INTRODUCTION:

Silver nanoparticles (AgNPs) are tiny particles of silver, measuring between 1 and 100 nanometers in size. Thanks to their remarkable physical, chemical, and biological properties, they have become a hot topic in fields like medicine, electronics, textiles, and environmental science.

What makes silver nanoparticles especially exciting is their powerful antimicrobial ability they can effectively fight off bacteria, viruses, and fungi. This has led to their use in medical products like wound dressings, coatings for medical tools, and water purification systems. Beyond their germ-fighting properties, their optical, electrical, and catalytic features make them useful in biosensors, conductive materials, and industrial processes.

Scientists have developed several ways to create silver nanoparticles, including physical, chemical, and biological (green) methods. While chemical techniques are the most common, there’s a growing interest in eco-friendly green synthesis, which uses plant extracts, bacteria, or fungi to produce nanoparticles without harmful chemicals.

Despite their many advantages, there are still concerns about their potential toxicity and environmental impact. Researchers are working hard to understand how these tiny particles might affect human health and nature in the long run. As a result, safety guidelines and regulations are being developed to ensure responsible use.

With on-going progress in nanotechnology, silver nanoparticles are set to make a big impact across multiple industries, bringing innovative solutions to healthcare, electronics, and environmental protection. ^1,7

Physical, Chemical, Biological Approaches for Synthesizing Silver Nanoparticles:

I) Physical Approaches for Synthesizing Silver Nanoparticles Physical methods for producing silver nanoparticles (AgNPs) rely on breaking down bulk silver into Nano sized particles or building them up from atomic silver, without using harmful chemicals. These techniques are known for producing high-purity nanoparticles, but they often require advanced equipment and significant energy input.⁸

1. Laser Ablation:

How it Works:

· A powerful laser is aimed at a piece of silver submerged in a liquid.

· The laser energy breaks the silver into tiny nanoparticles, which then disperse in the liquid.

Why It's Useful:

i. Produces ultra-pure nanoparticles with no chemical residues.

ii. Allows precise control over particle size and shape.

Challenges:

i) Requires expensive laser systems.

ii) The nanoparticles can sometimes be irregularly shaped. (9)

2. Evaporation-Condensation Method:

How it Works:

· Silver is heated in a vacuum chamber until it turns into vapor.

· The vapor cools rapidly and condenses into tiny nanoparticles.

Why It's Useful:

i) Produces very pure and uniform nanoparticles.

ii) No need for additional chemicals to stabilize the particles.

Challenges:

i) Requires a lot of energy to maintain high temperatures.

ii) Scaling up for large production can be difficult. (10)

3. Ball Milling:

How it Works:

· A chunk of silver is placed in a rotating mill with hard ceramic or metal balls.

· The mechanical force breaks the silver down into nanoparticles.

Why It's Useful:

i) A simple and cost-effective way to produce large amounts of nanoparticles.

ii) No harmful chemicals are required.

Challenges:

i) The particles can be irregular in shape and size.

ii) Additional steps are needed to prevent them from clumping together.¹¹

4. Electrical Explosion of Wire (EEW):

How it Works:

· A strong electrical current is sent through a thin silver wire.

· The wire explodes, turning into vapor, which then cools and forms nanoparticles.

Why It's Useful:

i) Produces highly pure and uniform nanoparticles.

ii) The process is very fast and efficient.

Challenges:

i) Requires a lot of energy.

ii) ii) Needs specialized equipment. (12)

Physical methods are a great way to produce clean, high-quality silver nanoparticles, but they often demand high energy and sophisticated machinery. While these methods are widely used in research and industrial applications, chemical and biological methods are sometimes preferred because they are cheaper and easier to scale.^2,3,4,5

II) Chemical Approaches for Synthesizing Silver Nanoparticles:

Chemical methods are the most commonly used techniques for producing silver nanoparticles (AgNPs) because they are easy to perform, scalable, and allow precise control over particle size and shape. These methods involve converting silver ions (Ag⁺) from a silver salt (such as silver nitrate, AgNO₃) into tiny metallic silver particles (Ag⁰) using a chemical reducing agent. To keep the nanoparticles from clumping together, stabilizing agents or surfactants are added.¹⁵

1. Chemical Reduction Method:

This is the simplest and most widely used method for making silver nanoparticles.

How It Works:

· Dissolving Silver Salt: A silver compound (e.g., AgNO₃) is mixed into a liquid, usually water.

