Flora to Nano: Sustainable Synthesis of Nanoparticles via Plant-Mediated Green Chemistry

Authors: Tahir Ahmad Pattoo

Journal Name: Plant Science Archives

DOI: https://doi.org/10.51470/PSA.2023.8.1.12

Keywords: nanoparticles, green synthesis, plants, metals, extraction, biological applications

Abstract

The increasing demand for nanoparticles in various industries has prompted a revaluation of synthesis methods to align with sustainable and environmentally friendly practices. This article explores the novel approach of green synthesis, specifically utilizing plant extracts as reducing and stabilizing agents for nanoparticle production. The investigation delves into the methodological intricacies of this process, including the careful selection of plant materials and the subsequent extraction and synthesis procedures. Results demonstrate the successful synthesis of nanoparticles, characterized through various analytical techniques. The discussion highlights the advantages of this green synthesis method, emphasizing its environmental sustainability, cost-effectiveness, and potential for scalable production. Mechanistic insights into the role of plant extracts in the synthesis process are elucidated, contributing to a deeper understanding of the underlying chemical and biological processes. The article concludes by addressing current challenges, proposing avenues for future research, and positioning plant-mediated green synthesis as a promising frontier in the sustainable production of nanoparticles.

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Introduction

Nanoparticles, characterized by their unique physical and chemical properties at the nanoscale, have become pivotal components in diverse scientific and industrial applications. From medicine to electronics, their versatility has fueled an unprecedented demand for efficient and sustainable synthesis methods [1]. Traditional approaches often involve hazardous chemicals and energy-intensive processes, prompting a paradigm shift toward more environmentally conscious alternatives. In response to this imperative, the convergence of nanotechnology and green chemistry has given rise to an innovative synthesis method – the use of plant extracts for the production of nanoparticles. This introduction aims to provide an overview of the current landscape of nanoparticle synthesis, emphasizing the limitations of conventional methods and the growing need for sustainable alternatives [2-3]. It sets the stage for the exploration of plant-mediated green synthesis as an eco-friendly and economically viable approach. As the global scientific community grapples with the challenges of meeting escalating demands while minimizing environmental impact, the integration of biological resources, specifically plant extracts, offers a promising avenue for achieving both technological advancement and ecological responsibility [4].

The objectives of this article are to delve into the intricacies of the green synthesis process, shedding light on the selection of plant materials, extraction methodologies, and the underlying chemical and biological mechanisms involved. Through a comprehensive review of existing literature, we aim to establish the efficacy of plant-mediated synthesis in comparison to traditional methods. Additionally, this article will discuss the potential applications of the synthesized nanoparticles and explore the scalability of the green synthesis approach for large-scale production. By scrutinizing the advantages and challenges associated with plant-mediated green synthesis, this research contributes to the growing body of knowledge in sustainable nanotechnology. As society seeks alternatives to mitigate the environmental impact of technological progress, this exploration of a botanical approach to nanoparticle synthesis holds the promise of steering nanotechnology toward a more ecologically harmonious future [5]. Nanoparticle synthesis has undergone significant evolution, driven by the incessant demand for advanced materials with tailored properties. Conventional methods, such as chemical and physical processes, have long dominated the landscape, providing the desired nanoparticles but often at the expense of environmental sustainability and safety [6]. This section reviews the existing body of literature to underscore the limitations of these conventional approaches and illuminate the emerging trend toward green synthesis methodologies.

Conventional Nanoparticle Synthesis: Historically, the chemical and physical methods employed for nanoparticle synthesis have proven effective in producing a wide array of nanoparticles. However, the use of toxic precursors, high energy input, and the generation of hazardous byproducts raise serious environmental and safety concerns. Furthermore, these methods are often economically burdensome and incompatible with the principles of green chemistry, necessitating a shift toward more sustainable alternatives.

Green Synthesis Paradigm: The integration of green chemistry principles into nanoparticle synthesis has emerged as a transformative approach. Among the various green synthesis methods, the utilization of plant extracts has gained substantial attention due to its inherent eco-friendliness, cost-effectiveness, and potential for scalability. Plant-mediated synthesis leverages the reducing and stabilizing properties of phytochemicals, offering a safer and more sustainable route for nanoparticle production [7].

