Effective Antibacterial Medical Mask Based on the Novel Biosynthesized Copper Nanoparticles (CuNPs)

TL;DR

This paper presents a new eco-friendly method to create copper nanoparticles for medical masks, which show strong antibacterial properties against common pathogens.

Contribution

The study introduces a green synthesis method using Smyrnium cordifolium extract to produce antibacterial copper nanoparticles for medical masks.

Findings

CuNPs synthesized with 14.7 mM CuSO4 and 14.7 mL of plant extract showed optimal antibacterial activity.

Masks coated with 1.5% CuNPs achieved over 85% antibacterial efficacy against Acinetobacter baumannii within 0.25 h.

The method produced CuNPs with a size range of 31 to 57 nm, confirmed through FE-SEM analysis.

Abstract

Developing effective antimicrobial treatments for face masks is an attractive aspect of medical applications. Copper nanoparticle (CuNP)–infused medical masks are preferred due to their superior antibacterial properties. However, producing CuNPs presents challenges in antimicrobial applications. This study introduces a green synthesis method using Smyrnium cordifolium extract, offering an eco‐friendly approach to CuNP production. A central composite design (CCD) was employed to optimize the biosynthesis of CuNPs, considering the effects of copper sulfate concentration, plant extract volume, pH, and temperature. The CuNPs were characterized using FE‐SEM, TEM, EDX, FTIR, zeta potential, and DLS techniques. The dip‐coating method was used to decorate CuNPs onto the melt‐blown layer of medical masks. The antibacterial efficacy of the coated masks against Acinetobacter baumannii and Staphylococcus aureus was evaluated using the colony count method. The green fabrication of CuNPs was carefully enhanced by employing 14.7 mM CuSO4 and 14.7 mL of Smyrnium cordifolium extract, adjusting the pH to 6.8, and maintaining a temperature of 54°C. FE‐SEM analysis revealed that the CuNPs had a nanostructure size ranging from 31 to 57 nm. Mask decoration with 1.5% CuNPs demonstrated the highest antibacterial activity. Antibacterial efficacy exceeded 85% against Acinetobacter baumannii within 0.25 h. Additionally, antibacterial activity was shown for Staphylococcus aureus with a potency of 85% after 2 h. These findings confirm the potential of biosynthesized CuNPs to enhance the antimicrobial properties of medical face masks, contributing to the development of sustainable protective equipment.

Figures

Schematic representation of the practical steps involved in the green synthesis of copper nanoparticles (CuNPs) and their decoration onto melt‐blown fabrics.

Color change observed during the green synthesis of CuNPs: (a) CuSO4 solution, (b) mixture of plant extract and CuSO4 solution, and (c) final CuNP solution, indicating the reduction of Cu2+ ions to Cu0 nanoparticles.

UV‐Vis absorption spectra of the Smyrnium cordifolium extract and the synthesized CuNPs, showing the characteristic surface plasmon resonance (SPR) peak of CuNPs.

FTIR spectra of Smyrnium cordifolium extract and CuNP slurry, revealing the functional groups responsible for the reduction and stabilization of nanoparticles.

FE‐SEM micrograph showing the surface morphology and approximate particle size distribution of the synthesized CuNPs.

EDX spectrum confirming the elemental composition and presence of copper in the synthesized nanoparticles.

TEM image showing the shape, size, and uniform distribution of the green‐synthesized CuNPs.

(a) DLS analysis and (b) zeta potential measurement of CuNPs, indicating average hydrodynamic diameter and surface charge stability.

FE‐SEM micrograph showing the uniform distribution of CuNPs on the fibrous surface of the melt‐blown fabric.

Antibacterial activity of decorated fabrics (1.5 wt%) against Acinetobacter baumannii. (a) Blank plate, (b) 0.25‐h exposure time, (c) 2‐h exposure time, (d) 4‐h exposure time, (e) 8‐h exposure time, and (f) 24‐h exposure time.

Antibacterial activity of decorated fabrics (1.5 wt%) against Staphylococcus aureus. (a) Blank plate, (b) 0.25‐h exposure time, (c) 2‐h exposure time, (d) 4‐h exposure time, (e) 8‐h exposure time, and (f) 24‐h exposure time.

Tables

Table 1. ANOVA analysis of the quadratic model.

