A PDMS-based cylindrical hybrid lens for enhanced fluorescence detection in microfluidic systems

Area of Science:

• Microfluidics
• Optical Engineering
• Biotechnology

Background:

• Microfluidic systems rely on fluorescence detection for biological and chemical applications.
• Weak fluorescence signals in microfluidic systems necessitate complex and costly optical setups.
• Existing methods often involve multiple optical components, leading to manufacturing challenges and high expenses.

Purpose of the Study:

• To propose a miniature, cylindrical hybrid lens for enhanced fluorescence detection in microfluidic systems.
• To simplify optical setups by integrating laser focusing and fluorescence collection functionalities.
• To leverage polydimethylsiloxane (PDMS) for cost-effective and straightforward fabrication.

Main Methods:

• Fabrication of a hybrid lens using polydimethylsiloxane (PDMS).
• Integration of laser focusing and fluorescence collecting lens capabilities into a single unit.
• Performance evaluation using fluorescent dyes (Rhodamine 6G, Nile Red) and labeled cells (Chlorella vulgaris).

Main Results:

• The hybrid lens increased collected fluorescence signal and detection sensitivity by over 220% for Rhodamine 6G and Nile Red.
• Detection limits were improved to 0.01 μg/mL for Rhodamine 6G and 0.05 μg/mL for Nile Red.
• Application to Nile red-labeled Chlorella vulgaris cells showed signal intensity and sensitivity increases exceeding 520%, with reduced signal variation due to incident angle.

Conclusions:

• The proposed PDMS hybrid lens offers a cost-effective and efficient solution for enhancing fluorescence detection in microfluidic devices.
• The integrated dual-function lens simplifies optical setups and significantly improves detection performance.
• This technology holds promise for advancing sensitive and robust analyses in various microfluidic applications.