A Novel Deep-Sea Nucleic Acid Preservation Structure Design Based on In-Plane Passive Fluidic Mixer

In situ fixation of deep-sea nucleic acids remains challenging, as conventional sampling often causes degradation due to abrupt environmental changes. This study developed a novel deep-sea nucleic acid preservation structure based on the Tesla valve principle, comparing it with traditional straight-tube structure. Experimental and CFD simulation results showed that the Tesla-valve structure significantly reduced fixative consumption under the same inlet velocity. At an inlet velocity of 0.2 m/s with a chamber fixative mass fraction of 87.2%, the Tesla-valve structure reduced fixative use by 48.9%. The fixative consumption decreases to minimum at 0.4 m/s in Tesla-value structure. Moreover, we investigated the effects of annular baffle quantity, baffle inclination angle, and central aperture diameter on fixative consumption across varying flow regimes using a numerical simulation method. Results indicated that the number of baffles exerted a significant influence on fixative consumption, with reduced baffle numbers correlating with increased consumption across all flow velocities. Baffle inclination angle and central aperture diameter demonstrated negligible effects on consumption metrics. This work provides an efficient structural design for deep-sea nucleic acid preservation, providing technical support for maintaining nucleic acid integrity during abyssal biological investigations.