COMPARISON OF DIFFERENT NANOPARTICLE PREPARATION METHOD – A REVIEW

COMPARISON OF DIFFERENT NANOPARTICLE PREPARATION METHOD - A REVIEW

Ali Mohammed Mohammed Ali AL-samman, Kashif Hussain *, Mohd Aasif and Vaibhav Singh

Pharmacy Department, Guru Nanak College of Pharmaceutical Sciences, Dehradun, Uttarakhand, India.

ABSTRACT: Nanoparticles have gained significant attention in various scientific and industrial field due to their unique physical, chemical and biological properties. The method of nanoparticle synthesis plays a crucial role in determining their size, shape, stability and functional efficiency. This review provides a detailed comparative analysis of various nanoparticle preparation method, primarily focusing on top-down and bottom-up approaches. Top-down methods such as laser ablation, ball milling offers past production and high purity; however, they often lack precise control over particle size. Bottom-up approaches, including sol-gel, spinning, biological synthesis employing plant extracts, bacteria and fungi has emerged as an eco-friendly and cost-effective alternative, although achieving consistent yield and particle size remain as challenge. This review highlights the advantages, limitations of each synthesis. The study also emphasizes the importance of selecting an appropriate synthesis technique based on the intended application and desired nanoparticle properties. Additionally, recent advancements in nanoparticle preparation and future directions of sustainable and large-scale productions are discussed. This comparative overview aims to assist researchers in selecting the most effective preparation method to enhance nanoparticle performance for targeted applications.

Keywords: Nanoparticles, Synthesis method, Top-down method, Bottom-up method

INTRODUCTION: Nanotechnology has been a prominent field of research since previous century. The term nanotechnology was introduced by Richard P. Feyman in his famous 1959 lecture, “There is plenty of room at the bottom ¹.” Nanoparticles (NPs) have gained significant attention in recent years due to their unique physiochemical properties, which make them valuable across various fields, including electronics, energy storage, and environmental applications.

Their small size, typically ranging from 1 to 100 nm and large surface area to volume ratio allows them to exhibit enhanced surface area, reactivity and tunable optical and mechanical properties compared to bulk materials ². Nanoparticle can be classified as 0D, 1D, 2D, 3D based on their shape ³. The importance became evident when researchers discovered that size influence the physiochemical properties of material including their optical characteristic.

Several approaches exist for nanoparticle synthesis, broadly categorized into top down and bottom-up methods. Top-down approaches such as mechanical milling and laser ablation, involve breaking down materials into nanosized particles, whereas bottom up approaches, including chemical reduction, sol-gel synthesis and biological synthesis, build nanoparticles atom by atom or molecule by molecule. Each method has its advantages and limitations concerning particle size control, stability, cost-effectiveness, environmental impact, and application suitability ^{4, 5}.

Classification of Nanoparticles: Nanoparticle vary in dimensions, shapes, sizes depending on their composition ⁶. They can be classified based in their dimensionality: zero dimensional nanoparticles have all three spatial dimensions confined to a single dot such as nanodots. One dimensional structure extends only in one direction, as seen in material like graphene. Two-dimensional nanoparticle have both length and bredth but are extremely thin, for example carbon nanotubes. Three dimensional nanoparticles possess length, breadth and height, such as gold nanoparticles. Nanoparticles also exhibit diverse shapes, size and structures, they may appear as spherical, cylindrical, tublar, conical, hollow core, spiral, flat or irregular forms, with sizes typically ranging from 1 nm to 100nm. Their surfaces can be smooth or rough, uniform or varied. Additionally, nanoparticles can exist in crystalline or amorphous state and may be composed of single or multiple crystals, either as discrete entities or agglomerated structures ⁷.

Classification: Nanoparticles are broadly categorized into inorganic, organic and carbon based.

Organic Nanoparticles: This category of nanoparticles, known as organic nanoparticles (ONPs) is composed of organic molecules and has a size of 100 nm or smaller ⁸. This category includes widely recognized nanoparticles or polymers such as ferritine, micelles, dendrimers, and liposomes. Micelles and liposomes, which feature a hollow interior known as nanocapsule, exhibit sensitivity to heat and light ⁹. These nanoparticles are biodegradable and non-toxic, making them ideal candidates for drug delivery applications, their effectiveness and areas of use are influenced by factors such as drug carrying capacity, stability and delivery mechanism – wheather through drug entrapment or adsorption. Additionally, their size, composition and surface characteristic play a crucial role in their overall performances ¹⁰.

Inorganic Nanoparticles: Inorganic nanoparticles are those that do not contain carbon in their composition. They are primarily classified into metal and metal oxide nanoparticles.

Metal Based Nanoparticles: Metal based nanoparticle are synthesized from metals at nanometric scale s using either top-down (destructive) or bottom-up (constructive) approaches. Nearly all metals can be converted into nanoparticles, with commonly used including aluminum (Al), ¹¹ cadmium (Cd), ¹² cobalt (Co), ¹³ copper (Cu), ¹⁴ gold (Au) ¹⁵, iron (Fe), ¹⁶ lead (Pb), ¹⁷ silver (Ag) ¹⁷, zinc (Zn) ¹⁸. These nanoparticles exhibit unique characteristic such as sizes ranging from 10 to 100 nm, high surface area to volume ratio, specific pore sizes, surface charge properties, and crystalline or amorphous structures. Their shapes can vary including spherical and cylindrical forms, while their properties such as color, magnetic and sensitivity can be influenced by environmental factors like air moisture, heat and sunlight ¹⁹.

