Introduction

Microbial infections are caused by microorganisms such as bacteria, viruses, fungi, and parasites, and can lead to a wide range of diseases and health complications1,2. These infections impose a substantial strain on global health systems and can lead to elevated rates of illness and death3,4. Effective treatment of microbial infections relies heavily on the use of antimicrobial drugs, which target and eliminate the causative microorganism5,6. Nevertheless, the rise and dissemination of antimicrobial resistance (AMR) have evolved into a significant worldwide health emergency7. Antimicrobial resistance (AMR) is the capacity of microorganisms to persist and reproduce when exposed to antimicrobial medications that were initially successful against them8. This condition makes previously successful treatments ineffective, resulting in longer periods of sickness, higher healthcare expenses, and increased mortality rates8. Current antimicrobial therapies face several drawbacks, including the emergence of antibiotic resistance9. Bacteria are rapidly evolving, developing resistance to existing antibiotics, making infections increasingly difficult to treat. This necessitates the development of new antimicrobial agents with novel mechanisms of action. Additionally, many antibiotics have undesirable side effects, impacting the gut microbiome and potentially leading to allergic reactions. The narrow spectrum of activity of many antibiotics also limits their effectiveness against a wide range of pathogens10,11.

Cancer cells often acquire resistance to medications intended to eradicate them, posing a major issue in the area of oncology known as anticancer resistance12. Resistance can arise through different processes, including as genetic mutations, changes in drug targets, activation of alternative signaling pathways, and improved DNA repair mechanisms13. It results in the failure of treatment, the advancement of the disease, and a restricted range of treatment choices for individuals with cancer14. Cancer therapies, while showing progress, still face significant limitations. Current treatments, such as chemotherapy and radiation, often have severe side effects, compromising the patient’s overall health and quality of life11. These therapies can also target healthy cells, leading to complications and further weakening the immune system. Moreover, many cancers develop resistance to existing treatments, necessitating the development of new and more targeted therapies15. The high cost of many cancer treatments also poses a significant barrier to access for many patients11. Gaining insight into the mechanisms that cause resistance to anticancer treatments is essential for enhancing the effectiveness of cancer therapies16. Scientists are currently studying the molecular and cellular mechanisms that cause resistance, aiming to discover techniques to overcome it17. This encompasses the advancement of combination medicines, targeted therapies, and immunotherapies that have the ability to bypass or reverse resistance mechanisms18.

In the battle against microbial infections and tumor therapy, the use of nano-biotechnology in pathogen resistance and cancer pandemic reduction has shown notable and durable results. This is due to the fact that nanotechnology enables improved attraction to fungus, and bacterial cells, through the generation of reactive oxygen species (ROS) which stimulates their inhibition19,20,21. Entire biological components have been included in the scope of biological methods to nanoparticles and nano-crystal production22,23. The use of macromolecules that are plants, bacteria, cyanobacteria, and fungi or other agricultural and industrial wastes as agreen materials in the biological synthesis of metal NPs has garnered significant interest recently due to its environmental friendliness and safety24,25,26,27,28,29,30,31,32,33. Natural polymeric cap agents, such as chitosan and gum Arabic, are used to regulate the inorganic polymer NPs’ particle size and improve their stability34,35. Gum Arabic is different from other macromolecules in biology in that it has a variety of attractive features that make it a preferred option for the production of bimetallic nano-materials9. These crucial attributes are lower toxicity, biological compatibility, affordability, and availability36.

Nanocomposites, materials composed of two or more components at the nanoscale, have emerged as promising candidates for biomedical applications37. The unique properties of these materials, such as their high surface area, enhanced mechanical strength, and tunable surface chemistry, offer significant advantages over conventional materials38. For instance, nanocomposites can be designed to deliver drugs specifically to target cells, improving therapeutic efficacy and minimizing side effects. They can also be used as biocompatible coatings for implants, promoting tissue regeneration and reducing the risk of infection39,40.

