Visible light inactivation of bacteria and fungi by modified titanium dioxide

Abstract

Visible light induced photocatalytic inactivation of bacteria (Escherichia coli, Staphylococcus aureus, Enterococcus faecalis) and fungi (Candida albicans, Aspergillus niger) was tested. Carbon-doped titanium dioxide and TiO2 modified with platinum(IV) chloride complexes were used as suspension or immobilised at the surface of plastic plates. A biocidal effect was observed under visible light irradiation in the case of E. coli in the presence of both photocatalysts. The platinum(IV) modified titania exhibited a higher inactivation effect, also in the absence of light. The mechanism of visible light induced photoinactivation is briefly discussed. The observed detrimental effect of photocatalysts on various microorganism groups decreases in the order: E. coli > S. aureus approximately E. faecalis>>C. albicans approximately A. niger. This sequence results most probably from differences in cell wall or cell membrane structures in these microorganisms and is not related to the ability of catalase production.

A preliminary study on antifungal effect of TiO2-based paints in natural indoor light

“…Due to C. crustacea did not grow on paint-coated MEA under both dark and light exposure conditions, the species was excluded from this list. The results have confirmed the findings by Maneerat and Hayata 21 and Mitoraj et al 34 ; concerning the inhibition effect of TiO 2 -mediated photocatalysis on fungal growth. Chen et al 25 also found that photocatalytic disinfection processes were effective in the A. niger growth inhibition only under UVA irradiation.…”

Pollution profiles, health risk of VOCs and biohazards emitted from municipal solid waste transfer station and elimination by an integrated biological-photocatalytic flow system: A pilot-scale investigation

“…After another 30-day operation, the PC reactor still maintained high disinfection ability to all biohazards with only very slightly decrease of inactivation efficiencies of bacteria and molds. In addition, it must be noted that, usually, molds were more difficult to be inactivated than bacteria with equal concentrations by PC treatment because molds are eucaryotic organisms surrounded by a rigid cell wall, and mold cell is much larger than that of bacteria [40,41]. Nevertheless, PC inactivation efficiency of molds was slightly higher than that of bacteria on day 30 in this work.…”

Boosting TiO2-anatase antimicrobial activity: Polymer-oxide thin films

“…8-9 logreduction/0.5 h) can be compared with water suspensions of TiO 2 promoted with Pt(IV) salts (ca. 6 log-reduction/0.5 h) [43]; TiO 2 supported on EVOH (6.3 log-reduction/0.5 h) [7a] or TiO 2 -Ni contains (2 log-reduction for extended period of times) [44]. Other biocides based on simple chemicals as trichlorosan on styrene-acetate copolymers (initial rate enhancement below 2 with respect to the polymer alone) [45]; organometallic complexes leading to oxygen radical formation (3.5 log-reduction/4 h) [46]; or UV-treated Nylon (1.8 log-reduction/6 h) [47] provide further support to our conclusion concerning the good performance of the nanocomposite films here described.…”