Integrating Optical Feedback Alignment and Fluidic Control for Multiphase Flow-Assisted In Situ 3D Printing

Area of Science:

• Microfluidics
• Additive Manufacturing
• Biotechnology

Background:

• Stereolithography (SLA) is a high-resolution 3D printing technique widely used for microfluidic devices and lab-on-a-chip applications.
• SLA faces limitations in multi-material integration and fabricating complex microstructures within enclosed channels, hindering advanced applications like analytical separation and tissue engineering.

Purpose of the Study:

• To present a novel multiphase flow-assisted in situ 3D printing method to overcome the limitations of traditional SLA for microfluidic fabrication.
• To enable precise, high-fidelity, multi-material microfabrication within confined microchannels.

Main Methods:

• The method utilizes an aqueous two-phase system (ATPS) for sequential layer generation via fluidic confinement.
• An image-guided alignment system with homography transformation ensures precise projection of printing patterns within microchannels.
• Viscosity tuning of ATPS phases allows dynamic control over layer thickness and adaptive 3D structure design.

Main Results:

• Demonstrated dynamic control of layer thickness through viscosity tuning of ATPS printing and blocking phases.
• Achieved precise mask alignment and high projection fidelity using the image-guided system.
• Successfully fabricated complex 3D microstructures (pyramids, cuboids, void structures) and multi-material patterns directly within microchannels.

Conclusions:

• The multiphase flow-assisted in situ 3D printing method offers a versatile solution for spatially controlled, high-fidelity microfabrication in confined spaces.
• This technique addresses key challenges in microfluidic device fabrication, paving the way for novel lab-on-a-chip applications.
• Enables advanced microfabrication for applications in analytical separation, tissue engineering, and beyond.