Int J Pharm Pharm Sci, Vol 16, Issue 5, 22-29Review Article

A REVIEW ON TEMPLATE SYNTHESIS OF NANOPARTICLE

SAKSHI GHARAT1, AISHWARYA GHADGE1, SWAPNIL D. PHALAK2, VISHAL BODKE2*, ADITI GAVAND1, DARSHANA GANVIR1, DEEPTI GAIKWAD1

1Konkan Gyanpeeth Rahul Dharkar College of Pharmacy and Research Institute, Karjat, Maharashtra, India. 2Department of Pharmaceutics, Konkan Gyanpeeth Rahul Dharkar College of Pharmacy and Research Institute, Karjat, Maharashtra, India
*Corresponding author: Vishal Bodke; *Email: vishalbodke77@gmail.com

Received: 15 Feb 2024, Revised and Accepted: 23 Mar 2024

ABSTRAC

In recent years, there has been a rise in interest in the development of novel drug delivery systems that utilize nanoparticles. In terms of high stability, high specificity, high drug-carrying capacity, controlled release, the ability to use different routes of administration, and the ability to deliver both hydrophilic and hydrophobic drug molecules, nanoparticles can offer significant advantages over conventional drug delivery. We try to provide a detailed overview of template techniques designed for nanomaterial production. The pores and channels in the nanoporous “template” structures are used to generate the desired nanomaterials in template synthesis. Because this process has advantages over other methods, like allowing precise control over their size, shape, and structure, it is commonly used to generate nanoparticles. The first half of the review provides information on various template preparation processes. Templates are classified as “hard” or “soft” templates. Soft templates are often fluid-like, whereas hard templates are typically solid-state materials with distinct morphology and structure. This study discusses the effect of templates on morphologies and methodology and compares hard and soft templates.

Keywords: Nanoparticles, Templates, Mesoporous, Polymer etc

© 2024 The Authors.Published by Innovare Academic Sciences Pvt Ltd. This is an open access article under the CC BY license (https://creativecommons.org/licenses/by/4.0/)
DOI: https://dx.doi.org/10.22159/ijpps.2024v16i5.50661 Journal homepage: https://innovareacademics.in/journals/index.php/ijpps

INTRODUCTION

The study of matter’s properties at the nanoscale is known as nanoscience, and it primarily focuses on the unique, size-dependent characteristics of solid-state materials. The famous speech by Nobel laureate Richard Feynman is usually called the birth of terms in nanoscience and nanotechnology. "There's Plenty of Room at the Bottom” was the subject of the American Physical Society meeting in 1959 [1]. The term “nanoparticle” originated from the Greek word for “dwarf” or “little.” The prefix “Nano” is used to refer to small living things [2, 3]. Nanotechnology comes from the prefix nano, which denotes a billionth (1×10-9). Nanotechnology is the study of different matter structures with sizes smaller than a billionth of a meter. 10-9 m is a nanometer. In general, nanoparticles are thought to consist of many atoms or molecules joined together with a radius of approximately 100 nm [4, 5].

Due to the unique physicochemical features of nanomaterials, research based on them is currently receiving increased attention. Among the rapidly expanding fields, the combination of nanomaterials with porous structures is the most attractive. Mesoporous (2–50 nm), macroporous (>50 nm), and microporous (<2 nm) materials are examples of porous materials with interconnected solid composite pore networks. Other than this, porous materials can include natural materials like clays, biological tissues (like bones), rocks, and synthetic materials, in addition to metal oxides, ceramics, carbonaceous materials, and membranes [6, 7].

These days, researchers have become more interested in the synthesis of nanomaterials. Metal nanoparticles can be produced through a variety of approaches. There are two known approaches to synthesis: the top-down approach and the bottom-up approach. Repeated quenching, lithography, and milling are examples of top-down methods [8]. The drawback of this method is that it does not have precise control over particle size and structure. While synthesizing nanoparticles, scientists usually use the bottom-up method, which develops material from the bottom up: molecule by molecule, atom by atom, and cluster by cluster [9]. Several factors are involved in the nucleation and subsequent formation of stabilized nanoparticles during the synthesis of nanomaterials.

