Surface-bound biocides and activated surfaces

Hiittinger (1987, 1988) has presented a system in which biocides such as aldehydes, hydroxyaniline, amino-phenylmercuryacetate, dibutyltinchloride and tributyltinchloride[II, 19.6.] were bound to cellulose as substratum, referring to earlier work of Isquith and McCollum (1978). The efficacy was evaluated by agar plate tests. From his results he concludes that only hydroxyaniline and tetrachlorobenzene, which were not active, had to be transported into the cytoplasm to be active. However, his study did not reveal whether this was only an effect of release of the other biocides into the medium which was less pronounced with the substances mentioned as ineffective. As plausible as this idea may appear in the first place, the approach must overcome a few serious problems  

If no biocide molecules are actually released, it is hard to understand how molecules which do not penetrate the cell wall can kill a microorganism. An explanation was not provided. 

If cells attach a surface impregnated with biocides and are actually killed, there is not much probability that they leave the surface. Thus, the surface will be soon covered with dead bacteria and loose its efficacy. 

Not only can bacteria adhere to the surface but also macromolecules of all kind. They may kinetically compete with adhering cells and mask the active groups, an effect which is called fouling . 

The authors claim a killing efficacy against planktonic cells also which seems to be a clear indication that the biocide must have been released into solution, as a remote biocidal effect of biocides covalently bound to surfaces conferred to suspended organisms is scientifically not understandable and it was not discussed by the authors. 

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