· Reduction Process: A reducing agent (such as sodium borohydride, citrate, or ascorbic acid) is added, which donates electrons to silver ions, turning them into tiny silver nanoparticles.

· Stabilization: A stabilizing agent (such as polyvinyl alcohol or cetyltrimethylammonium bromide) is used to prevent the particles from sticking together.

Why It’s Useful:

i) Easy and efficient – can be done in a simple lab setup.

ii) Good control over the size and shape of nanoparticles.

iii) Scalable – can be used for large-scale production.

Challenges:

i) Some reducing agents are toxic and may require careful handling.

ii) The nanoparticles may need extra purification to remove unwanted residues.¹⁶

2. Micro emulsion Method:

This method takes advantage of tiny reaction chambers formed by mixing oil, water, and surfactants.

How It Works:

· A micro emulsion (a stable mix of oil, water, and surfactants) creates tiny nanoreactors in which the reaction takes place.

· A silver salt is added to this system, and a reducing agent is introduced.

· The confined space inside the micro emulsion helps regulate the size of the nanoparticles. (17)

Why It’s Useful:

i) Produces uniform nanoparticles with well-controlled sizes.

ii) Minimizes particle aggregation, leading to more stable nanoparticles.

Challenges:

i) Requires special surfactants, which may need to be removed later.

ii) The process is more complex than simple reduction methods.¹³

Why Chemical Methods Are Popular:

Chemical methods offer a balance between simplicity, efficiency, and scalability, making them the go-to approach for industries and researchers. However, concerns over toxicity and environmental safety have led scientists to explore greener, more sustainable synthesis methods using plant extracts, bacteria, and fungi.^2,3,4,5,18

III) Biological Approaches for Synthesizing Silver Nanoparticles:

In recent years, researchers have been exploring biological or green methods to synthesize silver nanoparticles (AgNPs) as a eco-friendlier and more sustainable alternative to chemical and physical approaches. This method harnesses the power of nature by using plants, bacteria, fungi, and algae to convert silver ions (Ag⁺) into silver nanoparticles (Ag⁰). These biological agents act as both reducing and stabilizing agents, making the process safer, energy-efficient, and free from toxic chemicals.¹⁹

2. Microbial Synthesis (Bacteria and Fungi):

Certain microorganisms can naturally produce silver nanoparticles as a defense mechanism against toxic silver ions. Scientists use this ability to develop biological nanoparticle synthesis methods.

A. Bacteria-Based Synthesis:

Bacteria have enzymes and proteins that help in reducing silver ions into nanoparticles.

How It Works:

· Bacteria such as Pseudomonas aeruginosa or Bacillus subtilis are exposed to silver ions.

· The bacteria absorb these ions and use their enzymes to convert them into silver nanoparticles.

Why It’s Beneficial:

i) Sustainable Uses a natural biological process.

ii) Produces stable nanoparticles without the need for additional chemicals.

Challenges:

i) Takes longer than chemical methods (hours to days).

ii) Requires sterile conditions to prevent contamination.

B. Fungi-Based Synthesis:

Fungi are excellent at producing nanoparticles because they secrete large amounts of enzymes and proteins that help in the synthesis process.

How It Works:

· Fungi like Aspergillus niger or Fusarium oxysporum are grown in a silver-containing solution.

· Their enzymes reduce silver ions, forming nanoparticles that are stabilized by fungal proteins.

Why It’s Beneficial:

i) More efficient than bacteria (fungi produce larger amounts of nanoparticles).

ii) Produces well-defined nanoparticles with good stability.

Challenges:

i) Requires careful monitoring of growth conditions.

ii) Some fungi may be pathogenic, requiring strict biosafety measures.

3. Algae-Based Synthesis:

Algae, like bacteria and fungi, can absorb silver ions and transform them into silver nanoparticles using their natural biomolecules (proteins, polysaccharides, and pigments).

How It Works:

· Algae are grown in a silver salt solution.

· Their natural biomolecules help convert Ag⁺ into silver nanoparticles.

Why It’s Beneficial:

i) Highly sustainable – Uses fast-growing algae species.

ii) Eco-friendly – No toxic chemicals involved.

iii) Scalable – Can be adapted for mass production.

Challenges:

i) Less researched compared to bacteria and fungi.

ii) Requires optimization for better control over nanoparticle size and stability.^6,14,21

Why Choose Biological Synthesis?

