Next Article in Journal
Exploring Bismuth Oxide Supported Kaolinite for Photocatalytic Application
Previous Article in Journal
Surface Migration of Fatty Acid to Improve Sliding Properties of Hypromellose-Based Coatings
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Surfaces
Volume 7
Issue 3
10.3390/surfaces7030044
surfaces-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Review

State of the Art Synthesis of Ag-ZnO-Based Nanomaterials by Atmospheric Pressure Microplasma Techniques

by
Ayesha Khalid
1,
Muhammad Naeem
1,*,
Omar Atrooz
2,3,
M. R. Mozafari
4,*,
Fatemeh Anari
4,
Elham Taghavi
5,
Umair Rashid
6 and
Bushra Aziz
1
1
Department of Physics, Women University of Azad Jammu and Kashmir Bagh, Bagh 12500, Pakistan
2
Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, Al-Ahliyya Amman University, Amman 19328, Jordan
3
Department of Biological Sciences, Mutah University, Mutah 617102, Jordan
4
Australasian Nanoscience and Nanotechnology Initiative (ANNI), Monash University LPO, Clayton, VIC 3800, Australia
5
Faculty of Fisheries and Food Science, Universiti Malaysia Terengganu, Kuala Nerus 21030, Terengganu, Malaysia
6
Department of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100811, China
*
Authors to whom correspondence should be addressed.
Surfaces 2024, 7(3), 680-697; https://doi.org/10.3390/surfaces7030044
Submission received: 12 July 2024 / Revised: 17 August 2024 / Accepted: 29 August 2024 / Published: 2 September 2024
Browse Figures
Versions Notes

Abstract

Atmospheric pressure microplasma is a simple, cost-effective, efficient, and eco-friendly procedure, which is superior to the traditional nanomaterials synthesis techniques. It generates high yields and allows for a controlled growth rate and morphology of nanomaterials. The silver (Ag) nanomaterials, with their unique physical and chemical properties, exhibit outstanding antibacterial and antifungal properties. Similarly, zinc oxide (ZnO) nanomaterials, known for their low toxicity and relatively lower cost, find wide applications in wound repair, bone healing, and antibacterial and anticancer applications. The use of core–shell nanomaterials in certain situations where some nanoparticles can cause serious harm to host tissues or organs is a testament to their potential. A benign material is coated over the core to reduce toxicity in these cases. This review compares the numerous configurations of microplasma systems used for synthesizing nanomaterials and their use in producing Ag, ZnO, and their core–shell (Ag-ZnO) nanomaterials for biomedical applications. The summary also includes the effect of control parameters, including cathode diameter, gas flow rate, precursor concentration, voltage, and current, on the nanomaterial’s characteristics and applications. In addition, it provides a research gap in the synthesis of Ag, ZnO, and core–shell nanomaterials by this technique, as well as the development and limitations of this technique and the use of these nanoparticles for biomedical applications.

Graphical Abstract

1. Introduction

Nanotechnology, one of the most promising technologies of the 21st century, can potentially convert nanoscience theory into beneficial applications. It enables us to observe, compute, handle, collect, monitor, and develop matter at the nanometer scales [1,2,3]. It is an emerging technology in many fields, such as electronics [4], gas sensors [4], photovoltaics [5,6], solar cells [7], photodetectors [7], nanophotonics [8], catalysts [9], and biomedical applications [9]. Nanomaterials, with their widespread applications in biomedical fields such as drug delivery, cancer treatment, immunotherapy, etc., are revolutionizing healthcare [10,11,12]. Nanoparticles are also applied to diagnostic instruments, pharmaceutical products, targeted medicinal products, and imagery and methodologies. Their high surface-area-to-volume ratio allows for maximum absorbance of medicine and quick movement in the bloodstream [13]. Owing to their excellent biocompatibility and biodegradability, nanoparticles can accumulate in defective organs with the most minor side effects. Furthermore, nanoparticles can be slowly released, reducing drug concentration and toxic side effects [14]. Diseases like cancer can be cured if they are detected at an early stage. Still, traditional diagnostic techniques cannot detect these tumors and cancers, and they cannot differentiate between malignant and benign lesions [15]. On the other hand, nanoparticle imaging can yield more appropriate and selective imaging of damaged and diseased tissues [16]. The nanoparticles are extensively applied to deliver chemotherapy drugs to the tumor cells, which reduces the toxicity of healthy tissues.
Zinc oxide (ZnO) nanoparticles are among the most common metal oxide nanoparticles, having distinctive chemical and physical properties that make them suitable for use in many fields as summarized in Figure 1 [17]. They are widely used in self-care products such as skincare, sunscreen, and cosmetics due to their beneficial properties against UV absorption [18]. They are also used in the textile industry; they are added to the fabric and have attractive features of visible light resistance and deodorant [19,20]. ZnO nanoparticles reveal brilliant biomedical applications such as wound healing, drug delivery, diabetes treatment, bio-imaging, antibacterial, anti-inflammation, and anticancer. They are less toxic and relatively cheaper than metal oxide nanoparticles [17,21]. In modern eras, immunotherapy is another approach to combat various diseases by providing immune molecules (antibodies and antigens). ZnO nanoparticles have received the utmost consideration owing to their high biocompatibility with human cells [22,23,24]. ZnO nanoparticles can hinder viral entrance, reproduction, and spreading all over the organ, which causes viral death because of stimulating reactive oxygen species, which results in oxidative stress [22,25].
Over the years, silver (Ag) nanoparticles have earned significant attention because of their exceptional electrical, optical, and antimicrobial properties [26]. It is commonly known that silver nanoparticles have remarkable antibacterial ability and admirable physical properties, which make them useful for applications in water purificants and the disinfection of medical devices [27,28]. Due to their tiny size, they acquire a large surface area, providing a high surface energy and further probable reactive locations. They have low volatility and high thermal stability and are less toxic to human cells [29,30]. They are used in medicine for treating burns, dental tools, and coated stainless steel materials [31,32]. In addition, they are utilized in various applications in textile fabrics, water treatment, and sunscreen lotion [33,34]. More importantly, Ag nanoparticles have the potential to be used for treating diseases that demand the maintained concentration of circulating drugs or the targeting of particular cells or organs [35,36].
Furthermore, the core–shell nanoparticles have also earned much importance because of their great biological stability and good performance [15,37,38,39,40]. Core–shell nanoparticles, including noble metal semiconductors, are the most interesting materials for biomedical applications [40,41,42]. Ag-ZnO core–shell nanoparticles have strong antibacterial and antifungal properties [43]. Core–shell nanoparticles consist of a material core covered in a layer of another material [44]. Compared to simple nanoparticles, core–shells offer significant advantages in biological applications, including improved properties like reduced cytotoxicity, increased dispersibility, biocompatibility, improved conjugation with other bioactive molecules, and enhanced thermal and chemical stability [44]. More specifically, if the desired nanoparticles are toxic, they can cause serious harm to the host tissues and organs. Then, the benign material can be coated over the core to reduce its toxicity. Sometimes, the shell layer enhances the core materials’ properties and is non-toxic. There are two main approaches for nano-synthesis: bottom-up and top-down [45]. Zhang et al. [46] reported a detailed review of the Ag-decorated ZnO-based nanocomposites, focusing on degradation mechanisms, synthesis techniques, and applications in photocatalytic degradation. Usliyanage et al. [47] comprehensively reviewed the biological synthesis approach for Ag/ZnO nanocomposites, physiochemical characteristics, morphological properties, and applications. The microplasma technique is a bottom-up technique with advantages over other techniques, such as its short processing time, environment-friendly nature, and low cost. It also has more benefits like small size, non-toxicity, control of growth, and flexibility, making it suitable for nanosynthesis [48,49].

2. Atmospheric Pressure Microplasma for Nanosynthesis

2.1. Background

In the past few years, research about nano-size particles has earned great attention because nanoparticles have distinct and unique properties compared to bulk materials due to their high surface-to-volume ratio [50]. The main task during nanoparticle synthesis is to control the nanoparticles’ shape, size, and stability because these characteristics greatly influence their properties [51]. This control can be attained by varying the conditions of reactions, such as the concentration of precursors, the stabilizer, and the reducing agents [50]. Various synthesis techniques have been investigated for the synthesis of nanoparticles, such as laser ablation [52], electrochemical [53], microwave-assisted synthesis [54], and chemical reduction [50]. Most of these techniques involve toxic chemicals, long treatment times of several hours or even days, expensive equipment, and high-temperature requirements for synthesis [55]. Plasma discharges with diverse arrangements are among the leading and eco-friendly techniques for nanoparticle synthesis. In particular, atmospheric pressure plasma systems are an essential technique, as they are cheap and simple and require no costly vacuum pumps and systems.

