Stretchable ECG Device with Liquid Metal Interconnects
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Solution Overview
Problem
Conventional wearable multi-lead ECG devices fail to provide accurate ECG waveforms due to inflexible electrode placement, lacking the ability to adjust positions like the standard 12-lead ECG method, which is essential for accurate cardiac disease diagnosis.
Innovation Solution
A wearable electrocardiographic device with stretchable electrodes and bridges containing liquid metal interconnects, made of Ecoflex and conductive hydrogel, allowing for adjustable and conformal adherence to the skin, enabling accurate multi-lead ECG monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional fixed-position electrodes are used, then device structure is simple, but electrode placement flexibility and diagnostic accuracy are insufficient
Solution Approach 1:
The electrode positions are made dynamic and adjustable through a modular patch design where electrodes can be repositioned on the flexible substrate according to different lead requirements, transforming the fixed structure into an adaptable system
Solution Approach 2:
The ECG device is divided into multiple independent electrode patches that can be separately positioned and adjusted on the patient's body, allowing flexible configuration of different lead arrangements without requiring a completely redesign of the entire device
2Reliability
If stretchable and conformal materials are used, then skin adherence and comfort are improved, but manufacturing precision and structural control become more difficult
Solution Approach 1:
The device utilizes flexible Ecoflex polymer substrates with embedded microchannels that maintain their structural integrity and precision while conforming to the skin surface, achieving both manufacturing precision and biological reliability
Solution Approach 2:
The electrode structure combines multiple materials including Ecoflex polymer, liquid metal, conductive hydrogel, and metal films, where each material contributes specific properties: Ecoflex provides flexibility and formability, liquid metal ensures electrical conductivity and stretchability, hydrogel provides adhesion to skin, and metal films provide structural support and electrical connection
3Reliability
If liquid metal interconnects are used, then electrical conductivity during stretching is maintained, but manufacturing complexity and material control become more difficult
Solution Approach 1:
Liquid metal is utilized as a fluid conductor that can be injected into microchannels and bridges, allowing the electrical interconnects to be filled and sealed within the flexible structure, maintaining conductivity while simplifying the manufacturing process
Solution Approach 2:
The electrical conductivity properties are maintained during stretching by utilizing the phase-change and flow characteristics of liquid metal, which adapts its shape and distribution in response to mechanical deformation, ensuring stable electrical contact throughout the stretching cycle
4Measurement precision
If multi-lead electrode configuration is implemented, then diagnostic accuracy is improved, but device complexity and electrode management become more difficult
Solution Approach 1:
The flexible ECG device is designed as a universal platform that can accommodate multiple lead configurations (standard 12-lead, modified leads, etc.) using the same basic electrode patch and bridge structure, allowing a single device to serve multiple diagnostic purposes without requiring different hardware designs
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 device provides stable and accurate ECG signal monitoring, maintaining conductivity and resistance during stretching, ensuring robust and comfortable long-term cardiac activity tracking.
Implementation Method 1
a second layer of liquid metal disposed between the first and third layers, and a fourth layer of conductive material disposed on the third layer, and the second layer of liquid metal is electrically connected with the fourth layer of conductive material
Implementation Method 2
The conductive material of the fourth layer is conductive hydrogel
Implementation Method 3
The first and third layers are formed with stretchable material such that the electrocardiographic (ECG) device is skin-adherent, highly stretchable, and conformal. Each of the stretchable first and third layers is formed with Ecoflex material
Implementation Method 4
Each electrode may further comprise a metal film, the metal film connects the second layer of liquid metal with the fourth layer of conductive material, and the metal film is made of copper
Data Source
AI summary
An electrocardiographic (ECG) device and fabrication methods of the ECG device are provided for sensing cardiac activities in a test subject. The ECG device includes a plurality of electrodes and a plurality of bridges connecting adjacent electrodes of the plurality of electrodes. The electrodes each has a structure including a first layer and a third layer disposed above the third layer, a second layer of liquid metal disposed between the first and third layers, and a fourth layer of conductive material disposed on the third layer, and the second layer of liquid metal is electrically connected with the fourth layer of conductive material. Each electrode may include a metal film connecting the second layer of liquid metal with the fourth layer of conductive material. The first and third layers are formed with stretchable material, making the ECG device skin-adherent, highly stretchable, and conformal.