Hydroxyl radical diffusion distance

The mean diffusion distance of various nitrogen and oxygen based species within one estimated lifetime. The diameter of the dot for hydroxyl radical is still 100-fold larger than the actual diffusion distance (Hutchinson, 1957). 

Hydroxyl radicals are probably the most toxic for microorganisms [30], They promote peroxidation of polyunsaturated phospholipid components of the lipid membrane and induce disorder in the cell membrane [31]. The damage of the outer membrane increases the permeability to ROSs. This process is possible thanks to a sufficient lifetime of ROSs generated at the Ti02 surface. ROS diffusion was studied by Fujishima et al. Their experiments demonstrated the bactericidal effect of irradiated Ti02 film on E. coli even at the distance of 50pm from the film [21], Furthermore, oxidative perforation of the cellular membrane allows the photocatalyst nanoparticles to penetrate the interior of the cell, causing severe, efficient oxidation of the cell content [27,32], ROSs are responsible for oxidation of amino acids, peptides [33], enzymes [34], and nucleic acids [32, 35-37]. Destruction of... 

Hydroxyl radical OH lO Very active in reactions of acceptance, donation and transfer of electrons. Diffusion distance is short... 

The hydroxyl radical, which is highly reactive, diffuses only a short distance before it reacts with whatever biomolecule it collides with. Radicals such as the hydroxyl radical are especially dangerous because they can initiate an autocat-alytic radical chain reaction (Figure 10.19). Singlet oxygen ( ()2), a highly excited... 

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