Plant-based synthesis is recognized as one of the most widely utilized methods to produce nanoparticles due to its simplicity, cost-effectiveness, and scalability. This approach employs aqueous extracts derived from various parts of plants, including leaves, roots, fruits, and seeds, which serve as both reducing and capping agents (Puri et al., 2024). These extracts are abundant in bioactive compounds, such as flavonoids, phenols, alkaloids, and terpenoids, that promote the reduction of metal ions to nanoparticles while simultaneously stabilising their surface. The procedure generally involves the combination of the plant extract with a metal precursor solution, carried out under meticulously controlled conditions of temperature, pH, and agitation (Vijayaraghavan and Ashokkumar, 2017; Samuel et al., 2022).

Despite its widespread application, plant-based synthesis is influenced by numerous factors that can significantly impact the properties of the resulting nanoparticles. Key parameters such as the type of plant, extraction method, and concentration of bioactive compounds play a crucial role in determining the size, shape, and stability of nanoparticles (Khan et al., 2022; Alsaiari et al., 2023). However, a commonly overlooked aspect is the standardisation of plant extracts. Variations in plant composition caused by factors like seasonality, geographical location, and cultivation practices can introduce inconsistencies in the synthesis process (Antunes Filho et al., 2023; Wang et al., 2023). These discrepancies are often disregarded, leading to challenges in reproducibility and scalability. To address this issue, it is essential to conduct rigorous characterisation and standardisation of plant extracts prior to their use in nanoparticle synthesis (Hano and Abbasi, 2022; Heinrich et al., 2022).

Plant-based synthesis demonstrates remarkable compatibility with a diverse range of metal precursors, including silver, gold, copper, and zinc salts, as well as metal oxides (Thatyana et al., 2023). This compatibility arises from the variety of phytochemicals present in plant extracts, which can effectively interact with different metal ions to facilitate their reduction and stabilisation (Shi et al., 2022). The fundamental principle of plant-based synthesis is rooted in the redox chemistry of the phytochemicals found in plant extracts (Thatyana et al., 2023). These compounds serve as reducing agents by donating electrons to metal ions, thereby reducing them to their zero-valent nanoparticle form. Additionally, certain bioactive molecules act as capping agents, creating a stabilising layer on the nanoparticle surface to prevent aggregation. This dual role of phytochemicals—as both reducers and stabilisers are essential for the success of the synthesis process (Javed et al., 2022; Villagrán et al., 2024). The size, shape, and stability of the nanoparticles are influenced by the relative concentrations of the reducing and capping agents, as well as the reaction conditions, including pH, temperature, and precursor concentration (Gulcin and Alwasel, 2022).

The nanoparticle synthesis process is initiated with the preparation of a plant extract by boiling or macerating plant material in water or another solvent (Alabdallah and Hasan, 2021). This initial step facilitates the extraction of bioactive compounds that are instrumental in both the reduction and stabilization of nanoparticles. Following the filtration to eliminate solid residues, the resulting clear extract is combined with a metal precursor solution, such as silver nitrate for the synthesis of silver nanoparticles or chloroauric acid for gold nanoparticles (Bharadwaj et al., 2021; Giri et al., 2022). The reaction mixture is then maintained under carefully controlled conditions of temperature and pH, which are optimised according to the specific plant extract and metal precursor used. During the reaction, the bioactive compounds in the extract reduce the metal ions to their zero-valent state, facilitating the nucleation and growth of nanoparticles (Khan et al., 2022). Concurrently, other constituent functions as capping agents, stabilising the nanoparticles and preventing aggregation. The final product is purified through centrifugation or filtration to remove unreacted precursors and impurities (Samuel et al., 2022).

The biomedical application of plant-based synthesis presents numerous advantages, making it a preferred method for nanoparticle production. This method is environmentally sustainable, as it does not necessitate the use of hazardous chemicals or energy-intensive processes (Singh et al., 2023). The incorporation of natural plant materials renders the technique not only cost-effective but also widely accessible. Moreover, nanoparticles generated via this process frequently demonstrate improved biocompatibility, attributable to the presence of bioorganic capping agents, thereby enhancing their suitability for biomedical applications. Additionally, the scalability of this methodology facilitates its application in industrial-scale production, provided that appropriate optimisations are implemented (Begum and Jayawardana, 2023).

Despite these advantages, there are several limitations to this method. A major challenge is variability in plant composition due to environmental factors such as seasonal changes, geographical location, and cultivation practice (Kulkarni et al., 2023). These variations can lead to inconsistencies in the synthesis process, affecting nanoparticle size, shape, and stability. Moreover, the lack of standardised protocols for extract preparation and reaction conditions can hinder reproducibility. Yield and purity may also be lower compared to conventional chemical methods, and the presence of organic residues from the plant extract can complicate downstream applications (Hano and Abbasi, 2022; Ying et al., 2022).

Microbial-based green synthesis of GMNPs uses the metabolic activity of microorganisms such as bacteria, fungi, algae or yeast to reduce metal ions and stabilise nanoparticles. These organisms secrete enzymes, proteins, and metabolites capable of acting as reducing and capping agents (Ghosh et al., 2021; Ali et al., 2024). This method is particularly advantageous for its specificity and the ability to produce nanoparticles with well-defined shapes and sizes. Microbial synthesis is also considered environmentally friendly, as it typically occurs under mild reaction conditions and without the use of hazardous chemicals (Iravani, 2014; Sudheer et al., 2022).

Key factors influencing microbial synthesis include the choice of microorganisms, the composition of the culture medium, and the environmental conditions, such as pH, temperature, and nutrient availability (Guilger-Casagrande et al., 2021; Ali et al., 2024). The pH of the medium is a critical factor influencing the size, shape, and stability of nanoparticles (NPs). Microorganisms exhibit various responses to different pH levels, which affect the redox potential and enzymatic activity that are integral to NP synthesis. Furthermore, temperature serves as another essential parameter, significantly impacting reaction rates and the kinetics associated with NP formation. Additionally, the concentration of precursor compounds within the growth medium is a fundamental determinant of both NP yield and size (Priyadarshini et al., 2021; Rami et al., 2024). However, significant challenges arise from the lack of standardised protocols for microbial cultivation and nanoparticle recovery. The metabolic activity of microorganisms can vary widely depending on the strain, growth conditions, and age of the culture. These variations are often not fully characterised, leading to inconsistencies in nanoparticle synthesis. Additionally, the purification of nanoparticles from microbial biomass can be complex and time-consuming, a step that is frequently underestimated in the overall process (Grasso et al., 2019; Kapinusova et al., 2023).