2.2. Synthesis of Nanomaterials

In recent years, various microplasma systems have been used for nanosynthesis, as shown in Figure 2. These systems illustrate the versatility and flexibility of microplasma’s processing conditions. Here, we classify the system into four categories based on electrode geometry, way of injecting precursors, power coupling method, and plasma power source, as described in the following sub-sections [49,50,51].

2.2.1. Plasma Jet System

The atmospheric pressure plasma jet system synthesizes nanoparticles by generating inert gas plasma. Habib et al. [55] demonstrated the synthesis of silver nanoparticles by atmospheric pressure plasma jet using silver nitrate as a precursor and trisodium citrate dihydrate. The microplasma jet system is shown in Figure 3, which consists of a gas flow system and power supply. A high-voltage electrode was coiled around the asymmetric source and was composed of a tube 3.77 mm in width. This system has a large reservoir with a diameter of 38.2 mm, connected to a ground electrode. The support was connected to another ground electrode. The discharge was generated by high voltage. The working gas used in this system was helium, and 8A current and 25 kHz frequency were applied. The surface of the liquid and plasma jet were kept at a distance of 7 mm. The samples were exposed to plasma for 5 min.
In addition, plasma jets have various configurations, such as hollow electrode micro discharge [56], microplasma jets with external electrodes [57], and microplasma jets having consumable electrodes [58].

2.2.2. Dielectric Barrier Discharge

The synthesis of silver nanoparticles by atmospheric pressure dielectric barrier discharge was demonstrated by Janith and co-workers [59], and the schematic diagram of the process is shown in Figure 4. The reactor is a quartz-based cylindrical structure. The sodium citrate solution (34 mM) and aqueous silver nitrate were mixed to prepare a solution of silver precursor. The precursor solution could be injected into the hollow central part of the plasma reactor, which could be sealed by a quartz lid. The central part was linked with the outlet and gas feeding line. The chamber has a total volume of 25 mL; the precursor solution used in this experiment was 4 mL. The bottom and lid of the quartz chamber acted as a dielectric barrier. The dielectric barriers were at a distance of 8 mm from each other. The power supply of 2000 K was used to apply a high voltage to the stainless steel electrodes. The frequency and power supply were 9.1 kHz and 39 kV, respectively [59].

2.2.3. Plasma Torch Method

Another technique for nanomaterials synthesis is the atmospheric plasma torch method. Bjelajac et al. [60] reported the synthesis of Au nanomaterials by the atmospheric pressure plasma torch method. Tetra chloroauric acid trihydrate dissolved in ethanol or water was used as a precursor. The atmospheric pressure plasma torch consists of two hollow quartz tubes. The plasma was generated between the outer plasma tube (7 mm inner diameter and 9 mm outer diameter) and the inner tube (4 mm inner diameter and 6 mm outer diameter). The inner tube was grounded, and its outer surface was coated with a thick Pt film of 300 nm. Physical vapor deposition was used to deposit Pt film. The aluminum foil 5 cm long covered the external quartz tube, and the aluminum foil was connected to the high-voltage (HV) generator. The plasma was produced in the space between the two tubes by applying a sinusoidal high voltage to the external electrodes. The internal hollow electrode carried the nebulized gold precursor solution close to the discharge. The schematic diagram of the plasma torch setup is given in Figure 5.

2.2.4. Plasma–Liquid System

A plasma–liquid system is extensively used for nanomaterial synthesis and is also called an atmospheric pressure microplasma or microplasma electrochemical synthesis, as shown in Figure 6. Ming and colleagues [61] reported the synthesis of cuprous oxide nanoparticles by microplasma electrochemical synthesis. It consisted of a stainless steel tube (0.7 mm inside diameter, 8 cm length) placed 3 cm away from the copper electrode. A 2 mm space was maintained between the liquid surface and the capillary tube end. The argon gas flow was connected to the tube, and the glass rotameter was used to control the flow rate at 60 mL/min. The discharge was ignited by applying a high voltage, keeping the current constant. The precursors used in this synthesis were NaOH, NaCl, and NaNO3 with H2O ethylene glycol or DI water as solvents. The plasma was generated at the interface of the gas solution. A ballast resistor stabilized the current and voltage. A magnetic stirrer was used to stir the solution gently to avoid agglomeration. The sediments collected were washed and centrifuged many times. The advantages and disadvantages of plasma-based nanosynthesis techniques are summarized in Table 1.