Nanocomposites are revolutionizing antimicrobial and cytocompatibility applications due to their unique properties41. Their high surface area allows for increased contact with microbes, enhancing their antimicrobial efficacy. Additionally, the incorporation of antimicrobial agents within the nanocomposite structure can provide sustained release, prolonging their activity42,43. These materials can also be designed to be biocompatible, minimizing cytotoxicity and promoting cell adhesion and proliferation This makes them ideal for applications like wound dressings, implantable devices, and drug delivery systems, where both antimicrobial and cytocompatibility are crucial for successful outcomes44.

Bimetallic nanomaterials are receiving a lot of attention because of the distinctive chemical, physical, and physiological characteristics that result from the combination of several metal elements35,45,46,47,48,49,50,51,52,53,54. Bimetallic GA@Ag-CuO nanocomposite offer a unique combination of properties that make them promising for various biological applications. Their enhanced antimicrobial activity, stemming from the synergistic action of silver and copper ions, combats a broader spectrum of microorganisms, including antibiotic-resistant strains55,56. These nanoparticles can also be functionalized for targeted drug delivery, enhancing therapeutic efficacy while minimizing side effects57, and in the treatment of some infectious diseases like foot and mouth disease (FMD)54. Their photothermal properties hold potential for cancer treatment, while their anti-inflammatory and antibacterial effects promote wound healing58.

Herein, the main aim of this study was to synthesize a novel nanocomposite based on Gum Arabic, silver, and copper oxide nanoparticles (GA@Ag-CuO nanocomposite), characterize it, and assess its biosafety, antimicrobial, and anticancer activities.

Materials and methods

Chemicals and reagents

To produce the bimetallic nanoparticles for the investigation, analytical-grade chemicals were acquired from Sigma Aldrich in the UK. These included Gum Arabic; purity 99% (Meron Company, India), silver nitrate; purity 99.9% (Ag NO3), and copper acetate; purity 97% (Cu (CH₃COO)₂. Furthermore, the microbiological examination medium used in the antimicrobial experiment, and other materials in anticancer test were supplied by Oxide (UK).

Green synthesis of GA@Ag-CuO nanocomposite

The exact concentration of the utilized salts (silver nitrate, and copper acetate) was used to synthesize GA@Ag-CuO nanocomposite. Specifically, 10 mL of Ag NO3 (2.0 mM) and 10 mL of Cu(CH₃COO)₂ (2.0 mM) were combined together in a 250 mL Erlenmeyer conical flask at room temperature for half an hour (Scheme 1). After that, 80 mL of the 20% Gum Arabic had been added drop-wise which used as a reducing and stabilizing agent. After combining the two solutions, we measured the combination’s pH and found to be 7.1.

The reaction conditions were selected to consist of temperature-controlled incubating at 30 °C and a 24-hour reaction period under rotation (500 rpm) in a shaking incubator in order to obtain the most efficient synthesis of Ag-CuO NPs (Scheme 1)59.

The optical density (OD) of the produced bimetallic NPs was measured using UV-Vis. spectrophotometer to determine the possibility of the preparation. After that, the produced GA@Ag-CuO nanocomposite was washed with distilled water, centrifuge (5000 rpm) to collect the solid materials, then dried in oven at 80 oC for about 12 h for preparing the powder GA@Ag-CuO nanocomposite for the next characterization methods (Scheme 1).

Scheme 1
Scheme 1
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Illustrated scheme regarding step by step preparation of GA@Ag-CuO nanocomposite, created by BioRender.com.

Characterization of the synthesized GA@Ag-CuO nanocomposite

A JASCO V-560 UV-Vis. spectrophotometer was utilized to investigate the absorption and spectral characteristics of GA@Ag-CuO nanocomposite that were synthesized at particular wavelengths ranged from 190 to 900 nm. Another step experiment devoid of any metal ions was offered for Auto-zero reasons. First, each specimen’s optical characteristics were examined to ascertain the overall number of wavelengths required to estimate absorbance.

Conducing the DLS-PSS-NICOMP 380-ZLS particle-sized equipment at the St. Barbara, California, USA facility, dynamic light scattering measurements were used to determine the mean size distribution of the synthesized GA@Ag-CuO nanocomposite. Samples of tested GA@Ag-CuO nanocomposite (100 µL) were briefly contained in a small cuvette. Following two minutes of equilibrium at 25.0 ± 2 °C ambient temperature, the procedures were performed three times.