Unlike chemical and physical methods, biological synthesis offers:

· Eco-Friendliness: No harmful chemicals or toxic by-products.

· Cost-Effectiveness: Uses natural materials instead of expensive reagents

· Biocompatibility: Safer for medical and pharmaceutical applications.

However, to fully replace chemical methods, researchers need to address challenges like standardization, scalability, and reaction control. With continued advancements, biological synthesis could become the future of sustainable nanotechnology. ^{2,3,4,5,13,20,21}

Comparing Physical, Chemical, and Biological Approaches for Silver Nanoparticle Synthesis

Silver nanoparticles (AgNPs) can be made in different ways, each with its own strengths and weaknesses. Some methods focus on purity, others on cost-effectiveness, and some prioritize environmental friendliness. Here’s a breakdown of the three main approaches:

· Physical Methods are great for ultra-pure nanoparticles, but they require expensive equipment and a lot of energy.

· Chemical Methods are the most widely used because they offer good control over particle size and shape, but they involve toxic chemicals.

· Biological Methods are eco-friendly and cost-effective, but they need more research and process improvements to be widely adopted.^{2,3 ,4,5,22}

Figure 1: Schematic diagram for different synthetic techniques of Ag NPs.¹³

Properties of Silver Nanoparticles:

Silver nanoparticles (AgNPs) are tiny particles of silver, typically ranging from 1 to 100 nanometers in size. Their unique properties make them incredibly useful in various fields, from medicine to electronics. Let’s take a closer look at what makes them special.

1. Physical Properties:

AgNPs come in different shapes, including spheres, rods, triangles, and cubes. Their small size gives them a large surface area, making them highly reactive. They also have impressive optical properties thanks to a phenomenon called surface Plasmon resonance (SPR), they can absorb and scatter light, leading to striking colour variations. Beyond that, they are great at conducting electricity and heat, which is why they’re used in things like conductive inks and coatings.

2. Chemical Properties:

One of the fascinating things about silver nanoparticles is their surface chemistry. They can easily bond with biomolecules, polymers, or other stabilizing agents, making them more stable and versatile. However, they are sensitive to oxidation, meaning they can release silver ions (Ag⁺), which play a big role in their antimicrobial power. They are also excellent catalysts, helping speed up chemical reactions.

3. Biological Properties:

AgNPs are well known for their strong antimicrobial properties—they can kill bacteria, fungi, and even viruses by disrupting cell membranes and generating reactive oxygen species (ROS). In medicine, they’re being studied for their potential in wound healing, drug delivery, and even cancer treatments. While they are generally safe at low concentrations, high doses can be toxic to human cells.

4. Optical and Plasmonic Properties:

One of the coolest things about silver nanoparticles is their interaction with light. Depending on their size and shape, they can appear in different colors smaller particles tend to look yellow, while larger ones can appear red or blue. This makes them useful in biosensors, imaging, and even artistic applications.

5. Mechanical Properties:

AgNPs aren’t just about electronics and medicine they can also strengthen materials when added to composites. They improve durability while maintaining flexibility, which is why they are being used in wearable electronics and flexible circuits.

6. Toxicological Aspects:

Despite their many benefits, silver nanoparticles come with some concerns. In high concentrations, they can be toxic to human cells. There’s also an environmental side to consider since they don’t easily break down, their long-term effects on ecosystems are still being studied.^23,24

Applications of Silver Nanoparticles:

Because of their unique properties, AgNPs have found their way into various industries:

· Medicine: Used in antibacterial coatings, wound dressings, drug delivery, and biosensors.

· Electronics: Found in conductive inks, flexible circuits, and sensors.

· Textiles and Coatings: Used to make antimicrobial fabrics and in water purification.

· Catalysis: Speeds up chemical reactions in different processes.

· Food Packaging: Helps prevent bacterial contamination and keeps food fresh longer.

With their wide range of applications, silver nanoparticles are becoming an essential part of modern technology. However, researchers continue to explore their long-term effects and potential risks, ensuring they can be used safely and effectively.²⁵

Challenges and Future Perspectives of Silver Nanoparticles:

Silver nanoparticles (AgNPs) have made a huge impact across various industries, from medicine to electronics. Their powerful antimicrobial properties and electrical conductivity have opened up exciting possibilities. However, like any emerging technology, AgNPs come with challenges that need to be addressed before they can be fully and safely integrated into everyday applications. Let’s take a closer look at some of the key hurdles and the future outlook for silver nanoparticles.

