PMID- 22595541
OWN - NLM
STAT- MEDLINE
DCOM- 20121002
LR  - 20131121
IS  - 1873-4367 (Electronic)
IS  - 0927-7765 (Linking)
VI  - 97
DP  - 2012 Sep 1
TI  - TiO2 nanoparticles suppress Escherichia coli cell division in the absence of UV 
      irradiation in acidic conditions.
PG  - 240-7
LID - 10.1016/j.colsurfb.2012.03.010 [doi]
AB  - TiO(2) nanoparticles (NPs) activated by UV irradiation are known to have a 
      bactericidal effect. In this study we report the details of TiO(2) NPs influence 
      on the colony-forming capacity of E. coli in the dark at pH 4.0-4.5. At this pH 
      the bacterial cells are negatively charged and TiO(2) NPs present a positive 
      charge. A 60 min contact between E. coli with TiO(2) at concentrations of 
      0.02-0.2 mg/mL led to a reduction of E. coli cell number from 10(8) to 
      10(4)CFU/mL. After the reduction the system remains unchanged during the 
      subsequent incubation. The observed reduction was a function on the initial E. 
      coli concentration. In the presence of 0.04 mg/mL TiO(2) the colony-forming units 
      (CFU) reduction after 60 min was of four-five orders of magnitude when the 
      initial concentration was 10(8) cells/mL. But when starting with an E. coli 
      concentration of 10(7) cells/mL the cell number reduction was less than one order 
      of magnitude. Less than one order of magnitude cell number reduction was also 
      observed for suspensions of E. coli 10(8) cells/mL and 0.002 mg/mL of TiO(2). The 
      bacteria number reduction was always accompanied by the formation of cell 
      aggregates. During cell incubation with TiO(2), the pH of the suspension 
      increased, but did not reach the TiO(2) isoelectric point (IEP). E. coli cells 
      stained with the fluorescent dye acridine orange (AO) showed that the 
      fluorescence of single cells remained unchanged after incubation in the presence 
      of TiO(2). The color change of fluorescence was revealed only in aggregated 
      cells. This suggests changes in the physiologic state of E. coli incorporated 
      into the aggregates. Aggregates of E. coli occur due to the electrostatic 
      interaction between TiO(2) NPs and the bacterial cell surface. A hypothesis is 
      suggested in this study to explain the CFU reduction and the retention of a 
      certain irreducible number of cells capable of further division in the suspension 
      in the presence of TiO(2) in the dark.
CI  - Copyright (c) 2012 Elsevier B.V. All rights reserved.
FAU - Zhukova, Lyudmila V
AU  - Zhukova LV
AD  - AN Bach Institute of Biochemistry Russian Academy of Sciences, Moscow, Russian 
      Federation.
FAU - Kiwi, John
AU  - Kiwi J
FAU - Nikandrov, Vitaly V
AU  - Nikandrov VV
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20120328
PL  - Netherlands
TA  - Colloids Surf B Biointerfaces
JT  - Colloids and surfaces. B, Biointerfaces
JID - 9315133
RN  - 0 (Anti-Bacterial Agents)
RN  - 15FIX9V2JP (titanium dioxide)
RN  - D1JT611TNE (Titanium)
SB  - IM
MH  - Anti-Bacterial Agents/chemistry/pharmacology
MH  - Escherichia coli/cytology/*drug effects
MH  - Nanoparticles/*chemistry
MH  - Titanium/*chemistry/pharmacology
MH  - Ultraviolet Rays
EDAT- 2012/05/19 06:00
MHDA- 2012/10/04 06:00
CRDT- 2012/05/19 06:00
PHST- 2011/11/15 00:00 [received]
PHST- 2012/03/09 00:00 [revised]
PHST- 2012/03/13 00:00 [accepted]
PHST- 2012/05/19 06:00 [entrez]
PHST- 2012/05/19 06:00 [pubmed]
PHST- 2012/10/04 06:00 [medline]
AID - S0927-7765(12)00180-4 [pii]
AID - 10.1016/j.colsurfb.2012.03.010 [doi]
PST - ppublish
SO  - Colloids Surf B Biointerfaces. 2012 Sep 1;97:240-7. doi: 
      10.1016/j.colsurfb.2012.03.010. Epub 2012 Mar 28.