**2.3 Sonoprinting**

Recently, Cock et al. put forward a new viewpoint on the mechanism of ultrasound-mediated gene delivery [26]. By using the real-time scanning confocal microscopy, they found that nanoparticle-loaded microbubbles could deposit the nanoparticles in patches onto the cell membrane during ultrasound irradiation and promote the particles that enter cell through the fluidity of the membrane. In their opinion, this method, termed sonoprinting, is neither the traditional sonoporation nor the material swallowing. The underlying mechanisms still need to be explored.
