Skip to main content
NCBI home page
ACS Omega logoLink to ACS Omega
. 2023 Sep 28;8(40):37147–37161. doi: 10.1021/acsomega.3c04722

Facile Hydrothermal Synthesis of BiVO4/MWCNTs Nanocomposites and Their Influences on the Biofilm Formation of Multidrug Resistance Streptococcus mutans and Proteus mirabilis

Zeena R Rhoomi †, Duha S Ahmed †,*, Majid S Jabir †,*, Balamuralikrishnan Balasubramanian ‡, Maged A Al-Garadi §, Ayman A Swelum §,*
PMCID: PMC10569021  PMID: 37841170

Abstract

graphic file with name ao3c04722_0015.jpg

This study utilized a simple hydrothermal technique to prepare pure BiVO4 and tightly bound BiVO4/multiwalled carbon nanotubes (MWCNTs) nanocomposite materials. The surfactant was employed to control the growth, size, and assembly of BiVO4 and the nanocomposite. Various techniques including X-ray diffraction (XRD), Ultraviolet–visible (UV–vis), photoluminescence (PL), Raman, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) were utilized to analyze and characterize BiVO4 and the BiVO4/MWCNTs nanocomposite. Through XRD analysis, it was found that the carbon nanotubes were effectively embedded within the lattice of BiVO4 without generating any separate impurity phase and had no influence on the BiVO4 monoclinic structure. TEM images confirmed the presence of MWCNTs within BiVO4. Furthermore, adding MWCNTs in the BiVO4/MWCNTs nanocomposite resulted in an effective charge transfer transition and improved carrier separation, as evidenced by PL analysis. The introduction of MWCNTs also led to a significant reduction in the optical band gap due to quantum effects. Finally, the antibacterial activity of pure BiVO4 and the BiVO4/MWCNTs nanocomposite was assessed by exposing Proteus mirabilis and Streptococcus mutans to these materials. Biofilm inhibition and antibiofilm activity were measured using a crystal violet assay and a FilmTracer LIVE/DEAD Biofilm Viability Kit. The results demonstrated that pure BiVO4 and BiVO4/MWCNTs effectively inhibited biofilm formation. In conclusion, both pure BiVO4 and BiVO4/MWCNTs are promising materials for inhibiting the bacterial biofilm during bacterial infections.

1. Introduction

The nanoparticles in the range of 1–100 nm have attracted research interest because of their specific physical properties and reactivity depending on their size. These nanoparticles have been used in a wide range of fields such as cosmetics, textile manufacturing, and biomedical applications.1 Among metallic oxide nanoparticles, semiconductor-based photocatalysts have received significant attention due to their various shape-dependent characteristics, low cost, chemical stability, and environmentally friendly features.2−4 In the areas of water treatment, food production, biomedical, and environmental fields, nanocomposites are highly significant. These newly discovered materials have a rapid role in inhibiting bacteria development and help in the fight against antibiotic-resistant bacteria in the healthcare system.5,6 However, most metal binary oxides suffer from limited response to visible light due to their large band gap (Eg > 3 eV), such as TiO2 and ZnO. Other studies are exploring new narrow-band-gap semiconductors, such as bismuth-based semiconductors, because they are chemically stable and nontoxic and exhibit visible light photocatalytic properties.7−9 Among the semiconductor photocatalysts, bismuth vanadate BiVO4 has received a great deal of research interest due to its distinct physical and chemical features, including its ability to degrade substances and pathogens in water treatment, its role as an antimicrobial agent, and its nontoxicity for cells in biomedical applications.10−13 The narrow band gap (2.4 eV) and suitable band positions of BiVO4 make it an excellent photocatalyst under sunlight.14−19 Various methods have been used to synthesize BiVO4, such as sol–gel, precipitation, and microwave synthesis.20−22 In recent years, the hydrothermal method has been widely used to create bismuth complexes due to its moderate preparation conditions, such as a relatively low temperature, short reaction time, controllable pH, and other factors. Furthermore, the hydrothermal method allows for easy control of parameters that affect photocatalyst performance, such as crystal structure, morphology, and band gap.23 One-dimensional multiwalled carbon nanotubes (MWCNTs) have gained interest due to their outstanding mechanical, electrical, and optical properties.24−30 MWCNTs have been used in recent research due to their excellent adsorption capacity and chemical stability. The cytotoxicity and low dispersion of MWCNTs can be overcome by oxidizing them, which reduces toxicity, increases solubility, and improves interaction with nanoparticles and organisms. Due to their higher electron-transfer ability, MWCNTs support charge separation, leading to improved photocatalytic activity in pollution removal.31 MWCNTs also increase the absorption of visible light by reducing the band gap of BiVO4. Additionally, 1D MWCNTs reduce transmission distance and promote electron transfer, inhibiting the recombination of electron–hole carriers.32,33 Moreover, MWCNTs offer more active positions due to their greater specific surface area and enhance the adsorption of nanocomposites.34−36 This study focuses on the effect of introducing functionalized MWCNTs into BiVO4 using the hydrothermal method and their application in antibacterial activity. The investigation and analysis highlight the potential of these nanocomposites by studying their size, morphology, and microstructure before and after embedding MWCNTs using X-ray diffraction (XRD), ultraviolet–visible (UV–vis), Raman, and transmission electron microscopy (TEM). Finally, the results demonstrate that both pure BiVO4 nanocomposites and nanocomposites with MWCNTs exhibit antibacterial efficiency against the studied bacterial strains. The findings suggest that the prepared nanoparticles have potential as antimicrobial and biofilm inhibition agents in the biomedical field.

2. Materials and Methods

2.1. Materials

Bismuth(III) nitrate pentahydrate (Bi(NO3)3·5H2O) with a purity of 98% was purchased from Sigma-Aldrich, a company in Germany. Ammonium metavanadate (NH4VO3) with a purity of 99% was purchased from glentham.com, a company in the United Kingdom. Sodium hydroxide (NaOH) was purchased from Chemical Reagent Company, a company in China. Multiwalled carbon nanotubes (MWCNTs) with a purity greater than 95 wt % and a diameter of 8–15 nm were purchased from Grafton Company, a company in the USA. Nitric acid (HNO3) with a purity of 69% was purchased from CDH, a company in India. Deionized water was used throughout the experiment.

2.2. Synthesis of BiVO4 and BiVO4/MWCNTs Nanocomposite

Pure BiVO4 was synthesized using a hydrothermal method.37−39 First, 2 mmol of Bi(NO3)3·5H2O and 4 mL of 4 mol/L HNO3 were dissolved in 50 mL of distilled water and stirred for 30 min to form solution A. Second, 2 mmol of (NH4VO3) and 4 mL of 2 mol/L NaOH were dissolved in water and stirred for 30 min to form solution B. The two solutions were then mixed and placed in a Teflon-lined autoclave, which was sealed and heated in an oven at 180 °C for 16 h. The resulting yellow precipitate of BiVO4 was cleaned with ethanol and distilled water and then heated in a convection oven at 60 °C for 12 h. The same procedure was used to synthesize the BiVO4/MWCNTs nanocomposite, with the addition of 0.64 g of Bi(NO3)3·5H2O, 0.12 g of NH4VO3, 0.4 g of functionalized MWCNTs, and 0.3 g of SDS dispersed in 100 mL of deionized water.

2.3. Characterization

The structure of the BiVO4 and BiVO4/MWCNTs nanocomposite products was analyzed using XRD analysis (X-ray Diffraction 6000, Shimadzu) with CuK radiation (λ = 1.542), and the data were recorded in a 2θ range of 10–70°. The optical properties and band gaps were measured using UV–visible spectroscopy (Shimadzu UV-1800 spectrophotometer). Photoluminescence (PL) spectroscopy was performed using a monochromatic excitation wavelength of about 250 nm (Cary Eclipse fluorescence model, Iran) at room temperature to analyze the emission wavelengths of BiVO4 and the BiVO4/MWCNTs nanocomposite in the range of 200–800 nm. Transmission electron microscopy (TEM, Philips-EM-208S) was used to visualize the surface morphology and size of the BiVO4 and BiVO4/MWCNTs samples, while scanning electron microscopy (SEM Apreo2, Thermo Fisher Scientific) was used to visualize the efficiency of the samples on bacterial cells. Energy-dispersive X-ray spectroscopy (EDS) was used for elemental analysis.