Challenges:

1. Concerns about Toxicity and Environmental Impact:

· While AgNPs are great at killing harmful microbes, they can also be toxic to human cells if used in high concentrations. Some studies suggest they may trigger oxidative stress, DNA damage, and even inflammation.

· Another concern is their environmental footprint. Once released into water or soil, silver nanoparticles don’t break down easily, potentially affecting aquatic life and beneficial microbes. Scientists are still trying to understand the long-term impact of this buildup.

· At the moment, there are no clear-cut safety guidelines for how much AgNP exposure is safe, either for humans or the environment. Regulatory agencies are working on setting limits, but more research is needed.²⁸

2. Stability and Aggregation Issues:

· Silver nanoparticles have a tendency to clump together over time, which affects their performance.

· To prevent this, scientists modify their surface with stabilizing agents, but these modifications can also change how the nanoparticles interact with biological systems. Finding the right balance is an ongoing challenge.²⁹

3. Cost and Scalability:

· Producing high-quality, uniform AgNPs on a large scale is expensive. The processes involved require precise control over size, shape, and stability, which adds to the cost.

· Keeping the production process consistent is another challenge—small variations can lead to big differences in effectiveness, especially for medical or electronic applications.³⁰

4. Risk of Antimicrobial Resistance:

· Just like overuse of antibiotics can lead to resistant bacteria, there’s concern that prolonged exposure to silver nanoparticles could trigger bacterial resistance over time.

· More research is needed to determine how microbes adapt to silver-based treatments and how we can prevent resistance from developing. ^31,32

Future Perspectives:

1. Moving Toward Safer and Greener Production:

· Scientists are exploring eco-friendly ways to produce silver nanoparticles, using plant extracts, bacteria, or fungi instead of harsh chemicals. These methods reduce toxicity and environmental concerns.

· Another promising direction is creating biodegradable coatings for AgNPs, which would help minimize their long-term accumulation in nature.

2. Advancing Medical Applications:

· Researchers are looking into targeted drug delivery, where AgNPs can be used to transport medication directly to cancer cells, reducing side effects and making treatments more effective.

· Smart wound dressings with AgNPs are being developed to release silver in a controlled manner, helping wounds heal faster while keeping bacteria at bay.

· AgNPs are also improving biosensors, making it easier to detect diseases at an early stage through highly sensitive diagnostic tools.

3. Better Regulation and Standardization:

· Governments and healthcare agencies are working toward setting clear safety standards for the production and use of AgNPs.

· Before silver nanoparticle-based therapies can be widely adopted in medicine, they’ll need to go through extensive clinical trials to ensure their safety and effectiveness.

4. Innovation in Electronics and Energy Storage:

· The future of electronics is flexible and wearable, and AgNPs are playing a key role in making that happen. Conductive inks made from silver nanoparticles are helping create bendable circuits for futuristic devices.

· Researchers are also exploring ways to integrate AgNPs into next-generation batteries and super capacitors, improving energy storage and efficiency.³³

REFERENCES:

1. Zahoor, M., Nazir, N., Iftikhar, M., Naz, S., Zekker, I., Burlakovs, J., Uddin, F., Kamran, A. W., Kallistova, A., Pimenov, N., and Ali Khan, F. A Review on Silver Nanoparticles: Classification, Various Methods of Synthesis, and Their Potential Roles in Biomedical Applications and Water Treatment. Water. 2021; 13(16): 2216

2. Lorraine Mulfinger, Sally D. Solomon, Mozghan Bahadory, Aravindan V. Jeyarajasingam, Susan A. Rutkowsky, and Charles Boritz Journal of Chemical Education. 2007; 84(2): 322

3. Hemalatha, P., and Premnath, A. Study on silver nanoparticle encapsulated curcumin for anticancer activity. World Journal of Pharmaceutical Research. 2016; 5: 958-973.

4. Mulfinger L., Solomon S. D., Bahadory M., Jeyarajasingam A. V., Rutkowsky S. A., and Boritz C., Synthesis and study of silver nanoparticles, Journal of Chemical Education. 2007; 84(2).

5. Iravani S, Korbekandi H, Mirmohammadi SV, Zolfaghari B. Synthesis of silver nanoparticles: chemical, physical and biological methods. Res Pharm Sci. 2014; 9(6): 385-406. PMID: 26339255; PMCID: PMC4326978.