GMNPs microbial synthesis supports a wide range of metal precursors, including iron, silver, gold, copper, and zinc salts, as well as metal oxides. Its compatibility stems from the metabolic versatility of microorganisms, which interact with metal ions through enzymatic and non-enzymatic pathways (Pulingam et al., 2022; Gonfa et al., 2023). The selection of compatible micro-organism plays a crucial role in determining the efficiency and characteristics of green-synthesized metal nanoparticles (G-MNPs). Bacteria like Pseudomonas aeruginosa and fungi such as Aspergillus flavus are commonly used due to their strong nanoparticle-producing capabilities. However, optimizing factors like pH, temperature, and nutrient composition is essential to enhance yield and quality (Ahmad et al., 2019b; Kumar et al., 2022; Noman et al., 2023). The synthesis process can occur intracellularly and extracellularly, where metal ions penetrate microbial cells and are reduced by enzymes, or extracellularly, where secreted biomolecules facilitate reduction and stabilization. Microbial redox reactions play a key role, with enzymes like nitrate reductase converting metal ions into nanoparticles while proteins and polysaccharides stabilize them. This process ensures nanoparticles form in specific shapes, such as spheres, rods, or triangles, and sizes ranging from a few to tens of nanometres (Markus et al., 2016; Mahdi et al., 2021; El-Bendary et al., 2021; Álvarez-Chimal and Arenas-Alatorre, 2023).

Microbial synthesis offers numerous advantages, making it a compelling method for green nanoparticle production. It is highly eco-friendly, as it utilizes renewable biological resources and operates under mild reaction conditions (Alsaiari et al., 2023; Álvarez-Chimal and Arenas-Alatorre, 2023). The method is cost-effective, given the low cost of microbial cultivation and the elimination of expensive chemicals. Additionally, the nanoparticles synthesized through this approach often exhibit enhanced biocompatibility due to the presence of biomolecular coatings, making them suitable for biomedical applications such as drug delivery and imaging and cell signalling. Furthermore, microbial synthesis provides an avenue for large-scale production, particularly when optimized for industrial applications (Lahiri et al., 2021; Alsaiari et al., 2023; Kiarashi et al., 2024). However, the method also has several limitations. The growth and metabolic activity of microorganisms can be sensitive to environmental factors, making the process less predictable and reproducible compared to chemical methods. Intracellular synthesis poses challenges in isolating nanoparticles from the cell matrix, which can add complexity to the purification process. The variability in microbial strains and culture conditions can lead to inconsistencies in nanoparticle size, shape, and yield. Moreover, microbial synthesis is slightly slower compared to other methods, which may limit its scalability without significant optimisation. (Álvarez-Chimal and Arenas-Alatorre, 2023; Kiarashi et al., 2024).

The biosynthesis of metal nanoparticles (MNPs) using plant extracts and microorganisms presents a clean, cost effective, and environmentally friendly alternative to conventional chemical and physical methods. At the heart of this process lies a complex cascade of biochemical events involving the reduction of metal ions and stabilization of nanoparticles via surface functionalization. This section elaborates on the molecular mechanisms underpinning these processes, supported by literature (Song and Kim, 2009).

In the green synthesis of nanoparticles, naturally occurring elements such as microbes and plant extracts are used to create environmentally safe components that serve as reducing and stabilizing agents. This method greatly reduces the need for dangerous chemicals that are usually used in traditional synthesis procedures. Compared to alternative techniques, the biological manufacturing of green nanoparticles within live cells is more effective and produces larger quantities (Ying et al., 2022). Numerous components and biochemicals that can function as stabilizers and reducers during the creation of nanoparticles can be found in abundance in plants. Green synthesis approaches are distinguished from conventional biological, physical, and chemical procedures by their greater stability, non-toxicity, affordability, and environmental friendliness. (Mustapha et al., 2022).

Green nanoparticles can be synthesized using three main techniques: extracellular, intracellular, and phytochemical-mediated. The phytochemical elements found in abundance in plant extracts serve as both stabilizing and reducing agents, making it easier for metal ions to be reduced to G-MNPs. Higher nanoparticle yields are produced by this method, which is also economical (Venkataraman, 2022).

Green synthesis, which frequently uses biological entities like plant extracts or microorganisms, produces nanoparticles with intrinsic biocompatibility. This technique makes them appropriate for a range of biomedical uses, such as treatment, imaging, and medication delivery. As a result, eco-friendly methods that make use of biopolymers, plant extracts, and biomolecules have gained importance (Ahmed et al., 2016b). In addition to acting as capping, reducing, and shape-modulating agents, these materials are accessible and biocompatible, making them perfect reagents. The many benefits and crucial significance of biogenic synthesis are illustrated in Figure 1. Clean analytical methods, environmentally friendly analytical chemistry, and green analytical chemistry are all heavily reliant on green chemistry, which uses chemicals to reduce pollution. The manufacturing of nanoparticles using green synthesis is especially appealing because of its environmental safety, inertness, and biocompatibility (Scala et al., 2022).

Green synthesis approaches often facilitate the production of nanoparticles with a narrow size distribution, a critical parameter for ensuring uniform physicochemical properties and reproducible performance in various applications. Microorganisms play a pivotal role in biogenic nanoparticle synthesis through both direct and indirect mechanisms. However, microbial-mediated synthesis is often characterized by slow reaction kinetics, posing challenges in controlling the heterogeneity of microbial species involved. Furthermore, nanoparticles synthesized via biological routes frequently exhibit variations in size distribution, necessitating specialized expertise during the manufacturing process. The requirement for skilled personnel can significantly elevate the costs associated with large-scale production and industrial translation (Saif et al., 2016).

The surface of green-synthesized nanoparticles can be effectively functionalized by modulating the biological components utilized during the synthesis process. This functionalization enhances their stability, biocompatibility, and specificity for targeted applications. Surface modification of nanoparticles can be accomplished through two principal approaches: (i) in situ functionalization, a one-step process wherein synthesis and surface modification occur concurrently, and (ii) post-synthesis modification, a sequential approach involving nanoparticle synthesis followed by subsequent surface modification. The physicochemical properties of the coating materials and the specific application requirements dictate the choice of coating strategy. Typically, nanoparticle surface functionalization involves ligand attachment, ligand exchange, or encapsulation, each tailored to optimize performance in diverse biomedical and technological applications (Thanh and Green, 2010). The surface functionalization of green-synthesized metal nanoparticles is illustrated in Figure 2.

