Microfluidic Loop Layout for Larger Sample Volume and Thermal Uniformity

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Solution Overview

Problem

Microfluidic devices face challenges in scaling up to accommodate larger sample volumes without proportionally increasing the amount of silicon used in their construction, which is costly, and struggle to maintain uniform temperature control during DNA amplification processes.

Innovation Solution

The design incorporates microfluidic loops and channels located outside the silicon chip boundary, with fluid actuators and heaters to increase fluid volume by 2 to 20 times without increasing silicon usage, ensuring uniform temperature control within 4°C variation through pumping and insulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If microfluidic devices are scaled up to accommodate larger sample volumes, then the sample volume capacity increases, but the amount of silicon used increases proportionally, leading to increased costs

Engineering Contradiction:
Improvesample volumeVSAvoidsilicon usage
Core Design Contradiction:
Quantity of substanceVSWeight of stationary object

Solution Approach 1:

The patent extends microfluidic channels outside the traditional silicon chip boundary into a separate support structure. This dimensional extension allows the fluid pathways to continue beyond the expensive silicon substrate, enabling larger sample volumes to be accommodated in the external portion while minimizing silicon consumption to only the essential control and actuation regions.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The device is divided into two distinct segments: a silicon chip portion containing fluid actuators and control elements, and an external support structure portion containing the extended microfluidic channels. This segmentation allows the expensive silicon material to be used only where functionally necessary, while the bulk of the fluid handling infrastructure is provided by a lower-cost external structure.

Inventive Principle:
Principle #1Segmentation

2Weight of stationary object

If the microfluidic device uses a compact design within the silicon chip boundary, then silicon usage is minimized, but temperature uniformity during DNA amplification deteriorates

Engineering Contradiction:
Improvesilicon usageVSAvoidtemperature uniformity
Core Design Contradiction:
Weight of stationary objectVSTemperature

Solution Approach 1:

By extending channels outside the silicon chip boundary into a support structure, the patent creates additional thermal management space. This external portion can incorporate thermal insulation, heat sinks, or temperature control elements that would be difficult to integrate within the constrained silicon chip area, thereby improving temperature uniformity without increasing silicon usage.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Temperature

If fluid volume is increased to improve mixing and heat transfer, then temperature control improves, but the device size and silicon usage increase

Engineering Contradiction:
Improvetemperature controlVSAvoidsilicon usage
Core Design Contradiction:
TemperatureVSWeight of stationary object

Solution Approach 1:

The patent resolves this contradiction by placing the expanded fluid volume in external channels rather than within the silicon chip. The extended microfluidic pathways in the support structure provide increased fluid volume for improved mixing and heat transfer, while the silicon chip itself maintains its compact size with minimal material usage.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

This approach allows for efficient DNA amplification techniques like PCR and LAMP by maintaining temperature uniformity and increasing sample volume without escalating silicon costs, enhancing mixing and heat transfer while reducing material usage.

Implementation Method 1

A heater can be located within the silicon-free substrate

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

A first fluid actuator can be on the silicon chip and associated with a fluid driving end of the first microfluidic loop to circulate fluid through the first microfluidic loop

Methodology Applied
Scientific EffectPumping: Pump

Implementation Method 3

ensuring uniform temperature control within 4°C variation through pumping and insulation

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP3658841B1Temperature-controlling microfluidic devices
Publication Date: 2024.03.27 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • EP3658841B1 patent drawingFigure 1
  • EP3658841B1 patent drawingFigure 2
  • EP3658841B1 patent drawingFigure 3A

AI summary

The present disclosure is drawn to microfluidic devices. In one example, a microfluidic device can include a driver chip and a fluid chamber located over the driver chip. First and second microfluidic loops can have fluid driving ends and fluid outlet ends connected to the fluid chamber. The first and second microfluidic loops can include a portion thereof located outside a boundary of the driver chip. A first fluid actuator can be on the driver chip associated with the fluid driving end of the first microfluidic loop to circulate fluid through the first microfluidic loop. A second fluid actuator can be on the driver chip associated with the fluid driving end of the second microfluidic loop to circulate fluid through the second microfluidic loop.