2.4. Antibacterial Activity Test

The antibacterial activity of pure BiVO4 and the BiVO4/MWCNTs nanocomposite was investigated against P. mirabilis and S. mutans using an agar well diffusion assay.40,41 Different concentrations (62.5, 125, 250 μg/mL) of the bacterial samples were cultivated at 37 °C overnight on Muller–Hinton (MH) agar (HiMedia, India) containing pure BiVO4 and the BiVO4/MWCNTs nanocomposite, and the average diameter of inhibition zones were recorded.42 The minimum inhibitory concentration (MIC) was measured by using a serial dilution method following the NCCLS guidelines. A colony-forming unit (2 × 106 CFU/mL) was inoculated in 96-well microplates, containing 100 μL of sterile Lysogenia broth media (HiMedia, India) in the presence of different concentrations of pure BiVO4 and BiVO4/MWCNTs (0.1220–500 μg/mL). DMSO (0.01%) without pure BiVO4 and BiVO4/MWCNTs was used as a negative control.

2.5. Crystal Violet Staining

In this test, P. mirabilis and S. mutans (1 × 106 CFU/mL) were grown in 24-well plates and treated with pure BiVO4 and the BiVO4/MWCNTs nanocomposite at a concentration of 125 μg/mL for 24 h. After that, the samples were washed with PBS, and P. mirabilis- and S. mutans-adhered wells were stained with crystal violet (0.1%, Sigma) after rinsing twice with D.W. To measure biofilm development, 0.2 mL of 95% ethanol was added to crystal violet-stained wells and incubated for 2 h while being shaken. The optical density was then calculated at 595 nm.

2.6. Antibiofilm Activity of Pure BiVO4 and BiVO4/MWCNTs

Biofilms formed on culture dishes of Lysogenia broth medium (HiMedia, India) were untreated (control) or treated with the pure BiVO4 and BiVO4/MWCNTs at a concentration of 125 μg/mL for 24 h and stained using the FilmTracer LIVE/DEAD Biofilm Viability Kit. The images were captured using a Leica TCS SP5 II confocal microscope.

2.7. Investigation of Biofilm Metabolic Activity

Biofilms were formed in glass tubes in the presence and absence of the pure BiVO4 and BiVO4/MWCNTs samples.43 After incubation at anaerobic conditions at 37 °C and for 48 h, the biofilm suspension was stained with a Live/Dead stain kit and analyzed by flow cytometry. Briefly, 10 μL of Syto 9 (30 μM) was added for 10 min, and then 10 μL of propidium iodide (500 μM) was added for 10 min; the samples were washed 2 times in PBS and centrifuged for 2 min at 2000 rpm. The sample with two stain components was excited at 488 nm, and the emission was registered using the FITC channel for Syto 9 (530/30) and the (670/LP) channel for propidium iodide. The results of the biofilm cell viability were expressed in the percentage of untreated control cells.

2.8. Statistical Analysis

The data from three independent experiments were represented as mean ± standard deviation. GraphPad Prism (7) was used to carry out the statistical analysis via the application of the one-way ANOVA analysis of variance. p values less than 0.05 were considered significant. *p < 0.05, **p < 0.01, ***p < 0.001, and ****p < 0.0001.

3. Results and Discussion

3.1. Structural, Optical, and Morphological Studies

XRD analysis was performed at room temperature on pure BiVO4 and the BiVO4/MWCNTs nanocomposite. As shown in Figure 1, the formation of the pure BiVO4 monoclinic structure (red line) was confirmed by the diffraction peaks at 2θ = 14.63, 18.33, 28.34, 30.03, 33.83, 34.69, 39.27, 41.91, 46.23, 46.82, 52.77, 57.74, 59.16, and 63.07°, which can be indexed to (110), (001), (121), (040), (200), (002), (211), (051), (−231), (132), (202), (161), (303), and (321) planes, respectively, as consistent with the reference code (JCPDS card no. 014-0,688). Besides, as shown in Figure 1, the new peak formed appears in the nanocomposite (black line) and not in pure BiVO4, which is related to the peak of the plane (111) at 2θ = 24.96° and is attributed to the peak characteristic of the tetragonal structure of MWCNTs. The results reveal that the MWCNTs were successfully embedded inside BiVO4. The Scherrer formula was used to determine the average crystallite size D = kλ/(βsizecos θ), where k is the shape factor crystal, λ is the wavelength of Cu–K radiation utilized, and θ is the angle of Bragg. As shown in Table 1, the crystalline size of BiVO4 was smaller than that of the BiVO4/MWCNTs nanocomposite, related to loading MWCNTs into BiVO4, which led to an increase in the crystalline size.43−45 Besides, increasing the diffusion of Bi3+ ions into VO43– anions through the crystallization process43,44 confirms the thermodynamic nucleation.45 Furthermore, carbon atoms with a relatively higher atomic radius of 0.077 nm replace oxygen atoms with a relatively smaller atomic radius of 0.074 nm.46 The carbon has been successfully incorporated into the BiVO4 lattice according to XRD measurements. XRD patterns show that a small amount of carbon was effectively integrated into the lattice BiVO4, inducing lattice expansion without generating any separated impurity phase (Table 2).

Figure 1.

Figure 1

Open in a new tab

Patterns of XRD of BiVO4 and the BiVO4/MWCNTs nanocomposite with the reference code by using the hydrothermal method.

Table 1. Crystalline Size of Pure BiVO4 and the BiVO4/MWCNTs Nanocomposite by Using the Hydrothermal Method.

materials 2θ (deg) Hkl fwhm (deg) grain size (nm) d (Aο)
BiVO4 nanostructure 18.33 001 0.6783 11.86 4.83
28.34 121 0.5373 15.25 3.14
30.03 040 0.4626 17.78 2.97
BiVO4/MWCNTs nanocomposite 18.91 001 0.2801 28.75 3.08
28.93 121 0.2143 38.28 2.92
30.58 040 0.2326 35.41 1.71
Open in a new tab

Table 2. Optical Band Gaps for BiVO4 and the BiVO4/MWCNTs Nanocomposite.

materials wavelength (nm) energy band gap (eV)
BiVO4 nanostructures before adding MWCNTs 466 2.6
BiVO4/MWCNTs nanocomposite 520 2.48
Open in a new tab

The UV–visible spectroscopy of pure BiVO4 and the BiVO4/MWCNTs nanocomposite was performed in the range of 250–800 nm, as shown in Figure 2. BiVO4 effectively absorbs visible light and operates as a light-driven active photocatalyst for the degradation of organic pollutants, as demonstrated in Figure 2(a), where a strong optical absorption is visible in a wavelength larger than 420 nm. As can be seen, pure BiVO4 samples have an absorption edge of around 466 nm and are yellowish-colored powders.47−51 Besides, the pure BiVO4 absorption edge shows a red shift. The band gap energy Eg value can be calculated using the Tauc plot of the (αhυ)2 versus photon energy (hυ) curve with n = 1/2 for direct transition, as shown in the inset of Figure 2(b). The calculated band gap of BiVO4 is Eg = 2.6 eV. In the case of the BiVO4/MWCNTs nanocomposite, the absorbance of the BiVO4/MWCNTs nanocomposite increased noticeably in the visible region at 520 nm after being synthesized at 180 °C for 12 h, as shown in Figure 3. The absorbance ability of BiVO4/MWCNTs increases after the addition of a tiny amount of MWCNTs, as shown in Figure 3(a). The addition of MWCNTs results in a greater ability of absorption of the nanocomposite. As well as the interesting property of the BiVO4/MWCNTs nanocomposite is a slight red shift compared with pure BiVO4. The process of visible light absorption is the transition from the valence band (VB) to the V 3d conduction band (CB), which results in a slight red shift.46 Additionally, compared to pure BiVO4, it was clear from the inset of Figure 3(b) that the BiVO4/MWCNTs nanocomposite exhibited the narrowest band gap energy of about Eg = 2.48 eV. The localized levels positioned between the valance band and the conduction band resulted in moving Fermi levels to the conduction band of the nanocomposite.

Figure 2.

Figure 2

Open in a new tab

(a) Optical absorbance spectra and (b) calculated band gap Eg using the plot of the variation of (αhυ)2 versus photon energy (hυ) of BiVO4 nanostructures.

Figure 3.

Figure 3

Open in a new tab

(a) Optical absorbance spectra and (b) calculated band gap Eg using the plot of the variation of (αhυ)2 versus (hυ) of the BiVO4/MWCNTs nanocomposite.

These findings are consistent with earlier research.52,53 Additionally, lowering the band gap energy of nanocomposites is related to the effects of the quantum volume effect, which results in a reduction in the energy gap band and a shift in absorbance from the valence band to the conduction band54 toward long wavelengths.

