Research on visual detection of nucleic acids using microfluidic chips with precipitation-induced obstruction for nucleic acid purification

With the increasing demand for rapid, safe, and convenient nucleic acid detection technologies, this study designs a visual detection microfluidic chip based on the principle of nucleic acid precipitation and channel blockage. Inspired by the ethanol purification process of nucleic acids and the filtration principle of microfilters, this method utilizes the physical blockage effect of precipitated nucleic acids to achieve visual detection. After specific amplification of the target nucleic acids, ethanol is used to precipitate them, thereby enabling visual detection of the target nucleic acid. We designed the microfluidic chip using poly(methyl methacrylate) (PMMA) microspheres as the porous medium. Thirty repeated experiments were conducted on this microfluidic chip, all of which successfully detected the target within 10 minutes, demonstrating practicality and high accuracy. This qualitative reading method is applicable to all pathogens in principle and is compatible with both isothermal and non-isothermal amplification techniques. Additionally, the chip’s internal environment is maintained under negative pressure throughout the process, and it is treated multiple times with alcohol, providing dual safety measures and enhancing the safety of its application in point-of-care testing (POCT).