Metal-oxide Based Nanoparticles: Metal-oxide compounds are formed through the combination of positively charged metal ions and negatively charged oxygen ions, resulting in strong and stable ionic interactions due to electrostatic forces ²⁰. For example, iron (Fe) nanoparticles readily oxidized to form iron oxide (Fe₂O₃) nanoparticles upon exposure to oxygen at room temperature. This transformation significantly enhances their reactivity compared to their pure metal counterparts. Metal oxide nanoparticles are synthesized to modify and improve the properties of their metal-based forms, leveraging their increased reactivity and efficiency ²¹. Commonly synthesized metal-oxide includes silicon dioxide (SiO₂), titanium dioxide (TiO₂), and aluminum oxide (Al₂O₃), zinc oxide (ZnO) ^22-26. These nanoparticles exhibit exceptional properties when compared to their metallic equivalents, making them valuable for various applications.

Carbon Based Nanoparticles: Nanoparticles made primarily of carbon are referred to as carbon-based nanoparticles. These nanoparticles can take various shapes including tubular, horn shaped, spherical and, or ellipsoidal forms.

They are broadly classified into two main categories fullerenes and carbon nanotubes (CNTs). Additionally, other types of carbon-based nanoparticles include graphene, carbon nanofibers, and carbon black ²⁷.

Fullerenes: Fullerene is the general term for C_n cage molecules composed of hexagonal and pentagonal faces ²⁸. Kroto and Smally named the family of molecules observed in their gas-phase experiments ²⁹ “fullerenes” due to their resemblance to the geodesic domes designed by R. Buckminster Fuller ^{30, 31}. The term “Buckminster fullerene” or simply “buckyball” specifically refers to the C₆₀ molecule ²⁸.

Graphene: Graphene, an allotrope of carbon, is crafted from sp2-hybridized carbon atoms meticulously arranged in a two-dimensional honeycomb lattice structure. It serves as the foundational unit for graphite materials across various dimensions, including zero-dimensional fullerenes, one-dimensional nanotubes, and three-dimensional graphite structures ^32-34. In a graphene sheet, every atom forms σ bonds with its three closest neighbours, along with a delocalized π-bond. This collective bonding arrangement contributes to a valence band that spans the entire sheet. This bonding pattern mirrors that found in carbon nanotubes and polycyclic aromatic hydrocarbons, as well as partially in fullerenes and glassy carbon structures ³⁵. In 2004, the material was rediscovered, isolated and investigated at the University of Manchester ³⁶, by Andre Geim and Konstantin Novoselov. In 2010, Geim and Novoselov were awarded the Nobel Prize in Physics for their "groundbreaking experiments regarding the two-dimensional material grapheme ³⁷."

Carbon Nanotubes: Carbon nanotubes (CNTs) are carbon allotropes first discovered by Japanese scientist S. Lijima in 1991 ³⁸. They exhibit remarkable properties including high rigidity, strength and elasticity. Additionally, CNTs possess excellent thermal and electrical conductivity. Structurally they are cylindrical nanomaterials composed of rolled graphene sheets, with diameters in the nanometerrange ³⁹. Based on their structural characteristics CNTs are categorized into two main types: 1. Single walled carbon nanotubes (SWCNTs) ⁴⁰ which have dimeters ranging from 1 to 3 nanometer and extends a few micrometers in length, and 2. Multi walled carbon nanotubes (MWCNTs), ³⁹ which have diameters between 5 and 40 nanometer and lengths of approximately 10 micrometers.

Synthesis of Nanoparticles: Nanoparticles are synthesized via different methods. A schematic diagram is shown below.

FIG. 1: COMPARISON OF NANOPARTICLES SYNTHESIS METHODS: ADVANTAGES, DISADVANTAGES, AND APPLICATIONS

From the above diagram we have the idea that the synthesis of nanoparticles are divided into two main classes:

1. Top down synthesis
2. Bottom up synthesis

Top-Down Synthesis: The top-down approach also known as the destructive method, involves breaking down larger materials into their smallest building blocks, such as atom. This method works best for materials with well-organized structures at larger scale. It allows larger pieces of material to be reduced into tiny, nano-sized particles. While top-down methods are easier to use, they are not ideal for creating nanoparticles with precise shape and sizes. One major challenge of this approach is controlling the final particle size and form. Some common techniques used in this method include mechanical milling, nanolithography, laser ablation, sputtering and thermal decomposition.

Mechanical Milling: mechanical methods are among the most cost-effective techniques for large scale production of nanoparticles ⁴¹. One of the simplest approaches is ball milling, which involves grinding material in a rotating chamber filled with small balls made of iron, hardened steel, silicon carbide and tungsten carbide ⁴².

