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Title: The biomedical application of biogenic silver nanoparticles produced from Cotyledon orbiculata

Samantha Meyer

Cape Peninsula University of Technology, South Africa

Biography

Dr. Samantha Meyer did her undergraduate qualification in Medical Biosciences at the University of the Western Cape (UWC), South Africa. She then proceeded with postgraduate studies in the field of Applied Herbal Science and Medicine, and graduated with BSc Honours degree Cum Laude. During her Doctoral studies, she spent some time at University of Missouri-Columbia under supervision of Prof John Cannon, and obtained her PhD degree in 2009 from UWC.
     She has since been employed at Cape Peninsula University of Technology, where she currently holds position of Senior Lecturer, and heads a research group (funded by South African National Research Foundation) where she conducts research on the antimicrobial potential of indigenous SA medicinal plants.

Abstract

The biogenic synthesis of nanomaterials is considered an eco-friendly approach to nanomaterial synthesis that produces nanomaterials that is more biocompatible and therefore more suitable for biomedical applications. Several studies have shown the antibacterial properties of biogenic silver nanoparticles synthesised from plant extracts. These nanoparticles can be applied in the manufacturing of products (e.g. wound dressings, topical creams and gels) used for the treatment of wounds. South Africa and the Western Cape in particular have a rich plant biodiversity and many of these plants are used in traditional medicine to treat a whole range of human health problems, including conditions that affect the skin. In South Africa Cotyledon orbiculata is used in traditional medicine for the treatment of skin infections and inflammation. There are indications that biogenic nanomaterials produced from plants can integrate the inherent medicinal properties of the plant and further enhance the therapeutic efficacy. In this study silver nanoparticle synthesis using extracts of C. orbiculata to reduce silver nitrate was investigated. The nanoparticles were characterised using TEM, dynamic light scattering and UV-vis spectroscopy. The synthesis of the silver nanoparticles was optimised by varying the reaction time, temperature of synthesis, concentrations of the plant extract and silver nitrate. Spherical, crystalline silver nanoparticles with sizes of 20-40nm were produced using the optimal conditions. The antimicrobial activity of solvent extracts (water, methanol, chloroform) of C. orbiculata as well as silver nanoparticles produced from the plant was investigated against Staphylococcus aureus, Staphylococcus epidermidis, Methicillin resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa and Candida albicans. The immunomodulatory activity of the extracts and silver nanoparticles were evaluated by determining the effects on cytokine (TNF-alpha, IL-1 beta and IL-6) production in THP-1 macrophage cells.  The results show that the extracts exhibited some antimicrobial activity, with the Minimum Inhibitory Concentrations of the extracts ranging from 3.13 to 50mg/ml. These extracts also exhibited anti-inflammatory properties. The same activities were observed for the silver nanoparticles. However, the bioactivities of the nanoparticles were significantly higher when compared to the extracts. The study gives credence to the traditional use of the plant and also shows that silver nanoparticles produced from this plant can be used in the production of products for the treatment of skin conditions.
Audience take away:
• The audience will get an understanding of how indigenous South African medicinal plants are studied in our country, with a view to drug screening.
• Similar methodologies can be employed in other medicinal plant projects
• Further research work can be proposed based on the results of this study
• Future inter-disciplinary collaborations/ collaborative projects can be developed to continue this study, or start new projects