3. State-of-the-Art of the Microplasma Technique Applications

Thong and colleagues [65] synthesized silver nanoparticles using a D.C. helium microplasma jet and examined the stabilizing effect of sucrose at various molar concentrations added to the AgNO3 solution. In this setup, the gap between the surface of the solution and the capillary was kept small to lower the voltage required to cause the microplasma to ignite. Bisht et al. [66] reported the synthesis of silver nanoparticles using atmospheric pressure microplasma. Silver nitrate solution in DI water was used as a precursor. In order to avoid agglomeration, sucrose was used as a stabilizing agent. They synthesized silver nanoparticles with uniform radii ranging from 7–13 nm. The microplasma caused the reduction and nucleation of aqueous metal ions into nanoparticles without using any chemical reducing agents. The obtained nanoparticles were analyzed using dynamic light scattering (DLS), SEM, and UV–visible absorption. Kondeti et al. [67] described the surfactant-free synthesis of silver nanoparticles using Argon and Ar + 0.64% H2 plasma. A sinusoidal voltage wave modulated at 20 kHz with a 20% duty cycle and 13.4 MHz radio frequency to generate the plasma. It was observed that Ar + 0.64%H2 synthesized nanoparticles of small size with a maximum 2–3 nm diameter, whereas Ar gas plasma synthesized nanoparticles of broad size distribution. Shepida et al. [68] demonstrated the formation of silver nanoparticles in a solution of AgNO3 and sodium polyacrylate, a non-toxic surfactant. This setup used tungsten wire as a cathode, and the voltage was kept constant at 250 V. The silver nanoparticles in the range 2–20 nm were formed at a concentration of 0.05–0.2 mMol L−1 of AgNO3 with 0.5 gL−1 of NaPA. The synthesized silver nanoparticles had established antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans. Huang et al. [69] declared the synthesis of silver nanoparticles by plasma-assisted electrochemical technique. They demonstrated that the interparticle spacing and the size of nanoparticles in the solution could be adjusted by altering the synthesis parameters so that the plasmonic response could be tuned. It was evident that larger-sized, highly dispersive silver nanoparticles were produced at higher solution concentrations and higher temperatures. Additionally, they revealed that silver nanoparticle synthesis can be accomplished without using a stabilizer, allowing control of nanoparticles dispersion. Shuaib et al. [70] synthesized AgNPs using the microplasma technique. They investigated the role of variation in the molar concentration of fructose on the size of nanoparticles. They concluded that AgNPs with better efficiency against fungi and bacteria can be obtained by using 2 mM fructose sample, due to the production of A g + ions. Lin et al. [71] demonstrated the combination of Gemini surfactant with AgNPs to attain a stable nano-surfactant system with strong antibacterial activities. Plasma-aided technique prepared high-quality crystalline nanostructures, where electrons acted as reductants, replacing conventional chemical reducing agents. The XRD results (as presented in Figure 7) showed that five diffraction peaks corresponding to fcc AgNPs at 38.20°, 44.37°, 64.50°, 77.48° and 81.64° were observed, and no impurity peaks appeared. It suggests that pure AgNPs can be formed using Gemini surfactant in a plasma-assisted technique. The TEM images of synthesized nanoparticles (presented in Figure 8a,b) reveal the formation of partially aggregated nanoparticles with a spherical geometry. The high-resolution TEM image (Figure 8c) and selected area diffraction (SAED) (Figure 8d) show the formation of nanoparticle lattice fringes, which indicates the crystalline nature of nanoparticles. The size and size distribution of nanoparticles were assessed using the histogram, as shown in Figure 8d, which shows the formation of nanoparticles with a size of 9.64 nm. It shows that nanoparticles assisted with the microplasma technique had a narrower size distribution than the conventional technique. The surfactants stabilized the silver nanoparticles by preventing AgNPs from aggregating. Antibacterial studies were conducted against S. aureus and E. coli, demonstrating the synergetic effects of the compounding systems [72].
Habib et al. [55] reported the silver nanoparticle synthesis in a quick and environment-friendly way using an atmospheric pressure plasma jet. They examined the role of variations in AgNo3 (precursor) and citrate concentration and determined the optimal conditions for synthesizing silver nanoparticles. They found their effective applications in the bio-medical field (antibacterial activities), photonic, and catalytic activities. Saleem et al. [73] demonstrated that by changing the type or concentration of capping agents in optimized microplasma parameters, the size of AgNPs could be modified. Therefore, it influenced the stability of AgNPs. The results from DLS indicated that Polyvinyl Alcohol (PVA) capped AgNPs were the most stable over 15 days compared to Polyvinyl Pyrrolidone PVP capping agents and sucrose. The AgNP’s size variations were within the range of less than 5 nm limit. They suggested that these stability results had practical applications in cancer therapy. Skiba et al. [74] examined the catalytic effect of silver nanoparticles synthesized by a non-equilibrium low-temperature plasma technique. The characteristics and formation of nanoparticles were analyzed by DLS, ultraviolet–visible spectroscopy, and scanning electron microscopy. Then, silver nanoparticles were effectively used in the catalytic reduction of 4-NP, and they demonstrated outstanding catalytic performance with a quick reaction time. Iqbal et al. [75] reported that the atmospheric microplasma approach was successfully employed to generate two-dimensional stumbled silver nanosheets. SEM analysis was used to verify the surface morphology of the synthesized nanosheets, and it showed that their lateral dimensions increased as the precursor concentration increased. The antibacterial activity of silver nanosheets was found to be highly effective against various types of bacteria and to be correlated with the size of nanosheets.
Iqbal and co-workers [76] reported the synthesis of ZnO nanostructure using different ionic surfactants and non-ionic fructose using the microplasma technique. The changes in the properties of nanoparticles were observed by changing the surfactant, including sodium dodecyl sulfate (SDS), fructose, and cetrimonium bromide (CTAB). The XRD pattern presented in Figure 9 shows the presence of characteristics peaks of ZnO at 31.73°, 34.3792°, 36.21°, 47.48°, 56.54°, 62.77°, 66.31°, 67.87° and 69.01°, which correspond to (1 0 0), (0 0 2), (1 0 1), (1 0 2), (1 1 0), (1 0 3), (2 0 0), (1 1 2) and (2 0 1) planes. The obtained peaks followed the standard peaks of JCPDS#76-0704. No impurity peaks were observed, and thus they suggested ZnO nanomaterials with high purity and hexagonal phase (Wurtzite structure) can be obtained using the atmospheric pressure microplasma technique. The SEM analysis was used to analyze the surface morphology of nanomaterials, as presented in Figure 10, and they found that morphology strongly depends on the type of surfactant used. Hexagonal ZnO nanosheets were observed (Figure 10a) while using the anion surfactant of SDS. On the other hand, when non-ionic fructose surfactant was used, hexagonal plates, termed ZnO nanodrum, were obtained (Figure 10b). In addition, a ZnO needle-like structure with orientation along the c-axis was obtained while using the CTAB surfactant. Thus, it shows that ZnO nanomaterials with high purity and numerous morphologies, including nanosheets, nano drums, and needle-like structures, can be obtained by changing the type of surfactant in atmospheric pressure microplasma.
Schwan et al. [77] successfully synthesized morphology-controlled ZnO nanoparticles using zinc powder and oxygen with an atmospheric pressure plasma jet. It was discovered that the rate of oxygen in carrier gas and plasma, the energy within the reactor, and the discharge current all affected the particle’s morphology. Jain et al. [78] described the synthesis and deposition of ZnO nanocrystalline materials by atmospheric pressure plasma synthesis. Radiofrequency power generated plasma, and the precursor was metallic zinc wire. The aggregation of synthesized nanostructures formed a porous film at the substrate. The synthesized nanostructures were thoroughly studied and characterized by UV–visible absorption, transmission electron microscopy, and X-ray diffraction. Abdullah et al. [79] demonstrated the capability of atmospheric pressure plasma jets to prepare high-purity, nanometer-sized ZnO in the gas or liquid phase. The obtained ZnO nanocrystals were characterized by transmission electron microscopy, Fourier transformation infrared (FTIR), and X-ray powder diffraction. The findings revealed that electrolytic media, current density, and reaction temperature influenced the morphology of ZnO nanocrystals.
Rawi and co-workers [80] reported the synthesis of core–shell nanoparticles of Ag-ZnO by an atmospheric pressure plasma jet technique and described their antibacterial and antifungal properties. The characterization of these Ag-ZnO core–shell nanoparticles was done using different techniques such as ultraviolet–visible spectroscopy (UV–vis), transmission electron microscopy (TEM), XRD, energy-dispersive X-ray spectroscopy (EDX), and field-emission scanning electron microscopy (FE-SEM). The pureness of synthesized Ag-ZnO core–shell NPs was proved by XRD and EDX analysis. The antibacterial activity of these core–shell nanoparticles was evaluated on two different types of Gram-positive (Staphylococcus aureus and Staphylococcus epidermidis) and Gram-negative bacteria (pneumonia and Escherichia coli). The TEM image is presented in Figure 11, which shows the appearance of two distinguishable areas. The contrast in the images specifies the formation of the dark and bright regions that correspond to the core and shell of nanoparticles, respectively. Furthermore, the antifungal activity of these core–shell N.P.s was evaluated against two distinct types of yeast. Khalid et al. [81] observed the formation of gold–silver core–shell nanoparticles using cold atmospheric pressure microplasma. They revealed that the precursor concentration affected the average size of particles; the average size of particles increased with the increase in concentration. Skiba et al. [78] recently reported synthesizing gold, bimetallic gold–silver core–shell, and alloy nanoparticles using the liquid-phase anode plasma technique. They examined the role of control parameters, including solution plasma discharge time and molar contents (0.25, 0.72, and 1.2-mM solution of silver nitrate), on the properties of nanoparticles. They observed that core–shell nanoparticles exhibit better antibacterial efficiency against C. albicans fungus and Gram-negative bacteria over other nanoparticles. Using a TEM image (shown in Figure 12), they observed that the core and shell of nanoparticles could be distinguished, and it was observed that the shell thickness of 1–2 nm, 10–12 nm, and 14–15 nm increased while using the silver nitrate solution of 0.25, 0.72, and 1.2-mM. The total diameter of core–shell nanoparticles was 18–20 nm. Thus, it showed that the core–shell nanoparticles could be obtained effectively using the liquid-phase anode plasma technique with a controlled diameter and shell thickness by tuning the control parameters. The review of plasma configuration and their use for the synthesis of silver, zinc oxide, and core–shell nanoparticles are also summarized in Table 2.

4. Summary of Review

Some important factors influencing nanoparticle size, morphology, and properties are discussed here and are summarized in Table 3. In nanoparticle synthesis, solution/precursor concentration affects the nanoparticles’ size and anti-microbial properties. Early studies revealed that increasing precursor concentration enhanced the nanoparticles’ size and anti-microbial properties. Another factor that is significantly important in nanoparticle size and morphology is processing time. The increase in processing time (5–45 min) causes an increase in the size of nanoparticles and improves the crystallinity of nanoparticles. The concentration of the stabilizing agent or surfactants added to the precursor to avoid agglomeration is important. (Usually, fructose and sucrose are used as stabilizers in the synthesis of nanoparticles). The increase in concentration or molar ratio of surfactants or stabilizing agents increases the average size of nanoparticles. The gas flow rate also affects nanoparticle size; when the flow rate rises, the nanoparticle size decreases. All these factors are of great importance in nanoparticle synthesis of silver and zinc oxide, as they affect the structural properties and their biomedical applications. By altering these factors, the properties of nanoparticles can be varied.

