1. INTRODUCTION:

Nanotechnology is an emerging field of study that is now in its nascent phase. This can affect a lot of things. Nanomaterials are tiny pieces of materials that are very small, which means that they can be used for a lot of different purposes. They have gained a large interest from scientist in both, applied science as well as in basic. Recently scientists have given a great interest to silver nanoparticles. Ag NPs have some unusual properties that make them useful in a variety of fields, including biomedical research (imaging, fast diagnosis, tissue regeneration, and drug delivery‎⁰, textile industry^‎0, food packaging‎⁰, cosmetic industry‎⁰, catalysis‎⁰, sensors‎⁰, coatings‎⁰, Plasmonics (SERS)‎⁰, optoelectronics‎⁰, antimicrobial activities‎⁰, DNA sequencing‎⁰, contamination control and climate change‎⁰, clean water technology‎⁰, information storage, and energy generation. Ag NPs are very conductive, which has made them useful in electronic devices, inks, adhesives, and other materials‎⁰. Several bottom-up-approach techniques such as bio-reduction (plants, fungi, bacteria, yeast, biopolymers), sono-chemical, chemical reduction, photochemical, microemulsion, electrochemical, microwave, pyrolysis, Coprecipitaion and as well as top-down-approach techniques such as Evaporation-condensation, pulsed laser ablation, Ball-milling, Spray-pyrolysis, vapor-and-gas phase have been implemented for the synthesis of silver NPs‎⁰. It has been revealed that biological methods are cheaper and more active, cleaner and safer than other methods‎⁰.

The nanoparticles generated by biosynthesis method have more defined sizes and shapes than other physiochemical methods‎⁰. Biological systems use natural chemicals to help keep nanoparticles stable. These chemicals act as capping agents, pushing the nanoparticles in the desired direction. A literature review indicates that plants offer many advantages over other biological systems. Since plant extracts make it easy to form nanoparticles, these particles are more stable than those made from chemicals‎⁰.

Plant components such as leaf, stem, seed, and root are frequently utilized in the creation of metal-based nanoparticles. There are several components in the plant extract, including phenolic acids, terpenoids, proteins, carbohydrates, bioactive polyphenols, and alkaloids. These substances work together reduce metallic ions and help to keep them stable‎⁰. Plant NPs biosynthesis occurs in three phases: reduction, growth, and stabilization‎⁰. Reducing agents are important in recovering metal ions from salt precursors. During the reduction phase, biomolecules help to reduce the metal ions. The metal ions change from a single type of atom to two different types of atoms as they move around. This happens because oxidation happens, which makes the metal ions become more different in size. Then, small bits of metal (called "reduced metal atoms") start to form. During growth, when metal atoms recombine to form metal nanoparticles, but then quickly break down again into smaller pieces, metal ions undergo further biological reduction. Nucleation can help to form larger clusters of nanoparticles, but the growth phase makes the nanoparticles more stable and allows them to form more different shapes.

The last step is the stabilization phase in which the nanoparticles are made smaller and more stable by coating them with metabolites‎⁰. The quality, size, and shape of the biosynthesized NPs are impacted by a number of extra reaction conditions, like the reaction temperature and time, solutions pH, concentration of plant extract, concentration of metal salt‎⁰. One of the first approaches that were made with plants extract for the production of Ag NPs used Alfalfa sprouts‎⁰. It appeared to be a faster process in contrast to the utilization of fungus and bacteria, and the production of Ag NPs was more rapidly. Also, the plant Geranium leaf was used in research by Shankar et al. and it took only 9 hours to reach 90% reaction, this is very short time compared to further researches which took 24 to 124 hours‎⁰.

Recently, scientists were able to create Ag NPs with very good antibacterial properties using Chrysanthemum indicum L.‎⁰ and acacia leucophloea‎⁰ extracts which have diameters that range from 38 to 72 nm, and 17 to 29 nm, respectively. Additionally, the plant Ganoderma neojaponicum is a species of fungus that belongs to the Ganoderma genus. The Imazeki method was employed for the manufacture of silver nanoparticles (Ag NPs), which were subsequently evaluated as possible cytotoxic agents against breast cancer cells. ^‎0. In this present study, the Ag NPs have been synthesized by using the plant extract of Lepidium Sativum. The effect of varying concentrations on the silver nanoparticles, which were manufactured using the green approach, was obtained and reported. The significance between the different concentrations on the Ag NP’s quality and concentration that is more appropriate has been investigated. Ag NPs can be used for many uses such as; disinfectants, broad-spectrum microbicides, and wound care products.

