Novel Optofluidic Imaging System Integrated with Tunable Microlens Arrays.

Area of Science:

• Optofluidics
• Microfluidics
• Optical Engineering

Background:

• Optofluidic tunable microlens arrays (MLAs) offer light manipulation capabilities for lab-on-a-chip systems.
• Integrating 3D MLAs into narrow microfluidic channels remains a significant fabrication challenge.
• Limited research exists on variable focal length imaging using optofluidic 3D MLAs.

Purpose of the Study:

• To propose and demonstrate a novel method for fabricating optofluidic tunable MLAs within microfluidic channels.
• To overcome the limitations of integrating 3D MLAs into narrow microfluidic systems.
• To enable variable focal length imaging for microfluidic applications.

Main Methods:

• Fabrication of MLAs in polydimethylsiloxane (PDMS)-based microchannels using electrohydrodynamic jet (E-jet) printing.
• Creation of MLAs with diameters ranging from 15 to 80 μm within 200 and 300 μm wide microfluidic channels.
• Utilizing solutions with different refractive indices for reversible modulation of microlens properties.

Main Results:

• Successful fabrication of optofluidic tunable MLAs using E-jet printing.
• Demonstration of reversible modulation properties by alternating solutions with varying refractive indices.
• Achieved threefold tunability in focal length, enabling an imaging depth of approximately 450 μm.

Conclusions:

• The proposed E-jet printing method effectively fabricates optofluidic tunable MLAs in microfluidic channels.
• The developed optofluidic chip demonstrates significant potential for cell counting and imaging applications.
• This technology facilitates in-situ observation of microspheres and cells within microfluidic systems.