Application Cases

Name of experiment：application of power amplifier based on microfluidic technology for droplet microparticle separation

Research direction：microfluidic

Content of experiment：a chip for the analysis and detection of biological samples was designed and prepared by soft lithography. The experiment was carried out in sodium alginate solution environment and different microparticles were used instead of biomolecules to simulate the effect of alginate in environment.

Purpose of experiment：for the detection of biomolecules, it is necessary to screen the microdroplet, and select the droplet that meets the target from a large number of droplet, thus greatly improving the detection efficiency and accuracy.  

Test equipment：microfluidic chip, signal generator, micro injection pump, fluorescence detection system, ATA-2161 power amplifier, etc.

Experimental process：

（1）Chip design and preparation

Using dimethylsiloxane as the basic material for the fabrication of the fluidic chip, the microfluidic chip can be formed by bonding it with glass.

microparticle sorting chip

（2）The construction of experimental platform

Injection pump and syringe for injecting sample solution, fluorescence detection system for observing droplet and related signal analysis (high-speed photography instrument, fluorescence excitation light source, etc.) and module for droplet sorting (DC high-voltage power supply, signal generator and ATA-2161 power amplifier,etc.).

microparticle sorting system

（3）Droplet separation process

When the droplet is decelerated, it can be sorted more accurately. The fluorescence particles are illuminated by the excitation light, which triggers the signal generator and generates a rectangular pulse voltage (voltage 700 V, pulse width 220 ms) through the signal amplifier. The figure shows the separation process of fluorescent particle droplets. When the droplets containing fluorescent target particles are detected by the system, the droplets flow into the lower flow passage under the action of electrostatic force. However, the empty droplet or the droplet coated with ordinary particles will not be affected by the electrostatic force, and maintain the same direction as the main channel flow out of the flow channel, so as to screen out the fluorescent particles from the sample solution. The particles collected at the outlet of the flow channel of fluorescent particles were observed and counted.

fluorescent particles in the deceleration zone

fluorescent particle sorting process

Result of experiment：by designing and producing a particle sorting chip that integrates the functions of micro-particle focusing, particle wrapping, droplet deceleration and droplet sorting, the droplet containing fluorescent particles is successfully separated from the droplet containing ordinary particles and empty droplet, and the sorting success rate can reach 87%. Sodium alginate solution was used as the dispersive phase, and droplets with different characteristics were separated by electric field force to select them from a large number of droplets containing different target objects, which provided an excellent sample treatment scheme for medical analysis and was convenient for subsequent detection.

Power amplifier's role in this experiment：amplify the signal and generate a pulse voltage

Specification of ATA-2161：