Source	Sum of squares	d f	Mean square	F‐value	p value
Model ∗	21.14	14	1.51	23.18	< 0.0001
A	2.33	1	2.33	35.82	< 0.0001
B	5.45	1	5.45	83.55	< 0.0001
C	2.26	1	2.26	34.66	< 0.0001
D	0.6257	1	0.6257	9.60	0.0073
AB	2.35	1	2.35	36.11	< 0.0001
AC	0.4851	1	0.4851	7.44	0.0155
AD	0.1180	1	0.1180	1.81	0.1984
BC	0.0279	1	0.0279	0.4280	0.5229
BD	0.1927	1	0.1927	2.96	0.1060
CD	0.0181	1	0.0181	0.2776	0.6060
A 2	0.0816	1	0.0816	1.25	0.2808
B 2	0.8226	1	0.8226	12.62	0.0029
C 2	0.1995	1	0.1995	3.06	0.1006
D 2	0.0221	1	0.0221	0.3399	0.5686
Residual	0.9775	15	0.0652	No data	No data
Lack of fit (ns)	0.8578	10	0.0858	3.58	0.0859
Pure error	0.1198	5	0.0240	No data	No data
Cor. total	22.12	29	No data	No data	No data

Table 2. FTIR band of the plant extract and CuNPs.

Wavenumber (cm−1)		Functional group	Assignment
Smyrnium cordifolium extract	CuNPs
~3420	~3426	O‐H/N‐H	Amines and amides
~3380	~3400	O‐H	Polyphenols and amino acids
~3367	~3375	N‐H	Amine
~1600	~1616	C=O/C=C	Carbonyl stretching of amides
—	~520	Cu‐O/Cu‐N	Metal–ligand vibration confirming CuNP formation

Table 3. Antibacterial properties for decorated fabrics with CuNPs.

Time (hour)	Antibacterial activity (%), n = 3a
	A. baumannii				S. aureus
	CuNP decoration%
	0.5	1	1.5	2	0.5	1	1.5	2
0.25	0	10 ± 0.0026	88 ± 0.0049	99 ± 0.0028	0	10 ± 0.0064	20 ± 0.032	30 ± 0.0091
2	0	40 ± 0.0032	99 ± 0.0015	99 ± 0.0073	0	50 ± 0.0070	85 ± 0.0084	90 ± 0.0025
4	0	75 ± 0.0062	99 ± 0.0090	100	10 ± 0.029	98 ± 0.0028	99 ± 0.0017	100
8	0	99 ± 0.0053	100	100	20 ± 0.0088	100	100	100
24	10 ± 0.014	100	100	100	30 ± 0.0056	100	100	100

Table 4. Antibacterial performance of CuNPs by different synthesis methods.

Synthesis method	Reducing agent	CuNP size (nm)	Application	CuNP %	Antibacterial efficacy/time		Rf.
					Positive Gram	Negative Gram
Green	Blueberries extract	3–12	Electrospun PES mask	1	S. aureus, 90%/24 h	E. coli, 99%/24 h	[44]
Chemical	Hydrazine	90−200	Melt‐blown	Not specified	S. aureus, 98.73%/24 h	E. coli, 99.07%/24 h	[9]
Chemical	NaOH	40–60	Cotton	2	S. aureus, 99%/24 h	E. coli, 72%/24 h	[45]
Commercial CuNPs + physical embedding (melt‐blending)	CuNPs + PEI	Not specified	IPP polymer‐CuNPs	2.5	S. aureus, 100%/6 h	P. aeruginosa, 100%/2 h	[46]
Green	Smyrnium cordifolium extract	31–57	Melt‐blown	1.5	S. aureus, > 85%/2 h	A. baumannii, > 85%/15 min	This Study

Full text

1. Introduction

Airborne pathogens, including bacteria, viruses, and fungi, significantly contribute to respiratory infections, especially in clinical and similar environments. The SARS‐CoV‐2 pandemic has intensified global efforts to develop protective strategies against these pathogens, positioning personal protective equipment, particularly medical masks, at the forefront of infection prevention. However, conventional masks offer only passive protection and lack inherent antimicrobial properties [1]. Therefore, the development of antibacterial properties is essential for effective protection during medical operation procedures [2].

