An Digitalized Isothermal Nucleic Acid Testing Platform Based on Pump-Free Open Droplet Array Microfluidic Chip

Digital PCR has shown great potential for quantitative nucleic acid testing (NAT), but most existing platforms are dependent on large auxiliary equipment (e.g., vacuum pump, amplification instrument, fluorescence microscope) to achieve target dispersion, amplification, signal capture and result analysis. Such complex, expensive and bulky NAT platforms have limited their applications in resource-limited areas, especially for point-of-care testing (POCT). In this work, we designed a digital isothermal NAT platform based on pump-free open droplet array microfluidic chip. A pump-free microfluidic chip was developed based on open microdroplet array in form of thousands of independent microdroplets for spontaneous sample dispersion, without need for external power. Combined with a handheld fluorescent signal reader based on smartphone, this digital NAT platform can accurately quantify as low as 1 copy/μL of λDNA. Therefore, our integrated NAT platform, as a potable, robust and low-cost tool for highly accurate NA quantitative analysis, holds great potential for POCT applications.