Impairment of Biofilm Formation by TiO2Photocatalysis through Quorum Quenching.
The release of nanomaterials into the environment, due to their massive production and application today, has caused ecological and health safety concerns. Semiconductor photocatalysts like TiO2exhibit cytotoxicity to bacterial cells when exposed to UV irradiation. However, information about their impacts on individual or group bacterial behaviors is limited. In this work, the biofilm formation of Escherichia coli K12 in the presence of TiO2with and without UV irradiation was investigated and biofilm formation was found not to be affected under the sole application of TiO2or UV irradiation. However, biofilm development was substantially delayed by TiO2under UV irradiation, although no obvious cytotoxicity to cell growth was observed. The reactive oxygen species photogenerated by TiO2were found to quench the autoinducer 2 (AI-2) signals secreted by E. coli K12. As a result, the initiation of quorum sensing for biofilm formation activated by AI-2 was restrained. The expressions of two biofilm-formation-related genes, motA and rcsB, were also suppressed. A dose of an AI-2 precursor, 4,5-dihydroxy-2,3-pentanedione, effectively restored the biofilm development. These results show that the photoexcited TiO2could suppress biofilm formation through quenching AI-2 signals. This work may facilitate a better understanding about the ecological effects of increasingly released nanomaterials and provide implications for development of antifouling membranes.
School of The Environment and Safety Engineering, Jiangsu University , Zhenjiang, 212013, China.|CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China , Hefei 230026, China.
Xiang
X
Xiao
School of The Environment and Safety Engineering, Jiangsu University , Zhenjiang, 212013, China.
Wen-Wen
WW
Zhu
School of The Environment and Safety Engineering, Jiangsu University , Zhenjiang, 212013, China.
Qiu-Yue
QY
Liu
Key Laboratory of Ion Beam Bioengineering, Institute of Technical Biology & Agriculture Engineering, Chinese Academy of Sciences , Hefei, 230031, China.
Hang
H
Yuan
CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China , Hefei 230026, China.
Wen-Wei
WW
Li
Key Laboratory of Ion Beam Bioengineering, Institute of Technical Biology & Agriculture Engineering, Chinese Academy of Sciences , Hefei, 230031, China.
Li-Jun
LJ
Wu
School of The Environment and Safety Engineering, Jiangsu University , Zhenjiang, 212013, China.
Qian
Q
Li
CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China , Hefei 230026, China.
Han-Qing
HQ
Yu
D001426:Bacterial Proteins; D018441:Biofilms; D002384:Catalysis; D004926:Escherichia coli; D006714:Homoserine; D007783:Lactones; D053038:Quorum Sensing; D014025:Titanium; D014466:Ultraviolet Rays
D001426:Bacterial Proteins; D007783:Lactones; D006714:Homoserine; D014025:Titanium