Assessing Bacterial Respiration in Response to Silver Nanoparticles

Begin with a slurry containing bacterial cells treated with silver nanoparticles suspended in an exopolysaccharide matrix.

Add a phosphate buffer to the slurry to maintain a stable pH.

Next, introduce a solution containing glucose and a soluble redox indicator, then incubate the mixture. The redox indicator acts as an electron acceptor.

During incubation, glucose and the redox indicator enter metabolically active bacterial cells.

The cells utilize glucose during respiration, generating electrons.

These electrons reduce the redox indicator to an insoluble, red-colored precipitate, which accumulates in the bacteria.

Centrifuge the mixture to separate the bacterial cells and discard the supernatant.

Add methanol and gently shake to dissolve the precipitate accumulated on the membrane, forming a colored solution.

Measure the color intensity of the solution.

Compare the measured intensity to a standard curve to determine the concentration of the solubilized precipitate that correlates with levels of cellular respiration.