Ultrasonic microbubbles promote mesenchymal stem cell homing to the fibrotic liver via upregulation of CXCR4 expression oleh Heming Xu, Yize Huang, Fasu Zhang, Wei Shi, Yan Cheng, Kai Yang, Pingping Tian, Fei Zhou, Yuan Wang, Xueqing Fang, Youliang Song, Bo Liu, Liwei Liu