Nucleic acid detection is mainly used to diagnose whether there is COVID-19 infection through nasopharyngeal swab specimens. The testing site is generally in a designated hospital or a designated place. During the epidemic, people's interviews were complicated, and it was not certain whether others were carrying COVID-19 virus. In this case, it is necessary to wear a mask on the way to the test.

Especially when going to the hospital, it is even more necessary to wear a mask, otherwise there is no need to enter the relevant area, because it is easy to pose a threat to human health.

physical features

Viscosity: the high axial ratio of DNA makes its aqueous solution very viscous, and long DNA molecules are easily damaged by mechanical force or ultrasonic wave, and the viscosity decreases.

Buoyancy density: DNA can be purified and analyzed according to its density. In high concentration molecular weight salt solution (CsCl), DNA has roughly the same density as the solution. If the solution is centrifuged at high speed, CsCl tends to settle at the bottom, thus establishing a density gradient, and DNA finally settles at the position corresponding to its buoyancy density, forming a narrow band. This technique is called balanced density gradient centrifugation or equal density gradient centrifugation.

Stability: The structure of nucleic acid is quite stable, which is mainly caused by hydrogen bonding between base pairs, base accumulation and cations in the environment.

spectral characteristic

Subtraction: dsDNA is the subtractive color of ssDNA, and ssDNA is the additive color of dsDNA.

DNA purity: It can be judged by measuring A260/A280 and A260/A230.