According to reports, the rapid spread of COVID-19 has led to a surge in the number of suspected infections and close contacts. The early detection of the virus can not only enable the infected person to be treated in time and reduce the risk of death, but also can effectively control the source of the infection and cut off the transmission route through isolation.
Generally, there are two detection strategies for infectious diseases: nucleic acid detection and immunological detection. Nucleic acid detection is the detection of viral RNA genome, including gene sequencing, quantitative real-time PCR, digital droplet PCR, gene chip and Loop-Mediated isothermal amplification. Immunological detection is the detection of specific antibodies produced by viral antigens or by human immune responses, including immunochromatographic strips, enzyme-linked immunosorbent assay (ELISA) and chemiluminescence immunoassay (CLIA).
The following compounds provieded by BOC Sciences can be used in the production of COVID-19 test kits:
Guanidine thiocyanate is a colorless crystal or white powder, soluble in water. It is an anticoupling agent and a strong protein denaturation agent, which can dissolve proteins, and quickly separate the nucleic acid from nuclear proteins. The combination of guanidine thiocyanate and mercaptoethanol is able to inhibit the activity of RNase. The combined action of guanidine thiocyanate and sodium dodecyl sarcosine can denature proteins and release RNA.
Guanidine hydrochloride, white or yellowish in color, is used as a protein denaturator. As a strong denaturation agent for extracting total RNA from cells, guanidine hydrochloride solution can dissolve proteins, destroy the secondary structure of nucleoproteins dissociated from nucleic acids. In addition, guanidine hydrochloride and other reducing agents can inactivate RNA enzymes. Using dicyandiamide and ammonium salt (ammonium chloride) as raw materials, crude guanidine hydrochloride products can be obtained at 170-230℃.
Tris(hydroxymethyl)aminomethane is a common buffer in molecular biology and cell culture. Tris buffer has a high buffering capacity, high solubility in water, and is inert to many enzyme reactions, which makes Tris a very satisfying buffer for many biochemical purposes. It is generally used to stabilize the pH of reaction system and has a strong buffering capacity between pH 7.5 and pH 9.0. Tris-HCl buffer system can also be used to stabilize the pH value in the gel. Tris buffer is widely used as a solvent for nucleic acids and proteins. Due to the low ionic strength, Tris buffer can also be used for the formation of intermediate fibers in nematodes. "TE buffer" prepared by adding EDTA into Tris hydrochloric acid buffer can be used for DNA stabilization and storage.
HEPES buffer, mainly composed of 2-[4-(2-hydroxyethyl)-1-piperazinyl]ethanesulfonic acid, is a non-ionic amphoteric buffer with good buffering capacity in the pH range of 7.2-7.4. Its greatest advantage is that it can maintain a relatively constant pH value in open culture or cell observation. Under these conditions, the cap of the cell culture bottle should be tightened to prevent the small amount of carbonate needed in the culture solution from being dispersed into the air. HEPES is difficult to dissolve in any other solvents, but it is readily dissolves in water, and does not precipitate with polyvalent metal ions. In addition, most natural factors such as temperature, concentration, medium salinity, and ion composition do not affect the dissociation of HEPES, so the stability of HEPES is excellent.
DTT, short for DL-dithiothreitol, is used to block the formation of intramolecular or intermolecular disulfide bonds between cysteines in proteins. The effect of DTT on proteins is that it can reduce disulfide bonds in proteins. One of the uses of DTT is as a reductant for sulfhydrylated DNA. Sulfur atoms at the ends of sulfhydrylation DNA tend to form dimers in solution, especially in the presence of oxygen. This dimerization greatly reduces the efficiency of some coupling experiments, such as DNA fixation in biosensors.