Synthesis and measurements of potential antibacterial effect of silver nanoparticles

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Supervisor:
Dr. Jedlovszky-Hajdú Angéla
SE Biomedical Engineering MSc

Nowadays the use of nanoparticles (NPs) for biomedical applications is unquestionable. The NPs are applied in various fields, such as: biosensors, imaging and drug delivery fields. The health care facilities take advantage of antibacterial effect of silver nanoparticles a long time. In most hospitals can be found dressing containing silver, sewing thread, textiles too. Our research group has been investigating a biocompatible polymer-based artificial fibre scaffold for a while, which operates as a support system for cells. If we mix silver nanoparticles with the polymer solution, we could form a fibre system what we could use as a wound for disinfection and covering layer. This artificial matrix can capture large amounts of liquids, the small molecules and gases can diffuse freely and if we give it antibacterial property with the silver nanoparticles, we can create a benefit coverage of wound (especially in case of fire).

In our work, we aimed to prepare silver nanoparticles in aqueous and organic media with different surface modifications, create membranes under micrometers with fiber diameter and the detection of antibacterial effect of these systems.

During my work, after optimizing the methods, I analysed the mean size distribution and shape of the particles (TEM). I prepared silver nanoparticles with two different synthesis methods, at first silver NPs were synthetized from the mixture of silver nitrate and citrate solutions (hydrodynamic diameter is 5 ± 1,5nm, with dynamic light scattering measurement, Malvern NanoS), however, the system is not monodispersed. The high negative zeta potential (-58mV) causes its stability which results an electrostatic stabilization. At the other synthesis method we used silver perchlorate and sodium borohydride solutions and we investigated the effect of mixing speed and reaction time on stability. Based on the dynamic light scattering measurements we got smaller hydrodynamic diameter, which is 2±1.2nm, but it is important to note that during the measurement we got a distribution curve indicating the presence of several populations of particles. In this case we got a slightly less negative zeta potential (-40mV). After that we performed the antibacterial tests where 200µl of silver nanoparticle addition was sufficient to prevent the bacterial colony from appearing. In organic media (DMF) I created silver nanoparticles in the presence of polysuccinimide. From these samples, we have fabricated a mesh with electrospinning successfully in the presence of different silver nanoparticle concentrations. Finally, we performed the antibacterial tests. In these result it was clear, that the shorter reaction time (3 day) proved a higher antibacterial effect.

Based on our results, we can conclude that fiber-based polymer membrans were created by electrospinning technique. The fibers contained silver particles and all these membranes have antibacterial effects, thus this method should be a suitable way to create antibacterial wounds.

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