Recent publications have highlighted that textiles decorated with nanoparticles exhibit significant antibacterial properties. Various studies have demonstrated the successful incorporation of silver, zinc oxide, titanium dioxide, and copper nanoparticles (CuNPs) into fabrics and face masks to inhibit microbial growth and reduce infection transmission [3–5]. Compared to different metals, the use of CuNPs is a more practical choice for textile functionalization [6] due to their lower cost and effective antibacterial properties.

These nanofunctionalized materials are increasingly being integrated into surgical masks, hospital gowns, wound dressings, and reusable medical textiles [7]. Several fabrication techniques, including dip coating, electrospinning, in situ synthesis, and layer‐by‐layer assembly, have been employed to achieve durable antibacterial effects [8]. Some studies have even developed washable and reusable antibacterial textiles that retain their functionality after multiple washing cycles [9]. These findings underscore a growing interest in nanotechnology, which aims to create long‐lasting, effective, and environmentally friendly healthcare materials.

CuNPs have garnered significant attention due to their potent antibacterial efficacy against both Gram‐positive and Gram‐negative bacteria, as well as their cost‐effectiveness and physicochemical stability. These characteristics make CuNPs highly attractive for use in healthcare‐associated textiles [10, 11]. However, traditional chemical and physical synthesis methods for CuNPs often involve toxic reagents, hazardous by‐products, and high energy consumption, raising environmental and safety concerns. Green synthesis approaches have emerged as eco‐friendly alternatives to address these limitations [12]. A wide variety of plant species and plant parts have been investigated as natural sources for the green synthesis of CuNPs. Extracts derived from leaves, roots, stems, bark, flowers, fruits, and seeds have successfully reduced and stabilized copper ions [13]. Previous studies have demonstrated the effectiveness of various plants, including Sida acuta Burm., Olea europaea, Bauhinia tomentosa, Cordia myxa, Aloe barbadensis Mill., Quercus sp., and Ocimum basilicum, in facilitating the biosynthesis of CuNPs through eco‐friendly processes [14].

In green synthesis, plant extracts serve as both reducing and capping agents, facilitating the eco‐friendly formation of metal nanoparticles [15]. This process generally involves three main stages: (1) activation, where metal ions (e.g., Cu^2+^) are reduced to neutral atoms, initiating nucleation; (2) growth, during which small particles aggregate to form larger, more stable structures; and (3) termination, where the nanoparticles reach their final size and morphology [16]. Bioactive compounds in the extract, such as phenolics, flavonoids, terpenoids, and alkaloids, play crucial roles in both reducing the metal ions and stabilizing the resulting nanoparticles [17, 18]. Among various plant sources, certain medicinal herbs from specific regions have exhibited phytochemical compositions that make them ideal candidates for green synthesis [19].

An indigenous Iranian medicinal plant, which is native to the Zagros region, was studied in our previous research. It was confirmed that the phytochemical richness of Smyrnium cordifolium includes phenolic acids (e.g., caffeic acid, sinapic acid, and coumaric acid), flavonoids (e.g., quercetin, tricetin, and gallocatechin), terpenoids (e.g., isorhamnetin 3‐O‐glucoside), and amino acids (e.g., phenylalanine and asparagine). This study leveraged the plant′s natural reducing and capping abilities to biosynthesize CuNPs in an eco‐friendly manner [20]. The bioreductant profile of Smyrnium cordifolium was introduced as an effective scenario for nanometal synthesis without the need for external chemical capping agents.

In this manner, the primary objective of this work was to optimize a green synthesis route for CuNPs using Smyrnium cordifolium extract and to evaluate their antibacterial efficacy when applied to the melt‐blown layer of medical face masks. By integrating green nanotechnology with a locally sourced medicinal plant and applying the synthesized nanoparticles to functionalize protective textiles, this research presents a novel and sustainable strategy to enhance the antimicrobial performance of personal protective equipment.

2. Materials and Methods

2.1. Chemicals

All reagents, including copper (II) sulfate pentahydrate (CuSO_4_·5H_2_O), hydrochloric acid 37%, sodium hydroxide, polyvinyl chloride (PVC), tetrahydrofuran (THF), ethanol 99% (C_2_H_5_OH), and Mueller–Hinton agar growth medium, were sourced from Merck Chemical and Sigma‐Aldrich.

