title: Capping Agent-Dependent Toxicity and Antimicrobial Activity of Silver Nanoparticles: AnIn VitroStudy. Concerns about Potential Application in Dental Practice.
abstract: Objectives:In dentistry, silver nanoparticles (AgNPs) have drawn particular attention because of their wide antimicrobial activity spectrum. However, controversial information on AgNPs toxicity limited their use in oral infections. Therefore, the aim of the present study was to evaluate the antibacterial activities against a panel of oral pathogenic bacteria and bacterial biofilms together with potential cytotoxic effects on human gingival fibroblasts of 10 nm AgNPs: non-functionalized - uncapped (AgNPs-UC) as well as surface-functionalized with capping agent: lipoic acid (AgNPs-LA), polyethylene glycol (AgNPs-PEG) or tannic acid (AgNPs-TA) using silver nitrate (AgNO3) as control.Methods:The interaction of AgNPs with human gingival fibroblast cells (HGF-1) was evaluated using the mitochondrial metabolic potential assay (MTT). Antimicrobial activity of AgNPs was tested against anaerobic Gram-positive and Gram-negative bacteria isolated from patients with oral cavity and respiratory tract infections, and selected aerobicStaphylococcistrains. Minimal inhibitory concentration (MIC) values were determined by the agar dilution method for anaerobic bacteria or broth microdilution method for referenceStaphylococcistrains andStreptococcus mutans. These strains were also used for antibiofilm activity of AgNPs.Results:The highest antimicrobial activities at nontoxic concentrations were observed for the uncapped AgNPs and the AgNPs capped with LA. It was found that AgNPs-LA and AgNPs-PEG demonstrated lower cytotoxicity as compared with the AgNPs-TA or AgNPs-UC in the gingival fibroblast model. All of the tested nanoparticles proved less toxic and demonstrated wider spectrum of antimicrobial activities than AgNO3solution. Additionally, AgNPs-LA eradicatedStaphylococcus epidermidis and Streptococcus mutans1-day biofilm at concentration nontoxic to oral cells.Conclusions:Our results proved that a capping agent had significant influence on the antibacterial, antibiofilm activity and cytotoxicity of AgNPs.Clinical significance:This study highlighted potential usefulness of AgNPs against oral anaerobic Gram-positive and Gram-negative bacterial infections and aerobicStaphylococcistrains provided that pharmacological activity and risk assessment are carefully performed.
authors.affiliation: Department of Medical Chemistry, Medical University Gdansk, Poland.
authors.forename: Karolina
authors.initials: K
authors.lastname: Niska
authors.affiliation: Department of Medical Chemistry, Medical University Gdansk, Poland.
authors.forename: Narcyz
authors.initials: N
authors.lastname: Knap
authors.affiliation: Department of Oral Microbiology, Medical University Gdansk, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Kędzia
authors.affiliation: Department of Inorganic Chemistry, Medical University Gdansk, Poland.
authors.forename: Maciej
authors.initials: M
authors.lastname: Jaskiewicz
authors.affiliation: Department of Inorganic Chemistry, Medical University Gdansk, Poland.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Kamysz
authors.affiliation: Department of Medical Chemistry, Medical University Gdansk, Poland.
authors.forename: Iwona
authors.initials: I
authors.lastname: Inkielewicz-Stepniak
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000633:toxicity; D001421:Bacteria, Anaerobic / Q000187:drug effects*; D018441:Biofilms / Q000187:drug effects; D002478:Cells, Cultured; D003764:Dental Materials / Q000494:pharmacology* / Q000633:toxicity*; D005347:Fibroblasts / Q000187:drug effects; D005881:Gingiva / Q000166:cytology / Q000187:drug effects*; D006801:Humans; D053768:Metal Nanoparticles; D008826:Microbial Sensitivity Tests; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry; D012834:Silver / Q000494:pharmacology* / Q000633:toxicity*; D013212:Staphylococcus epidermidis / Q000187:drug effects; D013295:Streptococcus mutans / Q000187:drug effects; D013634:Tannins / Q000737:chemistry; D008063:Thioctic Acid / Q000737:chemistry
chemical_list: D000900:Anti-Bacterial Agents; D003764:Dental Materials; D013634:Tannins; D012834:Silver; D011092:Polyethylene Glycols; D008063:Thioctic Acid
keywords: antibacterial activity; antibiofilm activity; capping agent; cytotoxicity; human gingival fibroblasts; silver nanoparticles