title: Simultaneous positioning of cells into two-dimensional arrays using ultrasound.
abstract: Contactless simultaneous positioning of micrometer-sized particles in suspension (e.g., copolymer beads, living cells, silicon microparts) can be performed using ultrasound. Current devices are capable of collecting particles into planes or lines by exciting a resonance in the fluid by means of a piezoelectric transducer located beneath the fluidic cavity and are designed such that a one-dimensional pressure field is created. The focus of this work is to collect cells in distinct point locations for potential drug screening array applications. A device to create two-dimensional arrays of cells within a micromachined chamber is described. The chamber is etched into a silicon wafer and sealed with glass; on the underside of the silicon layer a piezoelectric actuator is attached. A signal is applied to each of two orthogonally aligned strips electrodes defined on the surface of the piezoelectric plate. These two strip electrodes create independently addressable approximately one-dimensional pressure fields. It is shown that by applying the same signal to each electrode a diagonally aligned grid of cells can be produced. However, the independence of the two electrodes allows the application of two signals with slightly different frequencies to be applied which creates a grid of circular cell clumps highly suitable for the identified application. (c)
authors.affiliation: Center of Mechanics, ETH Zurich, CH-8092 Zurich, Switzerland. adrian.neild@imes.mavt.ethz.ch
authors.forename: Adrian
authors.initials: A
authors.lastname: Neild
authors.forename: Stefano
authors.initials: S
authors.lastname: Oberti
authors.forename: Gerald
authors.initials: G
authors.lastname: Radziwill
authors.forename: Jürg
authors.initials: J
authors.lastname: Dual
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques / Q000295:instrumentation* / Q000379:methods; D002460:Cell Line; D002469:Cell Separation / Q000295:instrumentation* / Q000379:methods; D004847:Epithelial Cells / Q000166:cytology* / Q000502:physiology / Q000528:radiation effects*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D051379:Mice; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods; D014159:Transducers; D014465:Ultrasonics