Ficus religiosa fruits-mediated synthesis of CeO2 nanoparticles and CeO₂/CuO nanocomposites: Structural insights and antimicrobial efficacy

Nagshabandi, M. K., Selim , S., Alruhaili, M. H., Gattan, H. S., Abdelghany, T. M., and Amin, M. A.-A. (2026). "Ficus religiosa fruits-mediated synthesis of CeO2 nanoparticles and CeO₂/CuO nanocomposites: Structural insights and antimicrobial efficacy," BioResources 21(1), 1224–1237.

Abstract

A novel, simple, and inexpensive technique, chemical coprecipitation, was employed to produce CeO₂ nanoparticles and CeO₂/CuO nanocomposite. It entailed reacting dehydrated metal nitrate salts with an aqueous extract of Ficus religiosa. The CeO₂ and CeO₂/CuO solids were identified by X-ray diffraction (XRD), FTIR, and transmission electron microscopy (TEM). The diffraction peaks of the CeO₂ and CeO₂/CuO revealed cubic and monoclinic structures, respectively, with average crystallite sizes of 20.5 and 26.8 nm, based on the XRD data. TEM examinations show that the mean sizes of CeO₂ and CeO₂/CuO particles were (39.8 and 66.5 nm, respectively). These results imply negligible agglomeration. This study evaluated the antimicrobial efficacy of CeO₂/CuO nanocomposite and CeO₂/CuO NPs against bacterial and fungal pathogens. The nanocomposite exhibited superior activity, producing larger inhibition zones (Bacillus subtilis: 26 mm; Candida albicans: 28 mm) compared to CeO₂ NPs and the standard drugs ciprofloxacin (as antibiotic) and nystatin (as antifungal). MIC and MBC/MFC assays confirmed stronger potency, particularly against Gram-positive bacteria and C. albicans. Time–kill kinetics revealed complete eradication of B. subtilis and K. pneumoniae within 180 min, while partial survival occurred in S. aureus and S. typhi. Both materials were inactive against Aspergillus niger, indicating selective but potent antimicrobial effects.

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Ficus religiosa Fruits-mediated Synthesis of CeO₂Nanoparticles and CeO₂/CuO Nanocomposites: Structural Insights and Antimicrobial Efficacy

Mohammed K. Nagshabandi,^a Samy Selim ,^b,*Mohammed H. Alruhaili,^c,e

Hattan S. Gattan,^d,e , Tarek M. Abdelghany ,^f and Mohamed A. Amin ,^f,*

DOI: 10.15376/biores.21.1.1224-1237

Keywords: Green synthesis; Pathogen control; CeO₂/CuO; Nanocomposites

Contact information a: Department of Basic Medical Sciences, College of Medicine, University of Jeddah, Jeddah, Saudi Arabia; b: Department of Clinical Laboratory Sciences, College of Applied Medical Sciences, Jouf University, Sakaka, Saudi Arabia; c: Department of Clinical Microbiology and Immunology, Faculty of Medicine, King Abdulaziz University, 21589, Jeddah, Saudi Arabia; d: Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia; e: Special Infectious Agents Unit, King Fahad Medical Research center, King Abdulaziz University, Jeddah, Saudi Arabia; f: Botany and Microbiology Department, Faculty of Science (Boys), Al-Azhar University, Cairo 11884, Egypt;

* Corresponding authors: sabdulsalam@ju.edu.sa; mamin7780@azhar.edu.eg

INTRODUCTION

New methods regarding multidrug-resistant bacteria and cancer cells and increasing the effectiveness of treatment can be provided by nanotechnology (Jelonek et al. 2018). Recent studies have revealed the active function of CeO nanoparticles (NPs) as an anticancer agent (Lu, et al 2022; Abbasi, et al 2022; Al-Attar et al. 2025). CeO₂ nanoparticles (NPs) are suitable and more and more prevalent in biological utilizations due to their intrinsic properties, which include reverse electrical state since Ce(III) shifts to Ce (IV) and oxidation-reduction activity triggered by interface vacancies in oxygen. This enables them to scavenge reactive oxygen species (ROS) (Sadidi et al. 2020). General particle size reduction to nanoscale levels in nanomaterials can have major effect on activities (Abdelghany 2013; Abdelghany et al. 2018; Al-Rajhi et al. 2022a; Amin et al. 2024, 2025; Soliman et al. 2024; Selim et al. 2025a, 2025b).

