People who work with bacteria, I have been looking at literature and every time a photolysis experiment to thermally kill bacteria is done, the bacteria are spun down, the supernatant growth solution is discarded and the cells are re-dispersed in a buffer/ salt solution before they are incubated with nanomaterial or the drug. Subsequently the photolysis experiment is also carried out while the bacteria are in buffer.
Is there any specific reason for this? Would a photolysis experiment with bacteria still in the growth solution not work?
The choice of buffer/ salt solution also seems to vary a lot. Is the choice dependent on the strain of bacteria or more on the bacteria recognizing (targeting) molecule? For instance, in Nano Lett. 2008, 8, 1, 302-306 they dispersed Pseudomonas aeruginosa in a 0.85% sodium chloride solution and antibodies were used to target bacterial cells. While in Article Controlled phage therapy by photothermal ablation of specifi...
, Pseudomonas aeruginosa and other bacterial strains were just washed with MilliQ water and phages were used as target agents.Any help or insight in this regarded is highly appreciated.
Hi Mohammad Azhar Mehfooz,
I would like to place my point here that, the use of NaCl is done for the adequate removal of non-specifically adsorbed ions and molecules from the bacterial cell surface so that any fluctuation should be prevented during antibody action on the particular bacterial spp. As there are some researches, that suggests the variations of NaCl concentration may lead to its altered effect (in terms of its action) on non-specifically adsorbed molecules or ions upon the cell surface. Ex.: For E. Coli, Minimum ionic strength required for such action is 0.15M (which also helps to reveal the exact surface charge of this bacteria) But when we use 0.6M it can remove ions intrinsic to the cell envelope. Similarly, concentration may vary according to the different bacterial spp.
In case of a particular buffer, I think by sustaining the desired pH level buffer may help in the complete/appropriate binding of the antibody-bacteria by preventing any alteration that can be caused by another ions/molecules in terms of its ambient conditions.
Thank you.
I think this has an important role in providing the chemical nature of the cell wall
Hi Mohammad Azhar Mehfooz,
I would like to place my point here that, the use of NaCl is done for the adequate removal of non-specifically adsorbed ions and molecules from the bacterial cell surface so that any fluctuation should be prevented during antibody action on the particular bacterial spp. As there are some researches, that suggests the variations of NaCl concentration may lead to its altered effect (in terms of its action) on non-specifically adsorbed molecules or ions upon the cell surface. Ex.: For E. Coli, Minimum ionic strength required for such action is 0.15M (which also helps to reveal the exact surface charge of this bacteria) But when we use 0.6M it can remove ions intrinsic to the cell envelope. Similarly, concentration may vary according to the different bacterial spp.
In case of a particular buffer, I think by sustaining the desired pH level buffer may help in the complete/appropriate binding of the antibody-bacteria by preventing any alteration that can be caused by another ions/molecules in terms of its ambient conditions.
Thank you.
Hey Gaurav Sharma thanks for the input! This is very useful. I was also thinking in terms of electrostatics but this makes a lot of sense.
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