Green-synthesized nanoparticles demonstrate enhanced stability due to the presence of natural stabilizing agents, which contribute to extended shelf life and consistent performance. Chemical vapor deposition (CVD) is a widely employed technique for depositing thin films onto surfaces using vapor-phase precursors, enabling the production of high-quality, uniform, and durable nanoparticles suitable for various applications (Baig et al., 2021). Green synthesis methodologies utilize bioactive agents derived from plant extracts, microorganisms, and biowastes to fabricate G-MNPs, presenting an eco-friendly, cost-effective, and scalable alternative with superior stability and non-toxic byproducts (Malhotra and Alghuthaymi, 2022). Within biological systems, NADH-dependent reductases facilitate electron transfer from metal ions to their elemental states, driving nanoparticle synthesis and stabilization through interactions with proteins and amino acids (Mohd Yusof et al., 2019).

Gold nanoparticles (AuNPs) are renowned for their unique optical properties, facile synthesis, and exceptional chemical stability, making them highly advantageous for applications in cancer therapy, bioimaging, biosensing, and targeted drug delivery (Sun et al., 2021). Their ability to facilitate controlled and site-specific drug release further enhances their therapeutic potential. Similarly, silver nanoparticles (AgNPs), zinc oxide nanoparticles (ZnONPs), and copper nanoparticles (CuNPs) exhibit distinct functionalities, including tumor-targeting capabilities, selective cytotoxicity toward cancer cells, and antimicrobial efficacy, respectively. The integration of nanoparticles into defence materials significantly enhances mechanical strength, thermal stability, and electrical conductivity, thereby improving overall performance and durability (Siddique and Chow, 2020; Anjum et al., 2021; Yuan et al., 2018). In energy storage applications, nanoparticles play a pivotal role in augmenting the efficiency and performance of batteries and fuel cells. As cathode materials in batteries, they contribute to increased energy density, enhanced rate capability, and improved cycling stability. In supercapacitors, nanoparticles effectively increase the specific surface area of electrode materials, leading to enhanced capacitance. Collectively, these advancements in nanotechnology substantially improve the performance, efficiency, and safety of energy storage systems utilized in defence applications (Morsi et al., 2022).

Green-synthesized nanoparticles (NPs) offer tunable physicochemical properties, including size, morphology, and surface chemistry, which can be precisely modulated during synthesis to meet specific application requirements. This adaptability makes them highly suitable for catalytic processes, sensing technologies, and environmental remediation. Green-synthesized metal nanoparticles (G-MNPs), in particular, exhibit exceptional catalytic efficiency, enabling chemical transformations at lower temperatures. For instance, platinum nanoparticles (PtNPs) are extensively utilized in fuel cell reactions, hydrogenation, and oxidation processes (Bhavani et al., 2021; Lara and Philippot, 2014); palladium nanoparticles (PdNPs) play a crucial role in hydrogenation and cross-coupling reactions (Pérez-Lorenzo, 2012); iron nanoparticles (FeNPs) facilitate hydrolysis and oxygen reduction reactions (Jiang and Xu, 2011); while nickel nanoparticles (NiNPs) contribute to hydrogenation and hydrolysis processes (Salem and Fouda, 2021).

Iron nanoparticles (FeNPs), typically ranging from 1 to 100 nm in size, find applications across diverse fields, including catalysis, targeted drug delivery, biosensing, energy storage, solar cell development, water purification, and as contrast agents in magnetic resonance imaging (MRI) (Khan et al., 2019). Mechanical milling techniques are commonly employed to downsize bulk materials into nanoscale structures, yielding reinforced aluminum alloys, wear-resistant coatings, and advanced nanocomposites with enhanced mechanical properties (Zhuang and Gentry, 2011; Jamkhande et al., 2019). Nanoparticles also play a critical role in biofuel production and environmental remediation. Platinum nanoparticles (PtNPs) have demonstrated efficacy in biomass-to-fuel conversion and in sensing applications, particularly for detecting Mercury(I) ions (Hg) in aqueous environments (Lam and Luong, 2014). While the application of green-synthesized metal nanoparticles (G-MNPs) holds significant promise, their development presents both challenges and opportunities for future advancements in electronics, energy storage, catalysis, and biomedical sciences (Kora and Rastogi, 2018).

Green-synthesized nanoparticles inherently exhibit potent antimicrobial properties, making them highly effective against a broad spectrum of microorganisms. This attribute is particularly valuable in applications such as antimicrobial coatings, food packaging, and water purification (Nandhini et al., 2023). Silver nanoparticles (AgNPs) are widely recognized for their broad-spectrum antibacterial efficacy and minimal cytotoxicity toward mammalian cells. As a result, they are extensively employed in wound dressings, antimicrobial gels, orthopedic implants, medical catheters, surgical instruments, implants, contact lens coatings, and additive manufacturing technologies (3D and 4D printing) (Pangli et al., 2021; Varaprasad et al., 2022). AgNPs synthesized using plant, fungal, and bacterial extracts exhibit significant antimicrobial potency (Ahmad et al., 2019a). For instance, AgNPs derived from Coriolus versicolor and Boletus edulis demonstrate strong antibacterial activity against both Gram-positive bacteria (Staphylococcus aureus, Enterococcus faecalis) and Gram-negative bacteria (Pseudomonas aeruginosa, Klebsiella pneumoniae). Furthermore, these nanoparticles enhance the antibacterial efficacy of chloramphenicol against methicillin-resistant S. aureus (MRSA) (Kaplan et al., 2021).

Zinc oxide (ZnO) nanoparticles exert antimicrobial effects by generating reactive oxygen species (ROS) upon exposure to light, effectively inhibiting microbial growth. ZnO nanoparticles are characterized by their biocompatibility, non-toxic nature, cost-effectiveness, environmental sustainability, and optical transparency, making them ideal for advanced biomedical applications (Kaushik et al., 2019). Green synthesis methodologies further enhance the functionality of ZnO nanoparticles by optimizing their particle size, photocatalytic activity, degradation efficiency, biocompatibility, antioxidant properties, and antibacterial potential, particularly in wound healing applications. Their high surface area and superior adsorption properties contribute to their enhanced antimicrobial efficacy (Faisal et al., 2021). We summarised the mechanism of wound healing and bactericidal activities of different G-MNPs in the below-mentioned Table 1.

The green synthesis of green-synthesized metal nanoparticles (G-MNPs) (NPs) leverages biological entities such as plants, bacteria, fungi, and algae to facilitate the bio-reduction of metal ions into nanoparticles. This environmentally sustainable approach yields biocompatible and biodegradable nanoparticles, making them highly suitable for various biomedical applications, particularly in wound healing. A key characteristic of G-MNPs is their enhanced biodegradability, primarily conferred by natural capping agents derived from biological sources. These capping agents, consisting of proteins, polysaccharides, and other biopolymers, play a pivotal role in regulating the gradual degradation of nanoparticles within biological systems. This controlled degradation enables the sustained release of metal ions, which actively contribute to tissue regeneration and the overall wound healing process (Radulescu et al., 2023).

