Cytotoxic Effects Of AgNPs Research Articles

Therapeutic Window of Ligand‐Free Silver Nanoparticles in Agar‐Embedded and Colloidal State: In Vitro Bactericidal Effects and Cytotoxicity

AbstractThe inhibition of bacterial growth through effective non‐toxic antimicrobial substances is of great importance for the prevention and therapy of implant infections in various medical disciplines. For the evaluation of a therapeutic window of silver nanoparticles (AgNPs), their bactericidal properties were tested in agar composites and colloids on four medical relevant bacteria. Therefore, we produced AgNPs using high‐power nanosecond laser ablation in water showing a log‐normal particle diameter distribution centered at 17 nm. Bacteria were incubated with AgNP concentrations ranging from 5 to 70 µg · mL−1 and the growth rate was recorded. Additionally, cytotoxic effects of AgNPs on human gingival fibroblasts were examined. The experiments demonstrated that laser‐synthesized AgNPs resulted in a significant bacterial growth inhibition of more than 80% at the indicated concentrations in a solid agar model (Pseudomonas aeruginosa 10 µg · mL−1, Streptococcus salivarius 10 µg · mL−1, Escherichia coli 20 µg · mL−1, Staphylococcus aureus 70 µg · mL−1). In a planktonic bacteria model, the growth of the tested bacteria was significantly delayed by the addition of AgNPs at a concentration of 35 µg · mL−1. The cytotoxic assays showed limited adverse effects on human fibroblasts at concentrations of less than 20 µg · mL−1. The present study illustrates the strong antibacterial effects of ligand‐free, laser‐generated AgNPs that exhibit moderate cytotoxic effects, resulting in a therapeutically applicable concentration of AgNPs for medical purposes between 10 and 20 µg · mL−1.

Implications of silver nanoparticle induced cell apoptosis for in vitro gene therapy

The impact of manufactured nanomaterials on human health and the environment is amajor concern for commercial use of nanotechnology based products. A judicious choice ofselective usage, lower nanomaterial concentration and use in combination withconventional therapeutic materials may provide the best solution. For example,silver nanoparticles (Ag NPs) are known to be bactericidal and also cytotoxicto mammalian cells. Herein, we investigate the molecular mechanism of Ag NPmediated cytotoxicity in both cancer and non-cancer cells and find that optimumparticle concentration leads to programmed cell death in vitro. Also, the benefit ofthe cytotoxic effects of Ag NPs was tested for therapeutic use in conjunctionwith conventional gene therapy. The synergistic effect of Ag NPs on the uracilphosphoribosyltransferase expression system sensitized the cells more towards treatmentwith the drug 5-fluorouracil. Induction of the apoptotic pathway makes Ag NPs arepresentative of a new chemosensitization strategy for future application in gene therapy.