3rd International Congress on Biomedicine (ICB2019)
Optimization of silver nanocrystalline dressing production for controlling of wound infection
Optimization of silver nanocrystalline dressing production for controlling of wound infection
Zahra valizadeh,1Marjan Enshaeieh,2,*
1. Department of Cellular and Molecular Biology, Faculty of Biological Sciences, North Tehran Branch, Islamic Azad University, Tehran, Iran 2. ¬Department of Biotechnology, Iranian Research Organization for Science and Technology (IROST), Tehran, Iran
Introduction: Nanocrystalline silver dressings can affect different gram-positive and gram-negative bacteria which are prevalence in infections. This ability has attracted lots of attention nowadays. Silver ion has a very broad antimicrobial spectrum and by applying an optimum concentration can affect against yeast, fungi, molds and antibiotic-resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci. Silver ion can inhibit bactericidal effect by inhibiting the respiratory cycle at the level of cytochromes and electron transfer. In addition, by denaturation of nucleic acids, it can inhibit DNA replication and can alter cell membrane permeability. The most important factors in selecting dressing are disinfecting factor, effecting on epithelization and also controlling of wound infection. Silver dressing affects infection due to its antimicrobial properties and maintaining proper moisture for wound healing. The continuous release of silver ions in these dressings results in their rapid and strong antimicrobial effect. In addition, it reduces the use of painkillers and reduces the stress of dressing replacement. The aim of this study was to optimize a high effective nanocrystalline silver dressing by using design of experiments.
Methods: In this study, silver nanocrystalline dressing was produced using nylon dressing and silver ions. After that validation test was done and its antibacterial effect against Staphylococcus aureus and Escherichia coli was evaluated. Designing of experiments based on Taguchi method using Qualitek-4 software was used for investigating different parameters on antimicrobial effect of silver dressing. Factors affecting the production of silver dressing and their levels were determined and assigned to the Taguchi program. The effective factors are as follows: silver nitrate, glucose, sodium hydroxide, mixing time and drying time which were designed in multi levels for evaluating their effects on optimization process.
Results: Silver dressing had a great effect on inhibiting the growth of mentioned bacteria which leads to the inhibition zone diameter of 57 mm around the dressing pieces. AgNO3 was the most important parameter in determining the antimicrobial effect of silver dressing and had highest effect among the other factors. The diameter of the inhibitory zone in the preliminary experiments was about 18 mm before optimization process. Since the dressings were 1 cm, the radius of growth zone was 3 mm from the dressing to the non-growth area. So, there was essential need for optimization and modification of the process. It should be noted that the growth zone diameter is important for both gram-positive and gram-negative strains at the same time and the optimal state is the trial in which both cases are considered. Taguchi method help for reduction of the numbers of trials and can predict the optimized condition effectively.
Conclusion: Silver nanocrystalline dressing was effective in inhibiting of micro-organisms growth and the inhibition zone with high diameter show this effect. Using of Taguchi method was so effective in optimization process of this investigation. This study showed the appropriate efficacy of silver nanocrystal dressings on laboratory microbial cultures. The diameter of the inhibition zone obtained in this study was very good and demonstrates the high potential of this method for mass production. The Taguchi statistical method was also very effective in optimizing the process. Thus, this study demonstrates the excellent antimicrobial effect of silver nanocrystals against gram-positive and gram-negative bacteria. As a result, new antimicrobial agents can be developed with the help of nanotechnology and bacteriology.