Dynamic dispersal of surface layer biofilm induced by n-TiO2 based on surface plasmon resonance and waveguide

Publication year: 2018
Authors: Zhang P. 1,2, Guo J.S. 3, Yan P. 2, Chen Y.P. 4,2, Wang W. 5, Dai Y.Z. 1, Fang F. 2, Wang G.X. 6, Shen Y. 7
Affiliations:

1 - College of Environment and Resources, Xiangtan University, Xiangtan, 411105, China
2 - Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China
3 - Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China
4 - College of Environment and Resources, Xiangtan University, Xiangtan, 411105, China
5  - School of Chemistry & Chemical Engineering, Nanjing University, Nanjing 210023, China
6 - College of Bioengineering, Chongqing University, Chongqing 400045, China
7 - National Base of International Science and Technology Cooperation for Intelligent Manufacturing Service, Chongqing Technology and Business University, Chongqing 400067, China

Published in: Applied and Environmental Microbiology, 2018
doi: 10.1128/AEM.00047-18

Pollutant degradation is mainly presented in the surface layer of biofilm, while the surface layer is the most vulnerable to the impairment of toxic pollutants. In this work, the effect of nanosized TiO2 (n-TiO2) on the average thicknesses of Bacillus subtilis biofilm and on bacterial attaching on different surfaces were investigated. The binding mechanism of n-TiO2 to the cell surface was also probed. The results revealed that the n-TiO2 caused biofilm dispersal and the thicknesses decreased 2.0-2.6 μm after several hours of exposure. The attachment abilities of bacteria with extracellular polymeric substances (EPS) on hydrophilic surface were significantly reduced 31% and 81% under 10 and 100 mg/L of n-TiO2, respectively, whereas those of bacteria without EPS were significantly reduced 43% and 87%, respectively. The attachment abilities of bacteria with and without EPS on hydrophobic surface were significantly reduced 50% and 56% under 100 mg/L of n-TiO2, respectively. The results demonstrated that the biofilm dispersal was attributed to the changes in the cell surface structure and the reduction of microbial attachment ability. 

Importance: Nanoparticles can penetrate into the outer layer of biofilm in a relatively short period, and can bind onto EPS and bacteria surfaces. Current work probed the effect of nanosized TiO2 (n-TiO2) on biofilm thickness, bacterial migration and surface properties of the cell in the early stage using surface plasmon resonance waveguide mode. The results demonstrated that n-TiO2decreased the adhesive ability of both cell and EPS, and induced bacterial migration and biofilm detachment in several hours. The decreased adhesive ability of microbes and EPS made against the microbial aggregation, reducing the effluent quality in the biological wastewater treatment process.


MP-SPR keywords: bacteria film growth on poly-L lysine, biofilm, biofilm growth, biofilm thickness, degradation of biofilm, interaction of nanosized TiO2, nanotoxicity, waveguide