In ball milling a powdered material is placed inside the chamber. As the mill rotates, the kinetic energy from the balls is transferred to material, breaking it down to nanoscaledimensions through mechanical attrition ⁴³. This widely used top-down technique is employed for synthesizing various nanoparticles and metal alloys. During the milling process, friction and collision between the milling balls generate heat and pressure ⁴⁴. At high temperatures, these forces can cause significant changes in the particle structure, leading to phase transformations. Ball milling is commonly used to: reduce particle size, modify surface properties, induce structural changes in materials, trigger certain reactions that do not occur typically at room temperature.

Several key factor affect the Mechanical Milling Process ⁴⁵: plastic deformation influences particle shape, fracture leads to a decrease in a particle size, cold welding causes an increase in particle size. Mechanical milling is often performed in an inert atmosphere to prevent oxidation and enhance the properties of the synthesized nanoparticles ⁴⁶.

Despite its Advantages, Ball Milling has Some Limitations: the final nanoparticle structure structures are highly sensitive to the milling environment and may become contaminated by the grinding media, producing extremely small particles requires prolonged milling time, noise pollution and environmental disturbances are major drawback associated with this process ⁴⁷.

Nanolithography: nanolithography is a part of nanotechnology that focuses on creating and designing extremely small structures, usually at nanometer scale. It involves forming patterns with at least one dimension ranging from the size of a single atom up to about 100 nm ⁴⁸. Lithography techniques are categorized into two types based on the use of maskes: masked lithography and maskless lithography.

Masked lithography ⁴⁸ uses masks or templates to transfer patterns over a large area at once allowing fast and high-volume production, processing multiple wafers per hour. Examples include photolithography, soft lithography, and Nanoimprint lithography ^49-51.

Maskless lithography ⁴⁸ such as electron beam lithography, focused ion beam lithogtaphy, and scanning beam lithography creates pattern directly without masks by writing them one at a time ^{51, 52}.

These methods allow for extremely fine details, with feature sizes as small as a few nanometers. However, because it works in a step-by-step manner, it is much slower and not suitable for large scale manufacturing ⁵¹.

Laser Ablation Method: Laser ablation is a technique used to create different types of nanoparticles, such as semiconductors, quantum dots, carbon nanotubes, nanowires and core-shell nanoparticles. In this process a laser beam hits a material, turning it into vapor. The nanoparticles then form as the vapor cools and condenses in a gas. Because the cooling happens very quickly, this method helps produce very pure nanoparticles, often smaller than 10 nanometers ⁵³. In recent years, laser ablation synthesis in solution (LSAiS) has become a dependable alternative to traditional chemical methods for making noble metal nanoparticles (NMNp). LSAiS is an ecofriendly method that produces stable NMNp in water or organic solvents without needing extra chemicals or stabilizers. The resulting nanoparticles are easy to modify for different applications or can be used directly when pure nanoparticles are needed ⁵⁴.

However, this method has some drawbacks, when laser ablation is used for a long time, too many nanoparticles build up in the solution. This blocks the laser beam and causes the nanoparticles to absorb the laser energy instead of the targeted material. As a result, the ablation process slows down ⁵⁵.

Sputtering: Sputtering is a process where fast moving particles hit a material (called the target) and knock off its atoms. These atoms then move through the air and settle on another surface (the substrate) to form a thin layer ⁵⁶. There are many types of sputtering like DC sputtering- uses an electric field to create a charged gas(plasma) which shoots ion at the target, removing atom that deposite on the substrate. Reactive sputtering, similar to DC sputtering but includes a reactive gas (like oxygen or nitrogen) to form chemical compounds (e.g. oxides, nitrides). RF sputtering is used when the target is an insulator. It switches the electric charge back and forth to prevent buildup that would stop the process. Magnetorn sputtering uses magnets to improve efficiency by increasing the number of collisions, creating a denser plasma and a faster process ^{56, 58}.

Sputtering works with metals, semiconductors and compounds like oxides, nitrides, sulfides and carbides ⁵⁶.

The drawbacks of the sputtering method include the effect of the sputtering gas on the surface structure, composition, texture and optical properties of the nanocrystalline metal oxide coating. Additionally sputtering is slower than thermal evaporation, and most of the energy turns into heat when hitting the target which needs to be removed ^{59, 60, 61}.

Thermal Decomposition Method: Thermal decomposition is a widely used method to create inorganic nanoparticles. This technique produces stable and uniform nanoparticles that can self-assembles into structures. Nucleation (initial formation of nanoparticles) happens when a metal precursor is added to a heated solution containing a surfactant (a stabilizing agent that prevents clumping). Growth of the nanoparticles occurs at a high temperature, allowing them to develop into the desired size and shape. Hence, it is an endothermic process ⁶². The decomposition temperature is the specific temperature at which substance breaks down chemically. Nanoparticles formed as a result of the metal decomposing at this particular temperature ⁶³.

The thermal decomposition method has some limitations. Many metal compositions and combinations are difficult to deposite. Additionally, there are only a few processing options to controls the properties of the film and the available source materials may not always be sufficient ⁶⁴.

Bottom-up Synthesis: The bottom-up approach is a method of making nanoparticles assembling materials from their smallest building blocks, such as atoms or molecules ⁶⁵. This technique helps create materials with unique properties that differ from larger, bulk materials ⁶⁶. Compared to other methods, bottom-up synthesis is more cost effective and produces less waste.