Raman spectroscopy is a suitable method for examining the local structure of materials.55 In Figure 4(a,b), typical Raman spectra of pure BiVO4 and the BiVO4/MWCNTs nanocomposite were determined, respectively. As shown in pure BiVO4, the symmetric V–O stretching vibration mode is given to the dominant peak at 800 cm–1 in Figure 4(a). However, the resulting sample from the hydrothermal method is attributed to an unremarkable peak at 708 cm–1. The peak at 201 cm–1 was attributed to the external mode, whereas the peak at 323 cm–1 was related to the vanadate anion’s antisymmetric bending mode, as shown in Table 3. The Raman peak of the BiVO4/MWCNTs nanocomposite in Figure 4(b) indicates that the presence of MWCNTs had no impact on the short-range symmetry of VO4 tetrahedra, except for the characteristic peaks linked to BiVO4.56 Additionally, the peak at 1582 cm–1 was connected to the G-band of the order structures of MWCNTs, further confirming the inclusion and embedding of MWCNTs in the composite’s exterior mode.56,57 The Raman analysis of MWCNTs in the inset image of Figure 4(b) displays that the G-band is about 1571 cm–1. This shift to a high value is related to the chemical oxidation of MWCNTs and BiVO4 by the hydrothermal method.

Figure 4.

Figure 4

Open in a new tab

Raman spectra of (a) pure BiVO4 and (b) BiVO4/MWCNTs nanocomposite with the inset image of MWCNTs.

Table 3. Position and Assignation of Raman Bands for BiVO4 and the BiVO4/MWCNTs Nanocomposite Synthesized by the Hydrothermal Method.

material Raman bands (cm–1) assignation
BiVO4 nanostructure before adding MWCNTs 824 vs (V–O)
378 vs VO4–3
337 vas VO4–3
213 external mode
129 external mode
BiVO4/MWCNTs nanocomposite 820 vs (V–O)
362 vs VO4–3
323 vas VO4–3
206 external mode
130 external mode
1540 G-band of MWCNTs
Open in a new tab

The PL spectra of the resulting BiVO4 and BiVO4/MWCNTs nanocomposite samples were employed to verify the photoinduced charge recombination and electron migration, as shown in Figure 5. The PL spectrum of BiVO4 (black line) is compared with that of the BiVO4/MWCNTs (red line) nanocomposite under the excitation wavelength of 250 nm. It can be suggested that PL showed each sample had two relatively obvious peaks. PL measurement was carried out to investigate the effect of MWCNTs on the photocatalytic process. The addition of MWCNTs resulted in an increased amount of Bi5+, V+5, and surface-adsorbed oxygen species, in which all species enhanced the –OH generation and decreased the recombination rate of electron–hole pairs, as shown in Figure 5.58 The weaker PL intensity in the BiVO4/MWCNTs nanocomposite was related to lower recombination rate of the photogenerated (e–h) pairs. Thereby, the emission intensity of the BiVO4/MWCNTs nanocomposite is lower than that of pure BiVO4, which may be due to the existence of MWCNTs inhibiting the recombination of the photogenerated charges.59

Figure 5.

Figure 5

Open in a new tab

PL spectra of pure BiVO4 (black line) and the BiVO4/MWCNTs nanocomposite (red line).

The transmission electron microscopy images (TEM) were utilized to study the morphology and microstructure of pure BiVO4 and the BiVO4/MWCNTs nanocomposite, as demonstrated in Figures 6(a,b) and 7(a–d) at different magnifications, respectively. It can be seen from Figure 6(a,b) that the primary particles of pure BiVO4 are made of nanoparticles that are presented as somewhat larger particles and aggregated to create a cluster with an average diameter of about 0.044 μm during the hydrothermal method. Moreover, the resulting BiVO4 microsphere with irregular edges is built by many tiny nanoflakes, which were observed as smaller and more regular particles in a relatively large aggregate. The generated BiVO4 nanostructures were first combined into building blocks and then self-assembled by the Ostwald ripening process.60−62 Meanwhile, the structure of the synthesized BiVO4/MWCNTs nanocomposite is observed in Figure 7(a–d) at different magnifications. It was found that MWCNTs embedded inside the structure of BiVO4 nanoflakes form a ternary heterojunction of the BiVO4/MWCNTs nanocomposite with an average grain size of 34.9. It is worth noting that the nanocomposite appeared to be significantly greater than pure BiVO4, which is about 15.5 nm. These findings demonstrate that MWCNTs and BiVO4 have been successfully coupled.63−65

Figure 6.

Figure 6

Open in a new tab

TEM images of the pure BiVO4 nanostructures at different magnifications: (a) 450 and (b) 200 nm.

Figure 7.

Figure 7

Open in a new tab

TEM images of the BiVO4/MWCNTs nanocomposite at different magnifications: (a) 450, (b) 200, and (c, d) 100 nm.

In Figure 8 (right panel), the EDS spectrum indicates the BiVO4 sample elemental analysis including Bi, V, and O. This result is consistent with the XRD analysis.66 Besides, the EDS spectrum shows new strong signals of carbon such as Bi, V, O, and C, which belong to the BiVO4/MWCNTs nanocomposite, as shown in Figure 8 (left panel). The 1:1 Bi/V atomic ratio is quite close to the value predicted by theory for BiVO4. As stated in the literature,63 some MWCNTs are implanted inside BiVO4 and some are exposed on its surface.

Figure 8.

Figure 8

Open in a new tab

EDX spectrum of the pure BiVO4 nanostructures (right panel) with an inset table and the BiVO4/MWCNTs nanocomposite (left panel) with the inset table showing the percentage of each element in BiVO4 and the BiVO4/MWCNTs nanocomposite.

3.2. Antibacterial Activity of Pure BiVO4 and the BiVO4/MWCNTs Nanocomposite

The antibacterial activity of the pure BiVO4 nanostructure against P. mirabilis and S. mutans bacterial strains was evaluated at different concentrations of 26.5, 125, and 250 μg/mL. As shown in Figure 9(A–C), the pure BiVO4 nanostructure demonstrated a strong antibacterial effect against both bacterial strains. The inhibition zones at high concentrations were about 12 ± 0.6, 14 ± 0.7, and 19 ± 0.9 mm against S. mutans and about 11 ± 0.5, 17 ± 0.8, and 18 ± 0.9 mm against P. mirabilis a in Figure 9(A,B), respectively. It was also found that the inhibitory effect of pure BiVO4 increased as the concentration increased, especially at 125 and 250 μg/mL with IZ of about 18 and 17 mm in P. mirabilis, as shown in Figure 9(C) using data as mean ± SD of three independent tests. Our finding demonstrated that the antibacterial properties of the nanostructures are influenced by their size, surface morphology, and bacterial strains.

Figure 9.

Figure 9

Open in a new tab

Antibacterial activity of the pure BiVO4 nanostructure at different concentrations (26.5, 125, and 250 μg/mL) against (A) P. mirabilis and (B) S.mutans. (C) Data represented as the mean ± SD of three independent experiments.

The outcomes also reveal that the antibacterial effects of BiVO4 increased related to an increase in the bacterial membrane permeability for the entry of BiVO4 nanostructure shape with an abrasive texture, which causes membrane disorganization and alterations at the protein level. This ultimately causes cellular metabolism to be inhibited, which results in bacterial cell death. Besides, the hydrothermal synthesis resulted in a crystalline monoclinic structure nanostructure that offers high surface area and monodispersion evident from XRD analysis, which further contributes to the inactivation of bacteria.67,68Figure 10(A–C) illustrates the antibacterial effect of the synthesized BiVO4/MWCNTs nanocomposite at various concentrations (26.5, 125, and 250 μg/mL) against P. mirabilis and S. mutans bacteria using the agar well diffusion assay. The results in Figure 10(A,B) exhibited that the tested bacterial strain, P. mirabilis, was highly susceptible bacteria, revealing a large inhibition zone of about 22 ± 1.1, 23 ± 1.1, and 24 ± 1.2 mm, while S. mutans became less susceptible bacteria, revealing an inhibition zone of about 21 ± 1.0, 22 ± 1.1, and 23 ± 1.1 mm with increasing concentrations. Based on the results of mean ± standard deviation obtained in Figure 10(C), it was clear that the BiVO4/MWCNTs nanocomposite had superior antibacterial action against P. mirabilis bacteria to S. mutans bacteria. This might be due to differences in metabolism and cell physiology as well as the peptidoglycan (PG) layer of P. mirabilis being thinner than that of S. mutans.69−71 Additionally, MWCNTs are the sites where BiVO4 ions are stored after they are released from the BiVO4 oxide nanostructure and come into contact with harmful bacteria. This increases cell permeability, which in turn leads to cell deformation and leakage. In general, nanocomposites having a high surface-to-volume ratio, which boosts the number of ions released from the nanostructure, performed better against bacteria.72 In addition to the direct effect of the BiVO4 nanostructure, the antibacterial activity of the nanocomposites is also improved by accelerating the diffusion of Bi3+ ions into VO4–3 anions,73,74 which supports the thermodynamic nucleation and the production of reactive oxygen species (ROS). In general, pathogenic bacteria’s intercellular or cell walls undergo a complicated response as part of the nanostructures’ antibacterial mechanism,75 first distortion and then a leak. In general, nanocomposites having a high surface-to-volume ratio, which boosts the number of ions released from the nanostructure, performed better against bacteria.76 MIC values of pure BiVO4 and the BiVO4/MWCNTs nanocomposite against S. mutans and P. mirabilis have been measured. The MIC of pure BiVO4 is 31.232 μg/mL for both bacterial strains, while that of BiVO4/MWCNTs is 15.616 μg/mL.

