System for the biosynthesis of zinc oxide nanoparticles using Hylocereus undatus leaf extract

Abstract

A system (100) for the biosynthesis of zinc oxide (ZnO) nanoparticles using Hylocereus undatus leaf extract, consisting of: ◯ a reaction vessel (101) configured to contain a zinc precursor solution; ◯ a leaf extract preparation module (102) configured to process Hylocereus undatus leaves to produce an extract containing bioactive phytochemicals; ◯ a combination device (103) for combining the zinc precursor solution with the Hylocereus undatus leaf extract to initiate a reduction reaction under ambient conditions, wherein the bioactive phytochemicals reduce zinc ions to form zinc oxide nanoparticles; ◯ a nanoparticle collection unit (104) for isolating, purifying and drying the zinc oxide nanoparticles produced in the reaction.

Description

Scope of the invention:

[0001] The present invention relates to the field of nanotechnology, particularly to the biosynthesis of zinc oxide (ZnO) nanoparticles using a green, environmentally friendly approach. More specifically, the invention focuses on the use of Hylocereus undatus (dragon fruit) leaf extract as a biological reducing and stabilizing agent for the synthesis of ZnO nanoparticles that can be used in various industrial, biomedical, and environmental applications. Background of the invention:

[0002] Zinc oxide (ZnO) nanoparticles have attracted considerable attention in recent years due to their versatile properties and wide range of applications in various industries. ZnO nanoparticles exhibit unique chemical and physical properties, such as high surface area, antimicrobial activity, UV protection, photocatalytic activity, and excellent electronic and optoelectronic properties. These properties make ZnO nanoparticles ideal for use in fields such as pharmaceuticals, cosmetics, environmental remediation, sensing, and electronics.

[0003] Conventional methods for synthesizing ZnO nanoparticles include chemical vapor deposition, sol-gel techniques, hydrothermal synthesis, and precipitation methods. While these conventional methods are suitable for producing ZnO nanoparticles, they often require harsh chemicals, high temperatures, and complex processes, leading to environmental pollution and high energy consumption. Furthermore, chemical synthesis methods often use toxic solvents and surfactants, which pose a threat to human health and the environment. Therefore, there is a growing need for more environmentally friendly and sustainable approaches to nanoparticle synthesis.

[0004] In response to these challenges, biosynthesis methods have emerged as environmentally friendly alternatives that utilize natural resources such as plant extracts, microorganisms, or enzymes for the synthesis of nanoparticles. Among these green synthesis methods, the use of plant extracts has attracted considerable interest due to their abundance, low cost, and ability to act as reducing, stabilizing, and capping agents in the synthesis of nanoparticles. Plant extracts are rich in bioactive compounds such as alkaloids, flavonoids, phenolic acids, and terpenoids, which play a crucial role in the reduction of metal ions and the stabilization of nanoparticles.

[0005] One such plant, Hylocereus undatus, commonly known as dragon fruit or pitaya, has been identified as a potential candidate for the green synthesis of ZnO nanoparticles. Hylocereus undatus belongs to the cactus family (Cactaceae) and is known for its high content of bioactive plant compounds, including flavonoids, phenolic compounds, polysaccharides, and vitamins. These bioactive compounds can act as natural reducing agents for the conversion of zinc ions (Zn 2+ ) into zinc oxide nanoparticles and at the same time stabilize the nanoparticles to prevent aggregation

[0006] The leaves of Hylocereus undatus are a particularly rich source of bioactive molecules traditionally used for various medicinal purposes. The secondary plant compounds contained in the leaves have reducing properties that make them suitable for use in green nanotechnology. In the context of the synthesis of ZnO nanoparticles, the phytochemical-rich leaf extract can efficiently reduce zinc salts to ZnO nanoparticles under mild reaction conditions, thus offering a simple, sustainable, and non-toxic approach for the production of nanoparticles.

[0007] The biosynthesis of ZnO nanoparticles using Hylocereus undatus leaf extract offers several advantages over conventional chemical methods: 1. Environmental friendliness: The process eliminates the need for hazardous chemicals and solvents, significantly reducing environmental impact. 2. Energy efficiency: The synthesis takes place at room temperature, which reduces energy consumption compared to high-temperature chemical processes. 3. Cost efficiency: The use of naturally available plant materials and simple processing steps reduces the overall cost of nanoparticle production. 4. Biocompatibility: The plant-based synthesis method results in biocompatible ZnO nanoparticles that are more suitable for biomedical applications, such as drug delivery, wound healing, and antibacterial coatings. 5. Scalability: The process is easy to scale and is therefore suitable for large-scale applications.