This approach ensures precise control over nanoparticle size, shape and distribution ⁶⁷. It is commonly used in chemical synthesis, where precursor solutions are mixed to form uniform nanoparticles, such as zinc oxide, magnetite and brushite ⁶⁸. One example is the sol-gel method, which is used to create titanium dioxide (TiO₂) nanoparticles, assessed using environmental tools ⁶⁹.

A key challenge of the bottom-up method is ensuring nanoparticles properly attach to surfaces. However, it is widely used for making luminescent nanoparticles ⁷⁰ and has great potential in creating functional nanomaterials. This method enables extreme miniaturization and could be a cost-effective alternative to top-down nanofabrication ⁶⁵. Some bottom-up techniques are sol-gel, spinning, chemical vapor deposition (CVD), pyrolysis and biosynthesis.

Sol-gel Method: The sol-gel technique is a wet-chemical process used to synthesize metal oxide nanoparticles from a liquid precursor solution. The solution undergoes hydrolysis (breaking down in water or alcohol) and condensation (forming a gel like structure) to create nanoparticles ⁷¹.

The process involves typically metal alkoxide precursors. The sol-gel method of nanoparticles synthesis follows several steps. First, metal oxide undergoes hydrolysis in water or alcohol, forming a sol. Next, condensation increases the solution viscosity, creating porous structures that are left to age. During polycondensation, hydroxo (M-OH-M) and oxo (M-O-M) leading to metal-polymer networks in solution ⁷². As aging continues, structural and porosity changes occur, with decreasing porosity and increasing particle spacing. After aging, the materials undergo drying to remove water and solvents. Finally, calcination at high temperature completes the nanoparticle formation ⁷³. The key factors affecting the final product are precursor type, hydrolysis speed, aging time,ph and water to precursor ratio ⁷⁴.

The advantages of sol-gel methods are it is low cost, ecofriendly and works at lower temperatures. It produces high quality, uniform nanoparticles for films, powders or coating and enables complex nanostructure formation ⁷³. This method is widely used for iron oxide (Fe₃O₄) nanoparticles, often resulting in spherical shapes ^{75, 76}.

The main challenge of using the metal alkoxide-based sol-gel method includes its sensitivity to moisture and the limited availability of suitable precursor, especially for mixed-metal oxides. Since different metals react with water at varying rates, it can be difficult to control the hydrolysis process, leading to inconsistent mixing. As a result, instead of forming a uniform material, the components may separate, creating unwanted mixed phase in the final product ⁷⁷.

Spinning: A spinning disc reactor (SDR) is a machine used to synthesize nanoparticles by rapidly rotating a disc inside a controlled chamber. The reactor’s temperature and gas environment (often nitrogen or other inert gas) can be adjusted to prevent unwanted reactins ⁷⁸. The process is that liquid reagents are fed onto the center of spinning disc(rotating at 300 to 3000 rpm). As the disc spins, the liquids spreads into a thin film (1 to 200 nm thick), allowing fast mixing and heat transfer. The strong drag forces between the liquid and the disc surface ensure efficient micromixing, which helps control the formation of nanoparticles and prevent clumping. Micromixing happens extremely fast (within a millisecond), ensuring even chemical reactions.

The disc can be smooth or grooved to enhance mixing by creating waves in the liquid layer. Temperature control is achieved through a heating coil or a thermostatic fluid flow beneath the disc. Some SDRs have a vertical setup with a horizontally rotating shapt for easy slurry removed.

The advantages of SDR are continuous operation allows large-scale production. It is easier to scale up compared to traditional stirred tank reactors. The safer operation is due to controlled conditions. It can process upto 150 kg/h of low- viscosity materials (like water) using a 500 mm disc ^{50, 79}.

Chemical Vapor Deposition: Chemical vapor deposition is a process where gases, called precursors, react in the air to form a solid material that sticks to surface ⁸⁰. In CVD reaction can occur in two ways: 1. The gases can react in the air first, then attach to the surface, 2. The gases can attach to the surface first, then react and form the solid material on the surface. The second method generally gives better adhesion to the surface ⁸¹.

One of the main problems with CVD is the potential hazards from the gases used, which can be explosive, poisonous or corrosive. Another challenge is the difficulty in depositing materials that have more than one component ⁸².

There are different types of CVD based on the energy used to start the reaction, including thermally activated CVD, plasma-enhanced CVD, photo-initiated CVD ⁸⁰.

Prolysis: One promising technique for the synthesis of nanoparticles is CO₂ laser pyrolysis, which involves using a laser to heat gas and vapor phase reactants to create nanoparticles. This method allows for controlling the size and the shape of the particles and can produce nanoparticles in quantities large enough for testing in particle applications.

It has been used to create a variety of oxide and non-oxide nanopowders especially silicon-based nanoparticles (e.g. SiC, Si3N4) which are used in high temperature structural materials. The laser pyrolysis technique has also been used to produce other nanoparticles like TiO₂ for UV protection and links for printing. This demonstrates the versatility of laser pyrolysis in creating nanoparticles for various applications, with ongoing development in both the synthesis process and the use of the materials ⁸³. The method of laser pyrolysis is highly flexible and shows promise for producing nanoparticles for a wide range of applications.

