Acoustic manipulation of cells and particles based on disposable, light-guiding capillaries

Acoustic trapping, concentration and transport of cells and particles are demonstrated in a several-cm-long capillary. A cone-shaped acoustic transducer is coupled to an end of the capillary to generate a standing flexural wave along the entire length of the capillary. Because of the unique structure of the transducer, temporary, but stable, acoustic coupling was achieved using a water drop instead of permanent glue, and the capillary was easily replaced after use. The device also allowed light to be guided in the capillary for effective optical interaction with the particles trapped by the acousticwave. A pump beam was guided at low loss to optically excite the fluorescent particles distributed along the long capillary simultaneously. The study suggests the feasibility of a capillary-based acoustic device with integrated functions of acoustic manipulations and optical diagnosis.