Capillary Biofluid Sensor Chip for Continuous Wearable Monitoring

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current wearable technologies are limited in their ability to provide continuous and non-invasive monitoring of biofluids, such as sweat, saliva, and tears, which are essential for comprehensive health and wellness assessment, as they are bulky, non-scalable, and lack real-time capabilities.

Innovation Solution

A fully integrated multi-function device on a single chip, incorporating semiconductor sensors, micro/nano-fluidic channels, and a reference electrode, capable of detecting biochemicals and biomarkers in biofluids, with a compact form factor suitable for wearable applications, allowing for continuous and real-time monitoring without the need for active pumping or external energy sources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If blood testing is used for biomarker monitoring, then measurement precision is improved, but invasiveness increases and continuous monitoring capability deteriorates

Engineering Contradiction:
Improvebiomarker detection accuracyVSAvoidnon-invasive continuous monitoring capability
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent extracts the essential sensing function from traditional laboratory blood testing equipment and implements it in a miniaturized wearable form factor. The semiconductor sensor chip contains only the necessary sensing elements, fluidic channels, and electronics required for biomarker detection, separating the monitoring function from the invasive blood draw procedure itself by using alternative biofluids.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The device enables self-monitoring through passive capillary action that automatically draws biofluid through the microfluidic channels without requiring external pumps or power sources. The system serves itself by utilizing the natural capillary forces present in the biofluid to drive the analytical process.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If conventional biosensor systems are used for biofluid monitoring, then sensing capability is improved, but device size and complexity increase

Engineering Contradiction:
Improvebiofluid sensing capabilityVSAvoidsystem integration level
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges multiple previously separate components into a single integrated chip: the semiconductor sensor, microfluidic channels, reference electrode, and electronic circuitry are all combined on one substrate. This consolidation maintains full sensing capability while dramatically reducing device size and complexity for wearable applications.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The design embeds the microfluidic channels within and around the semiconductor sensor structure, with the reference electrode integrated into the chip substrate. The nested arrangement allows multiple functional elements to coexist in a compact configuration, with smaller features embedded within larger structures.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Measurement precision

If active pumping systems are used for biofluid transport, then flow control precision is improved, but energy consumption and device complexity increase

Engineering Contradiction:
Improvebiofluid flow controlVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The microfluidic channels are designed to exploit passive capillary action, where the natural surface tension and adhesion forces of the biofluid drive it through the channels without requiring external pumps. The channel geometry and surface properties are engineered to provide sufficient capillary pressure for reliable fluid transport.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces mechanical pumping systems with a passive capillary-based fluid transport mechanism. By substituting active mechanical components with passive physical phenomena, the system eliminates the need for motors, batteries, and control electronics associated with active pumping.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Measurement precision

If laboratory-based analytical methods are used, then measurement accuracy is improved, but portability and continuous monitoring capability deteriorate

Engineering Contradiction:
Improvebiomarker analysis accuracyVSAvoiddevice portability
Core Design Contradiction:
Measurement precisionVSWeight of moving object

Solution Approach 1:

The patent extracts the core analytical function from the laboratory setting and implements it in a portable wearable device. By taking out only the essential sensing and detection capabilities and removing unnecessary laboratory infrastructure, the system achieves laboratory-grade measurement accuracy in a lightweight form factor suitable for continuous wear.

Inventive Principle:
Principle #2Taking out (Extraction)

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 non-invasive, continuous, and real-time biofluid monitoring, providing comprehensive health data, enhancing the accuracy of health and wellness assessments, and facilitating preventive healthcare through wearable devices like smart patches and wrist-based devices.

Implementation Method 1

a plurality of micro/nano-fluidic channels (006) configured to transfer the biofluid from the inlets (007) to the outlets (008) by capillary motion

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

a plurality of semiconductor sensors (002) configured to analyze the received bio-fluid

Methodology Applied
Scientific EffectElectrical conductivity measurement: Conduction (electrical)

Data Source

PatentEP3510403B1Capillary flow device for bio-fluid collection with semiconductor sensors
Publication Date: 2023.12.20 ECOLE POLYTECHNIQUE FEDERALE DE LAUSANNE (EPFL)
  • EP3510403B1 patent drawingFigure 1A
  • EP3510403B1 patent drawingFigure 1B
  • EP3510403B1 patent drawingFigure 2

AI summary

An on-body wearable bio-fluid collection and sensing device including an interface or interface surface comprising at least one biocompatible material for contacting a bodily part; at least one inlet for receiving the bio-fluid, at least one outlet for evacuating the bio-fluid, a plurality of semiconductor sensors configured to analyze the received bio-fluid, at least one reference electrode for biasing a bio-fluid gate of at least one of the semiconductor sensors, and at least one micro-fluidic or nano-fluidic channel in fluid communication with the at least one inlet, the at least one outlet and the at least one reference electrode; the at least one micro-fluidic or nano-fluidic channel includes the plurality of semiconductor sensors.