Digital microfluidic chip

Digital microfluidic chip refers to the control of discontinuous liquid droplets, with the core technology being the use of electronic circuits to control the surface tension of the liquid, thereby controlling operations such as droplet generation, movement, splitting, and merging. The key to digital microfluidic technology is to achieve discretization of liquid flow. In this droplet based microfluidic system, droplets act as individual reaction vessels and are individually controlled through the electro wetting on dielectric (EWOD) phenomenon on a special medium.

Digital microfluidic chip refers to the control of discontinuous liquid droplets, with the core technology being the use of electronic circuits to control the surface tension of the liquid, thereby controlling operations such as droplet generation, movement, splitting, and merging. The key to digital microfluidic technology is to achieve discretization of liquid flow. In this droplet based microfluidic system, droplets act as individual reaction vessels and are individually controlled through the electro wetting on dielectric (EWOD) phenomenon on a special medium.

By utilizing the principle of dielectric wetting (EWOD), digital microfluidics can achieve operations such as droplet transport, separation, and mixing, thereby completing the preprocessing process of the tested biological sample. Usually, the sample exists in the form of droplets in the chip of the double-layer clamp structure. The programming control voltage is used to change the surface tension of the solid-liquid interface to deform the droplets, thereby driving them to move, separate, and mix according to the predetermined path and method. This technology can drive various aqueous sample reagents (such as lysis buffer, elution buffer, protease, hybridization buffer, etc.) to operate in different functional regions. According to different reagent systems, combined with control modules such as magnetron and temperature control, nucleic acid analysis operations such as lysis, extraction, cleaning, elution, amplification, hybridization, and detection can be achieved on a single chip.

Application of Digital Microfluidic Technology:

Devices typically use magnetic particles, optical tweezers, liquid-liquid extraction, or fluid dynamic effects to separate and extract the desired analyte.

For example, droplets can pass through the electrode array on the device to the magnetic electrode, where the magnetic particles are functionalized to bind with the target analyte.

Next, the droplet moves on the magnet, the magnetic field is eliminated, and the magnetic particles are suspended in the droplet. Then the magnetic field is restored to fix the particles while causing the droplets to move. Repeat the above process with washing and elution buffer to generate pure analyte.

This step has been tested using anti human serum albumin antibodies, demonstrating the potential of digital microfluidic technology in immunology.

Due to the small sample volume used in this technology, it is often difficult to extract biological principles. However, the combination of this control technology with macroscopic fluid systems can bypass this obstacle.

Digital microfluidic technology has also been applied to create immunoassay devices, simplifying and expanding complex experimental procedures in heterogeneous immunoassays by automatically delivering, mixing, culturing, and washing analytes on the chip. Some examples include detecting human insulin, troponin I, TSH (thyroid stimulating hormone), and 17- β estradiol.

In addition, it can also be combined with mass spectrometry to reduce the use of solvents and reagents, while reducing the time required for analysis.