Microfluidic Chip Capacitance Sensing for Real-Time Droplet Tracking
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Solution Overview
Problem
Existing microfluidic chips lack real-time droplet position feedback, leading to reduced experiment efficiency and potential failure, especially in complex droplet moving paths, and existing solutions like optical detection are cumbersome and costly.
Innovation Solution
A microfluidic chip design with drive electrodes and sensing electrodes arranged in arrays, allowing for real-time droplet position detection through capacitance changes as droplets move, using capacitors formed between sensing electrodes and common electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical detection is used to obtain droplet position, then droplet position can be detected, but the structure becomes complicated, on-site real-time diagnosis becomes difficult, and cost increases
Solution Approach 1:
The patent replaces the optical detection system with an electrical detection system using sensing electrodes. Instead of using external laser devices and optical components to detect droplet position, the invention uses capacitive sensing electrodes that directly measure changes in capacitance caused by the droplet's presence and movement, thereby substituting a complex optical-mechanical system with a simpler electrical sensing system integrated into the chip
Solution Approach 2:
The sensing electrodes are integrated directly into the microfluidic chip structure, allowing the chip to detect droplet position autonomously without requiring external detection equipment. The chip's own electrode structure serves the dual purpose of driving droplets and sensing their position, eliminating the need for separate external optical detection systems
2Productivity
If no droplet position feedback mechanism exists, then the device structure remains simple, but experiment efficiency decreases and experiments may fail
Solution Approach 1:
The drive electrodes and sensing electrodes serve multiple functions: drive electrodes both propel droplets and contribute to capacitive sensing, while sensing electrodes detect droplet position. This multi-functionality allows the system to implement real-time feedback without adding separate dedicated detection components, thereby improving experiment efficiency while keeping the device structure relatively simple
Solution Approach 2:
The patent implements a feedback mechanism where sensing electrodes continuously monitor droplet position by detecting capacitance changes, and this position information is used to control subsequent droplet movement and experimental processes. This real-time feedback enables the system to adjust droplet transport dynamically, improving experiment efficiency and preventing failures
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
Enables reliable real-time droplet position monitoring, enhancing experiment efficiency and reducing complexity and cost compared to optical detection methods.
Implementation Method 1
a position of the at least one droplet is determined according to a change in capacitance between one of the plurality of first sensing electrodes and an electrode corresponding to the one of the plurality of first sensing electrodes and a change in capacitance between one of the plurality of second sensing electrodes and an electrode corresponding to the one of the plurality of second sensing electrodes when the at least one droplet flows by
Implementation Method 2
Different drive voltage signals are applied to adjacent ones of the plurality of drive electrodes, to drive the at least one droplet to move
Data Source
AI summary
Provided is a microfluidic chip. The microfluidic chip includes a first substrate and a second substrate disposed opposite to each other and drive electrodes, first sensing electrodes and second sensing electrodes disposed on a side of the first substrate. A microfluidic channel is formed between the first substrate and the second substrate and configured to accommodate at least one droplet. Different drive voltage signals are applied to adjacent drive electrodes, so as to drive the at least one droplet to move. Detection signals are applied to the first sensing electrodes and the second sensing electrodes, and a position of the at least one droplet is determined according to a change in capacitance between one first sensing electrode and an electrode corresponding thereto and a change in capacitance between one second sensing electrode and an electrode corresponding thereto when the at least one droplet flows by.