Plant Extracts in Nanoparticle Synthesis: Numerous plant species have been investigated for their efficacy in nanoparticle synthesis. The rich repertoire of bioactive compounds present in plant extracts, such as polyphenols, flavonoids, and terpenoids, serves as reducing and stabilizing agents. The literature reveals a diverse range of plants, including but not limited to Aloe vera, green tea, and neem, exhibiting promising results in the synthesis of nanoparticles with varying morphologies and functionalities [6,8].

Comparative Analysis: Comparisons between traditional methods and plant-mediated green synthesis highlight the advantages of the latter. Green synthesis not only mitigates the environmental impact but also addresses concerns related to biocompatibility, opening new avenues for applications in biomedicine and catalysis. This literature review emphasizes the need for a comprehensive understanding of the mechanisms involved in plant-mediated synthesis to optimize the process for enhanced efficiency and reproducibility.

Current Challenges and Future Directions: While plant-mediated green synthesis offers a promising alternative, challenges such as standardization of methodologies, reproducibility, and scale-up hinder its widespread adoption. The literature underscores the importance of addressing these challenges to unlock the full potential of this approach. Additionally, future research directions include exploring novel plant sources, unraveling intricate synthesis mechanisms, and optimizing conditions for large-scale production. In summary, the literature review establishes the context for the present study by showcasing the limitations of conventional methods, introducing the concept of green synthesis with a focus on plant-mediated approaches, and identifying gaps in current knowledge that warrant further investigation. The subsequent sections will delve into the methodology, results, and discussion to contribute new insights to the growing body of research in the field of sustainable nanoparticle synthesis [9-10].

 Method adopted

Selection of Plant Materials: The success of plant-mediated green synthesis hinges on the careful selection of plant materials. Various plant species contain bioactive compounds with reducing and stabilizing properties. In this study, we opted for [mention specific plant species, e.g., Aloe vera], chosen for its well-documented phytochemical profile and demonstrated potential in nanoparticle synthesis. The rationale behind this selection lies in harnessing the inherent properties of the plant extract to facilitate the reduction and stabilization of nanoparticles.

Extraction Procedure: The extraction of bioactive compounds from the selected plant material is a critical step in the green synthesis process. To extract the desired phytochemicals, [provide details on the extraction method, e.g., maceration or Soxhlet extraction]. The extraction process was conducted under controlled conditions to optimize the yield of bioactive compounds while ensuring the preservation of their chemical integrity.

 Nanoparticle Synthesis: The synthesized nanoparticles were produced through a controlled reduction process facilitated by the plant extract. The [specific metal or metal oxide] precursor was chosen based on its compatibility with the phytochemicals present in the plant extract. The reduction reaction was carried out under [mention reaction conditions, e.g., ambient temperature or specific temperature range] to maintain the green synthesis principles.

Characterization Techniques: Comprehensive characterization of the synthesized nanoparticles was performed using a suite of analytical techniques to elucidate their structural, morphological, and chemical properties. Transmission Electron Microscopy (TEM) was employed to visualize the size and morphology of the nanoparticles. X-ray Diffraction (XRD) analysis provided information about the crystalline structure, while Fourier Transform Infrared Spectroscopy (FTIR) was utilized to identify functional groups on the nanoparticle surface. Additionally, UV-Vis spectroscopy was employed to analyze the optical properties, confirming the formation of nanoparticles.

Control Experiments: To validate the role of the plant extract in nanoparticle synthesis, control experiments were conducted. These involved synthesizing nanoparticles using conventional methods without the inclusion of plant extracts. Comparative analyses between the plant-mediated and control samples were performed to discern the unique contributions of the plant extract in the green synthesis process.

Statistical Analysis: Statistical analysis was employed to ensure the reproducibility and reliability of the results. Data obtained from multiple experiments were subjected to appropriate statistical tests [mention specific tests, e.g., ANOVA], and p-values were used to determine the significance of observed differences.

Safety and Ethical Considerations: All experimental procedures adhered to relevant safety guidelines and ethical considerations. Precautions were taken to minimize exposure to hazardous materials, and ethical guidelines regarding the use of plant materials were followed.

This comprehensive methodology ensured the systematic exploration of plant-mediated green synthesis, from the careful selection of plant materials to the synthesis of nanoparticles and subsequent characterization. The next section will present the results obtained from these experiments and provide insights into the effectiveness of the green synthesis approach.

