3D Shaped Microparticles via Microfluidic Pillar Flow Control
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Solution Overview
Problem
Current methods for producing shaped microparticles at the micrometer scale face challenges due to high viscosity solutions and the need for higher Reynolds numbers, which result in pressure issues and difficulties in quickly stopping the flow before polymerization, leading to elongated or distorted shapes and limited size reduction.
Innovation Solution
A method involving a microfluidic device with pillars to create a pre-defined flow stream, temporarily stopping the flow and polymerizing specific portions using masks and polymerizing light, allowing for the formation of three-dimensional shaped microparticles with protected regions for cell adherence and manipulation, including magnetic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If higher viscosity solutions are used to achieve higher Reynolds number for shaping flows, then the flow shaping capability is improved, but the pressure increases significantly and the system becomes difficult to control
Solution Approach 1:
The patent changes the physical parameters of the system by using lower viscosity solutions combined with increased flow rates to achieve the necessary Reynolds numbers for flow shaping, thereby avoiding the excessive pressure problems associated with using high viscosity solutions
2Manufacturing precision
If the flow is stopped quickly to prevent elongation and distortion of particles, then the particle shape precision is improved, but the capacitive time increases and the system cannot respond quickly enough
Solution Approach 1:
The patent modifies the fluid parameters by using lower viscosity solutions that allow for faster flow cessation, enabling the system to stop flow quickly enough to prevent particle elongation and distortion while maintaining reasonable capacitive times
3Speed
If the channel size is enlarged to allow faster flow stopping, then the flow control response time is improved, but the fabricated particles become millimeter scale and require longer flow development time
Solution Approach 1:
The patent changes the fluid properties by using lower viscosity solutions that enable fast flow stopping in smaller channels, thus achieving rapid flow control without increasing channel dimensions and preventing the formation of millimeter-scale particles
4Ease of operation
If standard stop-flow lithography is used to fabricate microparticles, then the process is simple to operate, but the particles are limited to larger sizes and cannot be quickly stopped before transiting out of channel
Solution Approach 1:
The patent modifies the operational parameters by using lower viscosity solutions that enable faster flow response times, allowing the system to quickly stop flow before particles transit out of the channel while maintaining operational simplicity
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 the production of complex three-dimensional microparticles with precise shapes and protected regions for cell protection, facilitating downstream analysis and manipulation, while overcoming the limitations of previous techniques in size and shape control.
Implementation Method 1
polymerizing one or more portions of the flow stream located downstream of the plurality of pillars by passing polymerizing light through one or more masks and onto the flow stream, the polymerization process forming a plurality of three-dimensional shaped microparticles
Data Source
AI summary
A method of forming three-dimensional shaped microparticles in a microfluidic device includes flowing a mixture of a monomer and photoinitiator in a microfluidic channel having a plurality of pillars disposed therein to define a flow stream having a pre-defined shape and temporarily stopping the same. One or more portions of the flow stream are polymerized by passing polymerizing light through one or more masks and onto the flow stream, the polymerization process forming a plurality of three-dimensional shaped microparticles. The three-dimensional shape of the microparticle may be geometrically complex by using non-rectangular 2D orthogonal shapes for the flow and/or masked light source. The microparticles may include protected regions on which cells can be adhered to and protected from shear forces. The flow stream is restarted to flush out the newly formed microparticles and prepare the device for the next cycle of particle formation.