Wound healing is a complex biological process that involves multiple phases, including hemostasis, inflammation, proliferation, and tissue remodeling. G-MNPs, such as Silver (AGNPs0, Gold (AUNPs), and Zinc Oxide (ZnO NPs), have shown significant potential in enhancing wound healing due to their antibacterial, anti-inflammatory, pro-angiogenic, and collagen-promoting properties.

One of the primary challenges in wound healing is infection, which can delay the process and lead to complications. G-MNPs exhibit strong antibacterial activity through various mechanisms. They disrupt bacterial cell membranes, causing increased permeability and structural damage, ultimately leading to cell death. Additionally. These nanoparticles induce the generation of reactive oxygen species (ROs), which contribute to oxidative stress, resulting in lipid peroxidation, protein degradation, and DNA fragmentation within bacterial cells. Furthermore, G-MNPs interfere with bacterial DNA replication, and protein synthesis, preventing microbial proliferation. By effectively eliminating infections at the wound site, these nanoparticles create a sterile environment, reducing the risk of complications and promoting faster healing (Shenashen et al., 2014; Jeyaraj et al., 2019). Inflammation plays a crucial role in wound healing; however, excessive inflammation can hinder tissue repair and lead to chronic wounds. G-MNPs help regulate inflammation by suppressing pro-inflammatory cytokines such as TNF-α, IL-6, and IL-1β, which are association with prolonged inflammation. At the same time, they enhance the expression of anti-inflammatory cytokines like IL-10, thereby ensuring a balanced immune response. Moreover, these nanoparticles reduce oxidative stress by neutralizing free radicals, minimizing cellular damage at the wound site. By modulating inflammation, G-MNPs create a favorable environment for tissue regeneration, leading to quicker and more efficient wound closure (Shenashen et al., 2014).

Angiogenesis, the formation of new blood vessels, is essential for supplying oxygen and nutrients to the wound site, facilitating tissue regeneration. Certain G-MNPs, particularly AUNPs and ZnO NPs, stimulate angiogenesis by upregulating vascular endothelial growth factor (VEGF) expression, which enhances new capillary formation. These nanoparticles also improve endothelial cell proliferation and migration, further supporting blood vessel development. Enhanced angiogenesis ensures an adequate oxygen and nutrient supply to the regenerating tissue, thereby accelerating wound closure, especially in chronic or non-healing wounds (Rajendran et al., 2018). Collagen is a fundamental component of the extracellular matrix (ECM), providing structural integrity and tensile strength to healed tissues. G-MNPs promote collagen synthesis by stimulating fibroblast proliferation and migration, which are essential for ECM deposition. Additionally, these nanoparticles regulate the expression of collagen-producing genes such as COL1 and COL3 while enhancing the activity of transforming growth factor-beta (TGF- β), a key factor in tissue remodeling and fibrosis. Increase collagen deposition leads to stronger, more resilient wound tissue, reducing the risk of reinjury and improving the overall healing outcome (Atala et al., 2010).

Green-synthesized nanoparticles are typically functionalized with natural biomolecules, which enhance their biocompatibility and minimize cytotoxic effects. These biologically derived coatings facilitate a controlled and sustained release of metal ions, promoting the safe biodegradation and excretion of nanoparticles from the body while mitigating potential adverse effects (Thomas et al., 2023).

The green synthesis of green-synthesized metal nanoparticles (G-MNPs) presents substantial environmental and economic benefits. This approach is inherently cost-effective, scalable, and eco-friendly, as it minimizes the reliance on hazardous chemicals and reduces energy consumption. The inherent biodegradability of these nanoparticles further mitigates environmental impact, making them particularly suitable for applications requiring controlled degradation (Selvan et al., 2018). Compared to conventional synthesis methods, green synthesis offers a more economical alternative by eliminating the need for costly and toxic reagents, while the utilization of abundant biological resources further lowers production expenses (Gowda et al., 2022).

The biological effectiveness of green-synthesized metal nanoparticles (G-MNPs), particularly in wound healing, antibacterial action, and anti-inflammatory therapy, is supported by their distinct physicochemical properties. Properties like surface charge, redox behavior, nanoscale size, and bifunctional surface ligands produced from microbial, or plant capping agents are important mechanisms (Guleria et al., 2022).

Because of their small size (usually between 10 and 100 nm), they can be efficiently taken up by cells by endocytosis, which allows for the targeted intracellular administration of reactive species or therapeutic substances. Both adhesion and internalization are impacted by the surface charge (zeta potential), which regulates electrostatic interactions with mammalian cell surfaces and microbial membranes. G-MNPs with a positive charge engage more strongly with negatively charged bacterial membranes, disrupting the membrane and killing the cell (Ahmed et al., 2016a).

Metal ions like Ag⁺ or Cu²⁺ in G-MNPs can catalyse the production of reactive oxygen species (ROS), such as superoxide and hydroxyl radicals, in terms of redox activity. Strong bactericidal actions are a result of the oxidative stress that harms the membranes, proteins, and DNA of microorganisms. By encouraging angiogenesis and fibroblast activation, ROS also affect wound healing at regulated doses (Kamaraj et al., 2024).

Further promoting tissue healing and immunomodulation are the anti-inflammatory and antioxidant qualities that phytochemical capping agents like flavonoids, terpenoids, and polyphenols provide. Through increased biocompatibility and less nonspecific protein adsorption, these surface ligands also lessen systemic toxicity (Karunakaran et al., 2023). G-MNPs are well suited for cutting-edge biomedical applications because of their combined physicochemical characteristics, which enable multifunctional therapeutic effects such as microbial clearance, inflammation suppression, oxidative balancing, and improved tissue regeneration (Soni et al., 2021).

Understanding the absorption, distribution, metabolism, and excretion (ADME) behavior, as well as the in vivo degradation and toxicity of green-synthesized metal nanoparticles (G-MNPs), is vital for their safe biomedical application. Different metallic nanoparticles exhibit diverse biological interactions depending on their composition, size, surface chemistry, and capping biomolecules produced from green synthesis techniques. The ADME properties and biological impacts of widely utilized G-MNPs, such as iron oxide (FeONPs), zinc oxide (ZnONPs), silver (AgNPs), and gold (AuNPs), are contrasted in this section (Hosseingholian et al., 2023).