5. Conclusions and Final Remarks

The atmospheric pressure plasma is an advanced and novel technique that can produce nanoparticles at ambient conditions. It has low thermal temperatures, faster processes, simplified equipment, and a cheap, eco-friendly system with various dimensions and configurations. Recent studies are presented here for nanomaterial synthesis by different configurations of atmospheric pressure microplasma depending on the slight difference in their setups. This brief review revealed that silver and zinc oxide and their core–shell nanomaterials have great biological properties such as antibacterial, anticancer, and antifungal. The contribution of numerous control parameters like electrode dimension, flow of gas, type of gas, precursors concentration, operating voltage and current, distance between electrodes, and configuration of plasma system on nanoparticle characteristics (size, shape, and applications) is summarized. Nowadays, wide research is being conducted on atmospheric pressure microplasma nano synthesis. Still, there is a broad scope for the development of research, and a research gap is provided in this article. This review highlights plasma-based Ag-ZnO-based nanoparticle synthesis techniques, which offer an eco-friendly, cost-effective approach with noteworthy biological applications. Although silver and zinc oxide nanoparticles by this technique are widely reported, the literature on their core–shell nanoparticles is very limited and needs to be investigated in the future, specifically the pros and cons of such core–shell nanoparticles for biomedical applications.

Author Contributions

Conceptualization, M.N., A.K. and M.R.M.; validation, B.A., U.R., M.N. and A.K.; resources, M.N.; writing—original draft preparation, A.K. and M.N.; writing—review and editing, U.R., B.A., O.A., F.A. and E.T.; supervision, M.N. and M.R.M.; project administration, M.N. All authors have read and agreed to the published version of the manuscript.

