When reviewing the MIC value for AgNPs used as antibacterial agents, I noticed that the value can vary in a very large range. Some can achieve within the order of 10 ug/mL, while others can be hundred or thousands ug/mL using AgNPs with an average size difference in just a single digit.
I read that the results can depend on various factors, like bacteria strain, or initial concentration.
But what is the major influence of this wide range of MIC values? Is there some limitation when interpreting MIC value? Should we take any report with MIC value with a pinch of salt?
*I may not have enough background to understand the mechanism behind it logically. It feels to me that there is some other mechanism than simply just "interaction" of the AgNPs with bacteria.
Thank you Sadia Ferdous
for your answer.To elaborate, I am looking at Staphylococcus aureus for the matter.
I curious because I saw an article that show how different particle size affect MIC (Agnihotri et.al, 2014, Article Size-controlled silver nanoparticles synthesized over the ra...
). The thing is, their particle size range is quite big (5, 7, 10, 15, 20, 30, 50, 63, 82, 100 nm) compared with most study in the field which usually below 20 nm. Not to mention, the MIC they report for particle size
Kharia, you are correct: NPs of different particle size vary considerably in antibacterial activity as well as physicochemical activity. In some cases, the shape of the NP is also a factor. We need to bear in mind also that NPs tend to aggregate into larger particles that lose a lot of their antibacterial activity. Other factors include the protein and chloride content of the culture medium, as silver NPs ahave a high affinity for these and will be inactivated.
Thank you sir Roger Bayston ,
Yes I make sure that the shape is spherical and confirm their size distribution to ensure minimal aggregation are present.
However, I didn't pay attention to the culture medium. Thank you for pointing this out and for the insight.
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