[0008] Despite the promising green synthesis methods, challenges remain in optimizing the yield, size control, and stability of nanoparticles produced with plant extracts. The present invention addresses these challenges by developing a system that standardizes the biosynthesis process using Hylocereus undatus leaf extract, ensuring consistent production of ZnO nanoparticles with controlled size, morphology, and high purity. Furthermore, the invention provides a method that is simple, cost-effective, and scalable for industrial applications, with the potential to replace conventional chemical methods that are environmentally harmful.

[0009] This invention contributes to the growing field of green nanotechnology by providing a sustainable solution for the production of ZnO nanoparticles and leveraging the unique properties of Hylocereus undatus leaf extract to achieve efficient biosynthesis under mild conditions. Given the increasing demand for environmentally friendly materials and processes, this system can serve as a basis for future innovations in the production of metal oxide nanoparticles using plant-based methods. Summary of the invention:

[0010] The present invention provides a novel and environmentally friendly system for the biosynthesis of zinc oxide (ZnO) nanoparticles using the leaf extract of Hylocereus undatus (dragon fruit). This system offers an environmentally friendly alternative to conventional chemical methods by utilizing the bioactive compounds in the leaf extract to produce zinc ions (Zn 2+) and to form ZnO nanoparticles in a sustainable, cost-effective and energy-efficient manner.

[0011] The system comprises a reaction vessel (101), a zinc precursor solution, a leaf extract preparation module (102), and a nanoparticle collection unit (104). The process begins with the preparation of the Hylocereus undatus leaf extract, which is mixed with a zinc salt solution (e.g., zinc acetate or zinc nitrate) under ambient conditions. The bioactive compounds in the extract serve as natural reducing and stabilizing agents, facilitating the formation of ZnO nanoparticles at room temperature without the need for harmful chemicals or excessive energy input.

[0012] Once the nanoparticles are formed, they are separated, purified, and characterized using techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-visible spectroscopy to confirm their size, structure, and optical properties. The resulting ZnO nanoparticles are of high purity and controlled size and are suitable for a range of applications, including antimicrobials, UV-blocking materials, and photocatalysts for environmental remediation.

[0013] This invention offers significant advantages, including environmental friendliness, cost-effectiveness, biocompatibility, and scalability, making it an ideal solution for industries seeking sustainable methods for nanoparticle production. Short description of the drawing:

[0014] The accompanying drawings are included to provide a further understanding of the present disclosure and are incorporated into and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure. Fig. Figure 1 shows a block diagram of a system (100) for the biosynthesis of zinc oxide (ZnO) nanoparticles using Hylocereus undatus leaf extract Detailed description of the invention:

[0015] The present invention relates to an innovative and sustainable system for the biosynthesis of zinc oxide (ZnO) nanoparticles using the leaf extract of Hylocereus undatus (dragon fruit). This system (100) offers an environmentally friendly, cost-effective, and scalable approach for the synthesis of nanoparticles, in which the natural bioactive compounds present in the leaves of Hylocereus undatus are used to reduce and stabilize zinc ions (Zn 2+ ) to ZnO nanoparticles.

[0016] The process requires minimal energy input and avoids the use of hazardous chemicals, making it a highly environmentally friendly alternative to conventional chemical synthesis methods. At the heart of the invention is a systematic process in which several key components work together to achieve efficient synthesis of ZnO nanoparticles. These components include a reaction vessel (101) for conducting the synthesis, a zinc precursor solution, a leaf extract preparation module (102), and a unit for collecting and purifying the biosynthesized nanoparticles.

[0017] The process begins with the preparation of the extract from the leaves of Hylocereus undatus, which plays a crucial role as a reducing and stabilizing agent in the synthesis of the nanoparticles. Fresh Hylocereus undatus leaves are first collected and thoroughly washed to remove all impurities. The clean leaves are then finely ground into a paste, which is subsequently mixed with a solvent such as distilled water or ethanol. The mixture is gently heated to extract the bioactive compounds such as flavonoids, phenolic acids, and polysaccharides, which are important for the reduction of zinc ions. This extract is then filtered to remove any plant residue, leaving a clear solution rich in phytochemicals.

[0018] At the same time, a zinc precursor solution is prepared by dissolving a zinc salt, such as zinc acetate or zinc nitrate, in distilled water. The concentration of the zinc precursor solution can vary depending on the desired size and yield of the ZnO nanoparticles. Typically, a concentration range between 0.01 M and 0.1 M is used. The zinc ions (Zn 2+ ) in the solution are reduced to ZnO nanoparticles in the next step of the synthesis

[0019] Once the leaf extract and the zinc precursor solution are ready, the actual biosynthesis of ZnO nanoparticles takes place in the reaction vessel (101). The reaction vessel (101) is designed to maintain ambient conditions, control temperature, and ensure continuous stirring for even mixing. The leaf extract is added dropwise to the zinc precursor solution with constant stirring. During the reaction, the bioactive compounds in the extract facilitate the reduction of Zn. 2+ -ions to form ZnO nanoparticles. This process typically occurs at room temperature, so high energy input is not required. The reaction is carried out for 2 to 6 hours. During this time, a color change is observed, usually from light yellow to milky white, indicating the formation of ZnO nanoparticles.

