An Ultraviolet Sterilization Protocol for Microtitre Plates

Ultraviolet radiation is a commonly used method of sterilization. The effect of UV radiation energy dose, exposure time, coverage, and presence of liquid on the efficiency of sterilization of polystyrene and polypropylene plates was investigated in this study. Regrowth of Escherichia coli cells in plates exposed to UV radiation was used to assess successful sterilization. The transilluminator was found to completely kill all contaminating cells, regardless of concentration with 30 minutes of radiation, while the highest energy dose on the Stratalinker® 4 was able to completely sterilize wells containing less than 10 cells. Coverage with saran wrap caused no impedance in sterilization efficiency, while use of a polystyrene lid prevented cell death even at the lowest cell concentration. Presence of water in the wells did not impact sterilization. UV radiation is therefore a viable potential sterilization technique, but optimal parameters still need to be specifically determined.