Figure 2.

Controlled release from PSVs in solution under acoustic streaming. a) Chamber‐based release system. A filter membrane (molecular weight cut‐off=12–15 kDa) was sandwiched between two PDMS chambers to keep the PSV‐encapsulated CF dye in the lower chamber, while the liberated CF dye can pass through the filter membrane. Thus, the amount of the released dye can be determined by measuring the fluorescence intensity in the top chamber. b) The fluorescence intensities of the released CF dye as a function of time, and linear fits of the initial parts of these curves. The fluorescence intensity at 0 min was obtained by measuring the buffer solution in the upper chamber without stimulation after waiting for 20 min (Figure S6). c) Initial release rates as a function of power. TEM images of the PSVs d) before and e) after the acoustic stimulation (500 mW for 20 min). Scale bars=100 nm.