NANOPOSTER 2013 - 3rd Virtual Nanotechnology Poster Conference organized by Nanopaprika.eu - The International NanoScience Community
A NOVEL ‘GREEN’ SYNTHESIS AND ANTIMICROBIAL ACTIVITY OF SILVER NANOPARTICLES (SNP) USING LAGENARIA VULGARIS LEAF EXTRACT Rahul S. Adnaik, Pratibha S. Gavarkar, Shrinivas K. Mohite, Chandrakant S. Magdum Rajarambapu College of Pharmacy, Kasegaon, Tal. Walwa, Dist. Sangli 415404, Maharashtra, India
INTRODUCTION: Nanoparticles exhibit completely new or improved properties based on specific characteristics as size, distribution and morphology. Green synthesis of nanoparticles is an emerging branch of nanotechnology. The use of environmentally benign materials like plant extracts, bacteria and fungi for the synthesis of silver nanoparticles offers numerous benefits of eco-friendliness and compatibility for pharmaceutical, biomedical and agricultural applications as they do not use toxic chemicals in the synthesis protocols. Biosynthesis of nanoparticles provides advancement over chemical and physical methods as it is cost effective and environmental friendly method. Silver has been recognized as having inhibitory effect on microbes (Lok et al. 2007). The most important application of silver and silver nanoparticles is in medical industry such as topical ointment to prevent infection against burns and open wounds (Ip et al., 2006). Silver nanoparticles have been found effective against E. coli and Pseudomonas aeruginosa; Bacillus cereus, Staphylococcus aureus . Mechanisms of nanoparticle-based antimicrobial drug delivery to microorganisms: (a) nanoparticles fuse with microbial cell wall or membrane and release the carried drugs within the cell wall or membrane; (b) nanoparticles bind to cell wall and serve as a drug depot to continuously release drug molecules, which will diffuse into the interior of the microorganisms
Lagenaria vulgaris, commonly known as bottle-gourd, belongs to the Cucurbitaceae family. The plant is widely available throughout India. It is a climbing or trailing herb, with bottle- or dumb-bell shaped fruits. Both its aerial parts and fruits are commonly consumed as a vegetable. Traditionally, it is used as medicine in India, China, European countries, Brazil, Hawaiian island, etc. for its cardiotonic, general tonic and diuretic properties. In the present study we report the rapid synthesis of silver nanoparticles using leaf extract of bottle gourd and its antibacterial activity.
MATERIALS AND METHODS
Poster No. P13-32
RESULT AND DISCUSSION 1 .Visual observation: It is well known that silver nanoparticles exhibit dark brownish colour in alcoholic solution due to excitation of surface plasmon vibrations in silver nanoparticles. As the L. vulgaris leaf extract was mixed in the aqueous solution of the silver ion complex, it started to change the colour from watery to yellowish brown and finally to dark greenish brown colour due to reduction of silver ion; which indicated formation of silver nanoparticles. Fig.1 1mM AgNO3 solution before adding extract (L. vulgaris) (control), after adding extract to the solution (Test).
2. UV-VIS spectra analysis: The reaction mixture, L. vulgaris leaf extract extract with aqueous solution of silver nitrate, started to change its colour from yellowish brown to dark greenish brown. It indicated the formation of silver nanoparticles with the reduction of silver ion. The characteristic surface plasmon absorption bands were observed at 440 nm. There was also an increased in absorbance at 260 nm with regular time intervals observed.
Fig 2. UV-visible spectra of synthesized silver nanoparticles using the leaf ethanol extract of Lagenaria vulgaris
Plant collection: Leaves of fresh plant were collected from the residential areas of Kasegaon.
Preparation of the plant extract: The ethanolic leaf extract of Lagenaria vulgaris
Antimicrobial activity:
(200mg) was weighed and taken in a 250 ml beaker and 100 ml of ater was added to it. The solution was sonicated using ultrasonic bath for 15 mins to disperse the extract in water. The solution was filtered thrice using Whatman filter paper to get a clear solution.
Antimicrobial activities of synthesized silver nanoparticles synthesized using L. vulgaris leaf extract were checked on gram +ve bacteria (S. aureus), gram –ve bacteria (E. coli) and a P. aerogenosa and compared with that of pure extract and silver nitrate aqueous solution.
Synthesis of silver nanoparticles The silver nanoparticles were synthesized using a constant volume of the plant extract under various experimental conditions viz, room temperature (28 - 30°C), higher temperature (90°C) and sonication using ultrasonic bath with different volumes of 3mM silver nitrate solution. The appearance of reddish brown colour after 3 h indicates the formation of silver nanoparticles. The completion of the reaction was monitored by UV-visible spectroscopy.
Separation of silver nanoparticles: The synthesized silver nanoparticles were separated by centrifuging at 13,000 rpm for 15 mins. The process was repeated by dispersion of pellets in water, to obtain coloured supernatant solutions. The sample was then stored at -4°C .
Characterization of silver nanoparticles UV-visible spectroscopy: The formation and completion of silver nanoparticles was characterized by UV-visible spectroscopy using a Double beam spectrophotometer.
Antimicrobial activity study: Antimicrobial activities of synthesized silver nanoparticles were determined using the agar cup assay method. The assay was done on E. coli, S. aureus and P. aeruginosa. Nutrient Agar and Mueller Hinton Agar were used to cultivate bacteria and fungi respectively.
Figure 3: Antimicrobial activity Where, 1 = Leaf extract of L. vulgarisi, 2 = Silver nitrate solution and 3 = Silver nanoparticles
E. coli
S. aureus
P. aerogenosa
CONCLUSION The study included the synthesis of silver nanoparticles from the herbal leaves of L. vulgaris and their antimicrobial activity. From the study, it was concluded that the aqueous silver ions exposed to the herb were reduced and the nanoparticles were synthesized. The presence of nanoparticles was confirmed by the brown color formation. The antimicrobial efficacy of L. vulgaris was found to be significant against tested microorganisms. Thus it was confirmed that the composite release of silver at a core is capable of rendering antimicrobial efficacy and proved to be active against the microbes.