Application Cases

Experiment Name: Experiment on an Ultrasonically Driven Microneedle System for Cell Spheroid Assembly

Research Direction: Acoustic Tweezers

Experimental Content: The research team proposed a cell spheroid manipulation method based on the coupling effects of acoustofluidics and acoustic radiation force, enabling controllable capture and release operations of cell spheroids. This method achieves controllable assembly of cell spheroids in both two-dimensional and three-dimensional spaces.

Test Equipment: Signal generator, ATA-1372A broadband amplifier, oscilloscope, microscope, etc.

Experimental Process:

Figure 1: Ultrasonically driven microneedle system for cell spheroid assembly

Figure 2: Process flow for patterned assembly of cell spheroids

As shown in Figure 1, the system consists of four core components: a signal generator, a power amplifier, a 3D-printed microneedle, and a piezoelectric ceramic (PZT) transducer. When the PZT transducer is excited by an alternating signal generated by the signal generator, the resulting acoustic waves propagate along the microneedle axis and penetrate into the cell spheroid-containing culture medium at the needle tip, inducing a high-intensity acoustic streaming effect that drives the directional migration of cell spheroids along streamline paths. When cell spheroids approach the microneedle tip, stable capture in the tip region is achieved through the dynamic balance of multiple forces, including gravity, buoyancy, Stokes drag, and acoustic radiation force. Based on this physical mechanism, we further established a patterned assembly process for cell spheroids, as illustrated in Figure 2: First, the acoustically excited microneedle is inserted into a container filled with culture medium and cell spheroids to capture a cell spheroid at its tip. Then, a precision displacement platform controls the microneedle to move along a predefined trajectory, synchronously transferring the captured cell spheroid. Finally, the transducer is turned off to terminate the acoustic field, releasing the cell spheroid to complete patterned deposition.

Experimental Results:

Figure 3: Cell spheroids of various shapes

Figure 4: Experimental results of cell spheroid assembly

To validate the feasibility and precision of this acoustofluidic micro-manipulation system for patterned assembly of cell spheroids, as shown in Figure 3, we successfully assembled cell spheroids into various shapes in two-dimensional space, including straight lines, triangles, rectangles, circles, and concentric circles. Additionally, we assembled multiple cell spheroids into homogeneous or heterogeneous pyramid structures in three-dimensional space, further demonstrating the system's potential for constructing complex structures. Using this system, we assembled MC3T3-E1 cell spheroids, showcasing its application potential in osteogenic tissue preparation. As shown in Figure 4, we first assembled five cell spheroids into a ring-shaped structure using this device. After 48 hours of culture, the cell spheroids continued to fuse into a ring-shaped microtissue. Subsequent biological characterization confirmed that the prepared osteogenic tissue exhibited excellent biochemical properties.

Recommended Power Amplifier: ATA-1372A

Figure: ATA-1372A broadband amplifier specifications and parameters