Safe biomedical use of green-synthesized metal nanoparticles (G-MNPs) requires an understanding of their toxicity, in vivo degradation, and absorption, distribution, metabolism, and excretion (ADME) behavior. The biological interactions of various metallic nanoparticles vary based on their size, content, surface chemistry, and capping biomolecules that come from green production methods. This section contrasts the ADME properties and biological impacts of widely utilized G-MNPs, such as iron oxide (FeONPs), zinc oxide (ZnONPs), silver (AgNPs), and gold (AuNPs) (Vijayaram et al., 2024).

Long circulation periods and delayed clearance are caused by the poor reactivity and chemical inertness of gold nanoparticles (AuNPs). According to biodistribution studies, the liver, spleen, and lymph nodes exhibit preferential accumulation. Hepatic routes and Kupffer cell phagocytic uptake are the main mechanisms in which they are cleared. Concerns regarding long-term biopersistence are raised by the fact that AuNPs are frequently kept in tissues longer than other metal NPs because of their stability. However, in green production, surface functionalization with biocompatible plant chemicals decreases the formation of protein corona and increases cellular absorption, increasing their usefulness in drug administration and imaging applications (Balasubramanian et al., 2010).

Because zinc oxide nanoparticles (ZnONPs) are partially soluble in physiological solutions, they exhibit special behavior. ZnONPs easily break down into Zn2+ ions, which are absorbed throughout the body and support metabolic processes. Ionic degradation decreases long-term buildup and increases their biodegradability. Usually, ZnONPs are eliminated through the stools and urine. Their biological effects include fibroblast proliferation and cytokine expression regulation; nevertheless, at larger concentrations, excessive ROS generation from Zn2+ may cause oxidative tissue damage. Green-synthesized ZnONPs with polyphenolic capping agents typically have stronger anti-inflammatory properties and less cytotoxicity (Smaoui et al., 2023).

Iron oxide nanoparticles (FeONPs) are known for their magnetic characteristics and therapeutic usage in imaging and hyperthermia. After administration, they are transported largely to the liver and spleen, where they are taken up by macrophages (Dadfar et al., 2019). Iron ions are released when FeONPs break down inside lysosomes and enter the body’s iron metabolic pathways, such as ferritin storage and hemoglobin formation. The risk of poisoning is greatly decreased by this natural metabolism. Good tolerance is shown in vivo investigations, particularly when the surface is functionalized with biocompatible coatings made from green synthesis, like flavonoids or tannins (Jacinto et al., 2025).

Green synthesis can reduce some toxicity by reducing chemical residue and improving biocompatibility, but careful control of dose, route of administration, and particle characteristics remains crucial. Further research involving systematic in vivo models, long-term biodistribution tracking, and mechanistic toxicology studies will be necessary for the safe clinical translation of G-MNPs. Overall, the in vivo fate and safety of G-MNPs are highly dependent on particle size, solubility, and surface properties conferred by the natural reducing and capping agents (Kyriakides et al., 2021).

Nanoparticles exhibit immense potential in drug delivery, particularly in enhancing drug efficacy and bioavailability while enabling reduced dosages compared to traditional bulk drugs. Targeted drug delivery, essential for minimizing damage to healthy tissues, particularly in cancer therapies, can be achieved by delivering drugs directly to tumor sites. Magnetic nanoparticles, particularly iron oxide, are commonly employed for this purpose, with other nanoparticles, such as silver (Ag), titanium dioxide (TiO2), iron-platinum (Fe–Pt), zinc oxide (ZnO), and gold (Au) nanoparticles, also demonstrating promise in drug delivery applications (Chatterjee et al., 2014). Nanoparticles’ high surface-to-volume ratio allows for extensive surface modifications that enhance drug release control, improve pharmacokinetics, and increase bioavailability. Surface modification is essential for targeted drug delivery and monitoring drug release, leveraging nanoparticles’ size-dependent optical, electronic, and magnetic properties. Magnetic nanoparticles are widely used in diagnostic imaging as MRI contrast agents, while optical properties enable the use of nanoparticles as alternatives to organic dyes for imaging (Kelly et al., 2003; Guskos et al., 2008). Nanoparticles also enhance target specificity and bio-membrane permeability, enabling them to be ideal drug delivery vehicles. Research continues to explore the use of nanoparticles for signal detection, transmission, and amplification, employing their magnetic, optical, and electronic properties (Arora et al., 2011). Core/shell nanoparticles, which provide additional advantages, are increasingly employed in biomedical applications. However, concerns regarding the toxicity of nanoparticles, including their penetration across bio-membranes and interference with basal metabolic processes, remain a significant challenge. Accumulation in the body due to the lack of efficient elimination mechanisms can result in severe conditions, including Alzheimer’s and Parkinson’s diseases, potentially leading to long-term health complications (Buzea et al., 2007).

Magnetic hyperthermia (MH) represents a promising clinical approach for focal tumor treatment. This technique uses heat generated by magnetic nanoparticles when subjected to an alternating magnetic field (AMF) (Gilchrist et al., 1957). The advantages of MH, including high biosafety, deep tissue penetration, and selective tumor destruction, make it an attractive alternative to traditional cancer therapies (Ho et al., 2011). However, enhancing the efficiency of MH therapy remains a significant challenge, with particular focus on improving the thermal conversion efficiency of NPs. MH treatment involves heating tumors to temperatures above 42°C to induce cancer cell destruction, offering a targeted approach that spares surrounding healthy tissue. Iron oxide nanoparticles are commonly used for this application, but alternative NPs, such as bimetallic nanoparticles (Fe–Co, Cu–Ni) and other magnetic materials (Co–Fe2O4, Mn–Fe2O4), are also being explored (Liu et al., 2020).

For MH to be clinically viable, it is crucial to deliver adequate heat to the entire tumor while protecting healthy tissues. The therapeutic efficacy of MH is dependent on the magnetic susceptibility and thermal conversion efficiency of the NPs, with superparamagnetic iron oxide nanoparticles (SPIONs) being extensively studied for their biocompatibility (Hildebrandt et al., 2002; Vilas-Boas et al., 2020). Strategies to enhance thermal conversion efficiency include altering particle size (Mehdaoui et al., 2011), composition (Lee et al., 2011), shape (Lv et al., 2015), and surface characteristics (Liu et al., 2012). However, challenges remain due to the intrinsic limitations of NPs under AMF. Recent research suggests that localized induction heating at the nanoscale can modulate molecular properties, enhancing the effectiveness of MH therapy. MH is often used in combination with other cancer therapies, such as chemotherapy, radiotherapy, immunotherapy, and gene therapy, to improve treatment outcomes (Huang et al., 2010; Domenech et al., 2013).