2.2. Plant Extract Preparation

For the biosynthesis process, an extract of the local plant Smyrnium cordifolium, collected from Bankol Mountain in Ivan City, Ilam Province, Iran, was employed. Smyrnium cordifolium is a wild plant that grows naturally in hilly areas. The collection process, carried out with policies, guidelines, and regulations established by the International Union for Conservation of Nature (IUCN) and the Iran Natural Resources and Watershed Management Organization (NRWO) to ensure species preservation and prevent extinction (Figure S1). The specimens were identified at the Biotechnology and Medicinal Plants Research Center of Ilam University of Medical Sciences and assigned the herbarium code 1116. In summary, the aerial parts of the plant, including stems and washed leaves, were dried in the dark and subsequently ground into powder using an electric stirrer (model 350 A from Iran′s Gama Steel Company). Extraction was performed using the Soxhlet method for 3 h, during which 25 g of the powder was placed in a thimble filter and extracted with a solvent mixture of ethanol and water in a 7:3 ratio. The resulting plant extract was filtered through Whatman No. 1 filter paper and stored at 4°C until further experimentation [21]. According to our previous study, excessive extraction has not been preferred, while the complex phytochemical profile of Smyrnium cordifolium extraction performed an effective reduction and stabilization of nanoparticles.

2.2.1. Optimization of CuNP Synthesis Using Central Composite Design (CCD)

The copper sulfate concentration, plant extract volume, pH, and temperature were optimized for the formation of CuNPs using Design‐Expert Version 13, based on a CCD. The parameters were varied within the following ranges: copper sulfate concentration from 5 to 15 mM, extract volume from 3 to 15 mL, pH from 5 to 9, and temperature from 40 to 65°C (Figure S2). Absorbance at 460 nm was used as the dependent variable to indicate the efficiency of CuNP biosynthesis.

This method evaluates each variable at five levels, including three primary levels (−1, 0, and+1) and two central points (−α and +α), and includes five repetitions at the central point to estimate the test error. The number of tests in this method is determined by the following relationship: N = 2^ k ^ + 2k + n 0, where k represents the number of independent variables and n 0 denotes the number of repetitions of experiments at the central point (Table S1).

2.2.2. CuNP Characterization

The production of CuNPs was investigated using a UV‐Vis spectrophotometer (CE 2021 model, Agilent Co., United States), scanning within the 400–800 nm range. Fourier transform infrared (FTIR) spectroscopy (WQF‐510A) was employed to examine the molecular structures of the biosynthesized mixture, covering a range of 400–4000 cm^−1^. The surface morphology of nanoparticles was examined using field emission scanning electron microscopy (FE‐SEM) (MIRA II and III model, Tescan Co., Czech Republic) and transmission electron microscopy (TEM) (CM120 model, Netherlands). Energy‐dispersive X‐ray (EDX) spectroscopy evaluated the elemental composition of chemicals. Zeta potential and dynamic light scattering (DLS) (SZ 100 model, Horiba Co., Japan) were used to assess the stability of the particles.

2.3. Melt‐Blown Decoration With CuNPs

The melt‐blown fabric, with a thickness of 0.205 ± 0.018 mm and an initial weight of 0.0085 ± 0.0007 g, was sterilized using ethyl alcohol. A PVC solution, containing 0.5% in THF, was employed as a binder for CuNPs to the melt‐blown fabric, with stirring for 30 min. Subsequently, the fabrics, cut into 2 × 2 cm^2^ squares, were dip‐coated in the biosynthesized CuNP slurry in THF for varying durations. After preparation, the fabrics were left to dry at 70°C for 24 h. The CuNP loading was determined by comparing the fabric weights before and after the dip‐coating process. The effects of 0.5%, 1%, 1.5%, and 2% CuNP concentrations were evaluated [22]. The fabric morphology was examined using the FE‐SEM technique. CuNP sustainability in the melt‐blown fabric was measured by a leaching test. First, the decorated melt‐blown fabric with 2% CuNP was divided into two parts (Sections A and B). Section A was immersed in 50 mL of distilled water for 24 h and then dried at room temperature. Finally, Sections A and B were analyzed using atomic absorption spectroscopy (AAS) for copper leaching.

