title: Repair of abdominal wall defects in vitro and in vivo using VEGF sustained-release multi-walled carbon nanotubes (MWNT) composite scaffolds.
abstract: OBJECTIVE
  Porcine acellular dermal matrices (ADM) have been widely used in experimental and clinical research for abdominal wall repair. Compared to porcine small intestinal submucosa (SIS), the effect of these matrices on the regenerative capacity of blood vessels is still not ideal. Multi-walled carbon nanotubes (MWNTs) can more effectively transport VEGF to cells or tissues because of their large specific surface area and interior cavity. In this study, we explored the safety and efficacy of implanted VEGF-loaded MWNT composite scaffolds in vitro and vivo to repair abdominal wall defects.
  
  
  METHODS
  VEGF-loaded MWNTs were prepared by a modified plasma polymerization treatment. Four composite scaffolds were evaluated for cytotoxicity, proliferation, and release dynamics. We created 3 cm×4 cm abdominal wall defects in 43 Sprague-Dawley rats. After implantation times of 2, 4, 8, and 12 weeks, the scaffolds and the surrounding tissues were collected and examined by gross inspection, biomechanical testing, and histological examination.
  
  
  RESULTS
  A 5-10 nm poly(lactic-co-glycolic acid) (PLGA) film was evenly distributed on MWNTs. The 3% MWNT composite group showed lower cytotoxicity and appropriate release performance, and it was thus tested in vivo. In rats with the 3% composite implanted, host cells were prevented from migrating to the ADM at 2 weeks, vascularization was established more rapidly at 12 weeks, and the values for both the maximum load and the elastic modulus were significantly lower than in the ADM-alone group (p<0.01). Histological staining revealed that the MWNT was still not completely eliminated 12 weeks after implantation.
  
  
  CONCLUSIONS
  MWNTs were able to carry VEGF to cells or tissues, and the 3% MWNT composite material showed lower cytotoxicity and had an appropriate release performance, which prompted faster vascularization of the ADM than other scaffolds. Nevertheless, the MWNTs induced harmful effects that should be carefully considered in biomedical studies.
authors.affiliation: Department of General Surgery, Shanghai Ninth People's Hospital Affiliated to Shanghai JiaoTong University School of Medicine, Hernia and Abdominal Wall Surgery Center of Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Zhicheng
authors.initials: Z
authors.lastname: Song
authors.forename: Zhi
authors.initials: Z
authors.lastname: Yang
authors.forename: Jianjun
authors.initials: J
authors.lastname: Yang
authors.forename: Zhengni
authors.initials: Z
authors.lastname: Liu
authors.forename: Zhiyou
authors.initials: Z
authors.lastname: Peng
authors.forename: Rui
authors.initials: R
authors.lastname: Tang
authors.forename: Yan
authors.initials: Y
authors.lastname: Gu
mesh_terms: D034861:Abdominal Wall / Q000002:abnormalities*; D000818:Animals; D001696:Biomechanical Phenomena; D049109:Cell Proliferation; D066298:In Vitro Techniques; D008855:Microscopy, Electron, Scanning; D037742:Nanotubes, Carbon; D033362:Powder Diffraction; D051381:Rats; D017207:Rats, Sprague-Dawley; D017550:Spectroscopy, Fourier Transform Infrared; D054457:Tissue Scaffolds; D042461:Vascular Endothelial Growth Factor A / Q000008:administration & dosage*
chemical_list: D037742:Nanotubes, Carbon; D042461:Vascular Endothelial Growth Factor A