Copper oxide nanoparticles (CuO-NPs) as a key player in the production of oil-based paint against biofilm and other activities

Abstract

Copper oxide nanoparticles are among the metal nanoparticles gaining popularity in many biotechnological fields, particularly in marine environments. Their antimicrobial and antibiofilm activities make them appealing to many researchers. Among the various methods of producing nanoparticles, biosynthesis is crucial. Thus, a large number of reports have been made about the microbiological manufacture of these nanoparticles by bacteria. Nevertheless, bio-production by means of the cell-free supernatant of marine bacteria is still in its primary phase. This is landmark research to look at how bacteria make a lot (14 g/L) of copper oxide nanoparticles (CuO-NPs) via the cell-free supernatant of Bacillus siamensis HS, their characterization, and their environmental and medical approaches. The biosynthesized nanoparticles were characterized using a UV-visible spectrum range that provides two maximum absorption peaks, one obtained at 400 nm and the other around 550-600 nm. Diffraction of X-rays (XRD) clarifies that the size of the NPs obtained was estimated to be 18 nm using Debye-Scherrer's equation. Scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX) displays 91.93 % copper oxide purity. The Transmission Electron Microscope (TEM) image proves that the particles have a spherical form and an average diameter of 6.54-8.60 nm. At the environmental level, nanoparticles incorporated into oil-based paint can be used as antibiofilm tools to diminish the biofilm formed on the submerged surface in the marine environment. In disease management, NPs can be used as a wound healing agent to reduce the wound gap size as well as an anti-tumour agent to control liver cancer cells (hepatoma cells (HepG2)).

Keywords: Anti-cancer; Antibiofilm; Antimicrobial; Bacillus siamensis HS; CuO-NPs; Wound healing.

Graphical abstract

Fig. 1

Control and treated slides were dipped vertically in a 250 mL beaker containing 100 mL of NB medium and incubated at 37 °C for 24 h (a) and 48 h (b). The bacterial coverage was calculated following this equation: bacteria surface coverage (%) = 100 × (bacteria surface coverage/total area).

Fig. 2

CuO-NPs amounts produced during the biosynthesis process.

Fig. 3

Visual observation of colour change of CuSO₄ solution (a) to dark brown CuO-NPs (b).

Fig. 4

Colony morphology of CFS 36 isolated from calcareous red alga (Corallina officinalis (a)), grown on nutrient agar medium with seawater (b), phylogenetic tree-based on the 16S rRNA sequence of CFS 36 showing its similarity to Bacillus siamensis HS (c).

Fig. 5

UV–Vis spectra (a), EDX image and element ratio graph (b), TEM micrograph (c), and XRD pattern (d) of the biosynthesized CuO-NPs.

Fig. 6

Antibiofilm activity of CuO-NPs using the tube method.

Fig. 7

CuO-NPs impact on biofilm inhibition (%) of the biofilm-producing strains.

Fig. 8

Studying the biofilm inhibition activity of oil-CuO-NPs-based paint per area percentage on glass slides covered with bacterial consortium using the 2⁴ factorial design probabilities after 24 and 48 h of incubation (the trial numbers are shown in detail in Table 1).

Fig. 9

Inhibition zone diameters (cm) indicate antimicrobial activity for different concentrations of CuO-NPs.

Fig. 10

Agar well diffusion method showing dose-dependent zones of inhibition of CuO-NPs against various pathogens as test microorganisms.

Fig. 11

Wound healing activity of CuO-NPs after 24 h illustrated by wound gap size (μm).

Fig. 12

Wound healing activity of CuO-NPs: Untreated wound gap size at zero time (a); Untreated gap size after 24 h (b); Wound gap size treated with CuO-NPs after 24 h (c).

Fig. 13

Inhibition and viability percentage in HepG2 cells affected by CuO-NPs.