Funding

M. Naeem thanks the Higher Education Commission of Pakistan for granting PhD studentship to Ayesha Khalid under NRPU-14417.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Kumar, A.; Jayeoye, T.J.; Mohite, P.; Singh, S.; Rajput, T.; Munde, S.; Eze, F.N.; Chidrawar, V.R.; Puri, A.; Prajapati, B.G. Sustainable and consumer-centric nanotechnology-based materials: An update on the multifaceted applications, risks and tremendous opportunities. Nano Struct. Nano Objects 2024, 38, 101148. [Google Scholar] [CrossRef]
  2. Zhou, A.F.; Feng, P.X. One-Dimensional and Two-Dimensional Nanomaterials for Sensor Applications. Crystals 2024, 14, 622. [Google Scholar] [CrossRef]
  3. Yamaguchi, T.; Kim, H.-J.; Park, H.J.; Kim, T.; Khalid, Z.; Park, J.K.; Oh, J.-M. Controlling the Surface Morphology of Two-Dimensional Nano-Materials upon Molecule-Mediated Crystal Growth. Nanomaterials 2023, 13, 2363. [Google Scholar] [CrossRef] [PubMed]
  4. Bhatia, S.; Verma, N.; Bedi, R.K. Ethanol gas sensor based upon ZnO nanoparticles prepared by different techniques. Results Phys. 2017, 7, 801–806. [Google Scholar] [CrossRef]
  5. Prete, P.; Lovergine, N. Dilute nitride III-V nanowires for high-efficiency intermediate-band photovoltaic cells: Materials requirements, self-assembly methods and properties. Prog. Cryst. Growth Charact. Mater. 2020, 66, 100510. [Google Scholar] [CrossRef]
  6. Di Carlo, V.; Prete, P.; Dubrovskii, V.G.; Berdnikov, Y.; Lovergine, N. CdTe Nanowires by Au-Catalyzed Metalorganic Vapor Phase Epitaxy. Nano Lett. 2017, 17, 4075–4082. [Google Scholar] [CrossRef]
  7. Nagpal, K.; Rapenne, L.; Wragg, D.S.; Rauwel, E.; Rauwel, P. The role of CNT in surface defect passivation and UV emission intensification of ZnO nanoparticles. Nanomater. Nanotechnol. 2022, 12, 18479804221079419. [Google Scholar] [CrossRef]
  8. Bimberg, D. Semiconductor nanostructures for flying q-bits and green photonics. Nanophotonics 2018, 7, 1245–1257. [Google Scholar] [CrossRef]
  9. Mirzaei, H.; Darroudi, M. Zinc oxide nanoparticles: Biological synthesis and biomedical applications. Ceram. Int. 2017, 43, 907–914. [Google Scholar] [CrossRef]
  10. Lee, Y.-Y.; Sriram, B.; Wang, S.-F.; Kogularasu, S.; Chang-Chien, G.-P. Advanced nanomaterial-based biosensors for N-terminal pro-brain natriuretic peptide biomarker detection: Progress and future challenges in cardiovascular disease diagnostics. Nanomaterials 2024, 14, 153. [Google Scholar] [CrossRef]
  11. Gatou, M.-A.; Vagena, I.-A.; Pippa, N.; Gazouli, M.; Pavlatou, E.A.; Lagopati, N. The Use of Crystalline Carbon-Based Nanomaterials (CBNs) in Various Biomedical Applications. Crystals 2023, 13, 1236. [Google Scholar] [CrossRef]
  12. Cao, M. Recent Development of Nanomaterials for Chemical Engineering. Nanomaterials 2024, 14, 456. [Google Scholar] [CrossRef] [PubMed]
  13. Wang, N.; Chen, L.; Huang, W.; Gao, Z.; Jin, M. Current Advances of Nanomaterial-Based Oral Drug Delivery for Colorectal Cancer Treatment. Nanomaterials 2024, 14, 557. [Google Scholar] [CrossRef]
  14. Gaci, Y.; Guittoum, A.; Hemmous, M.; Nez-Blanco, D.M.; Gorria, P.; Blanco, J.A.; Aouaroun, T. Effect of Fe content on the structural and magnetic properties of ternary (Ni60Co40)100−xFex nanomaterials synthesized by hydrothermal route. Surf. Rev. Lett. 2024, 31, 1–9. [Google Scholar] [CrossRef]
  15. Gatou, M.-A.; Skylla, E.; Dourou, P.; Pippa, N.; Gazouli, M.; Lagopati, N.; Pavlatou, E.A. Magnesium Oxide (MgO) Nanoparticles: Synthetic Strategies and Biomedical Applications. Crystals 2024, 14, 215. [Google Scholar] [CrossRef]
  16. Hadi, A.J.; Nayef, U.M.; Jabir, M.S.; Mutlak, F.A.H. Titanium dioxide nanoparticles prepared via laser ablation: Evaluation of their antibacterial and anticancer activity. Surf. Rev. Lett. 2023, 30, 1–10. [Google Scholar] [CrossRef]
  17. Casiano-Muñiz, I.M.; Ortiz-Román, M.I.; Lorenzana-Vázquez, G.; Román-Velázquez, F.R. Synthesis, Characterization, and Ecotoxicology Assessment of Zinc Oxide Nanoparticles by In Vivo Models. Nanomaterials 2024, 14, 255. [Google Scholar] [CrossRef]
  18. Alhoqail, W.A.; Alothaim, A.S.; Suhail, M.; Iqbal, D.; Kamal, M.; Asmari, M.M.; Jamal, A. Husk-like zinc oxide nanoparticles induce apoptosis through ROS generation in epidermoid carcinoma cells: Effect of incubation period on sol-gel synthesis and anti-cancerous properties. Biomedicines 2023, 11, 320. [Google Scholar] [CrossRef]
  19. Zenkin, K.; Durmus, S.; Demir, A. Investigating Magnetic, Dielectric, Optic and Morphologic Properties of Nano-Nickel Oxide-Doped NdFeO3. Surf. Rev. Lett. 2024, 31, 1–16. [Google Scholar] [CrossRef]
  20. Kumar, P.; Ramesh, M.R.; Doddamani, M.; Suresh, J. Green synthesis of Fe/Ni/Cr oxide nanoparticles using Costus pictus plant extract: Microstructure and biological properties. Surf. Rev. Lett. 2024, 31, 2450065. [Google Scholar] [CrossRef]
  21. Ounis, T.-D.; Rahmouni, K.; Aouar, L.; Zaabat, M. Optical properties and antibacterial activity of Ni, Mg and Fe-doped ZnO. Surf. Rev. Lett. 2024, 2450104. [Google Scholar] [CrossRef]
  22. Kavya Prakash, K.M.; Prakash, V.; Gokul Gopinath, P. Influence of Precursor Molarity and Leaf Extract Concentration on Physical Properties of Zinc Oxide (ZnO) Nanoparticles Synthesized Using Moringa Oleifera Leaf Extract. Surf. Rev. Lett. 2024, 2450124. [Google Scholar] [CrossRef]
  23. Abdulgafour, H.I.; Zainulabdeen, F.S.; Karam, G.S.; Magid, H.C.; Najim, A.A.; Hassan, F.M. Synthesis and characterization of Al-doped ZnO thin films as anti-reflection coatings for solar cell applications. Surf. Rev. Lett. 2024, 31, 1–7. [Google Scholar] [CrossRef]
  24. Wiesmann, N.; Mendler, S.; Buhr, C.R.; Ritz, U.; Kämmerer, P.W.; Brieger, J. Zinc oxide nanoparticles exhibit favorable properties to promote tissue integration of biomaterials. Biomedicines 2021, 9, 1462. [Google Scholar] [CrossRef] [PubMed]
  25. Sugihartono, I.; Tan, S.T.; Arkundato, A.; Fahdiran, R.; Isnaeni, I.; Handoko, E.; Budi, S.; Budi, A.S. The Effect of Al-Cu Co-Dopants on Morphology, Structure, and Optical Properties of ZnO Nanostructures. Mater. Res. 2023, 26, e20220499. [Google Scholar] [CrossRef]
  26. Khan, S.; Zahoor, M.; Khan, R.S.; Ikram, M.; Islam, N.U. The impact of silver nanoparticles on the growth of plants: The agriculture applications. Heliyon 2023, 9, e16928. [Google Scholar] [CrossRef]
  27. Song, Y.; Yang, F.; Mu, B.; Kang, Y.; Hui, A.; Wang, A. Phyto-mediated synthesis of Ag nanoparticles/attapulgite nanocomposites using olive leaf extract: Characterization, antibacterial activities and cytotoxicity. Inorg. Chem. Commun. 2023, 151, 110543. [Google Scholar] [CrossRef]
  28. Hu, J.; Chen, F.; Mao, J.; Ni, L.; Lu, J. Direction regulation of interface carrier transfer and enhanced photocatalytic oxygen activation over Z-scheme Bi4V2O11/Ag/AgCl for water purification. J. Colloid Interface Sci. 2023, 641, 695–706. [Google Scholar] [CrossRef]
  29. Jaswal, T.; Gupta, J. A review on the toxicity of silver nanoparticles on human health. Mater. Today Proc. 2023, 81, 859–863. [Google Scholar] [CrossRef]
  30. Neciosup-Puican, A.A.; Pérez-Tulich, L.; Trujillo, W.; Parada-Quinayá, C. Green Synthesis of Silver Nanoparticles from Anthocyanin Extracts of Peruvian Purple Potato INIA 328—Kulli papa. Nanomaterials 2024, 14, 1147. [Google Scholar] [CrossRef]
  31. Francisco, P.; Neves Amaral, M.; Neves, A.; Ferreira-Gonçalves, T.; Viana, A.S.; Catarino, J.; Faísca, P.; Simões, S.; Perdigão, J.; Charmier, A.J. Pluronic® F127 Hydrogel Containing Silver Nanoparticles in Skin Burn Regeneration: An Experimental Approach from Fundamental to Translational Research. Gels 2023, 9, 200. [Google Scholar] [CrossRef] [PubMed]
  32. Holubnycha, V.; Husak, Y.; Korniienko, V.; Bolshanina, S.; Tveresovska, O.; Myronov, P.; Holubnycha, M.; Butsyk, A.; Borén, T.; Banasiuk, R. Antimicrobial activity of two different types of silver nanoparticles against wide range of pathogenic bacteria. Nanomaterials 2024, 14, 137. [Google Scholar] [CrossRef]
