Microfluidic Device Thermal Management for Condensation-Free Optical Analysis

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Solution Overview

Problem

Existing methods for manipulating particles in conductive solutions at low temperatures face challenges due to uncontrolled temperature increases, which can harm biological samples and cause image blurring from condensation on microfluidic device covers during optical analysis.

Innovation Solution

A microfluidic device with integrated cooling means and a thermal resistance system that maintains the microchamber at low temperatures while keeping the outer surface above the dew point, using Peltier cells and a thermal resistance structure with different conductivity values to prevent condensation and allow optical analysis at temperatures below ambient.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the microchamber is cooled to low temperatures for particle manipulation, then particle manipulation at low temperature is achieved, but condensation occurs on the outer surface causing image blurring

Engineering Contradiction:

Improvemicrochamber temperatureVSAvoidcondensation on cover

Core Design Contradiction:

TemperatureVSObject-affected harmful factors

Solution Approach 1:

The device is divided into two distinct thermal zones: the microchamber interior is cooled to low temperatures for particle manipulation, while the outer cover surface is maintained at a higher temperature above the dew point. This spatial segmentation of thermal conditions allows simultaneous achievement of low-temperature particle manipulation and condensation-free optical observations.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different parts of the device are assigned different thermal properties: the microchamber interior is cooled to enable particle manipulation, while the outer cover surface is heated or insulated to prevent condensation. This local differentiation of thermal conditions resolves the contradiction between low-temperature operation and prevention of condensation on the cover.

Inventive Principle:

Principle #3Local quality

2Force

If electrical fields are applied for particle manipulation in conductive solutions, then particle manipulation is achieved, but temperature increases due to Joule heating

Engineering Contradiction:

Improvedielectrophoretic forceVSAvoidmicrochamber temperature

Core Design Contradiction:

ForceVSTemperature

Solution Approach 1:

The Joule heating effect, which normally causes unwanted temperature increase during particle manipulation in conductive solutions, is counteracted by the integrated cooling system. The cooling means actively remove the heat generated by electrical field application, converting the harmful thermal effect into a manageable parameter that allows continuous particle manipulation without temperature-induced damage to biological samples.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Object-affected harmful factors

If the outer surface is kept warm to prevent condensation, then optical analysis clarity is improved, but heat may transfer to the microchamber interior

Engineering Contradiction:

Improvecondensation preventionVSAvoidmicrochamber temperature stability

Core Design Contradiction:

Object-affected harmful factorsVSTemperature

Solution Approach 1:

A thermal management layer or interface is introduced between the outer cover surface and the microchamber interior. This intermediary structure allows the outer surface to be maintained at a higher temperature for condensation prevention while providing thermal isolation that prevents excessive heat transfer to the cooled microchamber interior, thus maintaining temperature stability in both zones.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 precise manipulation and optical analysis of particles at low temperatures without harming biological samples and prevents image blurring by maintaining the outer surface above the dew point, ensuring clear optical observations.

Implementation Method 1

using Peltier cells and a thermal resistance structure with different conductivity values to prevent condensation and allow optical analysis at temperatures below ambient

Methodology Applied

Scientific EffectPeltier effect: Peltier Effect

Implementation Method 2

a thermal resistance structure with different conductivity values to prevent condensation and allow optical analysis at temperatures below ambient

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS11921028B2Method and device for optical analysis of particles at low temperatures

Publication Date: 2024.03.05 MENARINI SILICON BIOSYSTEMS SPA

AI summary

Method and device (1b) for performing the optical analysis of particles (2) contained in suspension in a fluid (3) arranged inside a microfluidic device (4) which maintains it at a temperature significantly lower than the ambient temperature; the formation of humidity on the outer surface (8) of the cover of the microfluidic device is avoided by applying a thermal flow (P) which determines an increase in the temperature of the outer surface (8) of the cover to above the condensation temperature (Td), or reduction in the ambient temperature (and/or humidity) in the vicinity of the cover (8), so as to bring the condensation temperature (Td) (dew point) to below the temperature of the surface (8) of the cover determined by the internal operating temperature.