[0020] After biosynthesis, the reaction mixture undergoes a purification process to isolate the ZnO nanoparticles. The mixture is centrifuged at high speeds (typically 10,000 rpm for 15 minutes) to separate the nanoparticles from the remaining solution. The collected nanoparticles are then washed several times with distilled water and ethanol to remove any residual organic matter or unreacted precursors. The washed nanoparticles are then dried for 24 hours at approximately 60 °C to obtain the final product: purified ZnO nanoparticles.

[0021] The ZnO nanoparticles prepared using this method are characterized using various analytical techniques to evaluate their size, morphology, crystalline structure, and optical properties. X-ray diffraction (XRD) confirms the crystalline nature of the ZnO nanoparticles, while scanning electron microscopy (SEM) provides information on their surface morphology and size distribution. UV-Vis spectroscopy is used to evaluate the optical properties, including the absorption behavior and band gap of the nanoparticles. These characterization techniques ensure that the biosynthesized ZnO nanoparticles possess the desired properties for various industrial applications.

[0022] One of the most important advantages of the invention is the environmental friendliness of the process. Unlike conventional processes that rely on toxic chemicals, this system (100) uses only naturally occurring plant materials that are biodegradable and do not pollute the environment. The process is also energy-efficient, as it can be carried out at room temperature without the need for high energy input, such as heating or special equipment. Furthermore, the system (100) is suitable for industrial applications due to its scalability, as the process can be easily adapted to the production of large quantities of ZnO nanoparticles.

[0023] The ZnO nanoparticles produced with this system (100) have a wide range of potential applications. Due to their antimicrobial properties, they can be used in medical devices, wound dressings, and antimicrobial coatings. Their excellent UV-blocking ability makes them ideal for sunscreens, cosmetics, and textiles. Furthermore, ZnO nanoparticles are highly effective photocatalysts that can be used in environmental remediation processes, such as the degradation of organic pollutants in wastewater.

[0024] The system (100) for the biosynthesis of zinc oxide (ZnO) nanoparticles using Hylocereus undatus leaf extract utilizes a streamlined and environmentally friendly process that integrates natural, plant-derived materials with simple reaction conditions to achieve the desired nanoparticle synthesis. The mechanism of this invention can be divided into several key steps, each of which plays a crucial role in the successful production of ZnO nanoparticles with controlled size, morphology, and purity. The process begins with the preparation of the Hylocereus undatus leaf extract, which is fundamental to the biosynthesis. Fresh leaves of the plant are collected, washed, and finely ground into a paste.

[0025] This paste is mixed with a solvent such as distilled water or ethanol to extract the bioactive phytochemicals contained in the leaves. These phytochemicals include compounds such as flavonoids, phenolic acids, alkaloids, and polysaccharides, which possess natural reducing and stabilizing properties. After a gentle heating process to enhance the extraction of these compounds, the mixture is filtered to obtain a clear liquid extract. This extract serves as a natural reducing agent, promoting the formation of ZnO nanoparticles in the subsequent steps.

[0026] In parallel, a zinc precursor solution is prepared by dissolving a zinc salt, e.g., zinc acetate or zinc nitrate, in distilled water. This zinc solution is a source of zinc ions (Zn 2+), which are essential for the formation of ZnO nanoparticles. The concentration of the zinc precursor is selected according to the desired size and properties of the nanoparticles and maintained in the reaction vessel (101) with constant stirring to ensure homogeneity.

[0027] The actual synthesis of the ZnO nanoparticles is carried out by gradually adding the leaf extract of Hylocereus undatus to the zinc precursor solution. The reaction is carried out at ambient conditions, usually at room temperature, without the need for external heating or complex reaction equipment. When the leaf extract is added to the zinc solution, the bioactive compounds in the extract immediately begin to convert the zinc ions (Zn 2+) to zinc oxide (ZnO). During this reduction process, the phytochemicals not only reduce the zinc ions but also act as stabilizers, preventing the aggregation of the newly formed nanoparticles and ensuring their uniform distribution in the solution.

[0028] This reduction reaction is indicated by a significant change in the color of the solution. Initially, the mixture is colorless or light yellow, due to the presence of zinc ions and the leaf extract. As the reaction progresses, the solution becomes milky white, indicating the formation of ZnO nanoparticles. The entire synthesis process typically takes between 2 and 6 hours, depending on the concentration of the zinc precursor and the reaction conditions.

