ZnO is a n-type semiconductor. In contact with an electrolyte an under illumination with light below 450 nm electron - hole pairs at the surface are created. Holes in the valence band are strongly oxidizing! To fight fungal spots also oxidizing chlorine-containing compounds are used.

Is it shape of ZnO nanoparticles might affect?

Recent studies have shown morphology affects the antibacterial property...

We are also working on similar areas where our pore size and shape affected quiet a lot on their behaviour.

How pore size affects? whether increase in the pore size increases/decreases the antifungal property?

How the shape affects? plese could you tell.

by any chance ZnO nano powder with less porosity exhibit higher activity than ZnO with high porosity in antifungal studies?

ZnO is a n-type semiconductor. In contact with an electrolyte an under illumination with light below 450 nm electron - hole pairs at the surface are created. Holes in the valence band are strongly oxidizing! To fight fungal spots also oxidizing chlorine-containing compounds are used.

In my case ZnO with less porosity is acting as a better fungicide than ZnO with high porosity !!!

Explanation of Karl seems reasonable. It should be possible to check fungicidal action with light and in the dark.

If it is due to dissolved Zn ions microporosity would generate a diffusion limited situation.

Mainly concentration, size and shape of the particle affect more on antifungal properties. We find that if ZnO nanoparticle concentration is more than 10 ppm it has tremendous adverse effect on fungal growth and development. In general, cube shaped nanoparticles showed more antifungal properties due to its more cell penetration than other shapes . ZnO nanoparticle size less than 20 nm showed more adverse effect than bigger size nanoparticles again due to their higher penetration.

Dear J. Tarafdar,

are you sure that it is due to penetration. Or may it be also due to solution or photochemical action???

Penetration is one of the major cause because we are getting more concentration of the particle inside the cell. Please see our publication ;

Standardization of size,shape and concentration of nanoparticle for plant application-Applied Biological Research 14, 138-144.

Dear J. C. Tarafdar, is there any particular reason for cube shaped ZnO showing better activity ? and sir, could you please send me your paper?

There are many different parameters which affect antifunal and totally antimicrobial activity of nanoparticles. these parameters are size, shape or geometry, aggregation or agglomeration, porosity, crystal structure, solubility or dissolution, surface charge, chemical structure or composition. These are all the parameters which affect the toxicity of nanoparticles. I refer you to read this paper: Environ. Sci.: Processes Impacts, 2013, 15,23–38.

But I should mention about shape of particles that the particle with aspect ration greater than 100 (such as nanotube and nanorod) is more toxic than other particles because rod shape particle better could penetrate into cell membrane and disrupt it.

Also, as Mr. Tarafdar mentioned cube shaped maybe have better antifungal activity which is result of ability of this crystalline structure to disrupt cell membrane.

Hope this information be useful.