ORIGINAL PAPER The anti-adherence and bactericidal activity of sol–gel derived nickel oxide nanostructure films: solvent effect Nasrin Talebian • Monir Doudi • Maryam Kheiri Received: 2 August 2013 / Accepted: 28 October 2013 Ó Springer Science+Business Media New York 2013 Abstract This study presents the characterization and antibacterial activity of nanostructure NiO films synthe- sized by sol–gel dip coating method using solvents of different polarities and viscosities without any catalysts, templates or surfactants. Methanol, 1,4-butanediol, ethanol, and 2-propanol were used as solvent. The antibacterial activity was tested against two common foodborne patho- genic bacteria Staphylococcus aureus (ATCC 25922) and Escherichia coli (ATCC 29213) using the so-called anti- bacterial drop test. X-ray diffraction, scanning electron microscopy, atomic force microscopy, UV–vis spectros- copy and static contact angles test were used to analysis the structure and morphology character, surface topography, optical property and surface wettability of different coat- ings, respectively. The characterization results showed different preferred crystallographic orientations, particle sizes, surface properties and optical band gap of NiO films according to the solvent physicochemical properties. The antibacterial efficiencies were affected by the physiological status of the bacterial cells and degree of bacteria adher- ence, morphologies and crystal growth habits, surface and optical properties of NiO samples. Keywords NiO  Sol–gel preparation  Thin film  Structural characterization  Anitibacterial activity 1 Introduction Microbial infection remains one of the most serious com- plications in several areas, particularly in medical devices, drugs, hygienic applications, water purification systems, textiles, food packaging and storage, and filters used in air- conditioning systems. Both antibiotic-resistant Gram-neg- ative and Gram-positive bacteria are reported to be important causes of bacterial infections. Recent years have seen increased development of nanoparticle designs as treatments for various diseases and infections. The anti- bacterial activity of inorganic materials is of significant interest due to the need for infection control and rising antibiotic resistance. Bacterial adhesion that leads to bio- fouling is a widespread problem that affects the functioning of a variety of engineered systems. Both bacterial and solid surface properties (roughness, solid surface chemical structure, hydrophobicity, and surface charge, etc.) govern the initial adhesion phase of bacteria to a surface. The adhesion of bacteria cells to material surfaces and inter- faces represents the first step in bacterial colonization. It is clear that adhesion of viable bacteria to material surfaces is a necessary condition for antibiotic-resistant biofilm for- mation. Functionalized microbicidal coatings can actively fight the spread of bacterial infections by preventing bac- terial adhesion, killing the adherent bacteria, and inhibiting biofilm formation as three principal strategies for antibac- terial surface design [1–6]. These approaches have focused on (1) reducing the capacity of bacteria to achieve adhesion using hydrophobic surfaces; (2) contact killing surfaces to biochemically induce death of bacteria that have adhered stably to a surface; or (3) biocide leaching, in which cytotoxic compounds are released and diffuse over time from a material surface. The effect of metal oxides on adhesion is of particular interest for understanding bacterial N. Talebian (&) Department of Chemistry, Science Faculty, Shahreza Branch, Islamic Azad University, Razi Chemistry Research Centre, 86145-311 Shahreza, Isfahan, Iran e-mail: nasrin_talebian@yahoo.com; talebian@iaush.ac.ir M. Doudi  M. Kheiri Department of Microbiology, Falavarjan Branch, Islamic Azad University, Falavarjan, Isfahan, Iran 123 J Sol-Gel Sci Technol DOI 10.1007/s10971-013-3201-8