Immobilization of povidone-iodine on surfaces of silica gel particles and bactericidal property

A novel antibacterial material I2-PVP/SiO2, on which povidone-iodine (PVP-I2) was loaded, was synthesized by a two-step route. Polyvinylpyrrolidone (PVP) was firstly graft-polymerized onto the surfaces of micro-sized silica gel particles, obtaining the grafted particles PVP/SiO2. Subsequently, the grafted particles PVP/SiO2 were allowed to undergo a complexation reaction with iodine, resulting in a water-insoluble antibacterial material, I2-PVP/SiO2. The effects of various factors on the complexation reaction were examined. The antibacterial property of I2-PVP/SiO2 was investigated by using Escherichia coli (E. coli) as model bacterium and with the colony count method. The experimental results show that the fitting temperature for the complexation reaction between PVP/SiO2 and I2 is 60 °C, and the complexation reaction reaches equilibrium after 12 h. The particles I2-PVP/SiO2 have very strong antibacterial activity and they have the sterilizing mechanism similar to povidone-iodine.