Dynamic Vortex Generation, Pulsed Injection, and Rapid Mixing of Blood Samples in Microfluidics Using the Tube Oscillation Mechanism

Abstract

Here, we describe the generation of dynamic vortices in micro-scale cavities at low flow rates. The system utilizes a computer-controlled audio speaker to axially oscillate the inlet tube of the microfluidic system at desired frequencies and amplitudes. The oscillation of the tube induces transiently high flow rates in the system, which facilitates the generation of dynamic vortices inside the cavity. The size of the vortices can be modulated by varying the tube oscillation frequency or amplitude. The vortices can be generated in single or serial cavities and in a wide range of cavity sizes. We demonstrate the suitability of the tube oscillation mechanism for the pulsed injection of water-based solutions or whole blood into the cavity. The injection rate can be controlled by the oscillation characteristics of the tube, enabling the injection of liquids at ultralow flow rates. The dynamic vortices facilitate the rapid mixing of the injected liquid with the main flow. The controllability and versatility of this technology allow for the development of programmable inertial microfluidic systems for performing multistep biological assays.

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“…It is worth noting that the rapid mixing of liquids can also be achieved using inertial microfluidic systems and active mechanisms. 26 Based on the centrifugal separation of plasma, we used centrifugal force to mix and drive the sample, automating the entire blood pretreatment process without an additional pump.…”

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“…11 Thurgood et al reported a new mechanism for generating dynamic vortices in microfluidics at low static flow rates and demonstrated its application for cellular assays, fluid mixing, and pulsed injection. 12,13 new size-dependent particle trapping phenomenon in microvortices that enables tunable cell capture. 14 Liu et al proposed an acoustic microvortex-based strategy for cell capture, pairing, and fusion.…”

“…Instead, microvortices are of great use to microfluidic systems because they are conducive to the manipulation of fluids and particles, which have been used for the rapid and controlled synthesis of functional nanomaterials and tunable processing and analysis of particulate samples (such as cells and colloids). , For example, Zhang et al proposed flower-like micromixers based on acoustic microvortices for developing ZnO nanorod arrays . Thurgood et al reported a new mechanism for generating dynamic vortices in microfluidics at low static flow rates and demonstrated its application for cellular assays, fluid mixing, and pulsed injection. , Khojah et al uncovered a new size-dependent particle trapping phenomenon in microvortices that enables tunable cell capture . Liu et al proposed an acoustic microvortex-based strategy for cell capture, pairing, and fusion .…”