Silver Nanoparticles Assemblies Mediated by Functionalized Biomimetic Oligomers

Hagar Tigger, Schulich Faculty of Chemistry, Technion - Israel Institute of Technology , Hifa, Israel
Galia Maayan, Schulich Faculty of Chemistry, Technion - Israel Institute of Technology , Hifa, Israel

The organization or self-assembly of nanoparticles (NPs) in multiple dimensions harness their nanoscale attributes and provides unique electrical and optical properties. Ensembles containing both metal NPs and organic or bioorganic molecules are of special interest because they display the properties of both components, leading to a variety of applications in biology, medicine and sensing. Therefore, we are interested in the construction of organic-inorganic hybrid assemblies, which are stable in a wide range of temperatures, pH, chemical reagents and more. To this aim, we wish to investigate versatile oligomeric scaffolds that are easy to synthesize, modify and functionalize  as mediators for metal NPs aggregation

In this study, we are using N-substituted glycine oligomers, which are peptide mimics called “peptoids”. Their efficient synthesis employs primary amines, enabling the incorporation of innumerable functional groups, including capping agents for the binding of NPs, at specified N-positions along their spine. Thus, properties such as chirality, solubility, interaction with metallic surface, hydrophilicity and hydrophobicity, can be tuned in a precise manner via introduction of different side chains at various positions. Moreover, peptoids are stable in a large range of temperature and pH conditions.

Herein we present a simple method for the functionalization of Ag(0) NPs by peptoid oligomers, based on the affinity between aromatic amine ligands and Ag(0). Different lengths of peptoids bearing 1,10-phenanthroline at the N-terminus, as well as similar sequences containing different ligands were synthesized and used as Ag(0) stabilizers. The described methodology leads to the formation of unique aggregates with distinct shapes as confirmed by transmission electron microscopy (TEM) and UV–vis spectroscopy.