The synthesized GA@Ag-CuO nanocomposite’s size, form, and overall appearance were evaluated with a high-resolution transmission electron microscope (HR-TEM, JEM2100, Jeol, Japan). Additionally, the XRD-6000 lists, Shimadzu equipment, and SSI, Japan made it possible to examine the formed crystals, and crystallite sizes of the synthesized GA@Ag-CuO nanocomposite. The diffracted angle of 2θ was utilized to determine the X-ray power. A scanning electron microscope (SEM, ZEISS, EVO-MA10, Germany) was used to examine the formed Ag-CuO NPs surrounding GA in order to evaluate their surface form and arrangement. Finally, the surface charges of the produced GA@Ag-CuO nanocomposite were informally evaluated at the pH of preparation using a Zeta potential analyzer (they were performed in triplicate (n = 3)) from Malvern Device, UK60.

Antimicrobial activity

The antimicrobial activity of GA@Ag-CuO nanocomposite, silver nitrate, copper acetate against Staphylococcus epidermis ATCC 14,990, Staphylococcus aureus ATCC 25,922, Lactobacillus plantrum ATCC 8014, Salmonella typhimurium ATCC 14028 Candida albicans ATCC 90028, and C. neoformans ATCC 14116 was evaluated using the agar well diffusion technique61. GA@Ag-CuO nanocomposite, silver nitrate, and copper acetate were added to agar wells at a concentration of 1000 µg/mL. Additionally, a standard antibiotic (Ampicillin/sulbactam 20) as positive control was included. The mixture was then incubated at 37 °C for 24 h, allowing for observation and analysis. Alternatively, fungal strains were cultured on PDA plates and placed in an incubator at 30 °C for 3–5 days. The fungal suspension was prepared in a sterilized phosphate buffer solution (PBS) with a pH of 7.0. After counting in a cell counter chamber, the inoculums were adjusted to a concentration of 107 spores per milliliter. The distribution of one milliliter was done evenly across agar PDA Plates. Next, 100 µl of the tested GA@Ag-CuO nanocomposite, silver nitrate, copper acetate at a concentration of 1000 µg/mL, and the reference antifungal (Nystatin 100) as positive control were put. Following incubation at 30 °C for 72 h, the diameter of the inhibition zone was measured. In order to determine the minimum inhibitory concentration, a solution of GA@Ag-CuO nanocomposite was prepared in various concentrations, ranging from 1000 to 3.9 µg/mL. These concentrations were then tested individually against specific bacterial and fungal strains62,63,64.

Cytotoxicity

The cytotoxicity of GA@Ag-CuO nanocomposite and Taxol as positive control was determined using the MTT protocol65 with minor modifications. The normal Wi38 and cancerous MCF7 cell lines were collected from American type culture collection (ATCC). The optical density was measured at 560 nm. The cell quantity and the percentage of viable cell were totaled by the following formula:

$$\:{Viability}\:{\%}=\frac {Test\,OD}{Control\,OD}\times100$$
$$\:{Inhibition}\:{\%}=100{-}{Viability}$$

Results and discussion

Synthesis and characterization of GA@Ag-CuO nanocomposite

Gum Arabic’s ability to create Ag-CuO NPs as a capping and reducing agent was assessed. When the bimetallic Ag-CuO NPs were produced, the resulting solution’s initially pale-yellow tint turned to a deep brown hue. As a dependable spectroscopic sign of their presence, the deep brown color that resulted was related to the stimulation of the surface Plasmon resonance which happens in GA@Ag-CuO nanocomposite66,67.

The observed peak in the spectrum (Fig. 1) was formed by the observed OD at 0.755, and the UV-Vis. investigations revealed that the produced GA@Ag-CuO nanocomposite (diluted 5 times) were small and discernible at 360 nm. Conversely, Fig. 1 showed the UV-Vis. spectra of the initial precursors, silver nitrate and copper acetate, which had distinct wavelengths; silver nitrate at 283 nm68 and copper acetate at 203 nm69.

