الفهرس 
General introductionOnly 14 pages are availabe for public view
 |  | from | 143 |  |  |
| | | from | 143 | | |
Abstract
Recently, metallic NPs have gained interest due to their unique properties. In particular, NPs made from the noble metals, such as those of silver or gold. Owing to their large surface area and high reactivity compared with the bulk solid, nanosized metal particles exhibited remarkable physical, chemical, and biological properties. In particular, the optical properties of AgNPs which varied according to their size and shape, as well as their chemical environment.
The growing ineffectiveness of traditional antibiotics, and the continuous emergence of resistance among target microorganisms, had renewed interest in the extraordinary antimicrobial properties of silver. It was worth mentioning that microbes were unlikely to develop resistance against silver, as they did against conventional and narrow-target antibiotics, because the metal attacked a broad range of target sites in the organisms.
The use of AgNPs was advantageous over other ionic silver containing compounds as AgNO3 or SSD. The latter exhibited a rapid and immediate release of large quantities of Ag+ which might be neutralized by anions (chloride, bicarbonate) in body fluids or cause skin irritation and cosmetic abnormality (argyria, or blue-gray coloration) on prolonged use. Moreover, ionic silver compounds also could arrest the wound healing process via fibroblast and epithelial cell toxicity.
Synthesis of AgNPs using eco-friendly techniques provide an advancement over chemical methods as they were cost effective and environment friendly and in these methods there was no need to use high pressure, energy and toxic chemicals. Additionally, chemical synthesis methods lead to the presence of some toxic chemical species adsorbed on the surface of the NPs that may have adverse effects in medical applications.
The aim of the current thesis was to investigate the possibility of synthesis as well as characterization of AgNPs using eco-friendly techniques. In this context, AgNPs were prepared using various plant extracts which possesses high antioxidant activity. The work in the current thesis was divided into two chapters:
Chapter 1: Green synthesis of silver nanoparticles: characterization and antimicrobial activity
The current chapter conspired to prepare and characterize AgNPs using different concentrations of various plant extracts as; fenugreek (2, 5 and 10%) and cumin seeds (1, 3 and 6%) as well as cranberry fruit powder extract (0.2, 0.5 and 0.8%). The antioxidant activities of the different used extracts were determined using the DPPH method. The prepared NPs was characterized in terms of particle size, zeta potential, polydispersity index, morphology, Uv-vis absorption pattern, concentration, release pattern of Ag+, FT-IR spectroscopic behavior. Finally in vitro evaluation of their antimicrobial effects using various techniques was performed.