However, it is difficult to get the right size of nanoparticles with this method because once they leave the hot chamber, they tend to stick together and form chains. This is the main problem using pyrolysis to make nanoparticles ⁸⁴.

Biosynthesis: Biosynthesis is an ecofriendly and sustainable method for making nanoparticles that are non-toxic and biodegradable ⁸⁵. It involves using bacteria, plant extracts, fungi and other natural sources along with precursors to create nanoparticles, instead of using traditional chemicals for reduction of capping. The nanoparticles produced through biosynthesis have unique and improved properties, making them ideal for biomedical applications ⁸⁶.

The biological method for synthesizing nanoparticles is ecofriendly and non-toxic. However, a challenge with this approach is that plant extracts contain many other compounds, and it takes considerable time to remove impurities. Despite efforts to purify, there is still a risk of unwanted particles remaining in the final product ⁸⁷.

TABLE 1: FLOW DIAGRAM OF VARIOUS TYPE OF NANO PARTICLES

Top-down is generally more suitable for large scale industrial production of nanoparticles where precise control over size and shape is not critical, especially for simple materials like metals and ceramics. Bottom-up is preferably when high precision, and control over nanoparticle characteristics (such as size, shape and composition) are required. This method is particularly beneficial for specialized applications, including advanced materials and biomedical applications.

TABLE 2: COMPARISON BETWEEN TOP-DOWN AND BOTTOM-UP APPROACHES FOR NANOPARTICLE SYNTHESIS

Top-down approaches focuses on mechanical, laser based or vacuum assisted techniques to synthesize nanoparticles. They offer high purity and precise control, but methods like ball milling lack uniformity, while nanolithography and sputtering require expensive equipment. Bottom-up methods are widely used for their versatility, cost-effectiveness and scalability. Sol-gel, CVD etc. allow controlled synthesis but may aloe toxic precursors, high temperatures and long processing times. Biosynthesis use natural resources to synthesize nanoparticles, making them eco-friendly and biocompatible. However, they have limited scalability and size control, making them less reliable for industrial applications.

CONCLUSION: The synthesis of nanoparticles involve various top-down and bottom-up approaches, each offering unique advantages and challenges. Top-down method such as ball milling, laser ablation, sputtering, and nanolithography enable high purity and precise nanoparticle fabrication, though they often require specialized equipment and hence scalability limitations. Bottom-up methods including sol-gel, CVD etc. provide good control over particle size and shape, making them suitable for diverse applications in catalysis and drug delivery. However, some methods require high temperatures, toxic precursors and long processing times. Nanolithography a high precise fabrication method, enables the patterning of nanoparticles at the nanoscale, making it essential for electronics and biosensor applications. Despite its advantages in precision, it remains an expensive and complex technique. Biosynthesis, using plant extracts or microbes, offer an ecofriendly alternative but struggle with reproducibility and scalability. The choice of synthesis method depends on application requirements, including cost, scalability and environmental considerations. As nanotechnology advances, hybrid approach combining multiple techniques and green synthesis methods are likely to gain importance, balance efficiency, sustainability and precision.

ACKNOWLEDGEMENT: Nil

CONFLICTS OF INTEREST: Nil

REFERENCES:

