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Silver nanoparticles as a safe preservative for use in cosmetics
Satoshi Kokura1, Osamu Handa, Tomohisa Takagi
1Molecular Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Kyoto, Japan. s-kokura@koto.kpu-m.ac.jp
Nanomedicine : Nanotechnology, Biology, and Medicine
|January 12, 2010
Summary
Silver nanoparticles show promise as safe cosmetic preservatives. They are stable, effective against microbes, do not penetrate skin, and are non-toxic to skin cells, even under UV exposure.
Area of Science:
- Cosmetic Science
- Nanotechnology
- Microbiology
Background:
- Preservatives are essential in cosmetics but face safety concerns.
- Silver (Ag) has antimicrobial properties but limitations for preservative use.
- Novel silver nanoparticles (Ag NPs) offer potential alternative solutions.
Purpose of the Study:
- To evaluate the safety and efficacy of synthesized Ag NPs as cosmetic preservatives.
- To assess Ag NP stability, antimicrobial activity, skin permeability, and cytotoxicity.
- To investigate the impact of Ag NPs on human keratinocytes under UVB irradiation.
Main Methods:
- Synthesis and stability testing of Ag nanoparticles over one year.
- Antimicrobial efficacy testing against mixed bacterial and fungal cultures.
- In vitro human skin permeability assays using normal skin.
- Cytotoxicity assessment of Ag NPs on HaCaT keratinocytes with and without UVB exposure.
Main Results:
- Synthesized Ag nanoparticles demonstrated excellent stability, with no sedimentation observed for over a year.
- Ag nanoparticles exhibited significant preservation efficacy against both mixed bacteria and fungi.
- Normal human skin showed no penetration by Ag nanoparticles.
- Ag nanoparticles at concentrations of 0.002–0.02 ppm were non-cytotoxic to HaCaT keratinocytes and did not enhance UVB-induced cell death.
Conclusions:
- Synthesized Ag nanoparticles are stable and effective antimicrobial agents.
- Ag nanoparticles do not penetrate human skin and are non-cytotoxic to keratinocytes.
- Ag nanoparticles show significant potential for use as safe and effective preservatives in cosmetic formulations.
