Controlled Release of Biologically Active Silver from Nanosilver Surfaces

By Jingyu Liu, David A. Sonshine, Saira Shervani, R. Hurt. ACS Nano, 2010

1,048 citations recorded by the source corpus.

Major pathways in the antibacterial activity and eukaryotic toxicity of nano-silver involve the silver cation and its soluble complexes, which are well established thiol toxicants. Through these pathways, nano-silver behaves in analogy to a drug delivery system, in which the particle contains a concentrated inventory of an active species, the ion, which is transported to and released near biological target sites. Although the importance of silver ion in the biological response to nano-silver is widely recognized, the drug delivery paradigm has not been well developed for this system, and there is significant potential to improve nano-silver technologies through controlled release formulations. This article applies elements of the drug delivery paradigm to nano-silver dissolution and presents a systematic study of chemical concepts for controlled release. After presenting thermodynamic calculations of silver species partitioning in biological media, the rates of oxidative silver dissolution are measured for nanoparticles and macroscopic foils and used to derive unified area-based release kinetics. A variety of competing chemical approaches are demonstrated for controlling the ion release rate over four orders of magnitude. Release can be systematically slowed by thiol and citrate ligand binding, formation of sulfidic coatings, or the scavenging of peroxy-intermediates. Release can be accelerated by pre-oxidation or particle size reduction, while polymer coatings with complexation sites alter the release profile by storing and release inventories of surface-bound silver. Finally, the ability to tune biological activity is demonstrated through bacterial inhibition zone assay carried out on selected formulations of controlled release nano-silver.

Subfields: Biomedical Engineering, Electronic, Optical and Magnetic Materials, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/9592751db23bac93991cdf88ca09832aa0ec09d7

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Citations in the corpus

Distribution, elimination, and toxicity of silver nanoparticles and silver ions in rats after 28-day oral exposure. (2012, methodology): “The acidic mixture to digest silver suspensions is different to that used to digest tissue samples, since the presence of an excess of chloride (which is commonly present in tissue samples) was found to be imperative for complete dissolution of the silver nanoparticles.(9) Tissue samples of day 29, ”
The use of polyethyleneimine-modified reduced graphene oxide as a substrate for silver nanoparticles to produce a material with lower cytotoxicity and long-term antibacterial activity (2012, background): “The function of AgNP in these ion-based toxicity pathways is (i) to generate a sustained flux of Ag from an inventory of AgNP bound on substrates or imbedded in matrices or (ii) to transport active Ag to sensitive biological targets on cell membranes or within cells following particle attachment or ”
Antibacterial nano-structured titania coating incorporated with silver nanoparticles. (2011, neutral): “It has been reported that a variety of competing chemical approaches can accomplish this purpose [45] and they may be applied to control Agþ release from the Ag nanoparticles in NT-Ag.”
A novel green one-step synthesis of silver nanoparticles using chitosan: catalytic activity and antimicrobial studies (2012, background): “2011) and in the biomedical field (Xu et al. 2006; Liu et al. 2010; Krishna Rao et al. 2012).”