To begin evaluating the performance of the 3D-printed microfluidic droplet generator device, a simple flow test was carried out using green dye (Figure 1). This step was performed to verify that the channels were properly sealed and to check for any potential leakage points. After confirming that the fluid flow was continuous, the device was examined under a stereomicroscope to verify that the internal channel geometry performed as intended (see video below). As visible in the test, the flow requires more precise control; however, even without any adjustment of the fluid viscosity, droplet formation was successfully observed. Figure 1. Initial tests with green dye Test with oil and ultrapure water under a stereomicroscope