Low-cost acoustic force trap in a microfluidic channel

Vi-Hung Tsan; Daniel Fan; Sabina Caneva; Carlas S Smith; Gerard J Verbiest

doi:10.1016/j.ohx.2023.e00428

Low-cost acoustic force trap in a microfluidic channel

HardwareX. 2023 May 19:14:e00428. doi: 10.1016/j.ohx.2023.e00428. eCollection 2023 Jun.

Authors

Vi-Hung Tsan¹, Daniel Fan¹, Sabina Caneva¹, Carlas S Smith¹, Gerard J Verbiest¹

Affiliation

¹ Faculty of Mechanical, Materials, and Maritime Engineering, Technische Universiteit Delft, Delft 2628CD, The Netherlands.

Abstract

A low-cost glass-based microfluidic flow cell with a piezo actuator is built using off-the-shelf parts (total cost €9 per device) to apply acoustophoretic force on polystyrene micro-beads. The main challenge in the fabrication of these devices was to ensure their leak tightness, which we solved using double-sided tape and nail polish. Beads with 1.5 μm diameter flowing in a 100 μm deep channel were trapped at 7.5 MHz using a 23.7 peak-to-peak voltage ( $V_{pp}$ ) sinusoidal input. The trap located at 50 ± 0.1 μm depth was measured to have a stiffness of approximately 0.6 pN/μm. With this simple device we can trap and control the axial position of micrometer scale objects, which allows for the manipulation of beads and cells. We intend to use the device for force spectroscopy on micro-bead tethered DNA. This can be combined with super-resolution imaging techniques to study mechanics and binding of protein structures along a DNA strand as a function of induced tension.

Keywords: Acoustic force spectroscopy; Acoustic trapping; Acoustophoretic; Low-cost; Microfluidics.