Fig. 1. Working principles of acoustoelectronic nanotweezers (AENT).

a Acoustoelectronic fields are generated via dynamic acoustic wave interactions. These acoustic waves have minimal out-of-plane vibrations and associated acoustic attenuation losses in a fluid. F is the surface electric potential. b Schematic side-view of the electric field distribution and trapping positions for particles with different polarizabilities relative to the medium (red sphere: high polarizability; green sphere: low polarizability). c Schematic mechanism of AENT on manipulating nanoparticles with lower (p_np < p_m) or higher (p_np > p_m) polarizability than the medium in 3D space by tuning the phases and amplitudes of the acoustic waves. Δφ₁ indicates the phase variation of IDT₁. ΔA₁₂ indicates the amplitudes variation of IDT₁ and IDT₂. d Candidate excitation configurations based on nine potential single-crystal piezoelectric materials for AENT. κ_AET is the acoustoelectronic efficiency, which is defined as the ratio between the surface electric potential and the excitation voltage on the transducer in a standing wave mode. u_fluid is the acoustic streaming speed under consistent excitation amplitudes on different crystals. e Macroscopic materials with pre-designed nanotextures fabricated by AENT. Insets: microscopic images of PDMS films containing aligned carbon nanotubes and 100 nm PS beads, PEG hydrogels containing textured FITC-BSA proteins (66 kDa) and FITC-dextran (3 kDa). Scale bar: 60 μm.