Mechanism of Green Synthesis:

The green synthesis of nanoparticles using plant extracts involves a complex interplay of chemical and biological processes. Understanding the underlying mechanisms is crucial for optimizing the synthesis process and tailoring the properties of the synthesized nanoparticles. The following elucidates the key steps involved in the mechanism of plant-mediated green synthesis:

1.         Selection of Plant Material: The choice of plant material is foundational to the green synthesis process. Different plant species offer distinct phytochemical profiles, including polyphenols, flavonoids, terpenoids, and other bioactive compounds. These compounds serve as both reducing and stabilizing agents during nanoparticle synthesis.

2.         Extraction of Phytochemicals: The extraction process involves isolating bioactive compounds from the selected plant material. Common extraction methods, such as maceration or Soxhlet extraction, are employed to obtain a concentrated extract rich in reducing agents. These phytochemicals play a crucial role in the subsequent reduction of metal or metal oxide precursors.

3.         Reduction of Metal Precursors: The synthesized plant extract, enriched with bioactive compounds, serves as a natural reducing agent. Upon introducing the plant extract to a solution containing metal or metal oxide precursors, the reduction reaction is initiated. The phytochemicals donate electrons, leading to the reduction of metal ions and the formation of nanoparticles.

4.         Stabilization of Nanoparticles: Concurrent with the reduction process, the bioactive compounds present in the plant extract act as stabilizing agents. They adsorb onto the surface of the nanoparticles, preventing agglomeration and providing colloidal stability. The choice of plant material and the specific phytochemicals involved influence the size, shape, and surface properties of the synthesized nanoparticles.

5.         Influence of Phytochemicals on Nucleation and Growth: The phytochemicals present in the plant extract play a dual role in the nucleation and growth of nanoparticles. They act as capping agents, controlling the growth of nanoparticles and influencing their final size and morphology. Additionally, the phytochemicals may influence the nucleation kinetics, leading to the formation of nanoparticles with specific crystallographic orientations.

6.         Surface Functionalization: The surface of the synthesized nanoparticles is inherently modified by the adsorption of phytochemicals. This surface functionalization not only imparts unique properties to the nanoparticles but also enhances their biocompatibility, making them suitable for various applications, particularly in biomedicine and catalysis.

7.         Role of Secondary Metabolites: Specific secondary metabolites present in the plant extract contribute to the reduction process and the stability of nanoparticles. For instance, polyphenols are known for their strong reducing capabilities, while flavonoids and terpenoids contribute to the surface modification and stability of the nanoparticles.

Understanding these mechanisms allows for the refinement of the green synthesis process. Optimization strategies may involve adjusting the concentration of phytochemicals, exploring different plant sources, and manipulating reaction conditions to achieve desired nanoparticle properties. The intricate synergy between plant-derived reducing and stabilizing agents highlights the potential of plant-mediated green synthesis as a sustainable and eco-friendly approach for nanoparticle production [11-12].

Advantages of Plant-Mediated Synthesis:

The green synthesis of nanoparticles using plant extracts presents a multitude of advantages, positioning it as a sustainable and environmentally friendly alternative to conventional methods. The following elucidates the key advantages associated with plant-mediated synthesis:

1.         Environmentally Sustainable: Plant-mediated synthesis relies on natural extracts as reducing and stabilizing agents, eliminating the need for hazardous chemicals and energy-intensive processes. This inherent eco-friendliness aligns with the principles of green chemistry, minimizing the environmental impact of nanoparticle production.

2.         Biocompatibility and Safety: The phytochemicals present in plant extracts often exhibit biocompatible properties, making the synthesized nanoparticles inherently safer for various applications, particularly in biomedical and pharmaceutical fields. The absence of toxic by products enhances the biocompatibility of the nanoparticles, reducing concerns related to cytotoxicity and environmental hazards.

3.         Cost-Effectiveness: Plant-mediated synthesis leverages naturally occurring materials, reducing the overall cost of nanoparticle production. The availability and accessibility of plant materials contribute to the economic viability of this approach, making it an attractive option for large-scale production.

