Dual pH‐Induced Reversible Self‐Assembly of Gold Nanoparticles by Surface Functionalization with Zwitterionic Ligands. Issue 28 (9th June 2020)

• Record Type: Journal Article
• Authors: He, Huibin; Ostwaldt, Jan‐Erik; Hirschhäuser, Christoph; Schmuck, Carsten; Niemeyer, Jochen
• Is Part Of: Small. Volume 16:Issue 28(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-06-09
• Subjects: dual‐responsive systems -- hydrophobic effects -- nanoparticles -- self‐assembly -- zwitterions; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.202001044
• Languages: English
• ISSNs: 1613-6810

Abstract

Abstract: The dual pH‐induced reversible self‐assembly (PIRSA) of Au‐nanoparticles (Au NPs) is reported, based on their decoration with the self‐complementary guanidiniocarbonyl pyrrole carboxylate zwitterion (GCPZ). The assembly of such functionalized Au NPs is found at neutral pH, based on supramolecular pairing of the GCPZ groups. The resulting self‐assembled system can be switched back to the disassembled state by addition of base or acid. Two predominant effects that contribute to the dual‐PIRSA of Au NPs are identified, namely the ionic hydrogen bonding between the GCPZ groups, but also a strong hydrophobic effect. The contribution of each interaction is depending on the concentration of GCPZ on NPs, which allows to control the self‐assembly state over a wide range of different water/solvent ratios. Abstract : Au nanoparticles functionalized with guanidiniocarbonyl pyrrole carboxylate zwitterions (GCPZ) show a dual‐pH responsively self‐assembly behavior. Induced by the GCPZ groups, the Au NPs self‐assemble at neutral pH, while reversible disassembly can be achieved both at basic and acidic pH. Electrostatic interactions as well as hydrophobic effects are identified as two driving forces for self‐assembly.