Application Cases

Experiment Name: Application of Power Amplifier in Droplet and Microparticle Sorting Based on Microfluidic Technology

Experiment Objective:

To enhance the efficiency and accuracy of biomolecule detection by screening target droplets from a large number of droplets, thereby significantly improving detection efficiency and accuracy.

Experimental Equipment:

Microfluidic chip, signal generator, micro-injection pump, fluorescence detection system, ATA-2161 high-voltage amplifier.

Experimental Content:

A microfluidic chip suitable for biological sample analysis and detection was designed and fabricated using soft lithography. The experiments were conducted in a sodium alginate solution environment, with different microparticles used to simulate the behavior of biomolecules in this environment.

Experimental Procedure:

1. Chip Design and Fabrication
   Polydimethylsiloxane (PDMS) was used as the basic material for fabricating the microfluidic chip, which was then bonded to glass to form the microfluidic device.

1. Experimental Platform Setup
   The experimental setup included a micro-injection pump and syringe for injecting sample solutions, a fluorescence detection system (including a high-speed camera and fluorescence excitation light source) for observing droplets and analyzing signals, and a droplet sorting module (consisting of a DC high-voltage power supply, signal generator, and ATA-2161 power amplifier).

Application of Power Amplifier in Microparticle Sorting System

1. Droplet Sorting Process
   After the droplets were decelerated, they could be sorted more precisely. Fluorescent particles, when excited by light, emitted fluorescence that triggered the signal generator. This, in turn, activated the signal amplifier to produce a rectangular pulse voltage (700 V, 220 ms pulse width). As shown in the figure, when droplets containing fluorescent target particles were detected by the system, they were diverted into the lower channel due to the action of the electrostatic force. In contrast, empty droplets or droplets containing ordinary particles continued along the main channel without being affected by the electrostatic force. This process effectively separated fluorescent particles from the sample solution. The particles collected at the outlet of the fluorescent particle channel were observed and counted.

Fluorescent Particles in the Deceleration Zone

Fluorescent Particle Sorting Process

Experimental Results:

A microfluidic chip integrating functions of microparticle focusing, particle encapsulation, droplet deceleration, and droplet sorting was successfully designed and fabricated. The chip effectively separated droplets containing fluorescent particles from those containing ordinary particles or empty droplets, achieving a sorting success rate of up to 87%. Using sodium alginate solution as the dispersed phase, droplets with different characteristics were sorted using electrostatic forces, allowing the selection of droplets containing different target substances from a large number of droplets. This method provides an excellent sample processing solution for medical analysis, facilitating subsequent detection.