3D‐Printed Acoustofluidic Devices for Raman Spectroscopy of Cells

Acoustic manipulation of multi-body structures and dynamics

“…Embedding SAW generators into microfabricated structures has enabled microfluidic or whole lab-on-a-chip devices that can arrange small objects into patterns that are spatially and temporally controllable (figures 7(b) and (c)). Such devices, which can be 3D-printed [245], are integrated straightforwardly into setups employing various types of microscopy. In their simplest form the devices send sound from opposing sides across a fluidic channel or reservoir to form a 1D standing pressure wave, which drives objects inside the channel to aggregate in the pressure nodes or anti-nodes, depending on the acoustic contrast [250] (see equations ( 8) and ( 9) for rigid particles and equation (16) for bubbles in a liquid).…”

“…For example, these systems have been used for concentrating cells to enhance harvesting efficiency during sedimentation [256], to probe cell-cell interactions [257,258], or for separation or trapping of cells [59,248,255]. Concentrating cells within the levitation plane then facilitates investigation with microscopy and associated techniques such as Raman spectroscopy [245], or to mimic the arrangement of cells within a tumor [246]. Secondary acoustic forces have also been used to arrange liquid emulsion droplets into closepacked clusters and, at the same time, manipulate the relative orientations of small anisotropic cargo inside the droplets, such as small rigid discs [20].…”

“…In 3D acoustic cavities, where the standing wave nodes generated by plane waves form 2D planes, attractive secondary forces have been used to generate crystal-like, close-packed clusters and monolayer particle rafts in either liquid or air [7,40,43,197,198,229,245]. These forces also direct the assembly of particles of non-spherical shape by exploiting the local particle curvature (see section 2.1 and figure 5).…”