With the increasing use of synthesis techniques that control final form and size, nanoparticles now offer tremendous potential, especially for medical applications (Amiri et al. 2021; Al-Rajhi et al. 2022b; Alghonaim et al. 2024; Alghonaim et al. 2025). CeO₂ NPs are employed in a extensive range of biomedical scientific fields, involving catalytic processes, gas detection, and in optical devices (Nadeem et al. 2020). Aseyd Nezhad et al. (2020) reported that CeO₂-NP were created by utilizing leaf extract from Origanum majorana L. The biocreated CeO₂-NP verified antioxidant efficacy via scavenging free radicals from DPPH and ABTS. Therefore, the greater effects of CeO₂-NP on cancer of breast cell lines as opposed to non-cancer cells suggested that this NP might be used as an anti-cancer drug (Aseyd Nezhad et al. 2020). CeO₂ nano-decorated with copper (Cu/CeO₂), at 100 mg/L dose, was found to have a 100% free radical scavenging action, with the same level of activity as the reference substances ascorbic acid and Trolox at 50 mg/L (Şener et al. 2024). The pure cubic crystalline form with a face fluorite structure of CeO₂ NPs, which were made from Cassia glauca flower aqueous extract and had a mean diameter of 3.20 nm, showed poor to moderate efficiency against several types of bacteria in another investigation (Butt et al. 2022). When compared to Gram-positive bacteria, the naturally produced CeO₂NPs show significant antibacterial action as mentioned by Sarita Rai et al. (2024) contrary to Pseudomonas aeruginosa and Escherichia coli. Furthermore, the goal of the deliberate dual doping of copper and cerium is to enhance CuO NPs’ functional potential and biocompatibility; this idea has not been thoroughly reported in the literature. This duple-functionalization style suggests a capable new path toward the development of multifunctional nanomaterials with improved beneficial efficacy. Therefore, this study’s goal was to investigate how Ficus religiosa extract produced CeO₂ and CeO₂/CuO NPs for the first time. This is study is novel in that the generated NPs were assessed for their antibacterial qualities to fight resistant microorganisms.

EXPERIMENTAL

Material

Sigma Aldrich supplied 99.5% pure cerium nitrate (Ce (NO₃)₂⋅6H₂O) and copper nitrate (Cu(NO₃)₂⋅3H₂O), among other common chemicals.

Methods

Biogenic creation of cerium oxide nanoparticles

Cerium oxide NPs were synthesized using a modified version of the published methodology (Naz et al. 2019) using Ficus religiosa fruit extract. A light-red solution was produced by boiling ten g of the fruits (air dried) per 500 mL of distilled water for 10 min. A clear extract was then obtained by cooling and filtering the mixture. Then 100 mL of fruit extract at pH 9 was added to 2.5 g of cerium nitrate salt. For 3 h, the reaction was agitated at 1000 rpm and 75±5°C. After centrifuging at 8000 g for 10 min, the NPs were recovered and given three washes with distilled water. At 400 °C, the NPs were calcined for two hours.

Biogenic creation of cerium oxide/copper oxide nanoparticles

Copper nitrate (0.3M) with (0.7M) cerium nitrate were mixed independently in 50 mL of fruit extract, beside urea (100 mL) was gradually mixed with the binary solution while being stirred for an hour. The solution was treated with sodium hydroxide drop by drop until the pH reached to10 at 60 ℃. After the suspension was separated by centrifugation and rinsed with distilled water and ethanol, it was dried in an oven set at 100 °C for six hours. At 600 °C, the powder was calcined for 2 h. The dual nanocomposite (dark brown precipitate) was produced as a result (Salih et al. 2024).

