Temperature sensitive flow control agent

A temperature-sensitive polymer with no charge and high hydrophilicity (HLB≈18-22). Core mechanism: At low temperature, the flow control agent is dispersed in the aqueous solution to form a low viscosity transparent liquid; When the temperature rises to the critical gelling temperature, a three-dimensional mesh gel structure is formed, which significantly increases the viscosity of the solution.

Application principle:

Dynamic viscosity control: Through local heating (such as chip heating module) or ambient temperature changes, triggering the gelation of the flow control agent solution, increasing the fluid resistance in the microchannel, thereby delaying the chromatographic speed of the sample or reagent.

Reversibility: After cooling, the gel returns to liquid, which is easy to reuse the chip.

Concentration range: 15%-30% (w/v), depending on chip design and temperature control requirements.

Low concentration (15-20%) : high gelling temperature (25-30°C), suitable for delay of ambient temperature control.

High concentration (25-30%) : the gelling temperature is low (18-22°C), and active heating is required to trigger gelation.

Application steps:

Solution preparation: The flow control powder is dissolved in low temperature (4°C) deionized water, stirring until completely dissolved.

Chip perfusion: The solution is injected into the microfluidic channel to avoid bubbles.

Temperature control activation: Gel delay chromatography is formed when the target temperature (e.g. 25°C) is raised by a chip integrated heater or external temperature control device.

Release reset: After completing the delay, the temperature drops below 15°C, the gel dissolves, and the fluid flow resumes.

Case reference:

Case 1: DNA hybridization detection delay

Concentration: 20% flow control agent

Temperature control: 25°C gel, delay time 30 minutes

Effect: Hybridization signal strength increased by 2 times, background decreased by 50%

Case 2: Microfluidic PCR step by step reaction

Concentration: 25% flow control agent

Temperature control: 22°C triggers the gel, releasing primers and enzymes in steps

Effect: The non-specific amplification was reduced and the purity of the product was increased