Application of Ultrasound‐Responsive Reagents for Drug Delivery Systems

This chapter explores the use of ultrasound-responsive reagents for drug delivery systems (DDS). Since the discovery of the phenomenon of acoustic cavitation of microbubbles (MBs), DDS using ultrasound has made great strides. In recent years, highly developed focused ultrasound systems (FUS) and advanced ultrasound-responsive reagents have been developed one after another. Various MBs with phospholipid, polymer, or protein shells can target lesions or carry drugs and genes through various surface modifications. Novel reagents, known as nanobubbles (NBs) and nanodroplets (NDs), which are much smaller than MBs, less than 1 μm in diameter, are also being developed. These ultrasound-responsive reagents are being tried for the treatment of various diseases, including malignant tumors and central nervous system diseases. These will bring innovative treatments for intractable diseases in the near future.