Description of CeO₂ and CuO Nanocomposites

TEM (TEM, model JEOLJEM-2100, manufactured in Japan) was used to study size and morphology. X-ray diffraction was employed to determine the crystallinity structure (Philips PW17320). The Scherrer’s equation, D = Kλ/βcos θ, was employed to calculate the crystalline dimensions of NPs. D is the crystallite size, λ is the CuKα wavelength (1.5 Aº), θ is the diffraction angle, and β is the full width at half maximum (FWHM) of the diffraction peaks (in radians). FTIR spectroscopy of NPs was achieved via Nicolet TM380 to determine the functional groups of biomolecules enclosed on their surface.

The stability and hydrodynamic diameter of NPs in an aqueous medium were examined via the DLS technique. Zeta-potential was measured at 20±1°C using a semiconductor laser (40 mW, λ = 658 nm) using the Litesizer 500 photon linked to spectroscopy apparatus (Anton Paar GmbH, Austria).

Antimicrobial Activity (Well Diffusion) and MIC, MBC, and MFC Assays

The antibacterial potential of the created NPs was assessed via agar well diffusion approach, along with a standard antimicrobial agent ciprofloxacin (10 µg/mL, as antibiotic) and nystatin (100 µg/mL as antifungal) for comparison (Selim et al. 2025a). Mueller-Hinton agar (MHA) was used to cultivate fresh bacterial cultures of Staphylococcus aureus (ATCC 6538), Bacillus subtilis (ATCC 6633), Salmonella typhi (ATCC 6539), and Klebsiella pneumoniae (ATCC 13883) overnight at 37 °C, while other medium namely Sabouraud dextrose agar (SDA) was employed to propagate Candida albicans (ATCC 10221) and Aspergillus niger (ATCC 16888) at 28 to 30 °C). To create the microbial inoculum, freshly created colonies in sterile saline were suspended, and the turbidity was adapted to 0.5 McFarland standard (1 x 10² CFU/mL for bacteria). For fungi, suspensions of spores or yeast were made and adjusted to 10^-10 CFU/mL.

To create a uniform lawn of growth, 100 µL of the microbial slurry was evenly injected onto each sterile agar plate using a sterile cotton cloth. A sterile cork borer was functioned to aseptically create wells with a width of 8 mm after the surface had been allowed to dry for a few minutes. Each test sample (CeO₂/CuO nanocomposite and CeO₂ NPs) was added to the corresponding well in a constant volume (50 µL). Sterile DMSO was utilized as a negative control.

Before incubation, the plates were allowed to properly diffuse for 30 to 60 min at room temperature. Fungal plates were incubated at 28 to 30 °C for 48 to 72 h, while bacterial plates were kept at 37 °C for 24 h. A digital caliper was used to measure the inhibition zone diameters in millimeters after incubation. Every experiment was carried out in triplicate, and the results were reported as mean ± standard deviation. To ascertain relative inhibitory strength, the CeO₂/CuO nanocomposite’s antibacterial efficacy was compared to that of CeO₂ NPs and conventional medications (Al Abboud et al. 2024). The broth microdilution technique was employed to calculate the minimum inhibitory concentration (MIC) values.

In sterile nutritional broth, serial two-fold dilutions ranging from 1000 to 7.8 µg/mL of each nanoparticles suspension were made. 100 µL of the standardized microbiological solution was mixed to each dilution, and it was then incubated at the proper temperature (37 °C for 24 h for bacteria, 30 °C for 48 to 72 h for fungus). The MIC was defined as the lowest concentration exhibiting no discernible turbidity. 100 µL solutions from tubes with no discernible growth were plated on fresh agar and cultured under the same conditions once again in order to calculate the MBC/MFC. The MBC or MFC was the lowest concentration that produced no colony growth on agar plates.