Medical imaging is essential for early disease detection and monitoring therapeutic responses. Existing imaging techniques include X-ray, CT, MRI, ultrasound, PET, SPECT, and fluorescence imaging. The integration of multiple imaging modalities is often used to enhance lesion detection. Conventional contrast agents, however, face limitations such as rapid metabolism, non-specific distribution, and potential toxicity (Torres Martin DE Rosales et al., 2011).

Nanoparticles have revolutionized medical imaging by providing unique passive, active, and physical targeting properties that enhance detection and imaging. Their small size enables enhanced permeability and retention (EPR) effects in tumors, increasing the concentration of contrast agents at tumor sites (Cuccurullo et al., 2018; Oh et al., 2013). The biodistribution and tumor penetration of nanoparticles are influenced by their size (Hoshyar et al., 2016; Scott and Quaggin, 2015; Longmire et al., 2008), with nanoparticles ranging from 10 to 60 nm being particularly effective for cellular uptake. Surface modifications with specific ligands further enhance nanoparticle targeting capabilities (Zhou and Dai, 2018; Huang et al., 2012). In addition to passive targeting, nanoparticles can be functionalized with targeting ligands, such as antibodies, aptamers, and peptides, to improve specificity for imaging applications (Kim et al., 2010; Wang et al., 2017; Alibakhshi et al., 2017; Jo and Ban, 2016; Alshaer et al., 2018). Techniques like gold nanoparticle-based CT imaging and superparamagnetic iron oxide nanoparticle-based MRI for lung cancer detection are examples of how nanoparticle surface modifications can be employed to enhance imaging contrast. External stimuli, such as light, magnetic fields, and ultrasound, can also be used to direct nanoparticle localization and control drug release. Nanoparticle-based imaging technologies are expected to play a significant role in non-invasive diagnostic and therapeutic applications (Inaba and Matsuura, 2019; Zhong et al., 2014; Yu et al., 2016; Wang et al., 2018; Yang et al., 2018).

Biosensors are analytical devices that detect biological samples and convert biological responses into electrical signals. These sensors must be highly specific, stable, and capable of analyzing biochemical reactions independently of external conditions. Nanoparticles enhance biosensor performance by increasing surface area for interaction, improving sensitivity, and enabling real-time monitoring of biological responses.

Biosensors are typically classified based on their transducing system, including calorimetric, potentiometric, optical, piezoelectric, and amperometric types. Nanoparticles play a critical role in enhancing biosensor sensitivity, especially in piezoelectric, amperometric, and optical sensors, by leveraging their inherent magnetic, electro-sensitive, and optical properties (Arora et al., 2011). For example, nanoparticles can improve the resolution and response time of Field-Effect Transistor (FET)-based biosensors. Research is focused on developing nanoparticle-based biosensors for specific applications, such as glucose detection and in vivo diagnostics, by functionalizing nanoparticles with enzymes, antibodies, or other sensing molecules. Core/shell nanoparticles are particularly useful in improving the catalytic activity and stability of biosensors (Chatterjee et al., 2014). Piezoelectric biosensors exploit the oscillatory properties of piezoelectric materials to detect changes in mass (Guilbault, 1983; Wang et al., 2006). These systems are highly sensitive and offer advantages such as solid-state construction, chemical inertness, and cost-effectiveness. Nanoparticles enhance frequency detection by increasing the mass on the crystal surface and leveraging the inherent piezoelectric properties of the nanoparticles (Zhang et al., 2010). Recent advancements include the use of Fe oxide/Au nanoparticles to detect volatile organic compounds and Fe3O4/Au nanocomposites for DNA mutation detection. These systems rely on localized surface plasmon resonance (LSPR) and piezoelectric signals to enhance sensitivity and specificity (Hayashi and Ruppin, 1985). Amperometric biosensors detect redox reactions by generating a current in response to electron transfer (Li et al., 2012). These sensors benefit from nanoparticle enhancements that improve catalytic activity and stability (Luo et al., 2007). Core/shell nanoparticles enhance charge transport efficiency and enable the development of portable, fast-response biosensors for in-situ diagnostics (Qiu et al., 2007; Zhang et al., 2007; Jimenez et al., 2008; Tan et al., 2009). Recent innovations include nanoparticle-based sensors for detecting metabolic substrates such as glucose and H₂O₂. These sensors are designed with core metal transducer nanoparticles and insulating shells to enhance performance (Gupta and Gupta, 2005; Chen et al., 2010).

Optical biosensors use light-sensitive nanoparticles, such as quantum dots and noble green-synthesized metal nanoparticles (G-MNPs) (e.g., gold and silver), to detect biological interactions (Gole et al., 2008). Nanoparticles offer superior surface functionalization capabilities and can be used in combination with magnetic cores for enhanced dispersibility and chemical stability (Pita et al., 2008). These sensors utilize phenomena like Surface Enhanced Raman Scattering (SERS) and Dipole Plasmon Resonance (DPR) to detect target molecules with high sensitivity (Endo et al., 2010). In conclusion, G-MNPs hold vast potential in biomedical applications, offering solutions to challenges in drug delivery, disease detection, and therapeutic interventions. Further research into their properties, modifications, and interactions within biological systems will continue to drive advancements in nanomedicine (Hamer et al., 2010).

Photoablation therapy comprises two principal modalities: photodynamic therapy (PDT) and photothermal therapy (PTT). PDT leverages non-toxic, light-sensitive compounds known as photosensitizers, which exhibit cytotoxic properties upon activation by light of a specific wavelength. This approach is predominantly utilized for targeting diseased cells, including cancer cells (McNamara and Tofail, 2017). During PDT, photosensitizers such as TiO₂ nanoparticles are exposed to light at a particular wavelength, leading to the generation of photo-induced electrons and holes. These charge carriers interact with water molecules or hydroxyl ions, producing highly reactive oxidative species, including reactive oxygen species (ROS) and singlet oxygen, thereby inducing cell death. In contrast, PTT employs near-infrared (NIR) light to irradiate tumor cells. The absorbed light energy is converted into heat, causing localized hyperthermia and resulting in cell death. TiO₂ is an ideal candidate for PTT due to its biocompatibility, chemical stability, and intrinsic photocatalytic properties (Dougherty et al., 1998; Allison et al., 2006).

