each group), reproduced from [147], distributed under the terms of Creative Commons Attribution License.**  
Figure 18: SEM image of SMCs on the surface of the scaffolds after 120 h (a) PLLA alone, (b) nonwoven PLLA with 5% gelatin, (c) aligned PLLA with 5% gelatin, (d) nonwoven PLLA with 10% gelatin, (e) aligned PLLA with 10% gelatin (f) nonwoven PLLA with 20% gelatin and (g) aligned PLLA with 20% gelatin. (h)The electrospun PLLA/gelatin tubular constructs. Reproduced with permission from [149] (License number: 5232561220454).  
Results showed that fiber alignment had a significant effect on endothelial cells orientation so that cells have been elongated with the direction of the fibers, and the presence of gelatin led to an enhancement of human umbilical vein endothelial cells and smooth muscle cell adhesion (Figure 18) [149]. Although PLA nanofibrous scaffolds were most commonly applied for vascular tissue engineering, there are cases in which PLA nanofibrous patches are developed for the treatment of cardiac muscle [155].