Application Cases

Experiment Name: Application of Power Amplifiers in Non-contact Droplet Manipulation and Fluorescence Analysis Detection on Superhydrophobic Surfaces with Machine Vision Assistance

Experiment Content:
In this study, we developed a Machine Vision-Assisted Acoustic Tweezers (MVAAT) system for automated and non-contact droplet manipulation on superhydrophobic surfaces. This system utilizes ultrasonic standing waves generated between an ultrasonic transducer (UST) and the superhydrophobic surface to induce acoustic radiation forces, enabling non-contact droplet manipulation. A machine vision system based on an industrial camera is employed for real-time droplet detection and tracking, providing precise positional information for automated droplet transportation and merging. Finally, the MVAAT system was applied to fluorescence-based Cu²⁺ detection, demonstrating its potential in practical biochemical analysis.

Testing Equipment: ATA-1220D power amplifier, signal generator, ultrasonic transducer, etc.

Figure 1: Experimental Setup Diagram

Experimental Procedure:

Figure 2: Experimental Steps

As shown in Figure 1, all droplet manipulation experiments were conducted using the MVAAT system equipped with a 10 mm diameter ultrasonic transducer. The ultrasonic transducer has a center frequency of 40 ± 1 kHz, a bandwidth of 1.2 kHz, a sound pressure level of 105 dB, and an emission angle of 80° ± 12°. The ultrasonic transducer is fixed to the Z-axis of a Cartesian robot. Directly below it is the superhydrophobic substrate. An industrial camera with a resolution of 2048 × 1536 pixels and a frame rate of 120 fps, paired with a 12 mm fixed-focus lens, is positioned directly beneath the transparent superhydrophobic substrate for real-time droplet detection and tracking. To activate the UST, a signal generator is used to produce a 38 kHz sine wave with an emission voltage of 5 V, which is then amplified by a power amplifier. A microprocessor controls the movements of the Cartesian robot and the on/off state of the ultrasonic transducer. The MVAAT system was used for automated droplet manipulation to detect the concentration of Cu²⁺ in water, demonstrating its potential for practical biochemical applications. The experimental steps, as shown in Figure 2, involve virtually dividing the superhydrophobic substrate into a droplet pretreatment zone, a detection zone, and a recovery zone. In the droplet pretreatment zone, the MVAAT merges the target droplets and subsequently transports them to the fluorescence-based Cu²⁺ detection zone. After a 10-second dwell time in the detection zone, the droplets are transported to the recovery zone for processing.

Experimental Results:

Figure 3: Experimental Demonstration Effects

The actual demonstration effects are shown in Figure 3. Initially, the MVAAT was used to automatically merge two droplets ("Liquid0" and "Liquid1") containing RBH and Cu²⁺. Subsequently, the merged droplet was transported to the detection zone for Cu²⁺ concentration analysis using a fluorescence detector. After analysis, the merged droplet was moved to the recovery zone for processing. This process was then repeated for subsequent detection of "Liquid2" and "Liquid3."

Figure 4: Experimental Detection Results

The detection results, as shown in Figure 4, indicate that the ADC value of the fluorescence detector remained at 3 when no droplet was present in the detection zone. However, when the first merged droplet (10 μM Cu²⁺) arrived, the ADC increased to approximately 130. When the droplet was moved to the recovery zone, the ADC returned to 3. Subsequently, the arrival of the second merged droplet (1 mM Cu²⁺) in the detection zone caused the ADC to further increase to approximately 340. The entire experiment was completed in approximately one minute.

Recommended Power Amplifier: ATA-1200C Broadband Amplifier

Figure: ATA-1200C Broadband Amplifier Specifications

Xi’an Aigtek Electronics is a high-tech enterprise specializing in the research, development, production, and sales of electronic testing instruments, including power amplifiers, high-voltage amplifiers, power signal sources, preamplifiers for weak signals, high-precision voltage sources, and high-precision current sources. The company provides users with competitive testing solutions.