The antibacterial activity of silver nanoparticles has long been known and has found a variety of applications. In this work, we studied the antibacterial properties of nanosilver prepared using a one-step method based on the direct low-temperature reduction of aqueous solutions poly(N-vinylpyrrolidone) (PVP) with an aqueous solution of silver nitrate [1]. Figure 2 shows the UV-Vis spectrum of nanosilver synthesized with PVP. The absorption maximum for silver nanoparticles is 436 nm. The antibacterial properties of silver ion (Ag+), silver nanoparticles (Ag0/PVP) against gram-negative bacteria Escherichia coli on agar plates were studied (Fig. 2). Bactericidal actions of silver nanoparticles and silver ions were compared. It was shown that the interaction between silver ions and constituents of the bacterial membrane caused structural changes in the membranes, finally leading to cell death. Inhibition depends on the type of precursor. PVP is a water soluble and neutral polymeric substance providing steric stabilization for coated nanosilver particles. Nanosilver is kept isolated by coating the core of the nanoparticles with a thick layer of PVP. The preparation, surface modification, characterization, and functionalization of nanosilver particles with PVP opens the possibility of formulating a new generation of bactericidal materials.