Photocurable Polysiloxane-Based Microfluidic Chip for Convenient Sample Partitioning and Digital Nucleic Acid Assay

Digital nucleic acid assay, capable of absolute quantification with high accuracy, shows promising potentials in various fields. Among others, chamber-based digital assay (cDA) is one of the most important techniques. However, challenges in sample partitioning often cause a cDA chip to suffer from complicated design/fabrication or tedious surface modification. While the polydimethylsiloxane (PDMS)-based chip can partially solve this problem, its slow thermal curing process forms a serious obstacle in chip manufacturing. To address these issues, we herein propose a novel photocurable polysiloxane-based cDA chip (pcDA), which enables not only simple, rapid fabrication, but also convenient sample partitioning under either negative or positive pressure. The chip molding process can be completed in less than 1 minute, and sample partitioning in several minutes. Moreover, both the isothermal method (e.g., digital recombinase polymerase amplification, dRPA) and digital polymerase chain reaction (dPCR) have been achieved, with the proof-of-concept demonstration ofE.coli.andS.aureus. detection showing satisfactory results, which features a relatively wide dynamic range of 0-5000 copies/μL and high sensitivity at 1 copy/μL level. It is therefore reasonably believed that the proposed pcDA may well address the current issues of cDA technique, providing a new and viable platform for precise digital nucleic acid assay.