13.

Actuators and acoustic transducers based on piezoelectric biomaterials. A) Biodegradable ultrasonic transducer for opening the BBB. (a) Schematic of the implantation of the transducer on the mouse brain. (b) Treatment results of GBM tumor delivery of chemotherapeutic drug to the brain facilitated by the biodegradable ultrasonic transducer. Reproduced with permission. Copyright 2023, American Association for the Advancement of Science. B) Optical images showing the use of piezoelectric PLLA tweezers to grasp and remove thrombosis samples. Reproduced with permission. Copyright 2006, Wiley-VCH. C) Chitin-based transducer. (a) Schematic of the chitin transducer as a speaker and a microphone. (b) Short-time Fourier transform (STFT) spectrograms from the chitin speaker and the chitin microphone. Reproduced with permission. Copyright 2018, Elsevier.