2.4. Antimicrobial Activity Assessment

Assessment of the decorated mask′s antibacterial properties was conducted in accordance with the “Antimicrobial Evaluation of Textiles” standard (ISO 20743:2021). Staphylococcus aureus (ATCC 25923) was used as the Gram‐positive bacterium and Acinetobacter baumannii (ATCC 19606) as the Gram‐negative bacterium. Pasture Co. of Iran provided references for bacterial strains. Both bacteria were grown on Mueller–Hinton agar and incubated at 37°C for 24 h. The antibacterial activity (AA) of the medical masks was evaluated using the colony count method. Overall, the fabric specimens were set on the agar and maintained at 37°C for an additional 24 h. AA was measured at 0.25, 2, 4, 8, and 24 h. AA was calculated by counting the number of bacterial colonies using the following formula:

$$[eqn]$$

Co is the colony number for the control sample, while C is the number of colonies on the decorated fabrics containing CuNPs [23]

Negative controls consisted of noncoated melt‐blown fabric samples used to validate the antibacterial effect of CuNPs. These control samples underwent the same experimental conditions as the CuNP‐coated fabrics, including exposure to bacterial suspensions and incubation. AA was calculated using the standard formula defined in ISO 20743:2021, ensuring that the control group accurately reflected bacterial survival in the absence of CuNPs. A schematic representing the experimental setup employed in this study is presented in Figure 1.

Schematic representation of the practical steps involved in the green synthesis of copper nanoparticles (CuNPs) and their decoration onto melt‐blown fabrics.

3. Results and Discussion

3.1. Green Synthesis of CuNPs

The results of 30 runs from the CCD experiments ranged from 0.016 to 2.85 (Table S1). The supporting information file provides detailed information about the experimental runs, including experimental variables and their corresponding absorption responses. According to the CCD findings, the optimal conditions, based on the quadratic model (Table S2), were a copper sulfate concentration of 14.7 mM, 14.7 mL of extract, a pH of 6.8, and a temperature of 54°C. These optimized conditions are consistent with the study by Długosz et al., which reported a temperature of 60°C at a pH of 7 [24].

The following function illustrates the interaction between parameters:

$$[eqn]$$

where Y represents the absorbance response, A denotes the concentration of CuSO_4_, B indicates the extract volume, C signifies the pH value, and D refers to the temperature.

The statistical significance of each factor and interaction was evaluated using Design‐Expert software. Table 1 presents the ANOVA results, revealing an F‐value of 23.18 and a p value < 0.0001, confirming the significance of all model variables at the 95% confidence level. The lack‐of‐fit values for F and p were estimated at 3.58 and 0.0859, respectively, which are not significant. The coefficient of determination (R ^2^) was 0.9558, with a predicted R ^2^ of 0.9146 and an adjusted R ^2^ of 0.8048. These results indicate a well‐fitted model that correlates the parameters of CuSO_4_ concentration, plant extract volume, pH, temperature, and the response variable.

Briefly, the biosynthesis of CuNPs was carried out by adding 14.7 mL of fresh plant extract to 50 mL of 14.7 mM CuSO_4_ solution at 54°C and pH 6.8 for 4 h. The blue copper sulfate solution changed to green upon the addition of the leaf extract and eventually turned dark brown, indicating the formation of nanoparticles (Figure 2). The CuNP suspension was centrifuged at 8000 rpm for 15 min and then washed with distilled water and ethanol. Finally, the CuNPs were dried at 70°C for 24 h.

Color change observed during the green synthesis of CuNPs: (a) CuSO4 solution, (b) mixture of plant extract and CuSO4 solution, and (c) final CuNP solution, indicating the reduction of Cu2+ ions to Cu0 nanoparticles.

Nucleation rate, nanoparticle size, and particle dispersion are influenced by salt concentration [25]. However, higher levels of phytochemicals, such as flavonoids and polyphenols in extracts, support both the reduction and capping phases of nanoparticle synthesis [26, 27]. Our previous study [19] demonstrated that the extract of Smyrnium cordifolium contains a rich mixture of phenolic acids, flavonoids, terpenoids, and amino acids, which act as bioreductants and stabilizers during nanoparticle formation. These phytochemicals likely play a crucial role in achieving efficient nucleation and particle stability. Optimal pH values near neutrality are associated with effective nanoparticle formation, whereas highly alkaline or acidic conditions diminish nanoparticle stability or cause oxidation, as discussed by Długosz et al. and Amjad et al. [24, 28]. Moreover, temperature plays a significant role in biosynthesis. Vanaja et al. reported that temperatures exceeding 50°C increase the nucleation rate and promote the formation of smaller, more spherical nanoparticles [29].