Figure 10.

Figure 10

Open in a new tab

Antibacterial activity of the BiVO4/MWCNTs nanocomposite at different concentrations (26.5, 125, and 250 μg/mL) against (A) P. mirabilis and (B) S.mutans. (C) Data represented as mean ± SD of three independent experiments.

As shown in Figure 11(A–C), the SEM morphology indicates the visualization of the effect of pure BiVO4 and the BiVO4/MWCNTs nanocomposite on the cellular morphology to observe the membrane of cytoplasm deformation of S. mutans and P. mirabilis upon being treated. As shown in Figure 11(A), both untreated bacterial strains reveal normal shapes and sizes of bacteria. Besides, the bacterial strains showed changes in the cell membranes like damaged, blabbed, and clumped membranes. The morphology of P. mirabilis (Gram −ve) indicates that they exist as single-celled or rod-shaped. Whereas S. mutans (Gram +ve) has a coccus shape that usually occurs in clusters but also can be observed in single and pair cells in an untreated state. As shown in Figure 11(B,C), the morphology of P. mirabilis and S. mutans after being exposed to BiVO4 and the BiVO4/MWCNTs nanocomposite displays that some of the cells have changed. Besides, aggregation with bacteria cell membranes is common in many types of carbon-based nanoparticles. Moreover, after being treated with the BiVO4 /MWCNTs nanocomposite, the damaged membrane caused the loss of cytoplasmic components, which resulted in cell death. These created nanocomposites were extremely effective in killing both Gram +ve and Gram −ve bacteria due to the synergistic effects of the inherent multimodal killing mechanism of nanoparticles and the cell-penetrating capacity of MWCNTs.

Figure 11.

Figure 11

Open in a new tab

SEM morphology visualized the effect of pure BiVO4 and the BiVO4/MWCNTs nanocomposite on the cytoplasm deformation and alterations in the cell membranes like damaged, blabbed, and clumped S. mutans and P. mirabilis. (A) Untreated control bacterial strains. (B) Bacterial strains treated with pure BiVO4. (C) Bacterial strains treated with BiVO4 /MWCNTs.

According to the findings, the mechanism of nanostructures that inhibits bacteria in this way is accomplished by (i) damaging the bacterial cell wall, (ii) interfering with DNA replication and the production of reactive oxygen species (ROS), (iii) inhibiting protein synthesis, and (iv) interfering with the bacterium’s metabolism, as shown in Figure 11(A–C).77 The most crucial factors in determining whether pathogenic bacteria are inhibited are the magnitude and production of ROS (h+, •O2–, and OH–). Since ROS can cause oxidation of proteins and peroxidation of lipids, which changes the permeability of fluids and ion transport and damages the hardness of cell membranes, ROS can also hinder metabolic activities.78 A study by Ye et al.79 demonstrated that the MWCNT/BiVO4 nanocomposite plays a potential role as a therapeutic agent against multiple antibiotic resistance, Shigella flexneri HL, which is present in livestock and poultry breeding wastewater. A study by ref (80) represented that BiVO4@ACFs under different chelating agents showed highly antibacterial activity against Escherichia coli and Staphylococcus aureus. In the study of ref (81), the activity of different MO (Ag2Ox, CoOx, and CuOx) and different wt % loadings of CuOx in MoBiVO4 photocatalysts on photocatalytic inactivation and degradation of orange II dye in visible light irradiation was investigated. The CuOx loading significantly enhanced the photocatalytic degradation activity of Mo–BiVO4 photocatalysts for bacteria and orange II dye because of the appropriate charge separation and transfer at the Mo–BiVO4 interface. The optimum CuOx (2 wt %)/Mo–BiVO4 photocatalysts prepared using the wet impregnation method exhibited the maximum inactivation efficiency (98%) for E. coli and S. aureus over 120 min. Moreover, the optimized CuOx (2 wt %)/Mo–BiVO4 photocatalysts showed outstanding inactivation of E. coli and S. aureus (98%) compared to the other prepared photocatalysts. Taken together, the results of the current study confirmed that the BiVO4/MWCNTs nanocomposite has significantly enhanced antibacterial activity as compared to BiVO4 alone. The antibacterial activity of the BiVO4/MWCNTs nanocomposite could lead to ROS generation, which disrupts the plasma membrane and destroys metabolic pathways, leading to bacterial cell death. Consequently, we offer a novel antibacterial approach for future disinfection applications.

3.3. Inhibition of Biofilm Formation

Figure 12 exhibits the ability of pure BiVO4 and the BiVO4/MWCNTs nanocomposite to inhibit biofilm formation for both P. mirabilis and S. mutans. Biofilm formation represented an important step in the initiation of any infection. The adhesion of bacterial strains to a surface is an essential first step in biofilm formation and can occur through specific and nonspecific cell–surface interactions. These biofilms can be detected by staining the adhered bacterial cells with crystal violet. In this test, the effect of pure BiVO4 and BiVO4/MWCNTs in inhibiting biofilm formation was demonstrated, as shown in Figure 12 (upper panel). Besides, pure BiVO4 and BiVO4/MWCNTs showed high effectiveness in biofilm formation (lower panel). The results showed that pure BiVO4 and BiVO4/MWCNTs significantly impaired the growth of microbial strains. These reductions in biofilm formation could be related to the mechanism of reactive oxygen species (ROS) formation. These ROS can result in the oxidation of proteins and the peroxidation of lipids, which weaken the Gram +ve cell membrane, alter the permeability of fluids and ion transport, and prevent metabolic processes from occurring.82 In addition, the interactions between the cell and the NPs, whether electrostatic or direct, can cause harm to the outer membrane of Gram +ve and Gram −ve bacteria’s cell walls.

Figure 12.

Figure 12

Open in a new tab

Pure BiVO4 and BiVO4/MWCNTs reduce biofilm formation in bacterial strains (upper panel). The bottom panel represents the quantification of biofilm formation as determined by crystal violet staining. Data are represented as the mean ± SD of three independent experiments.

Our results suggest that nanotechnology has potential applications as an antibacterial agent during bacterial infections.83 The nanotechnology approved its potential applications as antiparasitic agents.84−86 Additionally, nanoparticles are used widely in fish87,88 and poultry89 production.

3.4. Role of BiVO4 and BiVO4/MWCNTs in Bacterial Biofilm Inhibition

To study the effect of pure BiVO4 and the BiVO4/MWCNTs nanocomposite on bacterial biofilm inhibition, confocal microscopy was used. The confocal results confirmed the antibiofilm effects of pure BiVO4 and the BiVO4/MWCNTs nanocomposite at a concentration of 125 μg/mL. The biofilm viability kit provides a two-color fluorescence stain and is used to distinguish between live and dead bacterial cells within the biofilm community based on membrane integrity. As shown in Figure 13(A–C), the Syto 9 green fluorescence dye stained healthy membranes, whereas propidium iodide red fluorescence dye penetrated and stained the bacterial strains with damaged membranes; bacteria with intact cell membranes were stained fluorescent green, whereas bacteria with damaged membranes were stained fluorescent red, as indicated in Figure 13(A). The control of untreated biofilm bacterial strains showed green fluorescence, whereas the biofilm of treated samples and the cells of the treated bacterial strain exhibited orange to red fluorescence; these results demonstrated the presence of dead bacterial strains after being treated with pure BiVO4 and the BiVO4/MWCNTs nanocomposite at a concentration of 125 μg/mL. The control untreated bacterial strains were aggregated and covered with a mature biofilm structure, while the bacterial strains that were treated with pure BiVO4 and the BiVO4/MWCNTs nanocomposite at a concentration of 125 μg/mL were less aggregated and had a less dense biofilm covering, as shown in Figure 13(B,C). Taken together, the results of the current study reveal the potential biofilm formation inhibition and effects of pure BiVO4 and the BiVO4/MWCNTs nanocomposite. The biofilm metabolic activity of S. mutans and P. mirabilis was investigated using a flow cytometry assay.

