Additionally, is there an effect of TiO2 on the membranes of bacteria or on their nucleus?
TiO2 generates reactive oxygen species ROS, i.e. highly oxidising radicals and H2O2 which react with the cells walls of the micororganisms and perforate leading to the cells death. see attached
Thank you very much...this is an interesting paper. Our research includes now TiO2 nanopartices (15 nm size).
But please, please note that this effect is due to the activation of the TiO2 by UV light. In Fig. 2 of the paper the TiO2 left in the dark had NO effect on survival of the bacteria. Under body-like conditions of pH and temperature and "in the dark", TiO2 does not react with living cells of any kind, and virtually no Ti ions are released into body fluids. That is why titanium implants (which innately have TiO2 surfaces) are the most tissue compatible. It is possible that TiO2 nanoparticles (not activated by UV light) might have some physical effect on bacteria, but I doubt any chemical interaction is possible.
That is right, pure TiO2 generates the ROS when excited by photons of energy greater than its band gap, i.e. 3.2 eV (upto 386 nm wavelength).
Dear Dr. Daniels and Dr. Joya,
Thank you for your e-mail. Indeed we did notice that UV has an effect on TiO2. Unfortunately our Raman is not that sensitive in the detection of TiO2 in solution and hence we will start playing also with the UV-VIS spectroscopy... If lucky, we will be able to asses the gap energy from UV-Vis data. This was not planned but happens ... We may try playing also with the FTIR. We are coming from the materials science side and I hope that we will be able to work out some reliable conclusions. We should be able to detect the Ti intake...if not extremely low....but I am afraid that we will need to kill the cells (bacteria). I will be pleased to keep in touch together....
I have no expertise in excitation of Ti my uv, etc. I just know a lot about med & surgical use of Ti and some of its alloys in solid form. Happy to provide you with info/advice in that realm. A true expert on photo excitation here at Uni Basel is Jakob Wirz.
See: https://www.researchgate.net/profile/Jakob_Wirz/
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