6. Gudikandula, K., and Charya Maringanti, S. Synthesis of silver nanoparticles by chemical and biological methods and their antimicrobial properties. Journal of Experimental Nanoscience. 2016; 11(9): 714–721.

7. Xu L, Wang YY, Huang J, Chen CY, Wang ZX, Xie H. Silver nanoparticles: Synthesis, medical applications and biosafety. Theranostics. 2020 Jul 11; 10(20): 8996-9031.

8. Lee SH, Jun BH. Silver Nanoparticles: Synthesis and Application for Nanomedicine. Int J Mol Sci. 2019 Feb 17;20(4):865.

9. Ratti M, Naddeo JJ, Griepenburg JC, O'Malley SM, Bubb DM, Klein EA. Production of Metal Nanoparticles by Pulsed Laser-ablation in Liquids: A Tool for Studying the Antibacterial Properties of Nanoparticles. J Vis Exp. 2017 Jun 2; 124: 55416.

10. Reza Sadrolhosseini, A., Adzir Mahdi, M., Alizadeh, F., and Abdul Rashid, S. Laser Ablation Technique for Synthesis of Metal Nanoparticle in Liquid. IntechOpen. 2019

11. Sportelli MC, Izzi M, Volpe A, Clemente M, Picca RA, Ancona A, Lugarà PM, Palazzo G, Cioffi N. The Pros and Cons of the Use of Laser Ablation Synthesis for the Production of Silver Nano-Antimicrobials. Antibiotics (Basel). 2018 Jul 28;7(3):67.

12. Égerházi, L., and Szörényi, T. The Potential of Wire Explosion in Nanoparticle Production in Terms of Reproducibility. Materials. 2024; 17(14): 3450.

13. Abbas, R., Luo, J., Qi, X., Naz, A., Khan, I. A., Liu, H., Yu, S., and Wei, J. Silver Nanoparticles: Synthesis, Structure, Properties and Applications. Nanomaterials. 2024; 14(17): 1425.

14. More PR, Pandit S, Filippis A, Franci G, Mijakovic I, Galdiero M. Silver Nanoparticles: Bactericidal and Mechanistic Approach against Drug Resistant Pathogens. Microorganisms. 2023 Feb 1; 11(2): 369.

15. Nguyen, N. P. U., Dang, N. T., Doan, L., and Nguyen, T. T. H. Synthesis of Silver Nanoparticles: From Conventional to ‘Modern’ Methods—A Review. Processes. 2023; 11(9): 2617.

16. Hayelom Dargo Beyene, Adhena Ayaliew Werkneh, Hailemariam Kassa Bezabh, Tekilt Gebregergs Ambaye, Synthesis paradigm and applications of silver nanoparticles (AgNPs), a review, Sustainable Materials and Technologies. 2017; 13: 18-23.

17. Tartaro, G., Mateos, H., Schirone, D., Angelico, R., and Palazzo, G. Microemulsion Microstructure(s): A Tutorial Review. Nanomaterials. 2020; 10(9): 1657.

18. Hussain, T., and Batool, R. Microemulsion Route for the Synthesis of Nano-Structured Catalytic Materials. InTech. 2017

19. Ahmad, A., Haneef, M., Ahmad, N., Kamal, A., Jaswani, S., and Khan, F. Biological synthesis of silver nanoparticles and their medical applications (Review). World Academy of Sciences Journal. 2024; 6: 22.

20. Anita Dhaka, Suresh Chand Mali, Sheetal Sharma, Rohini Trivedi, A review on biological synthesis of silver nanoparticles and their potential applications, Results in Chemistry. 2023; 6: 101-108.

21. Deeksha Chugh, V.S. Viswamalya, Bannhi Das, Green synthesis of silver nanoparticles with algae and the importance of capping agents in the process, Journal of Genetic Engineering and Biotechnology. 2021; 19(1): 126.

22. Duman, H., Eker, F., Akdaşçi, E., Witkowska, A. M., Bechelany, M., and Karav, S. Silver Nanoparticles: A Comprehensive Review of Synthesis Methods and Chemical and Physical Properties. Nanomaterials. 2024; 14(18): 1527.

23. Almatroudi A. Silver nanoparticles: synthesis, characterisation and biomedical applications. Open Life Sci. 2020; 15(1): 819-839.