The ability to produce Ag-CuO NPs by biosynthesis was associated with the depth of the deep brown color70,71,72. Surface Plasmon resonance (SPR) is frequently impacted by the size, morphology, dielectric properties, and structure of every generated nanoparticles73,74.

The longest-term stability of the generated NPs due to GA’s capping capacity, which enhanced their properties for prospective long-term applications in the pharmaceutical, cosmetic, and plant protection industries, is the scientifically sound aspect of this study75,76,77,78.

According to the literature35, the FTIR results revealed peak absorption values at 3291 cm−1 (attributed to –OH), 2985 cm−1 (symmetric and asymmetric –CH vibration), 1642 cm−1 (attributed to –COOH), 1462 cm−1 (uronic acid symmetrically stretched by carboxylic groups), 1066 cm−1 (perhaps due to arabinogalactan), and 890.0 cm−1 (attributed to galactose 1–4 linkage and mannose 1–6 linkage). The same peaks in the metal NPs spectra indicate that GA was successful in capping. Moreover, the galactose/mannose peak became less prominent and the arabinogalactan peak lost its doublet. Additionally, a clear peak at 715.25 cm−1 was seen, which may be the outcome of metal NPs interacting and combining with hydroxyl groups to create metal–O79.

According to El-Batal, et al.,35 results, all of the peaks were in identical wavenumbers, suggesting that the synthesized NPs were similarly incorporated and/or conjugated through the primary functional groups of the stabilizer GA. The lack of noise and additional unidentified peaks indicated the high purity of the synthesized sample78.

Fig. 1
Fig. 1
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UV-Vis. spectrum of copper acetate, silver nitrate, and the synthesized GA@Ag-CuO nanocomposite (diluted 5 times).

The consequent GA@Ag-CuO nanocomposite’ hydrodynamic width, particle size dispersion, and polydispersity index (PDI) were measured using DLS analysis. The average size of the produced nanoparticles was ascertained by contrasting the acquired data to the HR-TEM investigation80.

The generated GA@Ag-CuO nanocomposite was shown to be semi-spherical and connected to supporting gum Arabic in Fig. 2a’s HR-TEM image. With an average width of 25.53 ± 1.4 nm, the particles’ sizes ranged from 9.5 nm to 49.5 nm (Fig. 2a). The generated Gum Arabic filtrate was full of active groups that were functional, and the polydisperse NPs were added with the intention of, among other things, stabilizing, reducing, and capping the filtrate81.

Ag and Cu may decrease concurrently as a result of the radical-multi-position of gum Arabic produced, as described and compared in the study given. The HR-TEM image output (Fig. 2a) demonstrated uniform line spacing, which resulted in a single grade system, and copper equally distributed throughout the zinc matrix, resulting in a unique alloy35.

Using the SEM approach, the surface characteristics and surface form of the generated synthetic nanoparticles were examined. The produced Gum Arabic included the matching bright spherical particles, and the ZnO-Ag NP surfaces seem clear when seen in combination with the Gum Arabic SEM data (Fig. 2b). It was found that the produced Gum Arabic, which looks as lighted NPs fused and capped with it, effectively separated the GA@Ag-CuO nanocomposite as spheroidal particles united with one another (Fig. 2b). In contrast to previous studies on the topic of morphological shape, the Ag-CuO NPs produced in this work had a precise spherical formation, a confined size, and an even distribution. Mohsin et al.82 used the citrate reduction process to create bimetallic silver-gold nanoparticles at different pH and temperature levels. Since the permitted morphological form and border size indicated that they keep the size range around 50 and 65 nm while seeming like spheroidal particles, pH and temperature play a crucial role in the synthetic process.

Our mixture of Ag-CuO NPs was found to be polydisperse NPs, differed in size, and mostly possessed spherical particles as their primary shape after comparing them to articles in the literature on medium particle size and form. Although the produced NPs were essentially spherical or orbicular in shape, the process of creating them from extract may have produced a variety of morphologies, which explains why the asymmetrical form was observed. A permanent form is polydisperse NPs since in our study we only utilized the most practical reducing and covering agent (Gum Arabic)83. The role of Gum Arabic as a stabilizing agent had been confirmed in the literature, since El-Batal et al.,35, utilized the Gum Arabic as a stabilizing agents when synthesized bimetallic Ag-Au NPs and according to their FTIR data they confirm the incorporation of the synthesized bimetallic Ag-Au NPs with the stabilizer Gum Arabic as in our related study.

