Ultrahigh frequency ZnO silicon lens ultrasonic transducer for cell-size microparticle manipulation

In single beam acoustic tweezers application, the development of ultrahigh frequency ultrasonic transducer is crucial for trapping particles or cells with a size of few microns. In this study, A ZnO silicon-lens ultrasonic transducer with ultrahigh center frequency was designed and fabricated for single beam acoustic tweezers application. The silicon lens with small radius was developed through isotropic chemical wet etching technique. Finite element method was used for transducer design and evaluation. The transducer fabricated has a center frequency of 330 MHz, −6 dB bandwidth of 21% and the insertion loss of −68 dB. The transducer was shown to be capable of manipulating individual 5 μm polystyrene microsphere which demonstrated the potential of this type of ultrahigh frequency transducer for biophysical and biomedical applications. - Highlights: • Silicon based lens for ultrasound focusing was developed through isotropic chemical wet etching technique. • Focused ZnO ultrahigh frequency (>300 MHz) ultrasonic transducer is fabricated and characterized. • The ZnO ultrasonic transducer enable the high frequency ultrasound to manipulate individual cell-size particles.