1. Feynman R: There’s plenty of room at the bottom. In Feynman and Computation 2018; 63-76. CRC Press.
2. Eker F, Duman H, Akdaşçi E, Bolat E, Sarıtaş S, Karav S & Witkowska AM: A comprehensive review of nanoparticles: from classification to application and toxicity. Molecules 2024; 29(15): 3482.
3. Tiwari JN, Tiwari RN & Kim KS: Zero-dimensional, one-dimensional, two-dimensional and three-dimensional nanostructured materials for advanced electrochemical energy devices. Progress in Materials Science 2012; 57(4): 724-803.
4. Iravani S: Green synthesis of metal nanoparticles using plants. Green Chemistry 2011; 13(10): 2638-2650.
5. Khanna P, Kaur A & Goyal D: Algae-based metallic nanoparticles: Synthesis, characterization and applications. Journal of Microbiological Methods 2019; 163: 105656.
6. Cho EJ, Holback H, Liu KC, Abouelmagd SA, Park J & Yeo Y: Nanoparticle characterization: state of the art, challenges, and emerging technologies. Molecular Pharmaceutics 2013; 10(6): 2093-2110.
7. Machado S, Pacheco JG, Nouws HPA, Albergaria JT & Delerue-Matos C: Characterization of green zero-valent iron nanoparticles produced with tree leaf extracts. Science of the Total Environment 2015; 533: 76-81.
8. Qi H & Zhang C: Organic nanoparticles for electrogenerated chemiluminescence assay. Current Opinion in Electrochemistry 2022; 34: 101023.
9. Esakkimuthu T, Sivakumar D & Akila S: Application of nanoparticles in wastewater treatment. Pollut Res 2014; 33(03): 567-571.
10. Hamidi M, Azadi A & Rafiei P: Hydrogel nanoparticles in drug delivery. Advanced Drug Delivery Reviews 2008; 60(15): 1638-1649.
11. Ghanta SR & Muralidharan K: Chemical synthesis of aluminum nanoparticles. Journal of Nanoparticle Research 2013; 15: 1-10.
12. Prakash A, Sharma S, Ahmad N, Ghosh A & Sinha P: Bacteria mediated extracellular synthesis of metallic nanoparticles. Int Res J Biotechnol 2010; 1(5): 071-079.
13. Mondal A, Adhikary B & Mukherjee D: Room-temperature synthesis of air stable cobalt nanoparticles and their use as catalyst for methyl orange dye degradation. Colloids and Surfaces A: Physicochemical and Engineering Aspects 2015; 482: 248-257.
14. Din MI & Rehan R: Synthesis, characterization, and applications of copper nanoparticles. Analytical Letters 2017; 50(1): 50-62.
15. Jamkhande PG, Ghule NW, Bamer AH & Kalaskar MG: Metal nanoparticles synthesis: An overview on methods of preparation, advantages and disadvantages, and applications. Journal of Drug Delivery Science and Technology 2019; 53: 101174.
16. Herlekar M, Barve S & Kumar R: Plant‐mediated green synthesis of iron nanoparticles. Journal of Nanoparticles 2014; (1): 140614.
17. Schrand AM, Rahman MF, Hussain SM, Schlager JJ, Smith DA & Syed AF: Metal‐based nanoparticles and their toxicity assessment. Wiley interdisciplinary reviews: Nanomedicine and Nanobiotechnology 2010; 2(5): 544-68.
18. Esa YAM & Sapawe N: A short review on zinc metal nanoparticles synthesize by green chemistry via natural plant extracts. Materials Today: Proceedings 2020; 31: 386-393.
19. Wang ZL: Characterizing the structure and properties of individual wire‐like nanoentities. Advanced Materials 2000; 12(17): 1295-1298.
20. Devan RS, Patil RA, Lin JH & Ma YR: One‐dimensional metal‐oxide nanostructures: recent developments in synthesis, characterization, and applications. Advanced Functional Materials 2012; 22(16): 3326-3370.
21. Tai CY, Tai CT, Chang MH & Liu HS: Synthesis of magnesium hydroxide and oxide nanoparticles using a spinning disk reactor. Industrial & Engineering Chemistry Research 2007; 46(17): 5536-5541.
22. Fayad MA & Dhahad HA: Effects of adding aluminum oxide nanoparticles to butanol-diesel blends on performance, particulate matter, and emission characteristics of diesel engine. Fuel 2021; 286: 119363.
23. Song G, Cheng N, Zhang J, Huang H, Yuan Y, He X & Huang K: Nanoscale cerium oxide: Synthesis, biocatalytic mechanism, and applications. Catalysts 2021; 11(9): 1123.
24. Bulychev NA: Synthesis of gaseous hydrogen and nanoparticles of silicon and silicon oxide by pyrolysis of tetraethoxysilane in an electric discharge under the action of ultrasound. International Journal of Hydrogen Energy 2022; 47(84): 35581-35587.
25. Tilahun Bekele E, Gonfa BA & Sabir FK: Use of different natural products to control growth of titanium oxide nanoparticles in green solvent emulsion, characterization, and their photocatalytic application. Bioinorganic Chemistry and Applications 2021; 2021(1): 6626313.
26. Singh TA, Sharma A, Tejwan N, Ghosh N, Das J and Sil PC: A state of the art review on the synthesis, antibacterial, antioxidant, antidiabetic and tissue regeneration activities of zinc oxide nanoparticles. Adv. Colloid Interface Sci 2021; 295: 102495.
27. Bhaviripudi S, Mile E, Steiner SA, Zare AT, Dresselhaus MS, Belcher AM & Kong J: CVD synthesis of single-walled carbon nanotubes from gold nanoparticle catalysts. Journal of the American Chemical Society 2007; 129(6): 1516-1517.
28. Dresselhaus MS, Dresselhaus G & Eklund PC: Fullerenes. Journal of Materials Research 1993; 8(8): 2054-2097.
