pH Control of the Electrostatic Binding of Gold and Iron Oxide Nanoparticles to Tobacco Mosaic Virus

Abstract

We report the binding of nanoparticles (NPs) to wild type (unmodified) tobacco mosaic virus (TMV). The viruses are simply mixed with citrate-coated, negatively charged gold and iron oxide nanoparticles (IONPs) in acidic solution. This results in TMV decorated along its whole length by the respective particles. Such a decoration usually requires chemical modification or mutation of TMV (e.g., cysteine residues), but here we simply reduce TMV's natural negative charge by protonation. The particles are protonated to a much smaller extent. This charge-based mechanism does not operate for neutral particles.

Green Synthesis of Metallic Nanoparticles via Biological Entities

“…Because of these interesting properties, plants have been considered a more environment-friendly route for biologically synthesizing metallic nanoparticles and for detoxification applications [66,69]. Plant extracts containing bioactive alkaloids, phenolic acids, polyphenols, proteins, sugars, and terpenoids are believed to have an important role in first reducing the metallic ions and then stabilizing them as seen in Figure 1 [195,196].…”

“…Another interesting feature of many biological entities is their ability to act as templates in the synthesis, assembly and organisation of nanometre scale materials to fabricate well-defined micro and macro scale structures. For example, viruses have been used to assemble gold and iron oxide nanoparticles to form microstructures [66], bacteriophages have also been used to form intricate nanometre and micrometre scale structures [67,68,69] and phage based assemblies of liposomes have been used in targeted drug delivery procedures [70,71,72,73]. Comparing the above-mentioned biological identities and their potential to become efficient biological factories, synthesizing nanoparticles via plants, is a relatively straight forward and advantageous approach [74,75].…”

Engineering filamentous bacteriophages for enhanced gold binding and metallization properties

“…Theoretical isoelectric points (pIs) of mature p8 coat proteins (50 aa) carrying N-terminal YYYYY, AYSSG, AYGDD and AEGDD peptides were calculated as 9.31, 9.53, 8.31 and 6.28 respectively. Citrate stabilized AuNPs were previously reported to be negatively charged in a broad pH range (pH 3-pH 8) [32]. At pH 7 where AuNP binding experiments were conducted, although WT AEGDD phages were negatively charged; AYGDD, AYSSG and YYYYY phage surfaces were positively charged inducing attractive electrostatic forces between engineered phages and negatively charged AuNPs.…”

Nanoscale device architectures derived from biological assemblies: The case of tobacco mosaic virus and (apo)ferritin

“…117) The latter can be much better controlled when preformed NPs are bound to TMV. 61,118) For deposits that are much thicker than the virion, prolonged deposition produces smooth tubes. 119) An important criterion for applications is chemical stability.…”