Microfluidic Chip Local Temperature Control for Reagent Stability
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Solution Overview
Problem
Current microfluidic chip technologies face challenges in maintaining the homogeneity and independence of microcells due to reagent evaporation and condensation, leading to reagent reduction and cross-contamination across microcells, especially under uniform temperature control.
Innovation Solution
A microfluidic chip with a local temperature control device that heats the main channel to a higher temperature than the microcells, preventing reagent evaporation and condensation, thereby ensuring the homogeneity and independence of each microcell through the use of Pt electrodes, resistive films, Peltier elements, and other thermal control mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If uniform temperature control is applied to the entire chip, then the overall reaction conditions are stable, but reagent evaporation and condensation occur causing loss of substance and cross-contamination
Solution Approach 1:
The patent applies local temperature control to different regions of the chip. The main channel is heated to a higher temperature (e.g., 60-80°C) than the microcells (e.g., 20-40°C), creating a temperature gradient that prevents reagent condensation in the main channel while maintaining reaction conditions in microcells. This local differentiation resolves the contradiction by allowing overall stability through controlled local variations.
Solution Approach 2:
The temperature control system is segmented into at least two independent control zones: one for the main channel and another for the microcells. Each zone can be controlled independently with different temperature settings, allowing the main channel to be kept warmer to prevent condensation while microcells maintain optimal reaction temperatures.
2Loss of substance
If the main channel temperature is lowered to prevent evaporation, then reagent loss is reduced, but condensation occurs forming liquid films that cause cross-contamination
Solution Approach 1:
Different temperature conditions are applied locally to different regions: the main channel is maintained at a higher temperature to prevent condensation and liquid film formation, while microcells are kept at lower temperatures appropriate for their reactions. This eliminates the harmful effect of liquid films while preserving reagents.
3Reliability
If local temperature control is implemented, then reagent evaporation and condensation are prevented, but device complexity increases
Solution Approach 1:
The patent introduces a temperature control device as an intermediary component that can be integrated into the chip structure. This device includes heating elements (such as resistive heating traces) and temperature sensors that are built into the substrate or cover plate, allowing local temperature control without requiring complex external equipment. The intermediary device simplifies the overall system while achieving the desired temperature differentiation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The local temperature control device effectively prevents reagent reduction and cross-contamination, maintaining consistent reagent volumes in microcells and ensuring their independence, as demonstrated by consistent amplification reactions and absence of liquid films in experimental groups.
Implementation Method 1
The local temperature control device is Pt electrode set in the cover plate in the position corresponding to the main channel
Implementation Method 2
The local temperature device is a circular resistive film which is set in the substrate or the cover plate
Implementation Method 3
The local temperature control device is a cooling line set in a glass substrate affixed to the substrate or the cover plate
Implementation Method 4
the temperature of the chip containing microcells is generally controlled as a whole, however different areas of the chip are different in material and structural which cause the liquid in microcells to gradually evaporate and condense in the main channel
Implementation Method 5
the liquid in microcells to gradually evaporate and condense in the main channel which does not have liquid
Data Source
AI summary
Provided is a microfluidic chip, which comprises a substrate and a cover sheet, wherein a microreactor array is arranged on the substrate and comprises at least one main channel (401) and at least two micro cells (402) connected to the main channel (401). The microfluidic chip also comprises at least one local temperature control device, which is used for heating the main channel (401) or cooling the micro cells (402). The use of the microfluidic chip ensures uniformity and independency of the micro cells (402). Also provided is an application of the microfluidic chip in biological detection or medical inspection.