Photomask-Based Spatially Varying Hydrogel Fabrication

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Solution Overview

Problem

Current methods for fabricating spatially varying hydrogels in lab-on-a-chip devices are inflexible and time-consuming, requiring precursor exchange steps or long diffusion times, limiting their complexity and scalability in microfluidic channel networks.

Innovation Solution

A method involving exposure of a separation medium precursor solution to light through a photomask with varied light transmittance, allowing for the production of spatially varied separation media with regions of different polymerization densities, enabling efficient and high-throughput fabrication of microfluidic devices for protein sizing and analyte detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If precursor exchange steps or long diffusion times are used to establish monomer gradients, then spatially varying hydrogels can be produced, but the fabrication process becomes slow and time-consuming

Engineering Contradiction:
Improvespatially varying hydrogel compositionVSAvoidfabrication time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-patterned photomasks that define the desired monomer gradient geometry before polymerization begins. The photomask is designed with specific transmittance patterns that directly correspond to the intended spatial distribution of monomers, eliminating the need for time-consuming diffusion processes to establish gradients.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces the mechanical/diffusion-based gradient establishment method with a photochemical approach. Instead of relying on slow molecular diffusion to create monomer gradients, the invention uses light transmission through patterned photomasks to selectively initiate polymerization, directly creating the desired spatial variation in hydrogel composition.

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

2Device complexity

If conventional fabrication protocols are used, then low-to-moderate complexity geometries can be achieved, but the device complexity is limited

Engineering Contradiction:
Improvehydrogel geometry complexityVSAvoidfabrication flexibility
Core Design Contradiction:
Device complexityVSEase of manufacture

Solution Approach 1:

The patent applies local quality by using photomasks with spatially varying transmittance properties that create locally differentiated monomer concentrations. Different regions of the photomask have different light transmission characteristics, enabling precise control over the local composition and geometry of the hydrogel structure throughout the device.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs parameter changes by utilizing photomasks with varying light transmittance parameters across different regions. By changing the optical parameters of the photomask (transmittance, pattern, geometry), the invention can directly program complex hydrogel geometries without being constrained by the limitations of conventional fabrication methods.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If uniform light exposure is applied during polymerization, then homogeneous hydrogels are produced, but spatially varied separation media cannot be achieved

Engineering Contradiction:
Improvespatially varied polymerization densityVSAvoidseparation medium heterogeneity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by using photomasks with spatially varying transmittance properties that create locally differentiated monomer concentrations. Different regions of the photomask have different light transmission characteristics, enabling precise control over the local composition and geometry of the hydrogel structure throughout the device.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent introduces the photomask as an intermediary element between the light source and the monomer solution. This intermediary component modulates the light distribution pattern, translating the desired spatial gradient into actual polymerization density variations. The photomask acts as a mediator that converts uniform light input into spatially varied polymerization output.

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

This approach enables rapid production of microfluidic devices with non-uniform hydrogels, enhancing their analytical capabilities by allowing for high-resolution biomolecular separations and sample enrichment, while reducing processing time and increasing geometric complexity.

Implementation Method 1

exposing a separation medium precursor solution to light from a light source through a photomask that includes a region with varied light transmittance to produce the separation medium

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentEP3049867B1Producing a separation medium using grayscale mask
Publication Date: 2024.11.13 RGT UNIV OF CALIFORNIA
  • EP3049867B1 patent drawingFigure 1A~1C
  • EP3049867B1 patent drawingFigure 2A~2D
  • EP3049867B1 patent drawingFigure 3A~3B

AI summary

Provided are methods for producing a separation medium, where the method includes exposing a separation medium precursor solution to light from a light source through a photomask that includes a region with varied light transmittance to produce the separation medium. Systems that find use in performing the methods, microfluidic devices that include the separation medium, as well as methods of using the microfluidic devices, are also provided. Embodiments of the present disclosure find use in a variety of different applications, including detecting whether an analyte is present in a fluid sample.