Fig. 2
Fig. 2
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HR-TEM images (a), and SEM images of the synthesized GA@Ag-CuO nanocomposite (b).

As shown in Fig. 3a, the particle size distribution (PSD) for bimetallic Ag-CuO NPs, which were produced using gum Arabic, was determined to be 55.42 ± 2.3 nm using the DLS technique (they were performed in triplicate (n = 3).

Samples are considered monodisperse by the International Standards Organizations (ISOs) if the polydispersity index (PDI) findings are less than 0.05. On the other hand, particles with a variability distribution are supposed to be produced when PDI results exceed 0.784. The bimetallic Ag-CuO NPs had PDI values of 0.88, according to our findings. Based on the current values, the manufactured bimetallic nanoparticles demonstrated a reasonable range of polymorphism85. The results demonstrated that the HR-TEM imaging-derived particle estimations were smaller than the DLS analysis’s average and prevalent sizes. According to the following reference, the hydrodynamic radius within the generated bimetallic Ag-CuO NPs and the water that surrounds layers are the causes of the significant sizes of the developed bimetallic NPs86.

Because each measuring approach has its own set of principles and sensitivities, the technique used can have a substantial impact on the PSD data. Here are some important ways that this might occur such as sieve analysis87, laser diffraction88, DLS89, microscopy90, and sedimentation91. Every approach has advantages and disadvantages of its own, and the reported PSD values might be greatly impacted by the method used. Utilizing a variety of techniques is frequently advantageous in order to have a thorough comprehension of the particle size distribution distributions.

The Zeta potential of the resultant GA@Ag-CuO NPs was examined at a pH of 7.1 during the preparation, as shown in Fig. 3b. According to the current findings, during testing, the bimetallic Ag-CuO NPs contact’s Zeta potential maintains a negative value at the substance’s pH. Furthermore, the preparation’s Zeta potential at standard medium (pH 7.1) was − 27.5 ± 1.5 mV (they were performed in triplicate (n = 3)) as seen in Fig. 3b because of Gum Arabi’s negative electrical charge. Table 1, summarized the different values of PSD, PDI, and zeta potential of the synthesized GA@Ag-CuO nanocomposite.

Table 1 PSD, PDI, and Zeta potential values of the synthesized GA@Ag-CuO nanocomposite.
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Fig. 3
Fig. 3
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Particle size distribution, and surface charge of the synthesized GA@Ag-CuO nanocomposite where (a) DLS analysis, and (b) Zeta potential (they were performed in triplicate (n = 3)).

Figure 4 displays the XRD investigations for the produced NPs. This is the starting phase; the amorphous and crystal orientations in the NPs, respectively, show the resultant Ag NPs, CuO NPs, and Ag-CuO NPs. Figure 4 displayed the XRD diffraction peaks of Ag NPs. The peaks at 2Ɵ = 38.32o, 44.58o, 63.14o, and 78.25o matched Bragg’s reflections (111), (200), (220), and (311), and they were associated with the standard card JCPDS-ICDD number 04-078392,93, on the other hand, the XRD of the synthesized CuO NPs showed clear peaks at 2 Ɵ = 31.15o, 36.78o, 39.81o, 51.88o, 59.18o, 67.89o, and 70.21o. Bragg’s reflections (110), (002), (200), (202), (020), (022), and (220) were linked to these peaks, and they were accompanied by a special card with the JCPDS number 892,53194.

Furthermore, the XRD diffraction peaks of Ag NPs and the outcomes of the produced bimetallic Ag-CuO NPs are shown in Fig. 4. The typical card JCPDS number 361,451, which corresponds to these peaks, is associated with the Bragg’s reflections (111), (200), (220), and (311)95.

The orientations of Bragg’s reflections are (110), (002), (200), (202), (020), (022), and (220), as shown by the CuO NP diffraction peaks at 2Ɵ = 30.15o, 36.89o, 40.58o, 52.48o, 58.89o, 67.14o, and 71.78o. These peaks are supported by the JCPDS number 892,531 typical card94.