Killing Time (Time–Kill Kinetics) Assay

Using time-kill kinetics, the activity of CeO₂/CuO nanocomposite and CeO₂ NPs was evaluated. In short, overnight cultures of S. aureus, K. pneumoniae, S. typhi, and B. subtilis were adjusted to around 1 × 10² CFU/mL in sterile nutritional broth. The investigated substances were administered to aliquots at dosages that matched their corresponding minimum inhibitory concentrations. Samples were taken out of the bacterial suspensions at predefined intervals (0, 30, 60, 120, 150, and 180 minutes) while they were being gently shaken at 37 °C.

A serial dilution of 100 μL of the treated culture in sterile saline was applied to nutrient agar plates at each time point. Next a 24-h incubation time at 37 °C, the number of colonies that survived was measured in CFU/mL (Selim et al. 2024). A decrease in CFU with time relative to the original inoculum was used to describe the Time-Kill Kinetics effect.

Analytical Statistics

Minitab 18 was employed for statistical subtractions at 0.05, post hoc Tukey’s assessment were utilized to study quantifiable data.

RESULTS AND DISCUSSION

The fruit extract from Ficus religiosa produced brown CeO₂ NPs and dark green of CeO₂/CuO nanocomposite. Various researchers have also documented similar color changes in CeO₂NPs manufactured using different techniques (Butt et al. 2022). Another crucial physical characteristic for biological applications is the shape of the nanoparticles. The shapes of the green synthesized CeO₂ and CeO₂/CuO NPs are shown in Figs. 1(a,d). Agglomeration of these NPs is apparent. Particle size decreased with increase in the likelihood of agglomeration. Because nanoparticles tend to minimize the exposed surface area to lower surface energy, agglomeration is a common behavior that occurs; hence, smaller particle sizes result in stronger agglomeration (Valsaraj and Divyarthana 2019). CeO₂ and CeO₂/CuO NPs were revealed to be spherical and semispherical shapes, in the TEM images (Figs. 1a,d). The TEM images based on imagej program appeared that CeO₂ NPs and CeO_2/CuO nanocomposite have average size of (39.84 and 66.49 nm). Additionally, the TEM picture reveals a thin film encircling the generated NPs, which could be a plant extract acting as a capping or protecting agent. These substances are believed to aid in protecting the produced nanoparticles. The average size of the aforementioned particle, as determined by DLS, was 42.1 nm for CeO₂ and 70.5 nm for CeO/CuO (Figs. 1c, 1f). The produced Se/Zn and Se/Zn/GB NPs showed a crystal-like appearance in the SAED pattern (Figs. 1b, 1e).

Fig. 1. (a, d) HR-TEM images, (b, e) SAED pattern, and (c, f) DLS analysis of CeO₂ and CeO₂/CuO NPs, respectively

Zeta Potential, XRD, and FTIR Analysis of NPs

Zeta potential data were used to determine each sample’s isoelectric point (IEP). The IEP values for synthesized CeO₂ and CeO₂/CuO NPs both appeared at -31.5 mV (Figs. 2a, 2b). XRD was used to examine the structural properties of CeO₂ and CeO₂/CuO NPs (Figs. 2c, 2d, respectively). CeO₂ NPs were found to have diffraction peaks at 2θ = 29.4 (111) 31.9 (200), 47.8 (220), 55.6 (311), 59.8 (222) and 68.7 (400). CuO NPs’ crystalline phases, on the other hand, exhibited diffraction peaks at 2θ = 35.9 (002), 38.8 (111), 47.3 (200), 57.71(021), and 68.5 (220). These findings provide more evidence of the material’s cubic and monoclinic structures of CeO₂andCuO, respectively. The indexed crystalline planes agreed well with the standard values of JCPDS card Nos. (34–0394) and (48–1548) of CeO₂ and CeO NPs, respectively (Salih et al. 2024).