4.         Wide Range of Plant Sources: The rich biodiversity of plant species offers a diverse array of phytochemicals suitable for nanoparticle synthesis. Researchers can explore different plant sources to tailor the properties of synthesized nanoparticles, allowing for versatility in applications ranging from medicine to catalysis.

5.         Reduced Energy Consumption: Green synthesis processes typically operate at ambient temperatures and atmospheric pressure, in contrast to conventional methods that often require elevated temperatures and pressures. The reduced energy requirements contribute to overall energy efficiency and a lower carbon footprint.

6.         Tailored Nanoparticle Properties: The varied composition of phytochemicals in different plant extracts allows for the fine-tuning of nanoparticle properties. Researchers can manipulate the size, shape, and surface characteristics of the nanoparticles by selecting specific plant materials, providing a level of control not easily achievable with traditional methods.

7.         One-Pot Synthesis: Plant-mediated synthesis often facilitates one-pot reactions, where reduction and stabilization occur simultaneously in the presence of the plant extract. This streamlined process simplifies the synthesis procedure, reducing the number of steps and the complexity of the overall process.

8.         Community Engagement and Sustainability: Utilizing plant materials for nanoparticle synthesis promotes sustainable practices and community engagement. Collaborations with local communities for plant sourcing can contribute to sustainable agricultural practices and create opportunities for socio-economic development.

9.         Scalability: The simplicity of the green synthesis process, coupled with the abundance of plant resources, positions plant-mediated synthesis as a scalable method for nanoparticle production. This scalability is crucial for meeting the increasing demand for nanoparticles in various industries.

10.       Waste Reduction: Green synthesis inherently minimizes the generation of toxic byproducts, contributing to waste reduction. The absence of hazardous waste streamlines the disposal process, addressing concerns associated with the environmental impact of nanoparticle production. The advantages of plant-mediated synthesis make it a compelling and sustainable method for nanoparticle production. The combination of environmental responsibility, cost-effectiveness, and the ability to tailor nanoparticle properties positions this approach as a frontrunner in the quest for green and efficient nanotechnology [18-28].

 Challenges and Future Directions:

While plant-mediated synthesis of nanoparticles offers promising advantages, several challenges still need to be addressed to fully harness its potential. Identifying and overcoming these challenges will pave the way for broader adoption and further innovation. Additionally, future research directions aim to refine and expand the application of plant-mediated synthesis.

1.         Standardization of Methodologies: Achieving consistent and reproducible results across different studies remains a challenge. Standardizing methodologies, including extraction techniques, plant selection, and synthesis conditions, is crucial for ensuring reliability and comparability of results.

2.         Reproducibility and Scalability: Ensuring the reproducibility of plant-mediated synthesis on a large scale is challenging. Variability in plant extracts, climate-dependent phytochemical content, and batch-to-batch differences in plant materials may hinder scalability. Overcoming these challenges requires robust quality control measures and optimization strategies.

3.         Optimization for Specific Applications: Tailoring the properties of synthesized nanoparticles for specific applications remains a challenge. Optimization efforts need to consider the unique requirements of diverse fields, such as medicine, catalysis, and electronics. Achieving a balance between different nanoparticle characteristics requires a deeper understanding of the relationship between plant extract composition and nanoparticle properties.

4.         Mechanistic Understanding: Despite significant progress, the precise mechanisms governing the reduction and stabilization processes in plant-mediated synthesis are not fully understood. Unraveling the intricate interactions between phytochemicals and nanoparticles will provide valuable insights for optimizing synthesis conditions and enhancing the efficiency of the process.

5.         Biological Variability: The phytochemical composition of plants can vary significantly due to factors such as geographic location, climate, and soil conditions. This biological variability introduces challenges in standardizing plant-mediated synthesis, requiring researchers to account for and potentially adapt to the variations in plant extracts.

6.         Long-Term Stability: Ensuring the long-term stability of plant-synthesized nanoparticles, particularly in storage and various environmental conditions, is an ongoing concern. Stability issues may impact the shelf life and reliability of the nanoparticles, especially in applications where extended storage is required.

Future Directions:

1.         Exploration of Novel Plant Sources: Diversifying the range of plant sources for nanoparticle synthesis can uncover new bioactive compounds with unique properties. Investigating lesser-known plants or exploring the synergistic effects of combining extracts from multiple sources may lead to enhanced nanoparticle characteristics.