Figure 13.

Figure 13

Open in a new tab

Reduction of the level of bacterial biofilm formation. Untreated control bacterial strains (A). Bacterial strains were treated with pure BiVO4 (B). Bacterial strains were treated with BiVO4/MWCNTs (C).

Figure 14 shows the dot plots of the S. mutans and P. mirabilis biofilm evaluated by flow cytometry. This assay used to measure metabolic activity in the S. mutans and P. mirabilis biofilm generated for 48 h assisted the distinction between live and dead cell populations done with excitation/emission fluorescence Syto 9 and propidium iodide stains. In the control untreated bacterial strain, as shown in Figure 14 (upper panel), the percentage of live S. mutans was 83.13%, while that of P. mirabilis was 80.66% after being treated with pure BiVO4 and the BiVO4/MWCNTs nanocomposite at a concentration of 125 μg/mL. These percentages decreased to 10.44 and 5.41%, respectively, when the bacterial strain was treated with pure BiVO4, as shown in Figure 14 (middle panel). The percentages of live cells were 1.95 and 1.20%, respectively, when bacterial strains were treated with the BiVO4/MWCNTs nanocomposite, as indicated in Figure 14 (lower panel). The BiVO4/MWCNTs nanocomposite had a higher effect than pure BiVO4 in the reduction of live cells.

Figure 14.

Figure 14

Open in a new tab

Effect of pure BiVO4 and BiVO4/MWCNTs on metabolic activity in the S. mutans and P. mirabilis biofilm. (A) Control untreated bacterial strains (upper panel), (B) bacterial strains treated with pure BiVO4 (middle panel), and (C) bacterial strains treated with BiVO4/MWCNTs (lower panel).

4. Conclusions

In this study, BiVO4 and BiVO4/MWCNTs nanocomposites were prepared by using the hydrothermal method. The prepared materials were analyzed by using different characterization methods, which indicated that the introduction of a small number of MWCNTs does not affect the BiVO4 monoclinic structure, as revealed in XRD analysis. Additionally, related to the embedding of MWCNTs in BiVO4, the visible light absorption range shifts to the red region because of the localized levels positioned between the valence band and the conduction band, resulting in a reduction in the energy gap band, as shown in the UV–visible spectrum. The PL spectrum of the BiVO4/MWCNTs nanocomposite improved the separation of carriers considerably, which resulted in the creation of more active sites and increasing adsorption capacity. Both pure BiVO4 and BiVO4/MWCNTs exhibited promising antibacterial activity against tested bacterial strains and biofilm formation. Generally, the results of this study indicated that BiVO4 and BiVO4/MWCNTs nanocomposites significantly reduced bacterial biofilm formation. Furthermore, these results suggest that BiVO4 and BiVO4/MWCNTs nanocomposites could be promising materials for developing antimicrobial agents.

Acknowledgments

The authors extend their appreciation to the Researchers Supporting Project Number (RSPD2023R971), King Saud University, Riyadh, Saudi Arabia, for funding this research. The authors appreciated the University of Technology, Iraq, for their support.

Author Contributions

Conceptualization: Z.R.R., D.S.A., and M.S.J.; methodology: Z.R.R., D.S.A., and M.S.J.; software: B.B., M.A.A.-G., and A.A.S.; validation: B.B., M.A.A.-G., and A.A.S.; formal analysis: M.A.J.; investigation: Z.R.R., D.S.A., and M.S.J.; resources: M.S.J.; data curation: D.S.A.; writing original draft preparation: Z.R.R., D.S.A., and M.S.J.; writing—review and editing: D.S.A., M.S.J., B.B., M.A.A.-G., and A.A.S.; visualization: B.B., M.A.A.-G., and A.A.S.; supervision: D.S.A. and M.S.J.; and project administration: D.S.A. and M.S.J. All authors have read and agreed to the published version of the manuscript.

The authors extend their appreciation to the Researchers Supporting Project Number (RSPD2023R971), King Saud University, Riyadh, Saudi Arabia, for funding this research.

The authors declare no competing financial interest.

Notes

Institutional Review Board Statement The study was conducted according to the guidelines of the Declaration of Helsinki and approved by the Institutional Review Board of the University of Technology, Baghdad, Iraq (ref no. DAS 23–9–2021).