Scherrer’s equation was used to calculate the crystallite size based on X-ray data. According to the Scherer equation, the crystallite sizes of CeO₂ and CeO₂/CuO NPs were 20.5 and 26.8 nm, respectively. The following were calculated: d-spacing (dhkl=λ/(2sin θ), micro-strain (ε=β/4tan θ), and dislocation density (δ=1/D^2) (Tables 1 and 2).

Table 1. XRD Parameters for CeO₂ NPs

Table 2. XRD Parameters for CeO₂/CuO NPs

The FTIR spectra of the CeO₂ NPs and CeO₂/CuO NPs were also examined in order to pinpoint the precise functional groups that caused the reduction of the produced NPs. In the FTIR, the CeO₂/CuO NPs showed the most notable peaks at 3450, 2361, 1551, 1412, 1020, 930, 663, and 510 cm^-1, while the CeO₂ NPs showed the most prominent peaks at 3426, 2434, 2090, 1785, 1582, 1380, 1059, and 828 cm^-1. The large peaks at (3426, 3450 cm^-1) in Figs. (2e, 2f) were caused by the O-H stretching vibration caused by the alcoholic group. The absorbance peak at 1582 cm^-1 was caused by the scissor bending mode of the connected water (Kumar et al. 2010). At 1020 cm^-1, the stretching vibration of C-O was observed (Farahmandjou et al. 2016). The absorbance peaks at 930, 828, and 510 cm^-1 were caused by the metal-oxygen bonds, or Ce-O and Cu-O bonds, according to Kumar et al. (2010) and Pujar et al. (2018).

The appearance of peaks for the metal-oxygen link indicated the creation of copper oxide and cerium oxide nanoparticles. The FTIR data indicated the presence of biomolecules in the plant extract that were responsible for the synthesis and production of the CeO₂ NPs and CeO₂/CuO NPs by showing the adsorption of different functional groups on the surface of the NPs (Arunachalam et al. 2017; Pisal et al. 2019).

Fig. 2. Zeta potential (a,b), XRD (c,d), and FTIR (e,f) analysis of CeO₂ NPs and CeO₂/CuO nanocomposite, respectively

Anti-microbial Activity of CeO₂/CuO Nanocomposite NPs and CeO₂NPs

A panel of bacteria was employed to evaluate the antimicrobial activity of CeO₂/CuO nanocomposite in comparison to CeO₂ NPs and conventional antibiotic/antifungal drugs (Table 3). In comparison to CeO₂ NPs (24 ± 1.0 mm) and the control antibiotic (22 ± 0.1 mm), the CeO₂/CuO nanocomposite demonstrated the best inhibitory activity versus B. subtilis, generating an inhibition zone of 26 ± 0.4 mm. The MBC values of both nanomaterials were 62.5 µg/mL, and they both showed the identical MIC value of 31.2 µg/mL. The CeO₂ NPs demonstrated a marginally greater inhibitory zone (18 ± 0.5 mm) against S. aureus than the nanocomposite (16 ± 1 mm), which was similar to the control antibiotic (18 ± 0.3 mm). Despite both nanomaterials having the same MIC 62.5 µg/mL, the MBC of the nanocomposite was greater (125 µg/mL) compared to that of CeO₂ nanoparticles (62.5 µg/mL), indicating a diminished bactericidal effectiveness in this instance. For K. pneumoniae, both nanomaterials displayed nearly equivalent inhibition zones (19 ± 0.5 and 19 ± 0.8 mm, respectively), which were also similar to that of the antibiotic (18 ± 0.2 mm). The MIC and MBC values were consistent for both nanomaterials at 31.2 µg/mL. In a similar manner, S. typhi was inhibited to a comparable degree by the nanocomposite (16 ± 0.1 mm), CeO₂ NPs (15 ± 0.9 mm), and the antibiotic (16 ± 0.1 mm), with both nanomaterials demonstrating identical MIC (31.25 µg/mL) and MBC (62.5 µg/mL). A significant antifungal effect was noted against C. albicans, with the CeO₂/CuO nanocomposite demonstrating the largest inhibition zone of 28 ± 0.8 mm, surpassing both CeO₂ NPs at 24 ± 1.0 mm and the control antifungal at 21 ± 0.3 mm. Both nanomaterials exhibited MIC of 15.6 µg/mL and a MFC of 31.2 µg/mL, reflecting robust fungistatic and fungicidal properties. Conversely, no inhibitory effect was detected for either nanomaterial against A. niger, while the control antifungal showed a clear inhibition zone of 38 ± 0.8 mm. In general, these results suggest that the CeO₂/CuO nanocomposite has superior antimicrobial efficacy compared to CeO₂ NPs alone, especially against B. subtilis and C. albicans, whereas both materials were ineffective against A. niger. This is likely due to the thicker, multi-layered hyphal cell walls and the filamentous growth pattern, which limit nanoparticle penetration and reduce local nanoparticle concentration per active site. Additionally, slower metabolism in filamentous fungi may reduce susceptibility to oxidative stress induced by the nanoparticles.

