A Digital PCR Chip with 3D Structure and Composite Materials

We designed and fabricated a three-dimensional (3D) digital PCR (dPCR) chip for better sample compartmentalization and stronger fluorescent signals. The chip was made of glass, silicon and poly dimethylsiloxane (PDMS) layers, respectively. All the microstructures were fabricated on the silicon substrate, with high-density hexagonal-shape reaction units regularly arranged in the reaction zone. A common fed channel was located underneath the reaction units to maximize the use of the chip area. The reaction units and the flow channel were connected by cylindrical micro-holes, which made the oil-water two-phase system more stable and reduced the interference of fluorescence signals due to residual sample in the flow channel. In addition, fluorescent light reflection on the silicon surface enhanced the resolution of dPCR image.