Solid Phase PCR on 3D Microstructure ArrayChip for Pathogen Detection Application.

Area of Science:

• Microfluidics
• Optical Sensing
• Biotechnology

Background:

• Microfluidic devices require efficient optical sensing structures for applications like pathogen detection.
• Current fabrication methods for microstructures can be costly and limited in complexity.
• Supercritical angle fluorescence (SAF) offers enhanced signal detection but requires specialized microstructures.

Purpose of the Study:

• To present an advanced free angle photolithography (FAPL) method for fabricating 3D SAF microstructures.
• To demonstrate the transfer of these SAF structures onto polymeric chips via injection molding for low-cost microfluidics.
• To apply the fabricated SAF structures in a solid phase polymerase chain reaction (SP-PCR) for on-chip pathogen DNA detection.

Main Methods:

• Fabrication of 3D SAF structures using FAPL with a motorized stage for precise angle control.
• Injection molding of SAF structures onto polymeric chips.
• Implementation of SP-PCR using DNA oligos immobilized on SAF structures for pathogen detection.

Main Results:

• FAPL enabled increased density of SAF structures per mm² with controlled bucket-shape dimensions (50-150 μm).
• SAF structures enhanced fluorescence signals by 46 times.
• Reduced SAF structure size improved the limit of detection (LOD) and decreased required sample volume for SP-PCR.

Conclusions:

• FAPL is a viable technique for producing high-density 3D SAF microstructures for optical sensing.
• Injection molding allows for low-cost mass production of microfluidic devices with integrated SAF structures.
• On-chip SP-PCR using SAF structures demonstrates potential for sensitive, rapid pathogen detection in point-of-care applications.