  33. Naysmith, A.; Mian, N.S.; Rana, S. Development of conductive textile fabric using Plackett–Burman optimized green synthesized silver nanoparticles and in situ polymerized polypyrrole. Green Chem. Lett. Rev. 2023, 16, 2158690. [Google Scholar] [CrossRef]
  34. Ghazwani, M.; Hani, U.; Alqarni, M.H.; Alam, A. Development and Characterization of Methyl-Anthranilate-Loaded Silver Nanoparticles: A Phytocosmetic Sunscreen Gel for UV Protection. Pharmaceutics 2023, 15, 1434. [Google Scholar] [CrossRef] [PubMed]
  35. Patel, R.R.; Singh, S.K.; Singh, M. Green synthesis of silver nanoparticles: Methods, biological applications, delivery and toxicity. Mater. Adv. 2023, 4, 1831–1849. [Google Scholar] [CrossRef]
  36. Al-Serwi, R.H.; Eladl, M.A.; El-Sherbiny, M.; Saleh, M.A.; Othman, G.; Alshahrani, S.M.; Alnefaie, R.; Jan, A.M.; Alnasser, S.M.; Albalawi, A.E. Targeted drug administration onto cancer cells using hyaluronic acid–quercetin-conjugated silver nanoparticles. Molecules 2023, 28, 4146. [Google Scholar] [CrossRef]
  37. Adam, A.; Mertz, D. Iron oxide@ mesoporous silica core-shell nanoparticles as multimodal platforms for magnetic resonance imaging, magnetic hyperthermia, near-infrared light photothermia, and drug delivery. Nanomaterials 2023, 13, 1342. [Google Scholar] [CrossRef] [PubMed]
  38. Kar, N.; McCoy, M.; Wolfe, J.; Bueno, S.L.A.; Shafei, I.H.; Skrabalak, S.E. Retrosynthetic design of core–shell nanoparticles for thermal conversion to monodisperse high-entropy alloy nanoparticles. Nat. Synth. 2024, 3, 175–184. [Google Scholar] [CrossRef]
  39. Rani, P.; Varma, R.S.; Singh, K.; Acevedo, R.; Singh, J. Catalytic and antimicrobial potential of green synthesized Au and Au@ Ag core-shell nanoparticles. Chemosphere 2023, 317, 137841. [Google Scholar] [CrossRef]
  40. Hu, J.; Liu, X.; Zhang, J.; Gu, X.; Zhang, Y. Plasmon-activated NO2 sensor based on Au@ MoS2 core-shell nanoparticles with heightened sensitivity and full recoverability. Sens. Actuators B Chem. 2023, 382, 133505. [Google Scholar] [CrossRef]
  41. Subbotina, J.; Rouse, I.; Lobaskin, V. In silico prediction of protein binding affinities onto core–shell PEGylated noble metal nanoparticles for rational design of drug nanocarriers. Nanoscale 2023, 15, 13371–13383. [Google Scholar] [CrossRef] [PubMed]
  42. Liu, X.; Liang, X.; Yu, J.; Xu, K.; Shen, J.-W.; Duan, W.; Zeng, J. Recent development of noble metal-based bimetallic nanoparticles for colorimetric sensing. TrAC Trends Anal. Chem. 2023, 15, 117386. [Google Scholar] [CrossRef]
  43. Abuzeid, H.M.; Julien, C.M.; Zhu, L.; Hashem, A.M. Green synthesis of nanoparticles and their energy storage, environmental, and biomedical applications. Crystals 2023, 13, 1576. [Google Scholar] [CrossRef]
  44. Miao, W.; Hao, R.; Wang, J.; Wang, Z.; Lin, W.; Liu, H.; Feng, Z.; Lyu, Y.; Li, Q.; Jia, D. Architecture Design and Catalytic Activity: Non-Noble Bimetallic CoFe/Fe3O4 Core–Shell Structures for CO2 Hydrogenation. Adv. Sci. 2023, 10, 2205087. [Google Scholar] [CrossRef]
  45. Xinghao, L.I.U.; Cheng, C.; Zimu, X.U.; Shuheng, H.U.; Jie, S.; Yan, L.A.N.; Paul, K.C. Degradation of tetracycline in water by gas–liquid plasma in conjunction with rGO-TiO2 nanocomposite. Plasma Sci. Technol. 2021, 23, 115503. [Google Scholar] [CrossRef]
  46. Zhang, Q.; Li, J.; Xu, M. Ag-decorated ZnO-based nanocomposites for visible light-driven photocatalytic degradation: Basic understanding and outlook. J. Phys. D Appl. Phys. 2022, 55, 483001. [Google Scholar] [CrossRef]
  47. Usliyanage, J.P.; Perera, G.; Thiripuranathar, G.; Menaa, F. Synthetic strategies of Ag-doped ZnO nanocomposites: A comprehensive review. Biomass Convers. Biorefinery 2023, 1–21. [Google Scholar] [CrossRef]
  48. Thai, V.-P.; Furuno, H.; Saito, N.; Takahashi, K.; Sasaki, T.; Kikuchi, T. The essential role of redox potential/equilibrium constant in the ability of non-equilibrium plasma for nano-synthesis in liquids. J. Appl. Phys. 2020, 128, 043305. [Google Scholar] [CrossRef]
  49. Ingsel, T.; Gupta, R.K. Plasma at the nanoscale: An introduction. In Plasma at the Nanoscale; Elsevier: Amsterdam, The Netherlands, 2022; pp. 1–20. [Google Scholar]
  50. Abou El-Nour, K.M.M.; Eftaiha, A.; Al-Warthan, A.; Ammar, R.A.A. Synthesis and applications of silver nanoparticles. Arab. J. Chem. 2010, 3, 135–140. [Google Scholar] [CrossRef]
  51. Skiba, M.; Pivovarov, A.; Vorobyova, V.; Derkach, T.; Kurmakova, I. Plasma-chemical formation of silver nanoparticles: The silver ions concentration effect on the particle size and their antimicrobial properties. J. Chem. Technol. Metall. 2019, 54, 311–318. [Google Scholar]
  52. Verma, S.; Rao, B.T.; Srivastava, A.P.; Srivastava, D.; Kaul, R.; Singh, B. A facile synthesis of broad plasmon wavelength tunable silver nanoparticles in citrate aqueous solutions by laser ablation and light irradiation. Colloids Surf. A Physicochem. Eng. Asp. 2017, 527, 23–33. [Google Scholar] [CrossRef]
  53. Zheng, X.; Hu, J.; Li, J.; Shi, Y. Achieving Ultrahigh Hardness in Electrodeposited Nanograined Ni-Based Binary Alloys. Nanomaterials 2019, 9, 546. [Google Scholar] [CrossRef] [PubMed]
  54. Francis, S.; Joseph, S.; Koshy, E.P.; Mathew, B. Microwave assisted green synthesis of silver nanoparticles using leaf extract of elephantopus scaber and its environmental and biological applications. Artif. Cells Nanomed. Biotechnol. 2018, 46, 795–804. [Google Scholar] [CrossRef] [PubMed]
  55. Habib, T.; Caiut, J.M.A.; Caillier, B. Synthesis of silver nanoparticles by atmospheric pressure plasma jet. Nanotechnology 2022, 33, 325603. [Google Scholar] [CrossRef]
  56. Lin, L.; Li, S.; Hessel, V.; Starostin, S.A.; Lavrijsen, R.; Zhang, W. Synthesis of Ni nanoparticles with controllable magnetic properties by atmospheric pressure microplasma assisted process. AIChE J. 2018, 64, 1540–1549. [Google Scholar] [CrossRef]
  57. Mariotti, D.; Bose, A.C.; Ostrikov, K. Atmospheric-microplasma-assisted nanofabrication: Metal and metal–oxide nanostructures and nanoarchitectures. IEEE Trans. Plasma Sci. 2009, 37, 1027–1033. [Google Scholar] [CrossRef]
  58. Shimizu, Y.; Kawaguchi, K.; Sasaki, T.; Koshizaki, N. Generation of room-temperature atmospheric H2/Ar microplasma jet driven with pulse-modulated ultrahigh frequency and its application to gold nanoparticle preparation. Appl. Phys. Lett. 2009, 94, 191504. [Google Scholar] [CrossRef]
  59. Weerasinghe, J.; Li, W.; Zhou, R.; Zhou, R.; Gissibl, A.; Sonar, P.; Speight, R.; Vasilev, K.; Ostrikov, K.J.N. Bactericidal silver nanoparticles by atmospheric pressure solution plasma processing. Nanomaterials 2020, 10, 874. [Google Scholar] [CrossRef] [PubMed]
  60. Bjelajac, A.; Phillipe, A.-M.; Guillot, J.; Fleming, Y.; Chemin, J.-B.; Choquet, P.; Bulou, S. Gold nanoparticles synthesis and immobilization by atmospheric pressure DBD plasma torch method. Nanoscale Adv. 2023, 5, 2573–2582. [Google Scholar] [CrossRef]
  61. Du, C.; Xiao, M. Cu2O nanoparticles synthesis by microplasma. Sci. Rep. 2014, 4, 7339. [Google Scholar] [CrossRef]
  62. Lin, L.; Starostin, S.A.; Li, S.; Hessel, V. Synthesis of metallic nanoparticles by microplasma. Phys. Sci. Rev. 2018, 3, 20170121. [Google Scholar]
  63. Uytdenhouwen, Y.; Van Alphen, S.; Michielsen, I.; Meynen, V.; Cool, P.; Bogaerts, A. A packed-bed DBD micro plasma reactor for CO2 dissociation: Does size matter? Chem. Eng. J. 2018, 348, 557–568. [Google Scholar] [CrossRef]
  64. Hong, F.C.-N.; Yan, C.-J. Synthesis and characterization of silicon oxide nanoparticles using an atmospheric DC plasma torch. Adv. Powder Technol. 2018, 29, 220–229. [Google Scholar] [CrossRef]
  65. Thong, Y.L.; Chin, O.H.; Ong, B.H.; Huang, N.M. Synthesis of silver nanoparticles prepared in aqueous solutions using helium dc microplasma jet. Jpn. J. Appl. Phys. 2015, 55, 01AE19. [Google Scholar] [CrossRef]