The photocatalytic mechanism of TiO₂ involves three critical steps: excitation, diffusion, and surface transfer. Initially, TiO₂ nanoparticles absorb photons from an external light source, imparting sufficient energy to overcome the material’s band gap and promoting electrons into the conduction band, leaving corresponding vacancies (holes) in the valence band. These electrons and holes subsequently diffuse to the surface of the photocatalyst. In the final stage, chemical reactions are triggered on the surface due to the presence of these charge carriers. The holes react with adsorbed water molecules to form hydroxyl radicals, while the electrons interact with oxygen to generate superoxide radicals. This cascade of photocatalytic reactions underpins the therapeutic effectiveness of TiO₂ in both PDT and PTT (Yin et al., 2013).

Magnetic nanoparticles (MNPs) have emerged as a focal point of interest in the biomedical sciences due to their remarkable potential and diverse applications in nanotechnology. Their ability to form conjugates with ligands and drugs has led to a wide array of biomedical innovations, including magnetic separation, biotechnology, targeted drug delivery, analyte preconcentration, and diagnostic imaging. Nanomedicine, an interdisciplinary field integrating biomedicine, nanotechnology, and biomaterials, leverages MNPs as an innovative approach to address complex biomedical challenges (Quader and Kataoka, 2017). MNPs are particularly advantageous for cancer treatment due to their precise and tunable properties, such as size, shape, charge, and surface modifications. These nanoparticles exhibit enhanced cellular uptake compared to non-metallic nanoparticles of equivalent size, providing a distinct benefit for targeted cancer therapy (Evans et al., 2018). The use of MNPs in biomedicine dates back to 1857, when Michael Faraday first described the synthesis of silver nanoparticles (AgNPs) in aqueous solutions, which led to the formation of a ruby-colored solution upon reaction with gold salt (Faraday, 1996).

The unique physicochemical properties of MNPs, including a high surface area-to-volume ratio, enhanced surface energy (El-Sayed, 2001), surface plasmon resonances (SPR), abundant dangling bonds, electron storage capacity, and the presence of sharp edges and corners, render them highly suitable for biomedical applications. MNPs can be synthesized using a range of techniques, including physical, chemical, and biological methods (Abdal Dayem et al., 2018). Pure MNPs include materials such as silver, gold, and copper, while metal oxide nanoparticles, such as titanium dioxide, silica, zinc oxide, and iron oxide, are also employed in various pharmaceutical and biomedical applications. However, the high surface energy of MNPs can lead to metal-metal aggregation, posing challenges in maintaining stable colloidal solutions. Ongoing efforts are focused on developing strategies to enhance the stability and functionality of MNPs, thereby maximizing their biomedical utility (Khursheed et al., 2022).

MNPs can be utilized for both passive and active targeting in drug delivery systems. In passive targeting, the rapid growth of solid tumors often results in poor lymphatic drainage and aberrant vasculature, enabling MNPs to accumulate at tumor sites through the fenestrations in the circulatory system. This phenomenon, known as the enhanced permeability and retention (EPR) effect, facilitates the preferential accumulation of nanoparticles within tumor tissues (Gil and Parak, 2008). Surface functionalization of nanoparticles with hydrophilic moieties, such as polyethylene glycol (PEG), enhances their solubility, reduces macrophage uptake, prevents premature elimination from circulation, and offers protection against enzymatic degradation during in vivo studies. For active targeting, nanoparticles can be functionalized with specific targeting ligands, such as antibodies, which bind to tumor-specific receptors or surface proteins. This approach facilitates selective targeting of cancer cells, thereby enhancing the therapeutic efficacy of the encapsulated drugs while minimizing damage to healthy tissues. Numerous studies have demonstrated the promising therapeutic outcomes of drug-loaded MNPs in cancer treatment, underscoring their potential to improve the precision and effectiveness of cancer therapies (Conde et al., 2012). Figure 4 provides a schematic representation of novel MNP-based drug delivery strategies for cancer treatment (Tagde et al., 2022).

G-MNPs’ cytotoxicity to mammalian cells is much decreased when they have natural capping agents on them. According to studies, when compared to their chemically synthesized counterparts, silver and gold nanoparticles made with extracts from Azadirachta indica, Aloe vera, or Camellia sinensis show less oxidative stress and greater fibroblast compatibility in skin models (Ahmed et al., 2016a, Mostafavi and Shabani, 2024).

At the wound site, oxidative stress and inflammatory cytokines are actively modulated by bioactive phytochemicals incorporated in G-MNPs. For instance, green-synthesized ZnO and AgNPs made with extracts from Curcuma longa or Ocimum sanctum show inhibition of ROS formation, IL-1β, and TNF-α, which speeds up the shift from inflammatory to proliferative wound healing phases (Hamed et al., 2023).

To reduce infection-related problems throughout the healing process, green-synthesised AgNPs and CuNPs have shown broad-spectrum antibacterial action against Staphylococcus aureus, E. coli, and Pseudomonas aeruginosa. Interestingly, both metal ion release and phytochemical components are responsible for the synergistic antibacterial activity (Pourmadadi et al., 2024).

Certain G-MNPs encourage angiogenesis, which is essential to produce granulation tissue and the delivery of nutrients. For example, in excisional wound models, gold nanoparticles made with leaf extract from Salvia officinalis markedly enhanced capillary development and VEGF expression. G-MNPs also promote collagen deposition, fibroblast migration, and re-epithelialization (Cucci et al., 2021).

Biological entities like plant extracts, fungus, or bacteria that include naturally occurring reducing and stabilizing chemicals like flavonoids, alkaloids, terpenoids, polyphenols, and proteins are used to create green-synthesized metal nanoparticles (G-MNPs). In addition to aiding in the production of nanoparticles, these biomolecules also stabilize and cap their surfaces, greatly increasing their biocompatibility and lowering the possibility of cytotoxicity. Better integration with host tissues, less inflammatory response, and enhanced cellular connections are all facilitated by this bio-functional surface layer (Aigbe and Osibote, 2024). On the other hand, chemically produced nanoparticles frequently contain residual hazardous chemicals (such as hydrazine and sodium borohydride) that might cause immunogenic reactions, oxidative stress, or damage to cell viability. Because of its safer profile, G-MNPs are especially well-suited for applications involving cutaneous wounds, where it is impossible to avoid direct contact with delicate tissue. When compared to chemically synthesized silver nanoparticles, for instance, silver nanoparticles made with Azadirachta indica (neem) leaf extract demonstrated significantly higher fibroblast proliferation, antimicrobial activity, and wound closure rate in vivo models, demonstrating the dual advantages of metallic ion activity and bioactive phytochemical synergy (Singh et al., 2023).