24. T. Galatage, S., S. Hebalkar, A., V. Dhobale, S., R. Mali, O., S. Kumbhar, P., V. Nikade, S., and G. Killedar, S. Silver Nanoparticles: Properties, Synthesis, Characterization, Applications and Future Trends. IntechOpen. 2021

25. Zhang, X. F., Liu, Z. G., Shen, W., and Gurunathan, S. Silver Nanoparticles: Synthesis, Characterization, Properties, Applications, and Therapeutic Approaches. International Journal of Molecular Sciences. 2016; 17(9).

26. Krishnan PD, Banas D, Durai RD, Kabanov D, Hosnedlova B, Kepinska M, Fernandez C, Ruttkay-Nedecky B, Nguyen HV, Farid A, Sochor J, Narayanan VHB, Kizek R. Silver Nanomaterials for Wound Dressing Applications. Pharmaceutics. 2020 Aug 28; 12(9): 821.

27. F. Moradifar, N. Sepahdoost, P. Tavakoli, A. Mirzapoor, Multi-functional dressings for recovery and screenable treatment of wounds: A review. Heliyon. 2025; 11(1): e41465.

28. Ferdous Z, Nemmar A. Health Impact of Silver Nanoparticles: A Review of the Biodistribution and Toxicity Following Various Routes of Exposure. Int J Mol Sci. 2020 Mar 30; 21(7): 2375.

29. Sujoy Das, Krishnan Bandyopadhyay, M.M. Ghosh, Effect of stabilizer concentration on the size of silver nanoparticles synthesized through chemical route. Inorganic Chemistry Communications. 2021; 123.

30. Rangasamy, G., and Vo, D. V. N. Innovative eco-friendly silver nanoparticles: various synthesis methods, characterization and prospective applications. Chemical Engineering Communications. 2024; 212(3): 472–507.

31. McNeilly O, Mann R, Hamidian M, Gunawan C. Emerging Concern for Silver Nanoparticle Resistance in Acinetobacter baumannii and Other Bacteria. Front Microbiol. 2021 Apr 16; 12: 652863.

32. Zhuoran Wu, Brian Chan, Jessalyn Low, Justin Jang Hann Chu, Hwee Weng Dennis Hey, Andy Tay, Microbial resistance to nanotechnologies: An important but understudied consideration using antimicrobial nanotechnologies in orthopaedic implants. Bioactive Materials. 2022; 16: 249-270.

33. Jain AS, Pawar PS, Sarkar A, Junnuthula V, Dyawanapelly S. Bionanofactories for Green Synthesis of Silver Nanoparticles: Toward Antimicrobial Applications. Int J Mol Sci. 2021 Nov 5; 22(21): 11993. doi: 10.3390/ijms222111993.

Received on 05.03.2025 Revised on 23.05.2025

Accepted on 28.06.2025 Published on 18.10.2025

Available online from November 03, 2025

Res. J. Pharma. Dosage Forms and Tech.2025; 17(4):279-285.

DOI: 10.52711/0975-4377.2025.00039

This work is licensed under a Creative Commons Attribution-Non Commercial-Share Alike 4.0 International License. Creative Commons License.

Factor	Physical Methods (e.g., Laser Ablation, Ball Milling)	Chemical Methods (e.g., Reduction of Silver Salts)	Biological (Green) Methods (e.g., Plant, Bacteria, or Fungi-based)
Purity	Extremely pure (since no chemicals are used)	May have traces of chemical residues	Generally pure but may contain some natural by products
Control Over Size and Shape	Good control with advanced equipment	Excellent control with stabilizers and reducing agents	Moderate control, depends on the biological source
Cost	Expensive due to specialized equipment and energy use	More affordable, but may require additional purification	Cost-effective (uses natural, inexpensive materials)
Scalability	Hard to scale up for large production	Easily scalable, widely used in industries	Potential for scalability but still needs optimization
Eco-Friendliness	High energy consumption, not very eco-friendly	Uses toxic chemicals, posing environmental risks	Very eco-friendly, avoids harmful chemicals
Reaction Time	Quick but energy-intensive	Fast (can be completed in minutes to hours)	Slower process (may take hours or days)
Ease of Process	Requires advanced technology and expertise	Relatively simple but requires precise chemical control	Involves biological processes, which need optimization
Common Uses	Electronics, sensors, and optical applications	Medicine, textiles, coatings, water purification	Biomedicine, eco-friendly applications, drug delivery