  66. Bisht, A.; Roshan Deen, G.; Ilyas, U. Synthesis of Nanoparticles Using Atmospheric Microplasma Discharge. IAEA 2013. Available online: https://www.osti.gov/etdeweb/biblio/22127895 (accessed on 5 July 2024).
  67. Kondeti, V.; Gangal, U.; Yatom, S.; Bruggeman, P. Ag+ reduction and silver nanoparticle synthesis at the plasma–liquid interface by an RF driven atmospheric pressure plasma jet: Mechanisms and the effect of surfactant. J Vac. Sci. Technol. A 2017, 35, 061302. [Google Scholar] [CrossRef]
  68. Shepida, M.; Kuntyi, O.; Sukhatskiy, Y.; Mazur, A.; Sozanskyi, M. Microplasma synthesis of antibacterial active silver nanoparticles in sodium polyacrylate solutions. Bioinorg. Chem. Appl. 2021, 2021, 4465363. [Google Scholar] [CrossRef] [PubMed]
  69. Huang, X.; Zhong, X.; Lu, Y.; Li, Y.; Rider, A.; Furman, S.; Ostrikov, K. Plasmonic Ag nanoparticles via environment-benign atmospheric microplasma electrochemistry. Nanotechnology 2013, 24, 095604. [Google Scholar] [CrossRef] [PubMed]
  70. Shuaib, U.; Hussain, T.; Ahmad, R.; Zakaullah, M.; Mubarik, F.E.; Muntaha, S.T.; Ashraf, S. Plasma-liquid synthesis of silver nanoparticles and their antibacterial and antifungal applications. Mater. Res. Express 2020, 7, 035015. [Google Scholar] [CrossRef]
  71. Lin, L.; Li, X.; Zhou, J.; Zou, J.; Lai, J.; Chen, Z.; Shen, J.; Xu, H. Plasma-aided green and controllable synthesis of silver nanoparticles and their compounding with gemini surfactant. J. Taiwan Inst. Chem. Eng. 2021, 122, 311–319. [Google Scholar] [CrossRef]
  72. Vashistha, V.K.; Bala, R.; Das, D.K.; Mittal, A.; Pullabhotla, R.V. Transition Metal Nanoparticles As Promising Antimicrobial Agents. Surf. Rev. Lett. 2024, 31, 84. [Google Scholar] [CrossRef]
  73. Saleem, M.T.; Bashir, S.; Bashir, M. Microplasma assisted synthesis of silver nanoparticles capped with PVA, PVP and Sucrose. Nano Express 2021, 2, 020026. [Google Scholar] [CrossRef]
  74. Skiba, M.; Vorobyova, V.; Pivovarov, A.; Trus, I. Preparation of silver nanoparticles using atmospheric discharge plasma for catalytic reduction of p-nitrophenol: The influence of pressure in the reactor. Pigment. Resin Technol. 2020, 49, 449–456. [Google Scholar] [CrossRef]
  75. Iqbal, T.; Mukhtar, M.; Khan, M.; Khan, R.; Zaman, R.; Mahmood, H.; Zaka-ul-Islam, M. Atmospheric pressure microplasma assisted growth of silver nanosheets and their inhibitory action against bacteria of clinical interest. Mater. Res. Express 2016, 3, 125019. [Google Scholar] [CrossRef]
  76. Iqbal, T.; Aziz, A.; Khan, M.; Andleeb, S.; Mahmood, H.; Khan, A.A.; Khan, R.; Shafique, M. Surfactant assisted synthesis of ZnO nanostructures using atmospheric pressure microplasma electrochemical process with antibacterial applications. Mater. Sci. Eng. B 2018, 228, 153–159. [Google Scholar] [CrossRef]
  77. Schwan, A.; Chwatal, S.; Hendler, C.; Kopp, D.; Lackner, J.; Kaindl, R.; Tscherner, M.; Zirkl, M.; Angerer, P.; Friessnegger, B. Morphology-controlled atmospheric pressure plasma synthesis of zinc oxide nanoparticles for piezoelectric sensors. Appl. Nanosci. 2023, 13, 6421–6432. [Google Scholar] [CrossRef]
  78. Jain, G.; Macias-Montero, M.; Velusamy, T.; Maguire, P.; Mariotti, D. Porous zinc oxide nanocrystalline film deposition by atmospheric pressure plasma: Fabrication and energy band estimation. J. Plasma Process. Polym. 2017, 14, 1700052. [Google Scholar] [CrossRef]
  79. Abdullah, E.A.; Anber, A.A.; Edan, F.F.; Fraih, A.J. Synthesis of ZnO Nanoparticles by Using an Atmospheric-Pressure Plasma Jet. Open Access Libr. J. 2018, 5, 1–7. [Google Scholar] [CrossRef]
  80. Al-Rawi, B.K.; Mazhir, S.N. Evaluation of Antimicrobial Agents of Ag-ZnO Core-Shell Prepared by Micro-Jet Plasma Technique. Int. J. Nanosci. 2023, 22, 2350016–2350044. [Google Scholar] [CrossRef]
  81. Khalid, A.; Murbat, H.H.; Shanan, Z. Synthesis and characterization of gold–silver au/ag-core-shell nanoparticles by cold atmospheric pressure plasma. Biochem. Cell. Arch. 2019, 19, 3409–3414. [Google Scholar]
  82. Skiba, M.; Khrokalo, L.; Linyuchev, A.; Vorobyova, V. State of the Art on Plasma-liquid Route Synthesis monometallic Au, bimetallic Au/Ag core–shell and alloy nanoparticles: Toxicological, canalytical, antimicrobial activity for environmental control. J. Mol. Struct. 2024, 139293. [Google Scholar] [CrossRef]
  83. Sun, D.; Turner, J.; Jiang, N.; Zhu, S.; Zhang, L.; Falzon, B.G.; McCoy, C.P.; Maguire, P.; Mariotti, D.; Sun, D. Atmospheric pressure microplasma for antibacterial silver nanoparticle/chitosan nanocomposites with tailored properties. Compos. Sci. Technol. 2020, 186, 107911. [Google Scholar] [CrossRef]
  84. Aadim, K.A.; Abbas, I.K. Synthesis and Investigation of the Structural Characteristics of Zinc Oxide Nanoparticles Produced by an Atmospheric Plasma Jet. Iraqi J. Sci. 2023, 64, 1743–1752. [Google Scholar] [CrossRef]
  85. Bose, A.C.; Shimizu, Y.; Mariotti, D.; Sasaki, T.; Terashima, K.; Koshizaki, N. Flow rate effect on the structure and morphology of molybdenum oxide nanoparticles deposited by atmospheric-pressure microplasma processing. Nanotechnology 2006, 17, 5976. [Google Scholar] [CrossRef]
Surfaces 07 00044 g001
Figure 1. Applications of Zinc Oxide nanoparticles in diverse fields and conventional synthesis techniques.
Figure 1. Applications of Zinc Oxide nanoparticles in diverse fields and conventional synthesis techniques.
Surfaces 07 00044 g001
Surfaces 07 00044 g002
Figure 2. Atmospheric pressure plasma-based approaches for nanosynthesis.
Figure 2. Atmospheric pressure plasma-based approaches for nanosynthesis.
Surfaces 07 00044 g002
Surfaces 07 00044 g003
Figure 3. Schematic diagram of atmospheric pressure plasma jet system for nanomaterials synthesis (redrawn from Reference [55]).
Figure 3. Schematic diagram of atmospheric pressure plasma jet system for nanomaterials synthesis (redrawn from Reference [55]).
Surfaces 07 00044 g003
Surfaces 07 00044 g004
Figure 4. Schematic diagram of atmospheric dielectric barrier discharge for nanomaterials synthesis (redrawn from Reference [59]).
Figure 4. Schematic diagram of atmospheric dielectric barrier discharge for nanomaterials synthesis (redrawn from Reference [59]).
Surfaces 07 00044 g004
Surfaces 07 00044 g005
Figure 5. Schematic diagram of atmospheric pressure plasma torch method for nanomaterials synthesis: 1: quartz tube, 2: Pt coated injection tube, 3: aluminum foil, 4: generator (redrawn from Reference [60]).
Figure 5. Schematic diagram of atmospheric pressure plasma torch method for nanomaterials synthesis: 1: quartz tube, 2: Pt coated injection tube, 3: aluminum foil, 4: generator (redrawn from Reference [60]).
Surfaces 07 00044 g005
Surfaces 07 00044 g006
Figure 6. Schematic diagram of atmospheric pressure plasma method for nanomaterials synthesis (redrawn from Reference [61]).
Figure 6. Schematic diagram of atmospheric pressure plasma method for nanomaterials synthesis (redrawn from Reference [61]).
Surfaces 07 00044 g006
Surfaces 07 00044 g007
Figure 7. XRD pattern of silver nanoparticles prepared using the microplasma-assisted technique. (Reprinted with permission from Ref. [71].)
Figure 7. XRD pattern of silver nanoparticles prepared using the microplasma-assisted technique. (Reprinted with permission from Ref. [71].)
Surfaces 07 00044 g007
Surfaces 07 00044 g008
Figure 8. (a,b) TEM images of nanoparticles, (c) high-resolution TEM image of nanoparticles, (d) SAED image, and (e) size distribution histogram of nanoparticles. (Reprinted with permission from Ref. [71].)
Figure 8. (a,b) TEM images of nanoparticles, (c) high-resolution TEM image of nanoparticles, (d) SAED image, and (e) size distribution histogram of nanoparticles. (Reprinted with permission from Ref. [71].)
Surfaces 07 00044 g008
Surfaces 07 00044 g009
Figure 9. XRD pattern of ZnO nanomaterials prepared by numerous surfactants, (a) SDS, (b) fructose, and (c) CTAB. (Reprinted with permission from Ref. [76].)
Figure 9. XRD pattern of ZnO nanomaterials prepared by numerous surfactants, (a) SDS, (b) fructose, and (c) CTAB. (Reprinted with permission from Ref. [76].)