Table 4 presents the killing kinetics of B. subtilis, S. aureus, K. pneumoniae, and S. typhi when subjected to treatment with CeO₂/CuO nanocomposite NPs in comparison to CeO₂ NPs alone. Bacterial counts, represented as colony-forming units (CFU), were tracked at various exposure intervals (0 to 180 min). For the CeO₂/CuO nanocomposite, all four bacterial species exhibited a gradual reduction in CFU as exposure time increased. At the starting point (0 min), bacterial counts ranged from 22 × 10⁵ to 34 × 10⁵ CFU. Following 30 min of treatment, CFU values significantly decreased, with B. subtilis dropping to 1.1 × 10⁵ CFU, K. pneumoniae to 4.5 × 10⁴ CFU, S. aureus to 2.7 × 10⁵ CFU, and S. typhi to 2.3 × 10⁵ CFU. By the 120-min mark, CFU counts had significantly fallen, reaching 6.4 × 10² for B. subtilis, 4.4 × 10² for K. pneumoniae, 1.2 × 10³ for S. aureus, and 3.7 × 10² for S. typhi. Complete bacterial elimination was noted at 180 minutes for B. subtilis and K. pneumoniae, while only a few survivors remained in S. aureus (14 CFU) and S. typhi (24 CFU). When treated solely with CeO₂ NPs, a comparable yet slightly slower trend in bacterial reduction was noted. After 30 min, reductions were observed, although they were less significant than those seen with the nanocomposite, with B. subtilis at 8.7 × 10⁴ CFU, K. pneumoniae at 1.3 × 10⁵ CFU, S. aureus at 1.1 × 10⁵ CFU, and S. typhi at 1.7 × 10⁵ CFU. At the 120-min mark, the counts for B. subtilis and S. aureus decreased to 1.7 × 10² and 1.3 × 10² CFU, respectively, while K. pneumoniae and S. typhi remained elevated at 3.6 × 10² and 1.9 × 10³ CFU. By 180 min, B. subtilis, K. pneumoniae, and S. aureus were entirely eradicated, whereas a small quantity of S. typhi cells (37 CFU) persisted.

Table 3. Anti-microbial Activity of CeO₂/CuO Nanocomposite NPs and CeO₂NPs with Standard Antibiotic/Antifungal

Fig. 3. Antimicrobial activity of CeO₂/CuO nanocomposite and CeO₂ NPs against (1) Staphylococcus aureus, (2) Bacillus subtilis, (3) Klebsiella pneumoniae, (4) Salmonella typhi, (5) Candida albicans, and (6) Aspergillus niger. (a) CeO₂/CuO nanocomposite (b) CeO₂ NPs, (c) standard antibiotic/antifungal, and (d) control (DMSO). Clear inhibition zones indicate the sensitivity of each microorganism to the tested nanoparticles.

