Epidermal Biofluid Patch With Passive Microfluidic Sensing
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Solution Overview
Problem
Existing wearable devices for monitoring biofluids face challenges in continuous, long-term use due to complex microfluidic systems, discomfort from mechanical fixtures, and lack of sample collection and storage, limiting their effectiveness in providing comprehensive health insights.
Innovation Solution
Development of skin-mounted devices with functional substrates that are mechanically and thermally matched to the skin, enabling durable adhesion and microfluidic transport of biofluids for analysis, using sensors that measure parameters like biofluid production rate, volume, and biomarker concentration, with mechanical, electrical, or chemical detection methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex microfluidic systems are used for sample handling, then measurement capability is improved, but device complexity increases
Solution Approach 1:
The patent extracts the microfluidic transport function from a complex system and implements it through simple passive capillary channels integrated directly into the substrate. The microfluidic channels are formed by depositing material layers and patterning them to create capillary structures that automatically transport sweat from the skin to the sensing zones without requiring external pumps or complex control systems.
Solution Approach 2:
The device uses self-powered capillary action for fluid transport, where the microfluidic channels automatically draw sweat from the skin through capillary forces without external energy input. The sensing elements also self-generate signals through electrochemical reactions with the biofluid, eliminating the need for external power sources or complex electronic control.
2Reliability
If mechanical fixtures and straps are used to maintain skin contact, then sensor stability is improved, but user comfort deteriorates
Solution Approach 1:
The patent employs a flexible substrate that can conform to the skin surface geometry, maintaining intimate contact without rigid mechanical fixtures. The thin-film structure allows the device to adapt to skin movements and contours, providing stable sensor contact while being comfortable for long-term wear without straps or tapes.
Solution Approach 2:
The device is designed with dynamic flexibility to move with the skin rather than restraining it. The flexible substrate and soft materials allow the sensor to dynamically adapt to skin deformations during normal body movements, maintaining reliable contact without causing discomfort or requiring rigid mechanical constraints.
3Loss of information
If existing wearable devices are used for biofluid monitoring, then health assessment capability is improved, but long-term monitoring reliability deteriorates due to discomfort and complex systems
Solution Approach 1:
The patent describes a device that can be applied and worn for extended periods without requiring complex maintenance or adjustment. The disposable or replaceable nature of the sensor patch allows for continuous monitoring over multiple days, with each patch designed for long-term stable operation and then replaced, ensuring continuous health data collection without compromising user comfort or system reliability.
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 devices provide reliable, long-term monitoring of health parameters by accurately measuring biofluid properties, including biomarker concentrations, with minimal discomfort, allowing for early detection of abnormal conditions.
Implementation Method 1
The functional substrates allow for the microfluidic transport of biofluids from the skin to one or more sensors
Implementation Method 2
Sensors within the devices may be mechanical, electrical or chemical, with colorimetric indicators being observable by the naked eye or with a portable electronic device
Implementation Method 3
The disclosed devices may mobilize and access biofluids by mechanical, electrical and/or thermal mechanisms including but not limited to surface wicking, microneedle extraction
Implementation Method 4
The devices comprise a functional substrate that is mechanically and/or thermally matched to skin to provide durable adhesion for long-term wear
Data Source
AI summary
Skin-mounted or epidermal devices and methods for monitoring biofluids are disclosed. The devices comprise a functional substrate that is mechanically and/or thermally matched to skin to provide durable adhesion for long-term wear. The functional substrates allow for the microfluidic transport of biofluids from the skin to one or more sensors that measure and/or detect biological parameters, such as rate of biofluid production, biofluid volume, and biomarker concentration. Sensors within the devices may be mechanical, electrical or chemical, with colorimetric indicators being observable by the naked eye or with a portable electronic device (e.g., a smartphone). By monitoring changes in an individual's health state over time, the disclosed devices may provide early indications of abnormal conditions.