What is the main principle of chemical transfection? and which molecules are used?

The two main principles of chemical transfection are - that certain positively charged molecules surround the negatively charged nucleic acids, thereby shield it and allow for entry into the cell. molecules that can do this are calcium phosphate, dendrimers, cationic polymers, nanoparticles. - that positively charged lipids surround the negatively charged nucleic acids, enabling merging with the cell membrane and thereby inserting the nucleic acids into the cell.