Polylysine solutions are typically used to coat glassware and plasticware for the attachment and growth of cells.
- Prepare a stock solution by dissolving 100 mg polylysine in 100 ml water (poly-L-lysine or poly-D-lysine can be used; check specific protocol for choice of isomer)and filter sterilize through a 0.22-micron filter.
- Store in 5-ml aliquots at -20°C.
Coating culture dishes, multiwell plates, or chamber slides
- When ready to use, dilute 1 part stock solution with 19 parts water to prepare a 50 ?g/ml working solution.
- Fill tissue culture dishes, multiwell plates, or slide wells with the working solution and incubate 1 hr in a 37°C incubator, then remove solution by vacuum aspiration and allow surface to dry.
- To coat coverslips: Sterilize coverslips by autoclaving or by incubating them in 95% ethanol and drying before coating. Place coverslips in a single layer in a petri dish containing working solution and incubate 1 hr at 37°C. Remove coverslips using sterile forceps and allow surface to dry.
- Store coated tissue culture ware up to 3 months at 4°C. Use diluted solutions only once.
When coating with poly-l-lysine, the efficiency of coating is relatively low when prepared with distilled water due to the acidic pH of the solution that can range between a pH of 3.3-6.6. One recommendation  to improve coating is to use an 8.5 pH borate buffer to dissolve the lysine, with thorough rinsing after coating. In addition to the basic techniques shown here, there are a variety of approaches recommended by vendors as shown below.
 Should I coat coverslips in dd-water? http://www.neuvitro.com/tips-and-calculations-polylysine-coating.htm