Actuation of microchannels for optimized acoustophoresis

Inventors

Fiering, Jason • Christianson, Rebecca

Abstract

The systems and methods of the present disclosure provide techniques for the design and use of an intermediate or transitional plate or block designed to couple acoustic energy at a given frequency from a transducer, such as a piezoelectric transducer, to one or more acoustophoretic devices, such as microfluidic channels, such that driving the chip occurs with a controlled wavelength and symmetry. Such techniques provide improved efficiency when driving a single acoustophoretic device, or for multiple acoustophoretic devices to be operated in concert from a single transducer, and therefore without complex electronics. Additionally, the techniques described herein allow for relaxed design constraints when considering transducer selection and fabrication, instead transferring design constraints to the more easily customized actuation plate.

Core Innovation

The invention provides an intermediate or transitional plate or block designed to couple acoustic energy at a given frequency from a transducer to one or more acoustophoretic devices such that driving the chip occurs with a controlled wavelength and symmetry. Such techniques provide improved efficiency when driving a single acoustophoretic device, or for multiple acoustophoretic devices to be operated in concert from a single transducer, and therefore without complex electronics. The techniques transfer design constraints from the piezoelectric element to the more easily customized actuation plate, allowing relaxed design constraints when considering transducer selection and fabrication.

The patent identifies deficiencies of conventional acoustophoresis systems that employ two or more transducers coupled directly to an acoustophoresis channel and driven out of phase, which can result in complicated electronics systems and unwanted secondary oscillations, especially when driving multiple channels. Alternatives that couple one continuous transducer directly to multiple microfluidic channels require transducers at least as large as the array of channels and can require undesirably large electrical power as size increases. The actuation plate approach is presented to address these drawbacks by providing a well-defined mechanical resonance with desired symmetry and frequency.

The actuation plate includes a first surface configured to be coupled to an acoustic transducer and a second surface, opposite the first surface, configured to be coupled to one or more microfluidic channels, and has a thickness selected such that the acoustic transducer generates a standing wave in the actuation plate that concurrently focuses target particles to flow within fluid along a center of each of the one or more microfluidic channels. Plate parameters including width, thickness, material elastic modulus, and optional grooves or slots that define beams are tunable so that the wavelength and number of standing wave nodes or antinodes correspond to the number and placement of microfluidic channels. The systems and methods separate chip design from piezoelectric element design and enable positioning each microfluidic channel on a center of a corresponding standing wave node or antinode generated in the actuation plate.

Claims Coverage

The independent claims recite three main inventive features corresponding to an actuation plate, a method of creating actuation plates, and a system comprising an acoustic transducer, microfluidic channels, and an actuation plate.

Collectively, the independent claims cover an actuation plate with slots and tuned thickness/material properties to generate a standing wave that focuses particles in multiple microfluidic channels, a method to select plate dimensions and material to achieve those standing wave nodes matching channel positions, and a system combining the transducer, plate, and channels to achieve concurrent focusing.

Stated Advantages

Documented Applications