Since the birth of recombinant DNA technology in the 1970s, the modern biotechnology industry with recombinant DNA technology as its core has flourished, and more than a dozen genetically engineered drugs have been on the market. Various genetic engineering products and cell engineering products, mainly genetic engineering drugs, have been commercialized one after another.

In gene therapy, gene carriers are the key to the entry of foreign genes into recipient cells. Among them, cationic liposomes are currently considered to be ideal carriers with good targeting, low side effects, good stability and high transfection efficiency. Cationic liposomes are usually compounded by a cationic lipid and a neutral auxiliary lipid under appropriate conditions. The transfection efficiency of cationic liposomes is closely related to the composition of cationic lipids.

Commonly used auxiliary lipids

Auxiliary lipids mainly include phosphatidylethanolamine (PE), phosphatidylcholine (PC), cholesterol (Chol) and so on. Dioleoylphosphatidylethanolamine (DOPE) is the most widely used auxiliary lipid.

Cationic liposomes can form complexes with macromolecular DNA, greatly compressing the volume of DNA molecules, thereby effectively entering cells for transfection, and avoiding the possible immunotoxicity of viral vectors to patients, so they are safe and effective gene therapy vectors.

DOTAP (trimethyl-2,3-dioleoyloxypropyl ammonium bromide), DOTMA (trimethyl-2,3-dioleoyloxypropyl ammonium chloride), DC-Chol (3β- [N-(N',N'-dimethylaminoethyl)carbamoyl]cholesterol) is a more commonly used cationic lipid, but the stability of liposomes, membrane fusibility, and transfection efficiency are poor when forming liposomes alone. So it is often necessary to add auxiliary lipids. Among them, DOPE (dioleoylphosphatidylethanolamine) is the most commonly used auxiliary lipid, which has higher fusion and transfection efficiency than DOPC (dioleoylphosphatidylcholine) and CHO (cholesterol) liposomes.

Most of the cationic liposomes that have been commercialized use DOPE as an auxiliary lipid.

What are the methods of cell transfection?
1. Liposome method. Neutral liposomes use lipid membranes to wrap DNA and introduce DNA into cell membranes with the help of lipid membranes. Positively charged cationic liposomes are different. DNA is not pre-embedded in liposomes, but negatively charged DNA is automatically bound to positively charged liposomes to form DNA-cationic liposome complexes. , Thereby adsorbing to the negatively charged cell membrane surface, and being introduced into the cell through endocytosis. The liposome method started in 1987. The emergence of this method has greatly improved the efficiency of transfection, the stability and reproducibility of transfection. Cationic liposomes have relatively high cytotoxicity and may interfere with cell metabolism for different cells.
2. Electroporation method. By treating the cells with short high-field electrical pulses, the voltage difference along the cell membrane will cause temporary perforation of the cell membrane. DNA is thought to diffuse through the pores into the cell. The optimization of electric pulse and field strength is very important for successful transfection, because too high field strength and too long electric pulse time will irreversibly damage the cell membrane and lyse the cells. Theoretically, electroporation can be used for a variety of cells, and does not require additional purchase of special reagents, but requires an expensive electroporator. This method requires more cells and DNA per transfection because of the high mortality of cells. The conditions of each cell electroporation need to be optimized many times.
3. Virus-mediated infection. Infection requires cloning the target gene into a specific virus system, and then the modified virus is packaged by packaging cells, and then infection is carried out. The advantage is that the transfection efficiency is particularly high, especially for primary cells and living cells that are difficult to transfect. The disadvantage is that the virus construction cycle is long, there are many links, error-prone, and the cost is high.
4. Non-liposomal transfection. The latest nano-polymer transfection reagents, such as Entranster reagents and nano-materials, have low cytotoxicity and high transfection efficiency, and have gradually become the first choice transfection reagents in major laboratories.

About us
BOC Sciences provides a wide range of liposome products, including: anionic liposomes, clodronate, dopc lipid, liposome fluorescence dye, etc., as well as a variety of high-quality liposome preparation materials.