Application Cases

Experiment Title: Application of High-Voltage Amplifier in Cell Sorting Based on Dielectrophoresis Effect

Research Field: Biomedicine

Purpose of the Test:

Cell sorting is crucial in analytical chemistry and biomedicine. Among various methods, microfluidic sorting stands out for its fast response and low sample consumption. Microfluidic cell sorting can be passive or active. Passive methods require no cell pre-treatment but demand intricate chip designs and risk clogging. Active methods offer high efficiency but often require cell pre-labeling, affecting cell activity.

This study proposes a novel cell sorting method combining passive and active approaches, using micro - structured filtration and dielectrophoresis (DEP). It integrates micro - electrodes into the filtration area, leveraging geometric parameters and AC signals to induce negative DEP, steering cells to low - field regions and preventing filter clogging.

Test Equipment: ATA-2042 high-voltage amplifier, function generator, peristaltic pump, laptop, scientific - grade camera, inverted fluorescence microscope, DSLR camera, etc.

Experiment Process:

① Sample Solution Preparation

Non-biological samples: Mixed particles of 37μm, 16.3μm, and 9.7μm in PBS buffer (1mM, 0.17S/m conductivity) with 0.1%v/v Tween20, diluted to 10⁴~10⁵/mL.

Biological samples: Mixed suspensions of Haematococcus pluvialis and Pleurochrysis dentata, cultured in BG11 medium, diluted to 10⁴~10⁵/mL with 0.4g sorbitol/mL to improve flow.

② Experimental Platform Setup

The platform includes a microfluidic chip connected to a peristaltic pump, a signal generator linked to a voltage amplifier and ITO electrodes, and a DSLR camera with an inverted microscope for real - time observation.

③ Chip Pretreatment

Load PBS buffer (for particle sorting) or BG11 medium (for algal cell sorting) into the chip. Use capillary action and hydrophilicity to fill the chip, then pump at 1mL/min for 5 minutes to remove air bubbles.

④ Sample Loading

Inject 50μL of the sample into the chip inlet using a pipette. The negative pressure from the peristaltic pump drives the sample toward the chip outlet.

⑤ Signal Application

Activate the signal generator and voltage amplifier to apply an AC signal to the ITO electrodes. Adjust frequency and amplitude to optimize sorting.

⑥ Experiment Documentation

Record the experiment using a DSLR camera.

Experimental Results:

A. Particle Sorting Process

As shown in Figure A1-A4, the first - level filtration allows 16.3μm and 9.7μm particles to pass through the 25μm gaps, while 37μm particles, too large to pass, oscillate near the filter holes due to negative DEP, avoiding clogging. In Figure B1-B4, the second - level filtration with a higher field gradient causes 16.3μm particles to behave similarly, while 9.7μm particles pass through or cluster before moving on.

B. Comparison of Results with and without Signal

Without a sinusoidal signal, the chip quickly clogs. With the ITO micro - electrode and negative DEP effect, clogging is prevented, and the sorting flux improves.

ATA-2042 High-Voltage Amplifier: