Applications of the Green Synthesized Gold Nanoparticles-Antimicrobial Activity, Water Purification System and Drug Delivery System

Abstract

Antibacterial efficacy by well diffusion method: The materials required were LB agar medium, bacterial culture, Petri plates and a cotton swab. The LB agar medium was poured into Petri plates and allowed to solidify. The inoculum was mixed in saline. The cotton swab was dipped in the saline and was streaked onto the plate. 4 wells around 10 mm were cut out aseptically with the help of a cork borer. The wells were filled with 50 µl of the synthesized nanoparticles. The plates were incubated at 37°C for 24 hrs. Fabricating gold nanoparticles in filter paper: The materials required were Whatman Filter paper and synthesized Gold nanoparticles. The filter paper was soaked in nanoparticles solution for about 30 mins. The paper was allowed for drying. Then the coated and non-coated filter paper was used to filter tap water. The filtered water was used for plating. The plates were incubated at 37°C for 24 hrs. Following day, the plates were noted for the number of colonies of bacteria grown. Anticoagulant ability: The materials required were Lancet, Ethanol, Cotton and a Glass slides. The finger was wiped with ethanol, pierced and two drops of blood was kept on glass slide. One was used as a control and other with the test sample, kept for 1 min and observed for the change. Drug loading: 50 µl of peptide protein drug insulin (Human Mixtard 40) was incubated with 200 µl of synthesized gold nanoparticle solutions and kept in stirring for different time periods such has 6 hrs, 12 hrs and 24 hrs. After the incubation time, the unbound drug was removed by centrifugation at 18,000 rpm for 20 min. The unbound drug in the supernatant solution was quantified using UV-visible spectrophotometer. The percentage of entrapment efficiency was calculated from the formula, Total amount of drug Amount of drug in supernatant 100 % Entrapment efficiency Total amount of the drug − × = Abstract It has been previously stated that gold nanoparticles have been successfully synthesized using various green extracts of plants [1-4]. The synthesized gold nanoparticles were characterized under SEM and EDX to identify the size of the nanoparticles [5,6]. It was found that the nanoparticles were around 30 nm in size, which is a commendable nano dimension achieved through a plant mediated synthesis [7-9]. The nanoparticles were further studied for their various applications like anti-microbial efficiency, [10] fabrication of gold nanoparticles in the filter paper and role in water purification, anticoagulant ability, MIC studies against microbial cells, drug loading and in vitro drug release [11]. And, we have made attempts to exploit the anticancer ability of the gold nanoparticles. The nanoparticles were studied against MCF 7 breast cancer cell lines and proved to be efficient with anticancer properties against the cell lines [12,13]. The nanoparticles yielded positive results in all the above-mentioned studies, thereby concluding that the nanoparticles can be extensively applied into various fields of interest and study.