Gels (Aug 2023)

Antibacterial Activity of PVA Hydrogels Embedding Oxide Nanostructures Sensitized by Noble Metals and Ruthenium Dye

  • Diana Pelinescu,
  • Mihai Anastasescu,
  • Veronica Bratan,
  • Valentin-Adrian Maraloiu,
  • Catalin Negrila,
  • Daiana Mitrea,
  • Jose Calderon-Moreno,
  • Silviu Preda,
  • Ioana Catalina Gîfu,
  • Adrian Stan,
  • Robertina Ionescu,
  • Ileana Stoica,
  • Crina Anastasescu,
  • Maria Zaharescu,
  • Ioan Balint

DOI
https://doi.org/10.3390/gels9080650
Journal volume & issue
Vol. 9, no. 8
p. 650

Abstract

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Nanostructured oxides (SiO2, TiO2) were synthesized using the sol–gel method and modified with noble metal nanoparticles (Pt, Au) and ruthenium dye to enhance light harvesting and promote the photogeneration of reactive oxygen species, namely singlet oxygen (1O2) and hydroxyl radical (•OH). The resulting nanostructures were embedded in a transparent polyvinyl alcohol (PVA) hydrogel. Morphological and structural characterization of the bare and modified oxides was performed using scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), UV–Vis spectroscopy, and X-ray photoelectron spectroscopy (XPS). Additionally, electrokinetic potential measurements were conducted. Crystallinity data and elemental analysis of the investigated systems were obtained through X-ray diffraction and X-ray fluorescence analyses, while the chemical state of the elements was determined using XPS. The engineered materials, both as simple powders and embedded in the hydrogel, were evaluated for their ability to generate reactive oxygen species (ROS) under visible and simulated solar light irradiation to establish a correlation with their antibacterial activity against Staphylococcus aureus. The generation of singlet oxygen (1O2) by the samples under visible light exposure can be of significant importance for their potential use in biomedical applications.

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