SILVER COLLOIDS IMPREGNATING OR COATING BACTERIA

We produce silver nanocolloids selectively within and on Escherichia c oli bacteria. Silver preferentially concentrates in the bacteria, dist ributes uniformly within them, or, alternatively, forms a rough coatin g over them. Oscillations in polarized light scattering vs scattering angle are more pronounced and shift to larger angles, compared to a co ntrol that has no silver. Very intense surface-enhanced Raman signals are observed for E. coli with a ''wall colloid''. The main bands can b e associated with peptides and polysaccharides in the cell wall and it s membrane. This work was extended to Gram-positive Bacillus megateriu m.