References

  1. Duan H.; Wang D.; Li Y. Green chemistry for nanoparticle synthesis. Chem. Soc. Rev. 2015, 44 (16), 5778–5792. 10.1039/C4CS00363B. [DOI] [PubMed] [Google Scholar]
  2. Yang H. G.; Liu G.; Qiao S. Z.; et al. Solvothermal synthesis and photoreactivity of anatase TiO2 nanosheets with dominant {001} facets. J. Am. Chem. Soc. 2009, 131 (11), 4078–4083. 10.1021/ja808790p. [DOI] [PubMed] [Google Scholar]
  3. Jun Y. W.; Choi J. S.; Cheon J. Shape control of semiconductor and metal oxide nanocrystals through nonhydrolytic colloidal routes. Angew. Chem., Int. Ed. 2006, 45 (21), 3414–3439. 10.1002/anie.200503821. [DOI] [PubMed] [Google Scholar]
  4. Sinclair T. S.; Hunter B. M.; Winkler J. R.; Gray H. B.; Müller A. M. Factors affecting bismuth vanadate photoelectrochemical performance. Mater. Horiz. 2015, 2 (3), 330–337. 10.1039/C4MH00156G. [DOI] [Google Scholar]
  5. Pandey M.; et al. Targeted specific inhibition of bacterial and Candida species by mesoporous Ag/Sn–SnO2 composite nanoparticles: in silico and in vitro investigation. RSC Adv. 2022, 12 (2), 1105–1120. 10.1039/D1RA07594B. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Roy K.; Poompiew N.; Pongwisuthiruchte A.; Potiyaraj P. Application of different vegetable oils as processing aids in industrial rubber composites: A sustainable approach. ACS Omega 2021, 6 (47), 31384–31389. 10.1021/acsomega.1c04692. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Guan D.-L.; Niu C.-G.; Wen X.-J.; Guo H.; Deng C.-H.; Zeng G.-M. Enhanced Escherichia coli inactivation and oxytetracycline hydrochloride degradation by a Z-scheme silver iodide decorated bismuth vanadate nanocomposite under visible light irradiation. J. Colloid Interface Sci. 2018, 512, 272–281. 10.1016/j.jcis.2017.10.068. [DOI] [PubMed] [Google Scholar]
  8. Sharma R.; Singh S.; Verma A.; Khanuja M. Visible light-induced bactericidal and photocatalytic activity of hydrothermally synthesized BiVO4 nano-octahedrals. J. Photochem. Photobiol., B 2016, 162, 266–272. 10.1016/j.jphotobiol.2016.06.035. [DOI] [PubMed] [Google Scholar]
  9. Regmi C.; Kshetri Y. K.; Jeong S. H.; Lee S. W. BiVO4 as highly efficient host for near-infrared to visible upconversion. J. Appl. Phys. 2019, 125 (4), 043101 10.1063/1.5064726. [DOI] [Google Scholar]
  10. Antuch M.; Millet P.; Iwase A.; Kudo A. The role of surface states during photocurrent switching: Intensity modulated photocurrent spectroscopy analysis of BiVO4 photoelectrodes. Appl. Catal., B 2018, 237, 401–408. 10.1016/j.apcatb.2018.05.011. [DOI] [Google Scholar]
  11. Kudo A.; Omori K.; Kato H. A novel aqueous process for preparation of crystal form-controlled and highly crystalline BiVO4 powder from layered vanadates at room temperature and its photocatalytic and photophysical properties. J. Am. Chem. Soc. 1999, 121 (49), 11459–11467. 10.1021/ja992541y. [DOI] [Google Scholar]
  12. Zhao Y.; Xie Y.; Zhu X.; Yan S.; Wang S. Surfactant-free synthesis of hyperbranched monoclinic bismuth vanadate and its applications in photocatalysis, gas sensing, and lithium-ion batteries. Chem. - Eur. J. 2008, 14 (5), 1601–1606. 10.1002/chem.200701053. [DOI] [PubMed] [Google Scholar]
  13. Marzano I. M.; Franco M.; Silva P.; et al. Crystal structure, antibacterial and cytotoxic activities of a new complex of bismuth (III) with sulfapyridine. Molecules 2013, 18 (2), 1464–1476. 10.3390/molecules18021464. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Abid H. N.; Ahmed D. S.; Al-keisy A. H. Constructed p-2D/n-2D BiOCl/BiVO4 Nanoheterostructure for Photocatalytic Antibacterial Activity. ECS Trans. 2022, 107 (1), 2283. 10.1149/10701.2283ecst. [DOI] [Google Scholar]
  15. Noor M.et al. Effect of pH Variation on Structural, Optical and Shape Morphology of BiVO4 Photocatalysts, 10th International Conference on Electrical and Computer Engineering (ICECE); IEEE, 2018; pp 81–84.
  16. Rahman M. F.; Haque M.; Hasan M.; Hakim M. Fabrication of Bismuth Vanadate (BiVO4) nanoparticles by a facile route. Trans. Electr. Electron. Mater. 2019, 20 (6), 522–529. 10.1007/s42341-019-00144-4. [DOI] [Google Scholar]
  17. Zhao H.; Tian F.; Wang R.; Chen R. A review on bismuth-related nanomaterials for photocatalysis. Rev. Adv. Sci. Eng. 2014, 3 (1), 3–27. 10.1166/rase.2014.1050. [DOI] [Google Scholar]
  18. Han M.; Chen X.; Sun T.; Tan O. K.; Tse M. S. Synthesis of mono-dispersed m-BiVO4 octahedral nano-crystals with enhanced visible light photocatalytic properties. CrystEngComm 2011, 13 (22), 6674–6679. 10.1039/c1ce05539a. [DOI] [Google Scholar]
  19. Madhusudan P.; Yu J.; Wang W.; Cheng B.; Liu G. Facile synthesis of novel hierarchical graphene–Bi2O2CO3 composites with enhanced photocatalytic performance under visible light. Dalton Trans. 2012, 41 (47), 14345–14353. 10.1039/c2dt31528a. [DOI] [PubMed] [Google Scholar]
  20. He N.; Li X.; Feng D.; et al. Exploring the toxicity of a bismuth–asparagine coordination polymer on the early development of zebrafish embryos. Chem. Res. Toxicol. 2013, 26 (1), 89–95. 10.1021/tx3004032. [DOI] [PubMed] [Google Scholar]
  21. Sharifi E.; Salimi A.; Shams E.; Noorbakhsh A.; Amini M. K. Shape-dependent electron transfer kinetics and catalytic activity of NiO nanoparticles immobilized onto DNA modified electrode: fabrication of highly sensitive enzymeless glucose sensor. Biosens. Bioelectron. 2014, 56, 313–319. 10.1016/j.bios.2014.01.010. [DOI] [PubMed] [Google Scholar]
  22. Rocha G.; Melo L.; Castro M. Jr; Ayala A.; de Menezes A.; Fechine P. Structural characterization of bismuth rare earth tungstates obtained by fast microwave-assisted solid-state synthesis. Mater. Chem. Phys. 2013, 139 (2–3), 494–499. 10.1016/j.matchemphys.2013.01.047. [DOI] [Google Scholar]
  23. Li H.; Li K.; Wang H. Hydrothermal synthesis and photocatalytic properties of bismuth molybdate materials. Mater. Chem. Phys. 2009, 116 (1), 134–142. 10.1016/j.matchemphys.2009.02.058. [DOI] [Google Scholar]
  24. Ahmed D. S.; Mohammed M. K.; Mohammad M. R. Sol–gel synthesis of Ag-doped titania-coated carbon nanotubes and study their biomedical applications. Chem. Pap. 2020, 74 (1), 197–208. 10.1007/s11696-019-00869-9. [DOI] [Google Scholar]
  25. Cioffi C.; Campidelli S.; Sooambar C.; et al. Synthesis, characterization, and photoinduced electron transfer in functionalized single wall carbon nanohorns. J. Am. Chem. Soc. 2007, 129 (13), 3938–3945. 10.1021/ja068007p. [DOI] [PubMed] [Google Scholar]
  26. Eder D. Carbon nanotube– inorganic hybrids. Chem. Rev. 2010, 110 (3), 1348–1385. 10.1021/cr800433k. [DOI] [PubMed] [Google Scholar]
  27. Heydari-Bafrooei E.; Askari S. Electrocatalytic activity of MWCNTs supported Pd nanoparticles and MoS2 nanoflowers for hydrogen evolution from acidic media. Int. J. Hydrogen Energy 2017, 42 (5), 2961–2969. 10.1016/j.ijhydene.2016.11.101. [DOI] [Google Scholar]
  28. Heydari-Bafrooei E.; Shamszadeh N. S. Synergetic effect of CoNPs and graphene as cocatalysts for enhanced electrocatalytic hydrogen evolution activity of MoS2. RSC Adv. 2016, 6 (98), 95979–95986. 10.1039/C6RA21610B. [DOI] [Google Scholar]
  29. Mohammad M. R.; Ahmed D. S.; Mohammed M. K. Synthesis of Ag-doped TiO2 nanoparticles coated with carbon nanotubes by the sol–gel method and their antibacterial activities. J. Sol–Gel Sci. Technol. 2019, 90 (3), 498–509. 10.1007/s10971-019-04973-w. [DOI] [Google Scholar]
  30. Mohammed M. K.; Taqi Z. J.; Hassen A. M. A.; Jabir M. S.; Ahmed D. S.. SWCNTs/ZnO-Ag/ZnO-Au Nanocomposite Increases Bactericidal Activity of Phagocytic Cells against Staphylococcus aureus, AIP Conference Proceedings; AIP Publishing LLC, 2021020001.