2. Materials and Method:

The used chemicals are silver nitrate AgNO₃ from the company Biochem Chemopharma_, which has a molecular weight of 169.88g/mol. It has a purity of 99.9% and sodium borohydride (NaOH) powder. For the synthesis of Ag NPs, a heater-stirrer (Model HS-12) and a pH meter (ECO Testr pH2) were utilized.

2.1. Preparation of the Lepidium Sativum plant:

Garden cress, derived from the old Germanic cresso, which means sharp, spicy, is commonly accessible around the world. It is an edible plant that grows quickly. Raw cress contains 89% water, 6% carbs (1% dietary fiber), 3% protein, and 1% fat. The plant was cleaned and allowed to dry after that. The plant water that was draining was then squeezed in a blender. Finally, 50g of the squeezed plant was combined with 50 ml of distilled water. This combination was heated at a temperature of 80ᴼC using the heater-stirrer until the plant seemed to have no extracted left to give to the water. The liquid was then filtered several times to make sure no impurities were left, and finally stored for future use.

2.2. Biosynthesis of Silver Nanoparticles (Ag NPs):

The Ag NPs have been prepared using the biosynthesis process and extract from Lepidium Sativum with silver nitrate (AgNO₃). After the plant extract was prepared, (AgNO₃) was added to another 50 ml of distilled water and stirred on the heater-stirrer for about 20 minutes. Drop by drop, the produced extract was added to the solution of silver nitrate (AgNO₃). Furthermore, the pH of this mixture was controlled to 8 by adding Sodium Hydroxide (NaOH) to the mixture. This mixture was kept stirred at 80ᴼC until it had a consistency like thick liquid (paste). After that, the paste was put into a porcelain crucible with a volume of 50 ml and kept on the heater at a high temperature. Finally, Ag NPs were prepared (Figure 1). This procedure was done several times for different concentrations of silver nitrate (0.1mol, 0.15mol, 0.2mol, 0.25mol, 0.3mol). The given concentrations above were applied to Equation (1, which gave the exact amount of silver nitrate in grams that had to be added to the distilled water. The NPs powder was then washed with ethanol in order to remove any contaminants. Finally, the samples were put in a furnace for about 2 hours at a temperature of 500ᴼC (calcination temperature), where the silver nanoparticles were obtained.

Figure 1: Schematic representation of Ag NPs for biosynthesis of Lepidium Sativum leaf exract in addition to the AgNO₃ salt

(1)

Where MW = molecular weight
M = molarity
V = the volume of the distilled water (ml)

2.3. Characterization of Ag NPs:

The optical characteristics of Ag NPs have been characterized using the Agilent Technologies Carrier Series UV-Visible double-beam spectrophotometer (FTIR), specifically the Cary 100 UV-Vis model. The Fourier Transform Infrared Spectroscopy technique has been applied to analyze the Lepidium Sativum extract and Ag NPs synthesized with different concentrations of Silver Nitrate (AgNO3). The FTIR analysis was conducted using a Nicolet IS 10 instrument manufactured by Thermo Scientific, located in Waltham, MA, USA. The spectral range examined was 400-4000 cm-1.

Ag nanoparticles were characterized and analyzed for their surface properties, size, shape, chemical composition, and orientation using energy-dispersive X-ray spectroscopy (EDX) and field emission scanning electron microscopy (FE-SEM) with an acceleration voltage ranging from 5 to 30 kV. The instrument utilized for this analysis was the Carl Zeiss AG Supra 55VP. The investigation focused on examining the strain, size, stress, crystal structure, epitaxial growth quality of Ag nanoparticles (NPs) created using the Pro MRD, PAN X-Pert high-resolution X-ray diffraction (HR-XRD) system model. The quantities of silver nitrate (AgNO3) were varied in order to assess their impact on these properties. The wavelength of CuK radiation is measured to be 1.54050 angstrom, while the scanning angle ranges from 20 to 80 degrees.