29. Kroto HW: JR heath, sco’brien, rf curl, and re smalley. Astrophys J 1987; 314: 352-356.
30. Fuller RB: Synergetics: explorations in the geometry of thinking. Estate of R. Buckminster Fuller 1982.
31. Buckminster R: Fuller, in The Artifacts of R. Buckminster Fuller: A Comprehensive Collection of His Designs and Drawings, edited by W. Marlin (Garland Publishing, New York 1984.
32. Wallace PR: The band theory of graphite. Physical Review 1947; 71(9), 622.
33. McClure JW: Diamagnetism of graphite. Physical Review 1956; 104(3): 666.
34. Slonczewski JC & Weiss PR: Band structure of graphite. Physical Review 1958; 109(2): 272.
35. Zdetsis AD & Economou EN: A pedestrian approach to the aromaticity of graphene and nanographene: significance of Huckel’s (4 n+ 2) π electron rule. The Journal of Physical Chemistry C, 2015; 119(29): 16991-17003.
36. "This Month in Physics History: October 22, 2004: Discovery of Graphene". APS News. Series II. 18 (9): 2. 2009.
37. "The Nobel Prize in Physics 2010"
38. Iijima S: Helical microtubules of graphitic carbon. Nature 1991; 354(6348): 56-58.
39. Dai H: Carbon nanotubes: opportunities and challenges. Surface Science 2002; 500(1-3): 218-241.
40. Iijima S & Ichihashi T: Single-shell carbon nanotubes of 1-nm diameter. Nature 1993; 363(6430): 603-605.
41. Damonte LC, Zélis LM, Soucase BM & Fenollosa MH: Nanoparticles of ZnO obtained by mechanical milling. Powder Technology 2004; 148(1): 15-19.
42. Zhang DL: Processing of advanced materials using high-energy mechanical milling. Progress in Materials Science 2004; 49(3-4): 537-560.
43. Tjong SC & Chen H: Nanocrystalline materials and coatings. Materials Science and Engineering: R: Reports 2004; 45(1-2): 1-88.
44. Mei QS & Lu K: Melting and superheating of crystalline solids: From bulk to nanocrystals. Progress in Materials Science 2007; 52(8): 1175-1262.
45. Ealia SAM & Saravanakumar MP: A review on the classification, characterisation, synthesis of nanoparticles and their application. In IOP conference series: materials science and engineering 2017; 263(3): 032019). IOP Publishing.
46. Yadav TP, Yadav RM & Singh DP: Mechanical milling: a top down approach for the synthesis of nanomaterials and nanocomposites. Nanoscience and Nanotechnology 2012; 2(3): 22-48.
47. Tavakoli A, Sohrabi M & Kargari A: A review of methods for synthesis of nanostructured metals with emphasis on iron compounds. Chemical Papers 2007; 61(3): 151-170.
48. Venugopal G & Kim SJ: Nanolithography. In Advances in micro/nano electromechanical systems and fabrication technologies. IntechOpen 2013.
49. Gates BD, Xu Q, Stewart M, Ryan D, Willson CG & Whitesides GM: New approaches to nanofabrication: molding, printing, and other techniques. Chemical Reviews 2005; 105(4): 1171-1196.
50. Khan Y, Sadia H, Ali Shah SZ, Khan MN, Shah AA, Ullah N & Khan MI: Classification, synthetic, and characterization approaches to nanoparticles, and their applications in various fields of nanotechnology: a review. Catalysts 2022; 12(11): 1386.
51. Pimpin A & Srituravanich W Review on micro-and nanolithography techniques and their applications. Engineering Journal 2012; 16(1): 37-56.
52. Menon R, Patel A, Gil D & Smith HI: Maskless lithography. Materials Today 2005; 8(2): 26-33.
53. Kim M, Osone S, Kim T, Higashi H & Seto T: Synthesis of nanoparticles by laser ablation: A review. KONA Powder and Particle Journal 2017; 34: 80-90.
54. Amendola V & Meneghetti M: Laser ablation synthesis in solution and size manipulation of noble metal nanoparticles. Physical Chemistry Chemical Physics 2009; 11(20): 3805-3821.
55. Ghorbani HR: A review of methods for synthesis of Al nanoparticles. Orient J Chem 2014; 30(4): 1941-1949.
56. Rane AV, Kanny K, Abitha VK & Thomas S: Methods for synthesis of nanoparticles and fabrication of nanocomposites. In Synthesis of Inorganic Nanomaterials 2018; 121-139. Woodhead publishing.
57. Wender H, Migowski P, Feil AF, Teixeira SR & Dupont J: Sputtering deposition of nanoparticles onto liquid substrates: Recent advances and future trends. Coordination Chemistry Reviews 2013; 257(17-18): 2468-2483.
58. Shah P & Gavrin A: Synthesis of nanoparticles using high-pressure sputtering for magnetic domain imaging. Journal of Magnetism and Magnetic Materials 2006; 301(1): 118-123.
59. Shahidi S, Moazzenchi B & Ghoranneviss M: A review-application of physical vapor deposition (PVD) and related methods in the textile industry. The European Physical Journal Applied Physics 2015; 71(3): 31302.
60. Zeng W, Chen N & Xie W: Research progress on the preparation methods for VO 2 nanoparticles and their application in smart windows. Cryst Eng Comm 2020; 22(5): 851-869.
61. Chandra R, Chawla AK & Ayyub P: Optical and structural properties of sputter-deposited nanocrystalline Cu2O films: Effect of sputtering gas. Journal of Nanoscience and Nanotechnology 2006; 6(4): 1119-1123.
62. Salavati-Niasari M, Davar F & Mir N: Synthesis and characterization of metallic copper nanoparticles via thermal decomposition. Polyhedron 2008; 27(17): 3514-3518.