3.2. CuNP Characterization

3.2.1. UV‐Vis Spectroscopy

Color change was investigated as a viable method for synthesizing CuNPs [30]. The excitation of electrons on the surface of nanoparticles results in UV‐Vis absorption, a phenomenon known as surface plasmon resonance (SPR) [31]. The maximum UV‐Vis wavelengths (λmax) are shown in Figure 3, with peaks observed at wavelengths of 350 nm for the extract and 460 nm for the biosynthesized CuNPs. Ebrahimi et al. reported a wavelength of 414 nm [32], while Murthy et al. identified an absorption peak at 403 nm for CuNPs [33].

UV‐Vis absorption spectra of the Smyrnium cordifolium extract and the synthesized CuNPs, showing the characteristic surface plasmon resonance (SPR) peak of CuNPs.

Slurry absorption at 460 nm indicated the reduction of copper ion (Cu^2+^) to metallic copper (Cu^0^) based on the SPR property. Additionally, UV‐Vis wavelength absorption spectra provided insights into the size and shape of green‐synthesized nanoparticles. This discussion examines the differences in SPR bands between biosynthesized CuNPs using Smyrnium cordifolium extract and findings reported in other studies [32, 33].

3.2.2. FTIR

FTIR analysis of the CuNPs slurry reveals four distinct bands for the Smyrnium cordifolium extract at 3400, 3426, 3375, and 1616 cm^−1^. The bands at 3375 and 3426 cm^−1^ are associated with primary and secondary amines and amides [34, 35]. The vibration observed at 3400 cm^−1^ corresponds to the hydroxyl group found in polyphenols and amino acids [36, 37]. Additionally, strong absorption bands at 1600 cm^−1^ are attributed to C=O stretching vibrations of carbonyl amides [38, 39]. The 520 cm^−1^ peak, as illustrated in Figure 4, signifies the O–Cu bond, highlighting the effective synthesis of CuNPs (Table 2).

FTIR spectra of Smyrnium cordifolium extract and CuNP slurry, revealing the functional groups responsible for the reduction and stabilization of nanoparticles.

3.2.3. FE‐SEM

The morphological characteristics of the synthesized CuNPs were examined using a scanning electron microscope, as shown in Figure 5. The sizes of spherical nanoparticles ranged approximately from 31 to 57 nm. These particles form dense clusters due to partial agglomeration. In our study, the agglomeration of CuNPs results in a cauliflower‐like aggregated structure. This morphological pattern is commonly observed in plant‐mediated syntheses, where the nature and concentration of phytochemicals, along with parameters such as pH and temperature, influence the nucleation and growth processes [26].

FE‐SEM micrograph showing the surface morphology and approximate particle size distribution of the synthesized CuNPs.

3.2.4. EDX Spectroscopy

The elemental composition of CuNPs was determined through EDX analysis. The EDX spectrum in Figure 6 indicates the presence of copper, with a weight percentage of 24.13% and an atomic fraction of 6.83%. Other elements, including carbon, phosphorus, and sulfur, are attributed to the phytochemicals present in the extract of Smyrnium cordifolium that surround the biosynthesized nanoparticles.

EDX spectrum confirming the elemental composition and presence of copper in the synthesized nanoparticles.

3.2.5. TEM

TEM image (Figure 7) revealed the spherical structure with a tendency to form cauliflower‐like structures. These results confirm the findings of the SEM image. The particle sizes were in the range below 100 nm.

TEM image showing the shape, size, and uniform distribution of the green‐synthesized CuNPs.

3.2.6. DLS and Zeta Potential Analysis

DLS showed that the polydispersity index (PDI) was 0.425 (Figure 8a). The zeta potential reached −18.3 mV, which is within the range commonly reported for stable colloidal systems synthesized via green methods (Figure 8b).

(a) DLS analysis and (b) zeta potential measurement of CuNPs, indicating average hydrodynamic diameter and surface charge stability.

3.2.7. Melt‐Blown FE‐SEM

A FE‐SEM micrograph was utilized to evaluate the presence of CuNP particles on the fibrous structures of the medical mask (Figure 9). There is a homogeneous distribution of nanoparticles on the fabric′s surface.

