Non-contact three-dimensional cell cluster formation on demand in open
dishware using focused surface acoustic waves through a couplant layer
Abstract
Three-dimensional cell agglomerates are broadly useful in tissue
engineering and drug testing. We report a well-free method to form large
(1-mm) multicellular clusters using 100-MHz surface acoustic waves (SAW)
without direct contact with the media or cells. A fluid couplant is used
to transformthe SAW into acoustic streaming in the cell-laden media held
in a petri dish. The couplant transmits longitudinal sound waves,
forming a Lamb wave in the petri dish that, in turn, produces
longitudinal sound in the media. Due to recirculation, human embryonic
kidney (HEK293) cells in the dish are carried to the center of the
coupling location, forming a cluster in less than 10 min. A few minutes
later, these clusters may then be translated and merged to form large
agglomerations, and even repeatedly folded to produce a roughly
spherical shape of over 1 mm in diameter for incubation—without
damaging the existing intercellular bonds. Calcium ion signaling through
these clusters and confocal images of multiprotein junctional complexes
suggest a continuous tissue construct: intercellular communication. They
may be formed at will, and the method is feasibly useful for formation
of numerous agglomerates in a single petri dish.