  31. Yan X.; Qian J.; Pei X.; et al. Enhanced photodegradation of doxycycline (DOX) in the sustainable NiFe2O4/MWCNTs/BiOI system under UV light irradiation. Environ. Res. 2021, 199, 111264 10.1016/j.envres.2021.111264. [DOI] [PubMed] [Google Scholar]
  32. Gan J.; Zhang J.; Zhang B.; et al. Active sites engineering of Pt/CNT oxygen reduction catalysts by atomic layer deposition. J. Energy Chem. 2020, 45, 59–66. 10.1016/j.jechem.2019.09.024. [DOI] [Google Scholar]
  33. Ali N.; Taha A.; Ahmed D. S. Characterization of Treated Multi-Walled Carbon Nanotubes and Antibacterial Properties. J. Appl. Sci. Nanotechnol. 2021, 1 (2), 1–9. 10.53293/jasn.2021.11636. [DOI] [Google Scholar]
  34. Eigler S.; Grimm S.; Hirsch A. Investigation of the thermal stability of the carbon framework of graphene oxide. Chem. - Eur. J. 2014, 20 (4), 984–989. 10.1002/chem.201304048. [DOI] [PubMed] [Google Scholar]
  35. Lee D.; Yang H.; Park S.; Kim W. Nafion/graphene oxide composite membranes for low humidifying polymer electrolyte membrane fuel cell. J. Membr. Sci. 2014, 452, 20–28. 10.1016/j.memsci.2013.10.018. [DOI] [Google Scholar]
  36. Song Y.; Zhu J.; Xu H.; et al. Synthesis, characterization and visible-light photocatalytic performance of Ag2CO3 modified by graphene-oxide. J. Alloys Compd. 2014, 592, 258–265. 10.1016/j.jallcom.2013.12.228. [DOI] [Google Scholar]
  37. Shan L.; Bi J.; Lu C.; Xiao Y. BiVO4 (010)/rGO Nanocomposite and Its Photocatalysis Application. J. Inorg. Organomet. Polym. Mater. 2019, 29, 1000–1009. 10.1007/s10904-018-0990-9. [DOI] [Google Scholar]
  38. Ye S.; Xu Y.; Huang L.; et al. MWCNT/BiVO4 photocatalyst for inactivation performance and mechanism of Shigella flexneri HL, antibiotic-resistant pathogen. Chem. Eng. J. 2021, 424, 130415 10.1016/j.cej.2021.130415. [DOI] [Google Scholar]
  39. Zhao D.; Wang W.; Sun Y.; et al. One-step synthesis of composite material MWCNT@BiVO4 and its photocatalytic activity. RSC Adv. 2017, 7 (53), 33671–33679. 10.1039/C7RA04288D. [DOI] [Google Scholar]
  40. Jihad M. A.; Noori F. T.; Jabir M. S.; Albukhaty S.; AlMalki F. A.; Alyamani A. A. Polyethylene glycol functionalized graphene oxide nanoparticles loaded with nigella sativa extract: a smart antibacterial therapeutic drug delivery system. Molecules 2021, 26 (11), 3067. 10.3390/molecules26113067. [DOI] [PMC free article] [PubMed] [Google Scholar]
  41. Khashan K. S.; Abdulameer F. A.; Jabir M. S.; Hadi A. A.; Sulaiman G. M. Anticancer activity and toxicity of carbon nanoparticles produced by pulsed laser ablation of graphite in water. Adv. Nat. Sci.: Nanosci. Nanotechnol. 2020, 11 (3), 035010 10.1088/2043-6254/aba1de. [DOI] [Google Scholar]
  42. Mohammed M. K.; Mohammad M.; Jabir M. S.; Ahmed D. In Functionalization, Characterization, and Antibacterial Activity of Single Wall and Multi Wall Carbon Nanotubes, IOP Conference Series: Materials Science and Engineering; IOP Publishing, 2020; p 012028.
  43. Veloz J. J.; Alvear M.; Salazar L. A. Evaluation of alternative methods to assess the biological properties of propolis on metabolic activity and biofilm formation in Streptococcus mutans. J. Evidence-Based Complementary Altern. Med. 2019, 2019, 1524195 10.1155/2019/1524195. [DOI] [PMC free article] [PubMed] [Google Scholar]
  44. Sun Z.; Yu Z.; Liu Y.; Shi C.; Zhu M.; Wang A. Construction of 2D/2D BiVO4/g-C3N4 nanosheet heterostructures with improved photocatalytic activity. J. Colloid Interface Sci. 2019, 533, 251–258. 10.1016/j.jcis.2018.08.071. [DOI] [PubMed] [Google Scholar]
  45. Pookmanee P.; Kojinok S.; Puntharod R.; Sangsrichan S.; Phanichphant S. Preparation and characterization of BiVO4 powder by the sol-gel method. Ferroelectrics 2013, 456 (1), 45–54. 10.1080/00150193.2013.846197. [DOI] [Google Scholar]
  46. Zhao D.; Zong W.; Fan Z.; et al. Synthesis of carbon-doped nanosheets m-BiVO4 with three-dimensional (3D) hierarchical structure by one-step hydrothermal method and evaluation of their high visible-light photocatalytic property. J. Nanopart. Res. 2017, 19 (4), 1–16. 10.1007/s11051-017-3818-6. [DOI] [Google Scholar]
  47. Guo-Cong L.; Zhen J.; Xi-Bing Z.; Xian-Feng L.; Hong L. Hydrothermal synthesis and photocatalytic properties of Cu-doped BiVO4 microsheets. Chin. J. Inorg. Mater. 2013, 28, 287–294. 10.3724/SP.J.1077.2013.12204. [DOI] [Google Scholar]
  48. Ma L.; Li W.-H.; Luo J.-H. Solvothermal synthesis and characterization of well-dispersed monoclinic olive-like BiVO4 aggregates. Mater. Lett. 2013, 102-103, 65–67. 10.1016/j.matlet.2013.03.111. [DOI] [Google Scholar]
  49. Sun J.; Chen G.; Wu J.; Dong H.; Xiong G. Bismuth vanadate hollow spheres: Bubble template synthesis and enhanced photocatalytic properties for photodegradation. Applied Catal., B 2013, 132-133, 304–314. 10.1016/j.apcatb.2012.12.002. [DOI] [Google Scholar]
  50. Wang X.; Li G.; Ding J.; Peng H.; Chen K. Facile synthesis and photocatalytic activity of monoclinic BiVO4 micro/nanostructures with controllable morphologies. Mater. Res. Bull. 2012, 47 (11), 3814–3818. 10.1016/j.materresbull.2012.04.082. [DOI] [Google Scholar]
  51. Zhu G.; Que W. Hydrothermal synthesis and characterization of visible-light-driven dumbbell-like BiVO4 and Ag/BiVO4 photocatalysts. J. Cluster Sci. 2013, 24 (2), 531–547. 10.1007/s10876-012-0531-6. [DOI] [Google Scholar]
  52. Obaid Z. S.Physical Properties of PMMA/ZnO Composite Material, Ph.D. Dissertations, University Al-Narhrain; 2017. [Google Scholar]
  53. Al-Ammar K.; Hashim A.; Husaien M. Synthesis and study of optical properties of (PMMA-CrCl2) composites. Chem. Mater. Eng. 2013, 1 (3), 85–87. 10.13189/cme.2013.010304. [DOI] [Google Scholar]
  54. Sathish M.; Viswanathan B.; Viswanath R.; Gopinath C. S. Synthesis, characterization, electronic structure, and photocatalytic activity of nitrogen-doped TiO2 nanocatalyst. Chem. Mater. 2005, 17 (25), 6349–6353. 10.1021/cm052047v. [DOI] [Google Scholar]
  55. Liu B.; Li Z.; Xu S.; Ren X.; Han D.; Lu D. Facile in situ hydrothermal synthesis of BiVO4/MWCNTs nanocomposites as high performance visible-light driven photocatalysts. J. Phys. Chem. Solids 2014, 75 (8), 977–983. 10.1016/j.jpcs.2014.04.014. [DOI] [Google Scholar]
  56. Sun T.; Cui D.; Ma Q.; Peng X.; Yuan L. Synthesis of BiVO4/MWCNT/Ag@ AgCl composite with enhanced photocatalytic performance. J. Phys. Chem. Solids 2017, 111, 190–198. 10.1016/j.jpcs.2017.08.006. [DOI] [Google Scholar]
  57. Zhang M.; Shao C.; Li X.; et al. Carbon-modified BiVO4 microtubes embedded with Ag nanoparticles have high photocatalytic activity under visible light. Nanoscale 2012, 4 (23), 7501–7508. 10.1039/c2nr32213g. [DOI] [PubMed] [Google Scholar]
  58. Zhao Z.; Dai H.; Deng J.; Liu Y.; Au C. T. Enhanced visible-light photocatalytic activities of porous olive-shaped sulfur-doped BiVO4-supported cobalt oxides. Solid State Sci. 2013, 18, 98–104. 10.1016/j.solidstatesciences.2013.01.009. [DOI] [Google Scholar]
  59. Song H.; Sun J.; Shen T.; Deng L.; Wang X. Insights into the mechanism of the Bi/BiVO4 composites for improved photocatalytic activity. Catalysts 2021, 11 (4), 489. 10.3390/catal11040489. [DOI] [Google Scholar]
  60. Liu B.; Zeng H. C. Mesoscale organization of CuO nanoribbons: formation of “dandelions. J. Am. Chem. Soc. 2004, 126 (26), 8124–8125. 10.1021/ja048195o. [DOI] [PubMed] [Google Scholar]
  61. Kale B. B.; Baeg J. O.; Lee S. M.; Chang H.; Moon S. J.; Lee C. W. CdIn2S4 nanotubes and “Marigold” nanostructures: a visible-light photocatalyst. Adv. Funct. Mater. 2006, 16 (10), 1349–1354. 10.1002/adfm.200500525. [DOI] [Google Scholar]
  62. Ajayaghosh A.; Varghese R.; Praveen V. K.; Mahesh S. Evolution of Nano-to Microsized Spherical Assemblies of a Short Oligo (p-phenyleneethynylene) into Superstructured Organogels. Angew. Chem. 2006, 118 (20), 3339–3342. 10.1002/ange.200600256. [DOI] [PubMed] [Google Scholar]
