Satisfactory Essays
4. Antibacterial aspects of silver nanomaterials.

Materials that encounter deleterious impact on an organism, are considered toxic but if the purpose is sterilization or disinfection, this toxicity can be considered as a positive outcome. Silver nanoparticles had shown to be toxic for bacteria’s hence they represent a class of antibacterial materials. Table 2 depicts a brief summary of studies related to antibacterial nature of silver nanomaterials.

Table 2: Antibacterial activity of various silver nanomaterials

Balogh et al. reported formation of a dendrimer-silver complex and a nanocomposite, antibacterial studies were carried out using agar overlay method and both construct displayed better or comparable bactericidal effect from silver nitrate solution.65
Inoue et al. introduced silver ions into a zeolite and antibacterial properties were studied for E. Coli in deionized water. Figure 6 shows significant decrease in viable cell count of bacterial cells within 5 minutes in presence of metal loaded zeolite. In presence of sodium loaded zeolite, there is no decrease in cell count means absorption of E. Coli cells on zeolite might be negligible and reduction is solely due to silver nanoparticles.66

Figure 6. Change in viable cell count after addition of silver loaded zeolite. a) control b) Sodium-Z
c) Silver-Z.66

Kim et al. synthesized silver nanoparticles by reduction of AgNO3 using NaBH4 and determined minimum inhibitory concentration for E. coli and S. aureus using agar disk diffusion method. They obtained that the MIC of as synthesized silver nanoparticles for E. coli was approx 5 nM while for S. aureus , it was approx 33 nM.25
Raffi et al. synthesized 16 nm silver nanoparticles and bacterial...

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...h, chemistry, capping agent, stabilizer etc. Proposed mechanism behind biocidal activities of these materials involves ROS production, cell damage, and uptake of silver ion that cascade ample of intracellular activities. Silver nanoparticles can be a good solution to the problem of growing antibiotic resistance in bacteria. Intensively examined bactericidal activities can be exploited in waste water treatment, bacteria resistant nanotextile, environmental remediation and many more.
Considerable work has been done for elucidating the mechanism underlying toxicity, further research is still required to completely understand the aspects involved so that safe use of these materials can be motivated. A growing concern is on the impact of these materials on higher organisms such as humans and the tolerable limit of these materials in environment should also be regulated.
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