FE‐SEM micrograph showing the uniform distribution of CuNPs on the fibrous surface of the melt‐blown fabric.

3.2.8. Cu Leaching From Melt‐Blown

The amount of metal leaching from decorated melt‐blown in distilled water was assessed as 0.5 μg from decorated melt‐blown with 12 μg of Cu. The percentage of Cu leaching from melt‐blown was 4%, which is lower than in other studies [9, 40].

3.3. AA of Decorated Medical Masks

The primary objective of this project was the green synthesis of suitable nanometal particles for antibacterial medical mask production. To achieve this, we utilized an extract from Smyrnium cordifolium, a local Iranian plant, to produce CuNPs. Smyrnium cordifolium Boiss (Vanegi), a member of the Apiaceae family, is the only species of the Smyrnium genus that naturally occurs in the high‐altitude regions of the Zagros Mountains in western and southwestern Iran [41].

The antibacterial characteristics of fabrics treated with CuNPs are presented in Table 3. S. aureus, as a Gram‐positive bacterium, and A. baumannii, as a Gram‐negative bacterium, were used for antibacterial assessment. One limitation of our study is the selection of two bacterial types as the indicators of Gram‐positive and Gram‐negative bacteria.

The minimum antibacterial potency was observed with 0.5% CuNP decoration on fabrics. As the concentration of nanoparticles increased, bacterial inhibition rose from 10% to 100% against A. baumannii and S. aureus over various time intervals. The inhibition activity for A. baumannii at the shortest duration (0.25 h) exceeded 85% for fabrics treated with 1.5% and 2% biosynthesized CuNPs. Figure 10 illustrates the AA of the coated fabric against A. baumannii over different time periods. Notably, A. baumannii exhibited an inhibition rate exceeding 99% after 2 h when decorated with 1.5% and 2% biosynthesized CuNPs.

Antibacterial activity of decorated fabrics (1.5 wt%) against Acinetobacter baumannii. (a) Blank plate, (b) 0.25‐h exposure time, (c) 2‐h exposure time, (d) 4‐h exposure time, (e) 8‐h exposure time, and (f) 24‐h exposure time.

Decorated fabrics exhibit greater antibacterial efficacy against A. baumannii, a Gram‐negative bacterium, compared to S. aureus, a Gram‐positive species. The thicker peptidoglycan layer in Gram‐positive bacteria acts as a significant barrier to the antibacterial effects of CuNPs [42]. These findings have been corroborated by multiple studies [43]. Since there is no substantial difference in antibacterial efficacy between fabrics decorated with 1.5% and 2% CuNPs, melt‐blown fabrics containing 1.5% CuNPs are the optimal choice for antibacterial medical masks. Notably, the 1.5% CuNPs correspond to 0.36 mg of copper content, as determined by EDS analysis.

The findings of this study align with the reports by Humphreys Salas et al., who observed enhanced AA with increasing CuNP concentration on face masks. In their research, they achieved 70% and 60% inhibition against E. coli and S. aureus, respectively, at a 1% CuNP loading. This supports the superiority of our method, which demonstrates over 85% AA at similar or lower concentrations [44]. Figure 11 shows that 1.5% and 2% biosynthesized CuNPs induced more than 85% AA against S. aureus after 2 h. Similarly, SadrHaghighi et al. synthesized CuNPs via in situ reduction on melt‐blown filters and reported over 98% bacterial reduction against E. coli and S. aureus after 24 h of exposure, which is consistent with our findings at 1.5%–2% CuNP loading. The green synthesis method employed in our study eliminated hazardous reagents, providing a safer and more sustainable approach [9].

Antibacterial activity of decorated fabrics (1.5 wt%) against Staphylococcus aureus. (a) Blank plate, (b) 0.25‐h exposure time, (c) 2‐h exposure time, (d) 4‐h exposure time, (e) 8‐h exposure time, and (f) 24‐h exposure time.

