Abstract
Myocardial infarction (MI) is known as a main cardiovascular disease that leads to extensive cell death by destroying vasculature in the affected cardiac muscle. The development of ultrasound-mediated microbubble destruction has inspired extensive interest in myocardial infarction therapeutics, targeted delivery of drugs, and biomedical imaging. In this work, we describe a novel therapeutic ultrasound system for the targeted delivery of biocompatible microstructures containing basic fibroblast growth factor (bFGF) to the MI region. The microspheres were fabricated using poly(lactic-co-glycolic acid)-heparin-polyethylene glycol- cyclic arginine-glycine-aspartate-platelet (PLGA-HP-PEG-cRGD-platelet). The micrometer-sized core-shell particles consisting of a perfluorohexane (PFH)-core and a PLGA-HP-PEG-cRGD-platelet-shell were prepared using microfluidics. These particles responded adequately to ultrasound irradiation by triggering the vaporization and phase transition of PFH from liquid to gas in order to achieve microbubbles. Ultrasound imaging, encapsulation efficiency cytotoxicity, and cellular uptake of bFGF-MSs were evaluated using human umbilical vein endothelial cells (HUVECs) in vitro. In vivo imaging demonstrated effective accumulation of platelet- microspheres injected into the ischemic myocardium region. The results revealed the potential use of bFGF-loaded microbubbles as a noninvasive and effective carrier for MI therapy.