Investigation of the effects on stability of silver nanoparticles

by Niyonshuti, Isabelle I.; Alqahtany, Meaad; Wang, Yong; Chen, Jingyi

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Silver nanoparticles (AgNPs) have unique chem. and phys. properties that have drawn a lot of attention for various applications. Many advances have been made to develop synthesis techniques to fabricate AgNPs with properties that permit their desired applications. For instance, morphol. control of the AgNPs which often involve the use of surface ligands has contributed to more understanding of their antimicrobial behaviors. Surface functionalization of these nanoparticles partially dictates their interaction with the bacterial/viral cells, which in turn affect their effectiveness. However, in some cases, these surface-modified nanoparticles tend to aggregate in aq. soln. esp. in the biol. medium due to their high reactivity with bio-mols. Stability of AgNPs depends on inter-particle behaviors from intermol. forces between surface ligands, and these behaviors can be affected by surface chem., storage conditions, and type of solvent. In this study, we modified the AgNPs with different polymer ligands through the ligand-exchange method. As-synthesized AgNPs capped with poly(vinyl pyrrolidone) (PVP) were exchanged to cover with branched polyethyleneimine (PEI) to make their surface pos. charged. The impact of the ligands on materials stability and antibacterial activity was examd. and revealed that PEI-coated AgNPs with a pos. zeta potential has better antibacterial activity compared to the PVP-coated AgNPs. This study aims to characterize changes in chem. and phys. properties of the AgNPs over time and assess how these properties are affected by storage conditions and type of ligand. Understanding the effects on the stability of AgNPs will not only give insights on how to enhance the AgNPs performance in biomedicine but also address the concern that is posed by these materials to environmental and human communities. [on SciFinder(R)]