Table 1 Lattice parameters of Ag wurtzite FCC structure characteristics at strong diffraction peaks for the (111), (200), (220), and (311) planes of Ag NPs produced with various AgNO₃ concentrations.

Concentration	2θ	X-ray Peaks	d-spacing (Å)	FWHM	a (Å)	ε_a%
0.1	37.6	111	2.38	0.118	4.134	1.10
0.15	37.8	111	2.37	0.177	4.115	0.64
0.2	37.8	111	2.37	0.314	4.116	0.64
0.25	37.3	111	2.40	0.236	4.169	1.94
0.3	37.6	111	2.39	0.236	4.140	1.23
0.1	43.8	200	2.06	0.275	4.127	0.92
0.15	44.0	200	2.05	0.236	4.113	0.57
0.2	43.8	200	2.06	0.354	4.125	0.88
0.25	43.5	200	2.07	0.196	4.158	1.67
0.3	43.7	200	2.07	0.354	4.141	1.26
0.1	64.0	220	1.45	0.314	4.109	0.49
0.15	64.1	220	1.45	0.393	4.103	0.33
0.2	64.1	220	1.45	0.393	4.106	0.40
0.25	63.7	220	1.45	0.393	4.127	0.91
0.3	63.9	220	1.45	0.393	4.117	0.69
0.1	77.0	311	1.23	0.118	4.107	0.43
0.15	77.1	311	1.23	0.472	4.101	0.28
0.2	77.0	311	1.23	0.472	4.103	0.33
0.25	76.7	311	1.24	0.157	4.118	0.69
0.3	76.8	311	1.23	0.472	4.112	0.54

The above table contains results for the lattice constant (a), the strain (εa), and the inter-planar distance (d) along diffraction peaks (111), (200), (220), and (311) for Ag NPs synthesized by different concentration of silver nitrate. The two parameters a, and ε_a have been calculated by the equations (2 and Error! Reference source not found., respectively.

(2)

Where h, k, and l are x-ray diffraction peak miller indices.

(3)

Table 2 The particle size (D), Volume (V), and bond length (L) of the dominant peaks at (111), (200), (220), and (311) planes of Ag NPs synthesized by different concentration of AgNO₃.

Concentration	X-Ray Peaks	D (nm)	V (Å³)	L (Å)
0.1	111	67.28	70.69	2.92
0.15	111	45.01	69.72	2.91
0.2	111	25.31	69.73	2.91
0.25	111	34.13	72.46	2.94
0.3	111	33.66	70.97	2.92
0.1	200	28.88	70.31	2.91
0.15	200	33.65	69.59	2.90
0.2	200	22.45	70.22	2.91
0.25	200	41.43	71.90	2.94
0.3	200	22.63	71.01	2.92
0.1	220	31.16	69.42	2.90
0.15	220	26.01	69.09	2.90
0.2	220	25.52	69.23	2.90
0.25	220	22.73	70.29	2.91
0.3	220	23.78	69.82	2.91
0.1	311	96.70	69.28	2.90
0.15	311	26.06	68.98	2.89
0.2	311	25.35	69.08	2.90
0.25	311	65.08	69.83	2.91
0.3	311	22.97	69.52	2.90

The average particle size of Ag NPs in the principal diffraction peaks was calculated using the Debye-Scherrer Equation (4, and the results are shown in

Table 2.

(4)

The Volume of Face-centered cell was explored by the following equation (5.

(5)

The Bond length (L) is defined as the distance between the centers of the two Atoms and is calculated by Equation (6. The Bond length results listed in

Table 2 represent how the change in concentration has effect on the bond length of Ag NPs along the diffraction peaks (111), (200), (220), and (311).

(6)

3. RESULTS AND DISCUSSION:

3.1. Characterization of Lepidium Sativum Plant Extract:

Metal ions in the plant extract are changed into metal nanoparticles by the phytochemicals. Additionally, the plant extract has reducing and stabilizing agents. This reaction’s development was seen using UV-Vis’ spectra (