  63. Pal S.; Dutta S.; De S. In A Facile Hydrothermal Approach to Synthesize rGO/BiVO4 Photocatalysts for Visible Light Induced Degradation of RhB Dye, AIP Conference Proceedings; AIP Publishing LLC, 2018; p 030205.
  64. Tan H. L.; Wen X.; Amal R.; Ng Y. H. BiVO4 {010} and {110} relative exposure extent: governing factor of surface charge population and photocatalytic activity. J. Phys. Chem. Lett. 2016, 7 (7), 1400–1405. 10.1021/acs.jpclett.6b00428. [DOI] [PubMed] [Google Scholar]
  65. Tachikawa T.; Ochi T.; Kobori Y. Crystal-face-dependent charge dynamics on a BiVO4 photocatalyst revealed by single-particle spectroelectrochemistry. ACS Catal. 2016, 6 (4), 2250–2256. 10.1021/acscatal.6b00234. [DOI] [Google Scholar]
  66. Reichel T.; Mitnacht M.; Fenwick A.; Meffert R.; Hoos O.; Fehske K. Incidence and characteristics of acute and overuse injuries in elite powerlifters. Cogent Med. 2019, 6 (1), 1588192 10.1080/2331205X.2019.1588192. [DOI] [Google Scholar]
  67. Han M.; Chen X.; Sun T.; Tan O. K.; Tse M. S. Synthesis of mono-dispersed m-BiVO4 octahedral nano-crystals with enhanced visible light photocatalytic properties. CrystEngComm 2011, 13 (22), 6674–6679. 10.1039/c1ce05539a. [DOI] [Google Scholar]
  68. Tian G.; Fu H.; Jing L.; Tian C. Synthesis and photocatalytic activity of stable nanocrystalline TiO2 with high crystallinity and large surface area. J. Hazard. Mater. 2009, 161 (2–3), 1122–1130. 10.1016/j.jhazmat.2008.04.065. [DOI] [PubMed] [Google Scholar]
  69. Brown L.; Wolf J. M.; Prados-Rosales R.; Casadevall A. Through the wall: extracellular vesicles in Gram-positive bacteria, mycobacteria and fungi. Nat. Rev. Microbiol. 2015, 13 (10), 620–630. 10.1038/nrmicro3480. [DOI] [PMC free article] [PubMed] [Google Scholar]
  70. Abo El-Yazeed W.; El-Hakam S.; Salah A.; Ibrahim A. A. Fabrication and characterization of reduced graphene-BiVO4 nanocomposites for enhancing visible light photocatalytic and antibacterial activity. J. Photochem. Photobiol., A 2021, 417, 113362 10.1016/j.jphotochem.2021.113362. [DOI] [Google Scholar]
  71. Saleem A.; Ahmed T.; Ammar M.; Zhang H.-l.; Xu H.-b.; Tabassum R. Direct growth of m-BiVO4@ carbon fibers for highly efficient and recyclable photocatalytic and antibacterial applications. J. Photochem. Photobiol., B 2020, 213, 112070 10.1016/j.jphotobiol.2020.112070. [DOI] [PubMed] [Google Scholar]
  72. Wang Y.-W.; Cao A.; Jiang Y.; et al. Superior antibacterial activity of zinc oxide/graphene oxide composites originating from high zinc concentration localized around bacteria. ACS Appl. Mater. Interfaces 2014, 6 (4), 2791–2798. 10.1021/am4053317. [DOI] [PubMed] [Google Scholar]
  73. Sun Z.; Yu Z.; Liu Y.; Shi C.; Zhu M.; Wang A. Construction of 2D/2D BiVO4/g-C3N4 nanosheet heterostructures with improved photocatalytic activity. J. Colloid Interface Sci. 2019, 533, 251–258. 10.1016/j.jcis.2018.08.071. [DOI] [PubMed] [Google Scholar]
  74. Safaei J.; Ullah H.; Mohamed N. A.; et al. Enhanced photoelectrochemical performance of Z-scheme g-C3N4/BiVO4 photocatalyst. Appl. Catal., B 2018, 234, 296–310. 10.1016/j.apcatb.2018.04.056. [DOI] [Google Scholar]
  75. Pookmanee P.; Kojinok S.; Puntharod R.; Sangsrichan S.; Phanichphant S. Preparation and characterization of BiVO4 powder by the sol-gel method. Ferroelectrics 2013, 456 (1), 45–54. 10.1080/00150193.2013.846197. [DOI] [Google Scholar]
  76. Wang Y.-W.; Cao A.; Jiang Y.; et al. Superior antibacterial activity of zinc oxide/graphene oxide composites originating from high zinc concentration localized around bacteria. ACS Appl. Mater. Interfaces 2014, 6 (4), 2791–2798. 10.1021/am4053317. [DOI] [PubMed] [Google Scholar]
  77. Jiang J.; Pi J.; Cai J. The advancing of zinc oxide nanoparticles for biomedical applications. Bioinorg. Chem. Appl. 2018, 2018, 1062562 10.1155/2018/1062562. [DOI] [PMC free article] [PubMed] [Google Scholar]
  78. Al Rugaie O.; Jabir M.; Kadhim R.; et al. Gold nanoparticles and graphene oxide flakes synergistic partaking in cytosolic bactericidal augmentation: role of ROS and NOX2 activity. Microorganisms 2021, 9 (1), 101. 10.3390/microorganisms9010101. [DOI] [PMC free article] [PubMed] [Google Scholar]
  79. Ye S.; Xu Y.; Huang L.; Lai W.; Deng L.; Lin Z.; Xie G.; et al. MWCNT/BiVO4 photocatalyst for inactivation performance and mechanism of Shigella flexneri HL, antibiotic-resistant pathogen. Chem. Eng. J. 2021, 424, 130415 10.1016/j.cej.2021.130415. [DOI] [Google Scholar]
  80. Saleem A.; Ahmed T.; Ammar M.; Zhang H. L.; Xu H. B.; Tabassum R. Direct growth of m-BiVO4@ carbon fibers for highly efficient and recyclable photocatalytic and antibacterial applications. J. Photochem. Photobiol., B 2020, 213, 112070 10.1016/j.jphotobiol.2020.112070. [DOI] [PubMed] [Google Scholar]
  81. Manikandan V.; Mahadik M. A.; Hwang I. S.; Chae W. S.; Ryu J.; Jang J. S. Visible-light-active CuO x-loaded Mo-BiVO4 photocatalyst for inactivation of harmful bacteria (Escherichia coli and Staphylococcus aureus) and degradation of orange II Dye. ACS Omega 2021, 6 (37), 23901–23912. 10.1021/acsomega.1c02879. [DOI] [PMC free article] [PubMed] [Google Scholar]
  82. Jabir M. S.; Nayef U. M.; Jawad K. H.; Taqi Z. J.; Ahmed N. R. In Porous Silicon Nanoparticles Prepared via an Improved Method: A Developing Strategy for a Successful Antimicrobial Agent Against Escherichia coli and Staphylococcus aureus, IOP Conference Series: Materials Science and Engineering; IOP Publishing, 2018012077.
  83. Aymen N.; Aqib A. I.; Akram K.; Majeed H.; Murtaza M.; Muneer A.; Alsayeqh A. F. Resistance modulation of dairy milk borne Streptococcus agalactiae and Klebsiella pneumoniae through metallic oxide nanoparticles. Pak. Vet. J. 2022, 42 (3), 424–428. 10.29261/pakvetj/2022.052. [DOI] [Google Scholar]
  84. Kandeel M.; Rehman T. U.; Akhtar T.; Zaheer T.; Ahmad S.; Ashraf U.; Omar M. Antiparasitic applications of nanoparticles: a review. Pak. Vet. J. 2022, 42 (2), 135–140. 10.29261/pakvetj/2022.040. [DOI] [Google Scholar]
  85. Jalil P. J.; Shnawa B. H.; Hamad S. M. Silver nanoparticles: green synthesis, characterization, blood compatibility, and protoscolicidal efficacy against Echinococcus granulosus. Pak. Vet. J. 2021, 41 (3), 393–399. 10.29261/pakvetj/2021.039. [DOI] [Google Scholar]
  86. Shnawa B. H.; Jalil P. J.; Aspoukeh P.; Mohammed D. A.; Biro D. M. Protoscolicidal and biocompatibility properties of biologically fabricated zinc oxide nanoparticles using Ziziphus spina-christi leaves. Pak. Vet. J. 2022, 42 (4), 517–525. 10.29261/pakvetj/2022.058. [DOI] [Google Scholar]
  87. Aziz S.; Abdullah S.; Anwar H.; Latif F. DNA damage and oxidative stress in economically important fish, Bighead carp (Hypophthalmichthys nobilis) exposed to engineered copper oxide nanoparticles. Pak. Vet. J. 2022, 42 (1), 1–8. 10.29261/pakvetj/2022.002. [DOI] [Google Scholar]
  88. Aziz S.; Abdullah S.; Anwar H.; Latif F.; Mustfa W. Effect of engineered nickel oxide nanoparticles on antioxidant enzymes in fresh water fish, Labeo rohita. Pak. Vet. J. 2021, 41 (3), 424–428. 10.29261/pakvetj/2021.044. [DOI] [Google Scholar]
  89. Khan I.; Zaneb H.; Masood S.; Ashraf S.; Rehman H. F.; Rehman H. U.; Ahmad S.; Taj R.; Rahman S. U. Supplemental selenium nanoparticles-loaded to chitosan improves meat quality, pectoral muscle histology, tibia bone morphometry and tissue mineral retention in broilers. Pak. Vet. J. 2022, 42 (2), 236–240. 10.29261/pakvetj/2022.007. [DOI] [Google Scholar]

Articles from ACS Omega are provided here courtesy of American Chemical Society

RESOURCES