Hexadimethrine bromide  别名：Polybrene; 1,5-Dimethyl-1,5-diazaundecamethylene polymethobromide; 聚凝胺

Polybrene（聚凝胺，hexadimethrine bromide）是一种多聚阳离子聚合物，常用于哺乳动物细胞的DNA转染实验以增强脂质体的转染效率。Polybrene目前广泛用于逆转录病毒介导的基因转染，慢病毒介导的基因转染，作用机理可能是通过中和细胞表面唾液酸与病毒颗粒之间的静电排斥从而促进吸附作用。Polybrene也是一种有名的抗肝素剂（肝素拮抗剂），常用来生产非特异性凝集的红细胞。另外Polybrene也多用于蛋白测序，因为小剂量的Polybrene在自动测序分析可明显改善多肽的降解现象。PVDF膜加入polybrene还能提高膜的亲和性。

Polybrene 增强哺乳动物细胞转染效率 (for reference only)
Polybrene (Cat. No. M9703) is supplied as a powder/solid and is soluble in water (up to 100 mg/mL). To generate a working solution, Polybrene should first be dissolved in 1 mL sterile water to generate a 10 mg/mL stock solution.
Polybrene working solution is generated from the polybrene stock solution (10 mg/mL in sterile water). This stock solution can be further diluted in the culture media to generate the desired working concentration for the transfection or transduction media.

Step 1: Prepare DNA Plasmid
Sufficient plasmid DNA must first be generated. Begin by amplifying the quantity of the plasmid by performing bacterial transformation. Grow the transformed bacterial culture overnight (in 37°C shaker) and extract the plasmid DNA using DNA MAXIprep kit.
Step 2: Prepare HEK Cells
Culture HEK293T cells in HEK media (DMEM/F-12 media, FBS, non-essential amino acids, L-glutamine) within humidified incubators (standard conditions of 37˚C, 5% CO2 and 21% O2). Once the culture has reached high confluency (>90%), the cells are ready for transfection.
Step 3: Prepare Transfection Media
Immediately before transfection, replace the HEK culture media with DMEM.
Prepare the transfection media, which consists of an optimized ratio of DMEM, DNA plasmid, lipofection reagent and polybrene stock solution. Typically, polybrene is used at a concentration of 4 µg/mL - 10 µg/mL.
Step 4: Transfection
Gently mix the transfection media before adding dropwise to the culture plate, to prevent damaging the cells.
Place the cells immediately in the incubator with the following settings overnight: 35˚C, 3% CO2 and 21% O2.
Step 5: Harvesting
Return culture to standard maintenance incubator. Leave the cells for 48-72 h post-transfection before proceeding to downstream application (i.e., harvesting of virus from media).