63. Ijaz I, Gilani E, Nazir A & Bukhari A: Detail review on chemical, physical and green synthesis, classification, characterizations and applications of nanoparticles. Green Chemistry Letters and Reviews 2020; 13(3): 223-245.
64. Mattox DM: Physical vapor deposition (PVD) processes. Metal Finishing 2002; 100: 394-408.
65. Abid N, Khan AM, Shujait S, Chaudhary K, Ikram M, Imran M & Maqbool M: Synthesis of nanomaterials using various top-down and bottom-up approaches, influencing factors, advantages, and disadvantages: A review. Advances in Colloid and Interface Science 2022; 300: 102597.
66. Ingole AR, Thakare SR, Khati NT, Wankhade AV & Burghate DK: Green synthesis of selenium nanoparticles under ambient condition. Chalcogenide Lett 2010; 7(7): 485-489.
67. Kumari S, Raturi S, Kulshrestha S, Chauhan K, Dhingra S, András K & Singh T: A comprehensive review on various techniques used for synthesizing nanoparticles. Journal of Materials Research and Technology 2023; 27: 1739-1763.
68. Betke A & Kickelbick G: Bottom-up, wet chemical technique for the continuous synthesis of inorganic nanoparticles. Inorganics 2014; 2(1): 1-15.
69. Pini M, Rosa R, Neri P, Bondioli F & Ferrari AM: Environmental assessment of a bottom-up hydrolytic synthesis of TiO 2 nanoparticles. Green Chemistry 2015; 17(1): 518-531.
70. Kumar S, Bhushan P & Bhattacharya S: Fabrication of nanostructures with bottom-up approach and their utility in diagnostics, therapeutics, and others. Environmental Chemical and Medical Sensors 2018; 167-198.
71. Danks AE, Hall SR & Schnepp ZJMH: The evolution of ‘sol gel’chemistry as a technique for materials synthesis. Materials Horizons 2016; 3(2), 91-112.
72. Tseng TK, Lin YS, Chen YJ & Chu H: A review of photocatalysts prepared by sol-gel method for VOCs removal. International Journal of Molecular Sciences 2010; 11(6): 2336-2361.
73. Parashar M, Shukla VK & Singh R: Metal oxides nanoparticles via sol–gel method: a review on synthesis, characterization and applications. Journal of Materials Science: Materials in Electronics 2020; 31(5): 3729-3749.
74. de Coelho Escobar C & dos Santos JHZ: Effect of the sol–gel route on the textural characteristics of silica imprinted with Rhodamine B. Journal of Separation Science 2014; 37(7): 868-875.
75. Takai ZI, Mustafa MK, Asman S & Sekak KA: Preparation and characterization of magnetite (Fe3O4) nanoparticles by sol-gel method. Int J Nanoelectron Mater 2019; 12(1): 37-46.
76. Habte L, Shiferaw N, Mulatu D, Thenepalli T, Chilakala R & Ahn JW: Synthesis of nano-calcium oxide from waste eggshell by sol-gel method. Sustainability 2019; 11(11): 3196.
77. Cui H, Zayat M & Levy D: Sol-gel synthesis of nanoscaledspinels using propylene oxide as a gelation agent. Journal of Sol-Gel Science and Technology 2005; 35: 175-181.
78. Hassellöv M, Readman JW, Ranville JF & Tiede K: Nanoparticle analysis and characterization methodologies in environmental risk assessment of engineered nanoparticles. Ecotoxicology 2008; 17: 344-361.
79. Boodhoo K: Spinning disc reactor for green processing and synthesis. Process Intensification for Green Chemistry: Engineering Solutions for Sustainable Chemical Processing 2013; 59-90.
80. Dion CD & Tavares JR: Photo-initiated chemical vapor deposition as a scalable particle functionalization technology (a practical review). Powder Technology 2013; 239: 484-491.
81. Choy KL: Chemical vapour deposition of coatings. Progress in Materials Science 2003; 48(2): 57-170.
82. Reina A, Jia X, Ho J, Nezich D, Son H, Bulovic V & Kong J: Large area, few-layer graphene films on arbitrary substrates by chemical vapor deposition. Nano Letters 2009; 9(1): 30-35.
83. D’Amato R, Falconieri M, Gagliardi S, Popovici E, Serra E, Terranova G & Borsella E: Synthesis of ceramic nanoparticles by laser pyrolysis: From research to applications. Journal of Analytical and Applied Pyrolysis 2013; 104: 461-469.
84. Dhand C, Dwivedi N, Loh XJ, Ying ANJ, Verma NK, Beuerman RW & Ramakrishna S: Methods and strategies for the synthesis of diverse nanoparticles and their applications: a comprehensive overview. Rsc Advances 2015; 5(127): 105003-105037.
85. Kuppusamy P, Yusoff MM, Maniam GP & Govindan N: Biosynthesis of metallic nanoparticles using plant derivatives and their new avenues in pharmacological applications–An updated report. Saudi Pharmaceutical Journal 2016; 24(4): 473-484.
86. Hasan S: A review on nanoparticles: their synthesis and types. Res. J. Recent Sci 2015; 2277: 2502.
87. Dikshit PK, Kumar J, Das AK, Sadhu S, Sharma S, Singh S & Kim BS: Green synthesis of metallic nanoparticles: Applications and limitations. Catalysts 2021; 11(8): 902.
    

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    AL-samman AMMA, Hussain K, Aasif M and Singh V: Comparison of different nanoparticle preparation method - a review. Int J Pharm Sci & Res 2025; 16(12): 3222-32. doi: 10.13040/IJPSR.0975-8232.16(12).3222-32.

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