Copper particles′ antibacterial properties are influenced by their dimensions, morphology, and functional groups, which in turn depend on the specific synthesis technique applied. Various techniques for producing CuNPs include physical, chemical, and green synthesis methods (see Table 4). Berendjchi et al. decorated cotton fabrics with chemically synthesized CuNPs, producing particles ranging from 40 to 60 nm in size. The antibacterial efficacy of these CuNPs exceeded 90% after 24 h against S. aureus [45]. In our study, we synthesized CuNPs using a green method with Iranian plant extracts, resulting in particle sizes ranging from 31 to 57 nm. The AA of our CuNPs reached 90% after just 2 h against S. aureus. The shorter effective action time of biosynthetic CuNPs compared to chemically synthesized ones makes them more suitable for medical applications. Additionally, green synthesis offers a safer and more environmentally sustainable approach.

Jardón‐Maximino et al. infused CuNPs into isotactic polypropylene (iPP) in their study. Higher time of antibacterial properties was assessed over a longer duration of 6 h, compared to the effective duration of 2 h in our study [46]. However, iPP‐based composites required melt processing and functionalization with ligands such as polyethyleneimine (PEI) and gamma‐aminobutyric acid (GABA) to optimize ion release. In contrast, the biosynthesis method achieved effective bacterial inhibition through a simple dip‐coating approach, highlighting its practical feasibility and cost‐effectiveness for biomedical textile production.

Three hypothesized mechanisms explain the antibacterial action of CuNPs. The first mechanism involves CuNPs attacking bacteria, adhering to their membranes, and altering their permeability. This process results in the removal of membrane proteins, lipopolysaccharides, and intracellular biomolecules, ultimately leading to bacterial cell destruction [47, 48]. The second mechanism involves the generation of reactive oxygen species (ROS) in the form of nanoparticles or ions, which induce oxidative damage, including lipid peroxidation and protein oxidation. The third mechanism entails the absorption of copper ions (Cu^+^ and Cu^2+^) into the bacterial cell, causing a decrease in intracellular ATP levels and disruption of DNA replication [49, 50]. On the other hand, it has recently been established that bacterial cell surfaces carry a negative charge. Consequently, CuNPs coated onto melt‐blown fabric adhere to the bacterial surface by releasing divalent copper ions, ultimately causing bacterial cell death through membrane destruction [51].

We investigated the melt‐blown process employed in the manufacture of medical masks. One limitation of our study is the scarcity of existing research on medical masks, particularly regarding breathability and antimicrobial durability, which are topics for future investigation. Additionally, this research is limited by the lack of cytotoxicity assessments, mechanistic evaluations such as ROS generation, and skin compatibility studies. Nevertheless, our work contributes to the existing literature by introducing Smyrnium cordifolium as a novel and underexplored botanical resource for CuNP production, expanding the range of green reductants available for nanotechnological applications. From an environmental and biosafety perspective, the use of biosynthesized CuNPs reduces the release of toxic by‐products compared to chemically synthesized alternatives, making them a more eco‐friendly option.

4. Conclusion

This study presents a green synthesis method for producing CuNPs using Smyrnium cordifolium extract, a novel plant‐based approach not previously reported for CuNP biosynthesis. The synthesized nanoparticles were successfully applied in the melt‐blown process for medical mask fabrics and demonstrated significant AA against A. baumannii and S. aureus. This research contributes to the development of eco‐friendly antimicrobial textiles by integrating sustainable synthesis with practical applications in personal protective equipment. The findings offer a promising foundation for future efforts to create scalable, biocompatible antibacterial coatings.

Author Contributions

Shiva Mohammadjani Kumeleh: writing an original draft, conceptualization, methodology, investigation, and formal analysis. Ali Hashemi: methodology, investigation, and project administration. Mostafa Pouyakian: writing review and editing, conceptualization, and resources. Mohammad Amin Rashidi: methodology, investigation, and data curation. Shahab Falahi: methodology and investigation. Rezvan Zendehdel: supervision, project administration, conceptualization, and writing review and editing.

Funding

No funding was received for this manuscript.

Conflicts of Interest

The authors declare no conflicts of interest.

Supporting information

Supporting Information Additional supporting information can be found online in the Supporting Information section. The supporting information includes tables and figures related to the experimental design and optimization of CuNP biosynthesis. Table S1: The experimental variables and response values obtained from CCD. Table S2: Summarization of the statistical analysis of the model. Figure S1: Illustration of the preparation process of Smyrnium cordifolium extract. Figure S2: Representative runs from the CCD optimization experiments.