This blog article is to discuss classification of cell transfection technology, as well as introducing the principles, applications and characteristics of different methods, and to compare various of transfection methods.
Conventional transfection technology can be divided into two categories: one is transient transfection and the other one is stable transfection (permanent transfection).
The foreign DNA/RNA after transient transfection does not integrate into the host chromosome, which can have multiple copies in one host cell, resulting in a high level of expression. But it usually only maintains a few days of high expressing mainly for the analysis of promoter and other regulatory elements. In general, supercoiled plasmid DNA have a high transfection efficiency that the results will be analyzed in 24-72 hours after transfection(dependent on the different constructions), and a number of reporting systems are used to help detect singals, such as fluorescent protein, β- galactoside, etc.
Stable transfection is also known as permanent transfection. Exogenous DNA can not only be integrated into the host chromosome, but also be existent as an episome. Although the quantity of linear DNA in host cells after transfection is lower than that of supercoiled DNA. Its integration rate is notably higher. Exogenous DNA has little probability to be integrated into chromosome, and about one in 104 transfected cells can have integrated genome. Furthermore, with a number of selective markers to be screened repeatedly, such as APH, HPH and TK, stable transfected homologous cell lines can be finally constructed.
The choice of the transfection technology has a great influence on the results of transfection. Many transfection methods need to optimize the proportion of DNA and transfection reagent, cell number, cell culture condition and detection time. Some traditional transfection techniques, such as DEAE dextran method, calcium phosphate method, electroporation method and liposome method, have advantages and disadvantages. The next article will introduce the main principles and application characteristics of the transfection methods in detail.