Digital Microfluidic Chip Based on Direct Ink Writing for Nucleic Acid Multiplex PCR Detection

This study presents a facile route to fabricate a novel kind of digital microfluidic (DMF) chip via direct ink writing. The manufacture of this device does not rely on conventional microfabrication processes and cleanrooms, which makes it easy to prepare and low cost. By measuring the change of contact angle (CA) and droplet velocity, we proved that it could perform droplet manipulation like traditional DMF chips. In addition, after optimizing the chip structure, through a peripheral support circuit, polymerase chain reaction (PCR) reagents could be automatically partitioned and mixed on the chip. Furthermore, we realized the multi-target end-point fluorescence detection of SARS-CoV-2 RNA on this chip, showing promising potential for automatic nucleic acid tests.