Transfection enhancers are additives or modifications to standard transfection protocols that can improve the efficiency of gene delivery into cells. They work by increasing the cellular uptake of transfection complexes or by promoting their release from endosomes after internalization. Some common transfection enhancers include:
- Chloroquine: Chloroquine is a lysosomotropic agent that can raise the pH of acidic intracellular compartments, such as endosomes and lysosomes. By inhibiting the acidification of these organelles, chloroquine can prevent the degradation of the transfection complexes and promote their release into the cytosol.
- Polybrene: Polybrene is a cationic polymer that can enhance transfection efficiency by neutralizing the negative charges on the cell surface and promoting the binding and internalization of the transfection complexes.
- Sodium butyrate: Sodium butyrate is a histone deacetylase (HDAC) inhibitor that can enhance transfection efficiency by promoting the transcription of the transfected genes. It is particularly useful for increasing the expression of exogenous genes when using viral vectors, such as lentiviruses.
- Proton-sponge effect reagents: Compounds such as 25 kDa branched polyethylenimine (PEI) and 2,3-dimethylmaleic anhydride (DMA) can act as “proton sponges” in endosomes, buffering the acidic environment and promoting the release of the transfection complexes into the cytosol.
- Dextran sulfate: Dextran sulfate is an anionic polysaccharide that can enhance transfection efficiency by promoting the interaction of the transfection complexes with the cell surface.
When using transfection enhancers, it is essential to optimize their concentrations and incubation times to achieve the desired enhancement in transfection efficiency without causing significant cytotoxicity. Additionally, the effectiveness of transfection enhancers may vary depending on the cell type and transfection method used, so it is crucial to test different enhancers and conditions to identify the optimal approach for your specific experimental system.