Overall, these findings suggest that both the CeO₂/CuO nanocomposite and CeO₂ NPs exhibit significant time-dependent bactericidal properties, with the nanocomposite achieving a quicker and more effective reduction, especially against B. subtilis and K. pneumoniae. Previous studies have demonstrated that Cu-doped CeO₂ NPs possess notable antimicrobial activity, with MIC values varying according to the tested strain: 16 mg/L against Enterococcus hirae and E. faecalis, 32 mg/L against S. aureus, 64 mg/L against Escherichia coli, 128 mg/L against Pseudomonas aeruginosa and Legionella pneumophila subsp. pneumophila, and 256 mg/L against Candida tropicalis and C. albicans (Şener et al. 2017). Although the exact antibacterial mechanism remains to be fully clarified, it has been suggested that the negatively charged bacterial cell walls may interact electrostatically with the positively charged Cu@nano-CeO₂, thereby facilitating their attachment and subsequent entry into the cells. This interaction may lead to changes in membrane fluidity and reduced cell viability, as observed in E. coli following 2 h of exposure (Şener et al. 2017). Nanoparticles–cell interactions are thought to involve electrostatic forces, van der Waals interactions, hydrophobic effects, and receptor–ligand binding, all of which can compromise the integrity of the bacterial membrane. Furthermore, Cu@nano-CeO₂ has been reported to strongly associate with membrane lipids, enabling penetration into the bilayer and promoting oxidation of phospholipids by Ce⁴⁺ ions, ultimately resulting in membrane instability and decreased fluidity (Zhuo et al. 2021). In agreement with these earlier findings, these results confirm that the CeO₂/CuO nanocomposite exhibits a potent inhibitory effect against pathogenic bacteria, supporting its potential as a broad-spectrum antimicrobial agent.

Table 4. Effect of Different Killing Kinetic Times of B. subtilis, S. aureus, K. pneumonia, and S. typhi, Treated by CeO₂/CuO Nanocomposite and CeO₂NPs

CONCLUSIONS

In this study CeO₂ NPs and CeO₂/CuO nanocomposite particles were prepared from the medicinally significant plant Ficus religiosa and its potential as an antibacterial agent was investigated.
XRD, FTIR, SAED, zeta potential, DLS, and TEM analyses were used to characterize the prepared nanoparticles. Based on the XRD data, the CeO₂ and CeO₂/CuO NPs’ diffraction peaks showed cubic and monoclinic structures, respectively, with average crystallite sizes of 20.5 and 26.8 nm, respectively. The mean sizes of the CeO₂ and CeO₂/CuO NPs (39.8 and 66.5 nm, respectively) are consistent with very little agglomeration, according to TEM analyses.
Ce-O, Cu-O bonds, and other bonds were identified using the CeO₂ and CeO₂/CuO NPs’ FT-IR spectra.
Wider inhibitory zones, low MIC/MBC/MFC numbers, and quick bacterial death after 180 minutes demonstrated that the CeO₂/CuO nanocomposite had more potent and extensive antibacterial activity than pure CeO₂ NPs. Its potency as an antibacterial and antifungal agent was demonstrated by its strong action against Bacillus subtilis, Staphylococcus aureus, Klebsiella pneumoniae, Salmonella typhi, and Candida albicans. But the absence of action against Aspergillus niger suggests a process of selection. According to these results, CeO₂/CuO nanocomposites may be a good option for creating novel antimicrobial formulations to fight microorganisms with resistance.

Funding

This work was funded by the Deanship of Graduate Studies and Scientific Research at Jouf University under grant No. (DGSSR-2025-FC-01007).

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Article submitted: October 4, 2025; Peer review completed: December 12, 2025; Revised version received and accepted: December 15, 2025; Published: December 21, 2025.

DOI: 10.15376/biores.21.1.1224-1237