Surfaces 07 00044 g009
Surfaces 07 00044 g010
Figure 10. SEM images of ZnO nanomaterials prepared by numerous surfactants, (a) SDS, (b) fructose and (c) CTAB. (Reprinted with permission from Ref. [76].)
Figure 10. SEM images of ZnO nanomaterials prepared by numerous surfactants, (a) SDS, (b) fructose and (c) CTAB. (Reprinted with permission from Ref. [76].)
Surfaces 07 00044 g010
Surfaces 07 00044 g011
Figure 11. TEM images of Ag-ZnO core–shell nanoparticles synthesized using the micro-jet plasma technique. (Reprinted with permission from Ref. [80], Copyright @2023, World Scientific Publishing Co Pte Ltd.)
Figure 11. TEM images of Ag-ZnO core–shell nanoparticles synthesized using the micro-jet plasma technique. (Reprinted with permission from Ref. [80], Copyright @2023, World Scientific Publishing Co Pte Ltd.)
Surfaces 07 00044 g011
Surfaces 07 00044 g012
Figure 12. TEM images of gold–silver core–shell nanoparticles using a silver nitrate solution of (a) 0.25 and (b) 1.2-mM. (Reprinted with permission from Ref. [82].)
Figure 12. TEM images of gold–silver core–shell nanoparticles using a silver nitrate solution of (a) 0.25 and (b) 1.2-mM. (Reprinted with permission from Ref. [82].)
Surfaces 07 00044 g012
Table 1. Summary of advantages and disadvantages of various plasma-based nano synthesis techniques.
Table 1. Summary of advantages and disadvantages of various plasma-based nano synthesis techniques.
TechniqueAdvantagesDisadvantagesRef.
Plasma jet systemEfficient, high-purity products, flexibleCostly and complex power supply, broad size distribution, large particle size[62]
Dielectric barrier discharge systemLonger lifetime, better stability, simple geometric configurationLower energy efficiency, deposition of surplus carbon[63]
Plasma torch methodContinuous process, no expensive vacuum systemThe wide distribution of particle size, low surface area[64]
Plasma liquid systemSimple, efficient, highly confined high radical density, ultra-fine particle size, flexible precursors, narrow size distributionUnclear mechanism, post-treatment required [62]
Table 2. A literature review of atmospheric plasma configurations for synthesizing silver, zinc oxide, and silver–zinc oxide core–shell nanomaterial.
Table 2. A literature review of atmospheric plasma configurations for synthesizing silver, zinc oxide, and silver–zinc oxide core–shell nanomaterial.
No.Plasma
Configuration		NanomaterialsApplicationsCapillary
Diameter		PrecursorGas Flow RateVoltage &
Current		Ref.
01Atmospheric Pressure Microplasma jetSilverOptoelectronics, sensing, biomedical applicationsInternal diameter 0.26 mmAgNO3 + sucrose26 sccm2 mA[65]
02Atmospheric Pressure MicroplasmaSilverNanosensorsInternal diameter 0.7 mmAgNO3 + sucrose25 sccm0–15 kV[66]
03R.F. atmospheric pressure Microplasma jetSilverPhotovoltaicInternal diameter 5.25 mmAgNO31.5 slm [67]
04Microplasma SynthesisSilverAntibacterial activityInternal diameter 0.1 mmAgNO3 + NaPA 250 V[68]
05Atmospheric Microplasma electrochemistrySilverPlasmonic applications as sensingInternal diameter 0.175 mmAgNO3 + fructose25 sccm3 mA and 2 kV[69]
06Plasma liquid synthesisSilverAntibacterial and antifungal activitiesInternal diameter 0.34 mmAgNO3 + fructose100 sccm15 mA and 600 V[70]
07Plasma-aided green and controllable synthesisSilverAntibacterial activityInternal diameter 0.5 mmAgNO3 + Acetone30 sccm [71]
08Atmospheric pressure Plasma jetSilverBioactivity, catalysisInternal diameter 3.7 mmAgNO3 + trisodium citrate3 L/min8 A[55]
09Microplasma assisted synthesisSilverCancer therapyInternal diameter < 1 mmAgNO3 + PVA, PVP & sucrose600 sccm3–5 kV[73]
10Atmospheric discharge plasmaSilverCatalytic propertiesInternal diameter 2.4 mmAgNO3 + AlgNa 500–1000 V[74]
11Atmospheric pressure MicroplasmaSilverAntibacterial activityInternal diameter 0.2 mmAgNO3 + fructose150 sccm1000 V[75]
12Atmospheric pressure Microplasma electrochemical processZinc oxideAntibacterial applicationsInternal diameter 0.2 mmZn (NO3)2 + surfactant150 sccm1000 V[76]
13Atmospheric pressure plasma jet techniqueZinc oxidePiezoelectric sensors Zinc powder10 L/min200–400 A[77]
14Atmospheric pressure plasma (R.F. Power)Zinc oxideLight-emitting diodesInternal diameter 0.7 mmZinc wire150 sccm [78]
15Atmospheric pressure plasma jetZinc oxideSolar cells, Gas sensorsInternal diameter
0.6 mm		Zinc anode + NaOH + HNO3 + sucrose60 mL/min3 kV
5–10 mA		[79]
16Atmospheric pressure Microplasma JetAg-ZnO core shellsAntimicrobial activity AgNO3 + Zn (NO3)2 13 kV[80]
17Atmospheric pressure MicroplasmaAu-Ag core shellsOptical and biological propertiesInternal diameter 1 mmAgNO3 + HAuCl4. 3H2O2 l/min10 kV[81]
18Liquid-phase anode-type plasma dischargeAu-Ag core–shellAntibacterial and antifungal properties2.4 mm diameterHAuCl4⋅3H2O+ AgNO3 + sodium citrate-0.5–1 kV[82]
Table 3. Summary of influence of control parameters on the properties of silver, zinc oxide, and core–shell nanoparticles.
Table 3. Summary of influence of control parameters on the properties of silver, zinc oxide, and core–shell nanoparticles.
MaterialControl ParametersEffect of ParametersRef.
SilverSolution concentration
  • The size of nanosheets increases with increase in solution concentration;
  • Antibacterial activity of silver nanosheets enhanced with an increase in solution concentration.
[75]
  • The average size of nanoparticles increases with an increase in precursor concentration;
  • An increase in precursor concentration causes a significant increase in the inhibition zone against bacteria and fungi.
[83]
  • The large size and highly dispersive nanoparticles formed by increasing solution concentration.
[69]
ZnOProcessing time
  • An increase in processing time improves the crystallinity.
[79]
  • The average diameter and size of nanoparticles increase with the increase in processing time.
[84]
Silver
  • Increasing the exposure time to plasma increases the average size of nanoparticles.
[66]
SilverStabilizing agent concentration
  • The greater the concentration of fructose as a stabilizing agent, the more dispersed and relatively smaller nanoparticles are formed, and it reduces agglomeration. At greater fructose concentrations, the smaller nanoparticles have enhanced properties against bacteria.
[70]
SilverStabilizing agent concentration
  • The average size of nanoparticles decreases by increasing the molar ratio of sucrose in the precursor.
[65]
Molybdenum oxideGas flow rate
  • The size of nanoparticles reduces as the flow rate of gases rises.
[85]
Silver–gold core–shell Silver nitrate solution 0.25, 0.72, and 1.2-mM
  • The size of nanoparticles and shell thickness increases as the solution concentration increases.
[82]
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Khalid, A.; Naeem, M.; Atrooz, O.; Mozafari, M.R.; Anari, F.; Taghavi, E.; Rashid, U.; Aziz, B. State of the Art Synthesis of Ag-ZnO-Based Nanomaterials by Atmospheric Pressure Microplasma Techniques. Surfaces 2024, 7, 680-697. https://doi.org/10.3390/surfaces7030044

AMA Style

Khalid A, Naeem M, Atrooz O, Mozafari MR, Anari F, Taghavi E, Rashid U, Aziz B. State of the Art Synthesis of Ag-ZnO-Based Nanomaterials by Atmospheric Pressure Microplasma Techniques. Surfaces. 2024; 7(3):680-697. https://doi.org/10.3390/surfaces7030044

Chicago/Turabian Style

Khalid, Ayesha, Muhammad Naeem, Omar Atrooz, M. R. Mozafari, Fatemeh Anari, Elham Taghavi, Umair Rashid, and Bushra Aziz. 2024. "State of the Art Synthesis of Ag-ZnO-Based Nanomaterials by Atmospheric Pressure Microplasma Techniques" Surfaces 7, no. 3: 680-697. https://doi.org/10.3390/surfaces7030044

APA Style

Khalid, A., Naeem, M., Atrooz, O., Mozafari, M. R., Anari, F., Taghavi, E., Rashid, U., & Aziz, B. (2024). State of the Art Synthesis of Ag-ZnO-Based Nanomaterials by Atmospheric Pressure Microplasma Techniques. Surfaces, 7(3), 680-697. https://doi.org/10.3390/surfaces7030044

Article Metrics

Back to TopTop