In the wound healing cascade, green-synthesized metal nanoparticles (G-MNPs) provide a multifunctional therapeutic profile that is very advantageous. These nanoparticles have a variety of bioactivities, such as angiogenic, antibacterial, anti-inflammatory, and antioxidant qualities, all of which are essential for encouraging tissue regeneration and repair. The bioactive substances found in the biological materials employed during synthesis frequently enhance the therapeutic potential of G-MNPs. In addition to the intrinsic qualities of the metal core, phytochemicals like polyphenols, flavonoids, terpenes, and alkaloids can stay adsorbed on the surface of the nanoparticle and have synergistic effects (Malik et al., 2025). By interfering with microbial membranes and biofilms, G-MNPs’ antimicrobial effect aids in preventing infection, which is a significant obstacle to wound healing. By lowering levels of pro-inflammatory cytokines like TNF-α and IL-6, their anti-inflammatory properties help to modulate the early inflammatory phase of healing and avoid chronic inflammation. As free radical scavengers, G-MNPs also promote cellular migration and proliferation while reducing oxidative stress in the wound microenvironment. Some metal nanoparticles, especially zinc oxide and gold, have angiogenic qualities that aid in tissue remodeling by encouraging neovascularization, which is necessary for the transport of nutrients and oxygen (Abuzeid et al., 2023). For example, bioactive curcuminoids, which have strong anti-inflammatory and antioxidant qualities, were preserved on the surface of gold nanoparticles made from Curcuma longa (turmeric). These nanoparticles greatly reduced pro-inflammatory cytokines like TNF-α and IL-6 in a diabetic wound model while encouraging tissue remodeling and epithelial regeneration, which sped up the healing process (Thiruvengadam et al., 2025).

Green-synthesized metal nanoparticles (G-MNPs) have been progressively included into a variety of cutting-edge wound care delivery methods in an effort to improve clinical translation and therapeutic efficacy. These consist of topical films, hydrogels, electrospun nanofibers, nanogels, and bio-composite dressings. In addition to acting as transporters, these formulations also act as useful scaffolding that actively aid in the healing of wounds. These delivery systems’ capacity to transport metal ions and nanoparticles in a controlled and maintained manner, guaranteeing a longer therapeutic effect at the wound site, is one of its main advantages. Furthermore, by keeping the environment moist, these systems promote cellular growth and re-epithelialization while thwarting microbial invasion and desiccation (Faghani and Azarniya, 2024). These materials frequently provide the wound bed with mechanical and structural support in addition to medication release. For example, fibroblast adhesion, migration, and the development of new tissue can be encouraged by electrospun nanofibers that imitate the extracellular matrix (ECM). For chronic and non-healing wounds, hydrogels—especially those derived from biopolymers like chitosan or alginate—offer exceptional biocompatibility and can be customized to react to the pH, temperature, or enzymatic activity of the wound (Liang et al., 2023). The addition of zinc oxide nanoparticles made with Aloe vera extract to a hydrogel matrix based on chitosan is a noteworthy illustration of this strategy. When tested on rat burn wound models, this composite dressing showed markedly faster wound contraction, increased angiogenesis, and decreased inflammation. Aloe vera’s inherent healing qualities, the bioactivity of ZnO nanoparticles, and the chitosan hydrogel’s moisture-retentive and biocompatible qualities were all credited with these therapeutic benefits. When included into cutting-edge wound dressings that satisfy both therapeutic and clinical usability requirements, such novel systems highlight the translational potential of G-MNPs(Alvandi et al., 2024).

A significant benefit of green-synthesized metal nanoparticles (G-MNPs) is their intrinsic economic viability and environmental sustainability, which makes them particularly appealing for clinical application in wound care, especially in environments with limited resources or low and middle incomes. As reducing and stabilizing agents, green synthesis uses naturally occurring materials like plant extracts, microbes, or agricultural waste, in contrast to traditional chemical or physical synthesis procedures that frequently call for significant energy inputs, hazardous solvents, and costly reagents. These biodegradable, renewable, and plentiful biological inputs greatly lower the environmental impact and production costs associated with the creation of nanoparticles (Aigbe and Osibote, 2024). Additionally, the green synthesis process can be scaled up in relatively mild conditions (ambient temperature and pressure), reducing the need for energy and infrastructure. For the industrial development of wound care solutions based on nanoparticles, which must be manufactured in large quantities without sacrificing efficacy or safety, scalability is essential. Furthermore, the low production of dangerous byproducts supports international objectives for green and sustainable nanotechnology, guaranteeing legal compliance and public health safety (Aigbe and Osibote, 2024). For example, Radulescu et al. (2023) found that the synthesis of plant-based nanoparticles supports environmentally aware, financially feasible clinical development by lowering the burden of disposing of hazardous waste and reducing the requirement for expensive synthetic chemicals. In this regard, G-MNPs offer a viable approach to creating accessible and reasonably priced wound care technologies with few legal and environmental restrictions (Radulescu et al., 2023).

Green-synthesized metal nanoparticles (G-MNPs) have shown promising therapeutic results and environmental benefits; nonetheless, several significant obstacles still stand in the way of their broad clinical application. The heterogeneity of synthesis procedures, especially when employing plant or microbial extracts, is one of the main obstacles. Batch-to-batch variations in nanoparticle size, shape, surface chemistry, and biological activity might result from the substantial variation in composition of these biological sources based on species, season, place of origin, and extraction conditions. These discrepancies make it challenging to meet regulatory requirements and produce repeatable therapeutic results (Kurul et al., 2025). A significant obstacle is the absence of thorough long-term safety data. The systemic toxicity, immunogenicity, biodegradation, and clearance profiles of G-MNPs over extended periods of time are still poorly understood, despite the fact that numerous studies have shown short-term biocompatibility and efficacy in vitro and in small animal models. Standardized in vivo testing frameworks and well planned preclinical research are required to fill in these toxicological data gaps (Kurul et al., 2025). Furthermore, the approval of nanomaterials originating from natural sources is surrounded by regulatory ambiguity. Uncertainty over classification, documentation requirements, and safety validation processes arises from regulatory authorities’ frequent absence of particular rules suited to green nanomaterials. This is a problem for both market authorization and large-scale manufacture (Singh et al., 2024). However, encouraging progress is being made to get over these obstacles. More control over the quality and consistency of nanoparticles is becoming possible thanks to developments in standardized synthesis processes, green chemistry validation frameworks, and high-resolution nanoparticle characterization techniques (such as TEM, DLS, FTIR, and XPS). Additionally, the incorporation of G-MNPs into translational pipelines is being expedited by interdisciplinary partnerships among materials scientists, toxicologists, and regulatory specialists. It is anticipated that these initiatives will soon open the door for safe, efficient, and economically feasible G-MNP-based wound care solutions with sustained research funding and policy development (Mulla, 2024).