Event Abstract Back to Event Oriented differentiation of MSCs to VECs by FMC assay on the micro-patterned TiO2 nanotubes Jingan Li1, Ping Yang1, Juejue Wu1, Zikun He1, Feng Wu1 and Nan Huang1 1 Southwest Jiaotong University, Key Laboratory for Advanced Technologies of Materials, Ministry of Education, China Introduction: Surface endothelialization of cardivascular implanted biomaterials has been generally accepted as a effective method for the therapy of thrombosis and hyperplasia[1],[2]. Although the VECs of the endothelialization mainly come from the migeration of the neighbor vessels and the capture of EPCs, the MSCs as abundant source should also be considered for endothelialization. Materials and Methods: Fabrication of ECM on the micro-patterned TiO2 nanotubes: The micro-patterned TiO2 nanotubes thin film and ECM loaded micro-patterned TiO2 nanotubes were fabricated as our previous work described[3]. The type IV collagen (CoIV), as the main component of endothelial ECM, was characterized to evaluate the ECM distribution and describe the surface morphology. In brief, all the samples were stained using a FITC labeled antibody (Boshide, China)[4], and then observed under a fluorescence microscopy. The fluorescence images were treated by a Ipwin 32 software, and the 3D images of the surfaces were obtained, subsequently the fluorescence intensity of the FITC on each samples were calculated by the software. The fluorescence intensity of the FITC was positively correlated to the ECM amount[5]. Inducing oriented differentiation of MSCs to VECs by FMC: The human umbilical mesenchymal stem cells (HUMSCs) were isolated from Wharton’s jelly tissue of newborn umbilical cord[6]. The HUMSCs were seeded on each samples with a concentration of 5×104 cells/ml and cultured as a method that was named “Frequently medium change” (FMC). After 2 weeks, the HUMSCs were immunofluorescence stained by the FITC labeled vWF antibody (Sigma, USA) and the nucleus were stained by DAPI (Sigma, USA) to evaluate the differentiation of HUMSC. Results and Discussions: Fig.1 showed that the ECM on the topo-nano, topo and gro-nano distributed more homogeneously compared with ECM on the TiO2 and nano surfaces, suggesting better loading ability of ECM. While the topo-nano showd higher fluorescence intensity of the FITC compared to other samples, which indicated the decreased amounts of ECM in the order: topo-nano> topo> gro-nano > nano> TiO2. Fig. 1 3D images of (A) TiO2, nano, gro-nano, topo, topo-nano surfaces and (B) ECM loaded TiO2, nano, gro-nano, topo, topo-nano surfaces Fig. 2 showed that the cells on the topo-nano surface exhibited positive expression of vWF, implying successful differentiation of HUMSCs to VECs, while the cells on the other surfaces showed negative expression. However, the positive expression of vWF of the HUMSCs on the ECM/topo-nano seemed weak, while this expression might be enhanced by longer FMC culture. Fig.2 Fluorescence images of the induced HUMSCs on all samples stained by FITC labeled antibody of vWF and DAPI Conclusions: In the present work, the endothelial ECM was prepared onto the micro-patterned TiO2 nanotubes for the purpose of inducing the oriented differentiation of HUMSCs to VECs. After the FMC for 2 weeks, the induced HUMSCs on the topo-nano presented positive expression of vWF, which demonstrated successful differentiation preliminarily. This method was anticipated potential application for surface endohelialization of cadiovascular biomaterials. The Key Basic Research Project of China (No. 2011CB606204); The National Natural Science Foundation of China (No. 30870629); China Postdoctoral Science Foundation (2014M562333); Postdoctoral Funds of Southwest jiaotong University (X1101512370435 and YH1101012371444)