[0029] After the biosynthesis of the ZnO nanoparticles, the reaction mixture undergoes a purification process to separate the nanoparticles from the remaining plant material and unreacted precursors. The mixture is first centrifuged at high speeds to separate the solid nanoparticles from the liquid phase. The resulting ZnO nanoparticles are then washed several times with distilled water and ethanol to remove impurities and organic residues. This washing process ensures that the final product consists of pure ZnO nanoparticles.

[0030] After purification, the ZnO nanoparticles are dried at moderate temperature (approximately 60 °C) to remove any residual moisture. The dried nanoparticles can then be collected for further characterization and use in various applications. Modern characterization techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-Vis spectroscopy are used to analyze the size, morphology, crystallinity, and optical properties of the synthesized nanoparticles. These analyses confirm that the biosynthesized ZnO nanoparticles possess the desired properties, including high purity and uniform size distribution.

[0031] The working mechanism of this invention is environmentally friendly, as it relies exclusively on natural plant extracts to drive nanoparticle synthesis without the use of hazardous chemicals or extreme reaction conditions. The bioactive compounds in Hylocereus undatus leaf extract not only reduce zinc ions to ZnO nanoparticles but also stabilize the particles, preventing them from aggregating into larger, less useful forms. This dual functionality of the leaf extract streamlines the process and simplifies the reaction setup, eliminating the need for additional chemical stabilizers or surfactants commonly used in conventional chemical synthesis methods.

[0032] The entire system is designed to operate under mild conditions, with minimal energy input, and without toxic byproducts, making it an ideal solution for large-scale, sustainable nanoparticle production. Furthermore, the process can be easily scaled up to an industrial level by increasing the volume of the reaction vessels and adjusting the amounts of zinc precursor and leaf extract accordingly.

[0033] In summary, the system (100) for the biosynthesis of ZnO nanoparticles involves the extraction of bioactive compounds from the leaves of Hylocereus undatus and their subsequent introduction into a zinc precursor solution. The natural reducing properties of the leaf extract facilitate the formation of ZnO nanoparticles under ambient conditions, and the nanoparticles are subsequently purified, characterized, and collected for further applications. This green synthesis method is not only cost-effective and scalable, but also environmentally friendly, offering an alternative to conventional chemical approaches for nanoparticle production.

[0034] In summary, the invention represents a novel and sustainable method for the biosynthesis of ZnO nanoparticles using Hylocereus undatus leaf extract. This green synthesis method offers a safe, cost-effective, and scalable approach for the production of ZnO nanoparticles with potential applications across a wide range of industries. The use of natural, plant-derived materials and the energy-efficient process address the growing demand for environmentally friendly nanotechnology solutions. LIST OF REFERENCE SYMBOLS 100 System for the biosynthesis of zinc oxide (ZnO) nanoparticles using Hylocereus undatus leaf extract 101 Reaction vessel 102 Leaf extract processing module 103 Combination device 104 Nanoparticle collection unit

Claims

[1] A system (100) for the biosynthesis of zinc oxide (ZnO) nanoparticles using Hylocereus undatus leaf extract, consisting of: ◯ a reaction vessel (101) configured to contain a zinc precursor solution; ◯ a leaf extract processing module (102) configured to process Hylocereus undatus leaves to produce an extract containing bioactive phytochemicals; ◯ a combining device (103) for combining the zinc precursor solution with the Hylocereus undatus leaf extract to initiate a reduction reaction under ambient conditions, wherein the bioactive phytochemicals reduce zinc ions to form zinc oxide nanoparticles; ◯ a nanoparticle collection unit (104) for isolating, purifying and drying the zinc oxide nanoparticles produced in the reaction. [2] The system (100) of claim 1, wherein the zinc precursor solution comprises a zinc salt selected from the group consisting of zinc acetate, zinc nitrate, and zinc chloride. [3] The system (100) of claim 1, wherein the leaf extract processing module (102) comprises a grinder for finely grinding Hylocereus undatus leaves and a solvent extraction unit for dissolving the bioactive compounds in water or ethanol. [4] The system (100) of claim 1, wherein the combining means (103) for combining the zinc precursor solution and the leaf extract further comprises a temperature control unit for maintaining the reaction at room temperature throughout the synthesis process. [5] The system (100) of claim 1, wherein the bioactive phytochemicals in the Hylocereus undatus leaf extract include flavonoids, phenolic acids, alkaloids, and polysaccharides that act as both reducing and stabilizing agents in the formation of zinc oxide nanoparticles. [6] The system (100) of claim 1, wherein the nanoparticle collection unit (104) comprises a centrifuge to separate the nanoparticles from the reaction mixture, followed by a washing system that removes residual organic matter using distilled water and ethanol.

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