I used polyarginine to make composite material antibacterial, the first time it was effective, the effect disappeared after repeated, is it because the performance of polyarginine disappeared after water absorption
How do you test for anti-microbial activity without adding water? Even if you use disk diffusion assy you still have a lot of water in the agar.
Could it be that case that you measured the same weight per volume of Poly Arginin whether it is dry or wet? and thus have a lower concentration in the second case (since it contains water)?