How is the fluid control mechanism of thin film microfluidic pouch implemented in chemiluminescent immunoassay?
Publish Time: 2025-01-21
In chemiluminescent immunoassay, the fluid control mechanism of thin film microfluidic pouch is the key to achieve precise flow and mixing of liquid. This mechanism is usually implemented through a variety of technologies and design means to ensure the efficiency and accuracy of the reaction.
1. Structural design of microfluidic bag
Multi-channel design: thin film microfluidic pouch usually consists of multiple micro channels, which are responsible for guiding the flow of liquid. For example, reagent addition channel, sample channel and reaction channel.
Film material: The bag body is usually made of flexible film material (such as PDMS, polyester film, etc.), which is both highly plastic and can effectively control the flow of fluid.
Integrated valves and pumps: Micro valves or pumps are integrated in the bag or at the connection of the bag to accurately control the direction and speed of liquid flow.
2. Key technologies for fluid control
Pressure control: The flow of liquid in the microfluidic bag is driven by external mechanical pressure or gas pressure (such as compressed air). Pressure can be controlled manually or by automated equipment.
Vacuum suction: In some designs, a vacuum pump is used to suck air from the bag, so that the liquid flows under negative pressure. This method is particularly suitable for scenarios that require rapid mixing.
Capillary action: The interaction between the surface energy of polymer materials and liquids is used to drive the liquid to flow naturally in the microchannel through the capillary effect.
3. Liquid mixing technology
Passive mixing: Through the geometric design of microchannels (such as curved channels and branch channels), the inertia and turbulence of liquid flow are used to achieve liquid mixing. This design does not require additional energy input and is simple and efficient.
Active mixing: Micro-stirrers or magnetic particles are integrated in the bag to accelerate liquid mixing through externally applied vibration, magnetic field or mechanical stirring.
4. Accurate metering of liquids
Volume control: The volume of the liquid is accurately controlled through the geometric design of the microfluidic bag (such as channel cross-sectional dimensions and length). For example, the flow rate of the liquid is adjusted by gas pressure to achieve quantitative injection.
Droplet generation: In some designs, microfluidics is used to generate droplets, and each droplet can be used as an independent reaction unit to ensure precise control of the liquid volume.
5. Integration of valves and pumps
Microvalves: Microvalves are integrated at key nodes of the channel to adjust the flow path of the liquid by controlling the opening and closing state of the valve. The valve can be driven mechanically, pneumatically or electromagnetically.
Micropumps: Integrated micropumps (such as peristaltic pumps and diaphragm pumps) are used to promote liquid flow. Micropumps are small in size and high in precision, making them suitable for use in microfluidic bags.
6. Automation and intelligent control
Automation system: Combined with automation equipment (such as robotic arms and servo motors), precise control of fluid control is achieved. Automation can reduce human operation errors and improve the repeatability and accuracy of analysis.
Sensor feedback: By integrating sensors (such as optical sensors and pressure sensors) in the bag or channel, the flow state of the liquid can be monitored in real time and dynamically adjusted.
Software control: Fluid control mechanisms can be implemented through computer software programming. For example, a control program written in LabVIEW or Python can accurately control the flow path, speed, and mixing state of the liquid.
The fluid control mechanism of the thin film microfluidic pouch is achieved through a variety of technical means such as structural design, pressure control, vacuum suction, capillary action, liquid mixing technology, precise metering, integration of valves and pumps, and automation and intelligent control. These mechanisms ensure the precise flow, mixing, and reaction of the liquid in the bag, thereby supporting the efficiency and accuracy of chemiluminescent immunoassay. Through continuous optimization of design and integration of advanced technologies, the thin film microfluidic pouch has become an important tool in modern immunoassay technology and is widely used in medical diagnosis, environmental monitoring, food safety and other fields.
