title: Silver nanoparticles modified by gelatin with extraordinary pH stability and long-term antibacterial activity.
abstract: The potential for application of any nanoparticles, including silver nanoparticles (AgNPs), is strongly dependent on their stability against aggregation. Therefore, improvement of this parameter is a key task, especially in the case of AgNPs, because a correlation between size and biological activity has been demonstrated. In the present work, a natural stabilizer, gelatin, was investigated for the stabilization of AgNPs in an aqueous dispersion. The particles were prepared via a modified Tollens process, and the gelatin modifier was added prior to the reducing agent. The stability against aggregation of the AgNPs prepared by this method was more than one order of magnitude higher (on the basis of the critical coagulation concentration (CCC)) than that of AgNPs prepared via a similar method but without the assistance of gelatin. Their high stability against aggregation was confirmed over wide pH range (from 2 to 13) in which the particles did not exhibit rapid aggregation; such stability has not been previously reported for AgNPs. Additionally, gelatin not only fulfills the role of a unique stabilizer but also positively influences the modified Tollens process used to prepare the AgNPs. The diameter of the gelatin-modified AgNPs was substantially smaller in comparison to those prepared without gelatin. The polydispersity of the dispersion significantly narrowed. Moreover, the gelatin-stabilized AgNPs exhibited long-term stability against aggregation and maintained high antibacterial activity when stored for several months under ambient conditions.
authors.affiliation: Department of Physical Chemistry, Faculty of Science, Palacky University, Olomouc, Czech Republic.
authors.forename: Martin
authors.initials: M
authors.lastname: Sivera
authors.affiliation: Department of Physical Chemistry, Faculty of Science, Palacky University, Olomouc, Czech Republic; Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacky University, Olomouc, Czech Republic.
authors.forename: Libor
authors.initials: L
authors.lastname: Kvitek
authors.affiliation: Department of Physical Chemistry, Faculty of Science, Palacky University, Olomouc, Czech Republic; Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacky University, Olomouc, Czech Republic.
authors.forename: Jana
authors.initials: J
authors.lastname: Soukupova
authors.affiliation: Department of Physical Chemistry, Faculty of Science, Palacky University, Olomouc, Czech Republic; Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacky University, Olomouc, Czech Republic.
authors.forename: Ales
authors.initials: A
authors.lastname: Panacek
authors.affiliation: Department of Physical Chemistry, Faculty of Science, Palacky University, Olomouc, Czech Republic; Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacky University, Olomouc, Czech Republic.
authors.forename: Robert
authors.initials: R
authors.lastname: Prucek
authors.affiliation: Department of Microbiology, Faculty of Medicine, Palacky University, Olomouc, Czech Republic.
authors.forename: Renata
authors.initials: R
authors.lastname: Vecerova
authors.affiliation: Department of Physical Chemistry, Faculty of Science, Palacky University, Olomouc, Czech Republic; Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacky University, Olomouc, Czech Republic.
authors.forename: Radek
authors.initials: R
authors.lastname: Zboril
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000494:pharmacology; D001419:Bacteria / Q000254:growth & development*; D004355:Drug Stability; D005780:Gelatin / Q000737:chemistry / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D053768:Metal Nanoparticles / Q000737:chemistry*; D012834:Silver / Q000737:chemistry / Q000494:pharmacology; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D012834:Silver; D005780:Gelatin
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