Optimization of ZnO Nanorods Growth on Polyetheresulfone Electrospun Mats to Promote Antibacterial Properties

Abstract

Zinc oxide (ZnO) nanorods grown by chemical bath deposition (CBD) on the surface of polyetheresulfone (PES) electrospun fibers confer antimicrobial properties to the obtained hybrid inorganic-polymeric PES/ZnO mats. In particular, a decrement of bacteria colony forming units (CFU) is observed for both negative (Escherichia coli) and positive (Staphylococcus aureus and Staphylococcus epidermidis) Grams. Since antimicrobial action is strictly related to the quantity of ZnO present on surface, a CBD process optimization is performed to achieve the best results in terms of coverage uniformity and reproducibility. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) provide morphological and compositional analysis of PES/ZnO mats while thermogravimetric analysis (TGA) is useful to assess the best process conditions to guarantee the higher amount of ZnO with respect to PES scaffold. Biocidal action is associated to Zn 2+ ion leaching in solution, easily indicated by UV-Vis measurement of metallation of free porphyrin layers deposited on glass.A wide selection of polymers can be used to produce fibrous scaffolds and surface functionalization or material doping tailor their composition for specific applications, spanning from biomedicine to environmental remediation [3][4][5][6][7]. In this perspective, polymeric nanofibers are often combined with other classes of materials-i.e., inorganic nanostructures and/or organic molecules-to achieve specific deliverable highlights. Combination of polymeric mats with semiconducting oxides, as zinc oxide and titanium oxide (ZnO, TiO2), improves mats performances by adding multifunctionalities such as photocatalytic properties and sensing actions [8,9].Antibacterial properties of fibrous mats are currently under investigation [10-13] to provide innovative materials against bacteria surface contamination that causes severe infection and human health treats: in fact, microorganism colonies-responsible for biofilm formation-are developing an antibiotic resistance that makes this kind of contamination difficult to eradicate.Both Gram-positive and Gram-negative bacteria are able to form biofilms [14], which represent the major causative agent of chronic and recurrent diseases [15,16]: in fact, it is estimated that more than 80% of human infections are biofilm-related [17,18]. In addition, the surfaces of commonly used prosthetic components-such as steel, titanium, and polymeric biomaterial-are susceptible to colonization of biofilm-forming bacterial species [19]. Antibiotics are often ineffective against biofilm-producing bacteria, due to their reduced growth rate and different gene expression [20,21]. It is well known that ZnO particles show antimicrobial activity against both Gram-positive and Gram-negative bacteria [22][23][24][25].Recently, antimicrobial behavior of hybrid polymeric-inorganic materials is under investigation: however, literature refers to incorporation of ZnO inside the fibers by electrospinning of nanoparticles dispersion inside polymeric mat...

Electrospinning Nanofiber Mats with Magnetite Nanoparticles Using Various Needle-Based Techniques

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Development of Highly Crystalline Polylactic Acid with β-Crystalline Phase from the Induced Alignment of Electrospun Fibers

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Catalytic and Photocatalytic Electrospun Nanofibers for Hydrogen Generation from Ammonia Borane Complex: A Review

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