Based on the available XRD data, the generated Ag-CuO NPs were created and had a face-centered (fcc) crystal structure (Fig. 4). The generated bimetallic NPs were highly crystalline and connected to gum Arabic heterogeneity, which improved their mobility in the solution to boost application, according to the XRD data96.

The average crystallite size of the bimetallic Ag-CuO NPs was calculated using Williamson-Hall’s Eq. (1)97,98, and was found to be 20.25 nm.

$$\:{\beta}\:{\cos}\:{\theta}=\frac{k\lambda}{D}_{{W-H}}+4\:{\epsilon}\:{\sin}\:{\theta}$$
(1)
Fig. 4
Fig. 4
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XRD of the synthesized bimetallic Ag- CuO- NPs, CuO NPs, and Ag NPs.

Antimicrobial activity

Bimetallic nanoparticles have garnered considerable interest in antimicrobial research owing to their distinctive characteristics and heightened antibacterial efficacy in comparison to monometallic nanoparticles99. Bimetallic nanoparticles consist of two distinct metals, and their combined effects result in enhanced antibacterial effectiveness. The study involved the synthesis and evaluation of GA@Ag-CuO nanocomposite for their antibacterial efficacy against pathogenic bacterial and fungus species, as depicted in Fig. 5. The results demonstrated that the synthesized GA@Ag-CuO nanocomposite shown exceptional antibacterial activity against the tested strains of microorganisms. The synthesized GA@Ag-CuO nanocomposite showed antibacterial activity toward S. epidermis, S. aureus, L. plantrum, S. typhimurium where inhibition zones at concentration 1000 µg/ml were 29.0, 16.0, 25.0 and 18.66 mm respectively. The tested S. epidermis was the most sensitive among bacterial strains, while the tested S. aureus was the least sensitive to GA@Ag-CuO nanocomposite as shown Fig. 5A&B. Furthermore, MICs of GA@Ag-CuO nanocomposite toward all tested bacterial strains were determined as illustrated in Fig. 6. Results revealed that, MICs of GA@Ag-CuO nanocomposite were 15.62, 125, 31.25 and 125 µg/ml against S. epidermis, S. aureus, L. plantrum, S. typhimurium respectively. The antifungal activity of GA@Ag-CuO nanocomposite was assessed against C. albicans and C. neoformans, as depicted in Fig. 5A&B.

Fig. 5
Fig. 5
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Antimicrobial activity of GA@Ag-CuO nanocomposite, silver nitrate, copper acetate and SAM/NS against S. epidermis, S. aureus, L. plantrum, S. typhimurium, C. albicans and C. neoformans using agar well diffusion method (Agar well (A) & Inhibition zones (B)).

The study found that the synthesized GA@Ag-CuO nanocomposite had significant antifungal efficacy against both C. albicans and C. neoformans, resulting in inhibition zones measuring 20.33 mm and 29.4 mm, respectively. In addition, MICs of Ag-CuO nanoparticles against C. albicans and C. neoformans were 62.5 and 15.62 µg/ml, respectively.

Fig. 6
Fig. 6
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Minimum inhibitory concentrations of GA@Ag-CuO nanocomposite toward tested bacterial and fungal strains.

Prior research has established that bimetallic silver/copper nanoparticles possess antibacterial properties. Al-Haddad, Alzaabi98 employed Phoenix dactylifera leaves for the eco-friendly synthesis of Cu-Ag bimetallic nanoparticles. Their study revealed that these nanoparticles have antibacterial properties against B. subtilis and E. coli. In addition, the Ag-Cu nanoparticles produced by the process of biosynthesis using Aerva lanata extract had antibacterial properties against both S. aureus and Pseudomonas aeruginosa. These nanoparticles were found to block the release of extracellular polysaccharides in a manner that depended on the dosage administered55.

