When PCR false positives, we often consider whether the primer/Mix/* and so on contamination template, and then one by one to check, labor tired and time-consuming, sometimes still can not find the reason, simply to collapse.
Here I think to extend the thinking, these reagents and instruments in the end why will be contaminated? In fact, it is nucleic acid aerosol contamination.?
Centrifuge centrifugation / violent shaking of the reaction tube / PCR open cap / pipetting and pipette repeated suction, etc., will produce air and liquid surface friction, will produce nucleic acid aerosols, that is, the laboratory (or pipette gun) is filled with nucleic acid fragments of varying lengths of the small beads of water or small particles, these small particles settled (hit) to the blank samples resulting in the final amplification of the bands.
As you can imagine, these small droplets of nucleic acid will also fall onto the benchtop/PCR instrument/pipette gun/*head*box and so on, and if we don't pay attention to them, these small droplets of nucleic acid will accumulate over time, which makes it particularly problematic to do experiments such as PCR false positives.
So what do we do with the huge contamination of nucleic acid aerosols (i.e., nucleic acid droplets) in our experiments or lab management?
Large-area nucleic acid contamination removal operations:
(1) on the contaminated area using nucleic acid aerosol contamination remover (PCR Cleaner) for a large area of the treatment, including: floors, walls, ceilings, doors, windows, etc., and at the same time to increase the amount of ventilation (the internal circulation is useless, as far as possible, the external circulation);
(2) on the contaminated area of the equipment. Use nucleic acid aerosol contamination remover (PCR Cleaner) for repeated treatment; for the ultra-clean table and other equipment containing air filtration system, please replace the filter; pipettes and other contaminated equipment using nucleic acid aerosol contamination remover (PCR Cleaner) for cleaning, high-temperature sterilization;
(3) to be contaminated areas and equipment devices cleaned up, the use of ultraviolet light irradiation for more than 4 hours;
(4) can ask the janitorial staff in accordance with the above requirements (1) (2) (3) three consecutive days to clean up;
(5) the design of the experimental control group (according to the source of contamination of the gene fragments), the yin and yang control experiments, according to the negative control to confirm the contamination can be used in the 8 consecutive rows of PCR tubes (2 yang + 6 yin); if the yang senators jumped, the yin senators jumped, then the Pollution needs to continue to clean up; if the male participant jumps, the female participant does not jump, it means that the pollution is under control, and normal experiments can be resumed;
Nucleic acid aerosol contamination cleaner (PCR Cleaner) a box of 500 mL; a room of 10 square meters need 2 boxes to complete the coverage; other equipment and devices according to the situation to be purchased;
Large-scale nucleic acid aerosol contamination is very difficult to remove, if not immediately take action to remove the contamination, the contamination is very difficult to remove, if not immediately take action to remove the contamination. Very difficult to remove, if you do not take immediate action to clean up, the contamination will be more solid, long-term release of contaminated nucleic acids, resulting in laboratory downtime.