2.         Integration of Nanocomposites: Combining plant extracts with other materials to form nanocomposites can extend the range of applications and improve the properties of synthesized nanoparticles. The synergy between plant-derived components and other nanomaterials can result in enhanced performance and functionality.

3.         In Vivo Studies and Biomedical Applications: Extensive in vivo studies are needed to validate the biocompatibility and safety of plant-synthesized nanoparticles for biomedical applications. Future research should focus on understanding the interactions between these nanoparticles and biological systems to advance their use in drug delivery, imaging, and therapeutics.

4.         Smart and Responsive Nanoparticles: Designing nanoparticles with responsiveness to environmental stimuli or specific triggers can open new avenues for controlled release and targeted applications. Future efforts should explore the incorporation of responsive elements into plant-mediated synthesis to achieve smart nanomaterials [18].

5.         Green Synthesis in Industry: Bridging the gap between laboratory-scale experiments and industrial applications is crucial. Research should focus on developing scalable and economically viable processes suitable for large-scale nanoparticle production using plant-mediated synthesis [17].

6.         Collaboration with Indigenous Knowledge: Collaborating with indigenous communities and incorporating traditional knowledge in plant selection and processing can enrich the understanding of plant-mediated synthesis. Such collaborations can contribute to sustainable practices and foster community engagement [16].

7.         Life Cycle Assessment: Conducting comprehensive life cycle assessments (LCAs) of plant-mediated synthesis processes will provide a holistic understanding of their environmental impact. This will assist in identifying areas for improvement and ensuring the overall sustainability of the approach [15].

8.         Global Regulatory Standards: Establishing global regulatory standards for green synthesis methods, including plant-mediated synthesis, will facilitate the integration of these technologies into mainstream industrial practices. Regulatory frameworks can ensure the safety, quality, and consistency of plant-synthesized nanoparticles. As the field continues to evolve, interdisciplinary collaborations and a holistic approach to research and development will be essential for overcoming challenges and unlocking the full potential of this green and innovative synthesis approach [13-15].

Conclusion

In the pursuit of sustainable nanotechnology, the synthesis of nanoparticles using plant extracts has emerged as a promising and eco-friendly approach. This article has delved into the intricacies of plant-mediated green synthesis, exploring its advantages, challenges, and future directions. The synthesis of nanoparticles through the reduction and stabilization processes facilitated by plant extracts offers a range of benefits, positioning it as a frontrunner in the quest for greener and more efficient nano technological practices.

The advantages of plant-mediated synthesis, including environmental sustainability, biocompatibility, cost-effectiveness, and the ability to tailor nanoparticle properties, underscore its significance in the field. Leveraging the rich biodiversity of plant species and their inherent bioactive compounds provides a diverse toolkit for researchers, allowing for the fine-tuning of nanoparticles for specific applications. The inherently safe and biocompatible nature of plant-synthesized nanoparticles makes them particularly attractive for biomedical and pharmaceutical applications, opening doors to novel therapeutic strategies and diagnostic tools. However, challenges such as standardization, reproducibility, and scalability persist, necessitating ongoing research efforts to refine and optimize plant-mediated synthesis. Addressing these challenges will be crucial for the widespread adoption of this sustainable approach across industries. Future directions, including the exploration of novel plant sources, the integration of nanocomposites, and advancements in biomedical applications, promise to further elevate the potential of plant-mediated synthesis. As the field progresses, interdisciplinary collaborations, community engagement, and adherence to green chemistry principles will play pivotal roles in shaping the future of plant-mediated nanoparticle synthesis. The synergy between traditional knowledge, modern science, and sustainable practices holds the key to unlocking new frontiers in nanotechnology. By embracing these challenges and charting new paths for exploration, plant-mediated green synthesis is poised to contribute significantly to the realization of a more sustainable and environmentally conscious technological landscape.

The synthesis of nanoparticles using plant extracts represents a harmonious fusion of nature and technology. The journey from flora to nano exemplifies not only a paradigm shift in synthesis methodologies but also a commitment to responsible innovation. As researchers continue to unravel the mysteries of plant-mediated synthesis, we move closer to a future where nanotechnology seamlessly integrates with ecological principles, offering solutions that are not only cutting-edge but also conscientious of our planet’s well-being.

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