Ultrasonic microbubble VEGF gene delivery improves angiogenesis of senescent endothelial progenitor cells oleh Yi-Nan Lee, Yih-Jer Wu, Hsin-I. Lee, Hsueh-Hsiao Wang, Chiung-Yin Chang, Ting-Yi Tien, Chao-Feng Lin, Cheng-Huang Su, Hung-I. Yeh