Electrospun nanofiber membranes functionalized with antibacterial particles

Abstract

Electrospinning is the most efficient method for the production of nanofibrous structures, which have unique characteristics such as high porosity, high absorption capacity, small pore size and high specific surface area. Thanks to this, they can be used as filtration membranes. Nanofiber membranes have high clean water permeability values, however the pathogen removal efficiency is currently not satisfactory. For this reason, we functionalized the membranes with antibacterial particles, such as silver nanoparticles and commercial biocides, by adding them into the spinning solution. Afterwards, the membranes were characterized to study the effect of the functionalization on the fiber diameter and pathogen removal efficiency. The distribution of the silver nanoparticles was studied with SEM and TEM images. TEM-images showed that the silver nanoparticles are trapped inside the nanofibers. SEM-images confirmed that the average fiber diameter is not affected by the functionalization. To evaluate the removal of pathogens, water samples were taken from waste water from a general hospital (107 – 108 colony forming units per 100 ml) and were filtered with different membranes. A non functionalized nanofiber membrane could not achieve the same reduction in culturable organisms as commercial membranes (2 log10 – 4 log10 removal). Higher reduction was reached when silver nanoparticles were added to the membrane. A 3 log10 – 4 log10 removal was reached by adding silver nanoparticles to the spinning solution. Nanofiber membranes with biocides as functionalization agents achieved even a much higher reduction, up to 5,5 log10, which is competitive with commercial membranes currently on the market. In conclusion, the electrospinning process allows the functionalization of nanofiber membranes with antibacterial particles. This highly improves the pathogen removal efficiency of the membranes