Furthermore, Bakina, Glazkova, Pervikov, Lozhkomoev, Rodkevich, Svarovskaya, Lerner, Naumova, Varnakova and Chjou100 reported that Ag–Cu bimetallic nanoparticles displayed antibacterial activity of the nanoparticles against E. coli and S. aureus MRSA. Additionally, Ashishie, Inah and Ayi101 verified that the Cu/Ag nanoparticles they created have antibacterial properties against S. aureus, resulting in a 21 mm inhibitory zone. Also, cotton fabrics based on Ag-Cu NPs were prepared and evaluated as antimicrobial agent, where results illustrated that these cotton fabrics have antimicrobial activity toward E. coli, Enterobacter aerogenes, Proteus mirabilis, K. pneumonia and C. albicans 102. Paszkiewicz, Gołąbiewska, Rajski, Kowal, Sajdak and Zaleska-Medynska103, reported that, Ag-Cu NPs showed promising antibacterial and antifungal activity toward E. coli, S. aureus and C. albicans.

Bimetallic Ag-CuO NPs have antibacterial action through multiple routes. The antibacterial activities of Ag-CuO NPs are attributed to the release of silver and copper ions when they come into contact with moisture or biological fluids (Scheme 2). Metal ions damage microbial cells through the mechanisms of destroying the cell membrane, interfering with DNA replication and transcription, and denaturing or affecting vital proteins (Scheme 2). In addition, Ag-CuO nanoparticles produce ROS that cause oxidative stress, resulting in cellular harm (Scheme 2)57,104. The combined actions of these many mechanisms contribute to the antibacterial properties of Ag-CuO NPs. Nevertheless, it is crucial to acknowledge that the precise methods can differ based on the characteristics of the nanoparticles and the microorganisms they are targeting.

Scheme 2
Scheme 2
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The following reactions are indicative of the anticipated interaction between the produced GA@Ag-CuO nanocomposite and the bacterial cell (using Gram-positive bacteria as an example): Bimetallic nanoparticles affect bacterial cells in four primary ways: It does four things to the bacterial cell: (1) it prevents ions from entering the cell; (2) it creates and multiplies reactive oxygen species (ROS), which cause oxidative stress and may be a sign that the cell wall is beginning to weaken; (3) it adheres to the cell’s exterior and results in membrane failure, endocytosis, the formation of endosomes, and altered transport potential; and (4) it enters the cell and interacts with organelles, such as DNA, to change their functions and cause bacterial cell lysis. In the cytoplasm and layer, where the presence of a proton motive force may cause the pH to drop below 3.0 and induce the discharge of Ag and Cu ions, GA@Ag-CuO nanocomposite may also function as a carrier to effectively release Ag and Cu ions. The scheme was designed by BioRender.com.

Cytotoxicity of GA@Ag-CuO nanocomposite toward Wi 38 normal cell line

An essential component of preclinical research, assessing the cytotoxicity of compounds on normal cell lines is the determination of a compound’s potential toxicity to healthy cells105. In this regard, determining the biosafety of compounds is regarded as the initial step toward their implementation in various disciplines. In the current study, the biosafety of GA@Ag-CuO nanocomposite was checked using Wi 38 normal cell line as shown in Fig. 7. Results revealed that, cell viability of Wi 38 cell line at conentrations 31.25, 62.5 and 125 µg/mL of GA@Ag-CuO nanocomposite were 99.3, 94.89 and 59.28% respectively. Also, IC50 of GA@Ag-CuO nanocomposite toward Wi 38 cell line was 154.2 µg/ml. Typically, if the IC50 is equal to or more than 90 µg/mL, the substance is categorised as non-cytotoxic106. Consequently, the synthesised GA@Ag-CuO nanocomposite are deemed to be safe for use. Therefore, we examined the safe concentrations and maximal non-toxic concentrations of this chemical to determine its anticancer activity.

Fig. 7
Fig. 7
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Cell viability of Wi 38 cell line at different concentrations of GA@Ag-CuO nanocomposite.

Anticancer activity of GA@Ag-CuO nanocomposite

The synthesis of anticancer compounds is critical because it facilitates the identification and advancement of novel pharmaceuticals, which may result in significant advances in the treatment of cancer107. By synthesizing and modifying compounds, researchers can establish the structure-activity relationship, optimize drug properties, and overcome drug resistance, providing alternative options for patients108.

In the current study, anticancer activity of GA@Ag-CuO nanocomposite was assessed toward MCF-7 and Hep-G2 cancerous cell lines. Results showed that, safe concentrations of GA@Ag-CuO nanocomposite exhibited promising anticancer activity toward both MCF-7 and Hep-G2 as shown in Fig. 8. Safe concentrations of GA@Ag-CuO nanocomposite (125 and 62.5 µg/mL) showed anticancer activity higher than 50% against both cancerous cell lines. Moreover, IC50 of GA@Ag-CuO nanocomposite toward MCF-7 and Hep-G2 was 26.11 and 59.5 µg/ml respectively. In compared to Taxol as positive control, IC50 of Taxol toward MCF-7 and Hep-G2 cell lines was 7.25 and 11.87 µg/ml.

Nanometals have received much attention due to their high efficacy as antimicrobial as well as anticancer agents28,109,110. Yang, Zhang, Velu, Liu and Vijayalakshmi111, used Leucas aspera aqueous leaf extract for biosynthesis Ag-Cu NPs, these bimetallic nanoparticles showed promising anticancer activity against alveolar cancer cell line. The Ag–Cu NPs which phyto-fabricated by Aerva lanata extract exhibit potent cytotoxic activity against cancerous HeLa cell lines, with an inhibitory concentration (IC50) of 17.63 µg/ml55.

In their study, Banik, Patra, Dutta, Mukherjee and Basu112 found that bimetallic Cu-Ag nanoparticles (NPs) exhibited a higher level of toxicity towards cancer cells compared to normal cells. The dose of the NPs, which ranged from 4 to 5 µg ml−1, is responsible for killing approximately 75% of the various human cancer cell lines, including HepG2 (for liver cancer), A549 (for lung cancer), and AGS (for stomach cancer). However, the dose of the NPs was only sufficient to kill approximately 22.5% of the normal cell lines, specifically WRL68 (for liver) and WI38 (for lung cancer). Ag-Cu nanoparticles, which are bimetallic, exhibit significant anticancer action through a variety of different routes.

These nanoparticles combine the anticancer characteristics of silver and copper, which are both known to be effective against cancer. Ag-Cu nanoparticles have the ability to result in oxidative stress by means of the production of ROS, which in turn can result in DNA damage, cellular death, and the prevention of cancer cell proliferation. Furthermore, Ag-Cu NPs can interfere with cellular signaling pathways, inhibit angiogenesis, and modulate the tumor microenvironment. The synergistic effects of silver and copper in these bimetallic nanoparticles make them promising candidates for anticancer therapeutics, offering potential benefits in cancer treatment and control113.

The diverse array of mechanisms by which bimetallic nanoparticles exert their anticancer effects underscores their potential as highly promising therapeutic candidates for cancer.

Fig. 8
Fig. 8
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Anticancer activity of GA@Ag-CuO nanocomposite toward two cancerous cell lines MCF-7 (Top) and Hep-G2 (Bottom).

Conclusion

In the current study, a novel GA@Ag-CuO nanocomposite was synthesized and thoroughly characterized. The biosafety assessment of this nanocomposite toward the Wi 38 normal cell line showed that it was safe, with an IC50 value of 154.2 µg/ml. The antimicrobial results confirmed that the synthesized GA@Ag-CuO nanocomposite exhibited promising antibacterial activity against S. epidermis, S. aureus, L. plantrum, and S. typhimurium, with MIC values ranging from 15.62 to 125 µg/ml. Additionally, the nanocomposite displayed antifungal activity against C. albicans and C. neoformans, with MIC values of 62.5 and 15.62 µg/ml, respectively. Furthermore, the GA@Ag-CuO nanocomposite demonstrated significant anticancer activity, with IC50 values of 26.11 and 59.5 µg/ml against MCF-7 and Hep-G2 cell lines, respectively. However, the study was limited in scope, focusing on a small set of microorganisms and cell lines, and lacked detailed mechanistic insights. Future research should delve into the mechanism of action, conduct in vivo studies, and optimize the synthesis process for enhanced efficacy. If successful, this research could lead to the development of novel therapeutic agents for various diseases, contributing to the fight against antibiotic resistance pathogenic microbes and cancer cells.