Fig. 1: Types of synthesis of nanoparticles [10]

The template-assisted method is a synthetic method that uses a scaffold or template to direct and control the development of materials with desired characteristics. The term “template” refers to any entity possessing nanostructured qualities whose dimensions, shape, and distribution of charges significantly impact the attributes directing the structure [11]. By employing a preset template as a guide throughout the synthesis process, this method is frequently used to create nanoparticles, giving exact control over their size, shape, and structure. Template-assisted methods are preferred options for many applications due to their efficiency and homogeneity. These methods provide a structured framework or template that makes process simplification easier and ensures tasks are completed consistently. Benefits from this could include reduced errors, time savings, consistency, and a simplified training process.

Template synthesis of nanomaterials has become known as an advanced method since the 1990s. Early in 1992 C. T. Kresge et al. researched ordered Mesoporous molecular sieves synthesized by a liquid crystal Template mechanism [12]. In 1995 Dmitri Routkevitch et al. did research on a technique which is described for fabricating arrays of uniform CdS nanowires with lengths up to 1 µm and diameters as small as 9 nm by electrochemically depositing the semiconductor directly into the pores of anodic aluminum Oxide films from an electrolyte containing Cd2+and S in dimethyl sulfoxide [13]. Isamu Moriguchi et al. in 1999 studied phenol-formaldehyde polymer and surfactant assembly was structuralized into lamella and disordered mesophases depending on surfactant/phenol molar ratio at the synthesis [14]. Tae-Wan Kim et al. studied the Assembly of mesostructured silica using Pluronic P123 triblock copolymer (EO20-PO70-EO20) And the n-butanol mixture is a facile synthesis route to the MCM-48-like ordered large mesoporous silica with the cubic Ia3hd mesostructured [15].

Particularly in the case of mesoporous materials, morphology is the most important aspect for characterizing the properties of the material. Particle size, surface area, pore structure, and morphology all contribute together to define the morphology of mesoporous materials, which in turn helps determine their specific uses [16-18]. The most common method by which the template approach affects product morphology is by controlling crystal nucleation and growth during the nanomaterial preparation process [19, 20]. The following three steps are usually involved in the template syntheses of nanostructured materials: template preparation, target material synthesis (using sol-gel, precipitation, hydrothermal synthesis, and other methods) based on the template, and lastly template removal [21, 22]. The proper removal technique must be selected to ensure that the product’s chemical and physical qualities are unaffected. Physical and chemical techniques including dissolution, sintering, and etching are examples of common removal techniques [23].

The ease and speed with which template synthesis, electrodeposition, and Chemical Vapor Deposition (CVD) can be modified and applied to new study areas is a huge benefit. Thus, there are still many opportunities to investigate alternative approaches to nanoscience and nanoscale manufacturing [24, 25]. One of the main challenges with these techniques is that it takes a lot of work to remove the template completely, which gradually reduces the purity of the nanoparticles. These methods have gained a lot of interest recently due to their simple and fast preparation process, which produces a crystalline powder that is fine, homogenous, and free of agglomerations [26].

Types of template method

Mesoporous materials are being manufactured using a wide range of synthetic techniques. The two most popular approaches are “hard” (also known as “nanocasting”) and “soft” (also known as “soft”) [29].

Fig. 2: Schematic presentation of nanoparticles using template synthesis [27, 28]

Fig. 3: Types of templates [30-32]

Hard template

The size and shape of the sample particle are directly determined by the hard template, which is a rigid material with a fixed structure. By using a cooperative assembly between the surfactant and inorganic species, the hard-template approach is an effective way to create Mesoporous materials that are challenging to synthesize by conventional methods [33]. The idea is extremely straightforward and was first put forward by Ryoo et al. and Hyeon and coworkers. There are three primary steps in the synthetic pathway: selecting and creating the original template (ideally, mesoporous carbon or silica is used as the original templateIntroducing the target precursors to the mesoporous and turning them into an inorganic solid (creating a composite that includes the original template and the target inorganic solid); andRemoving the original template [34-36].

Porous Anodic Aluminum Oxide (AAO)

It is a self-organized material with a honeycomb-like structure formed by a high-density array of uniform and parallel nanopores. Anodization, or the electrochemical oxidation of a metal, is a straightforward and inexpensive electrochemical technique that covers a sizable portion of the target metallic surface with an oxide layer [37-40]. Via anodization of aluminum metal in an acidic solution, porous alumina membranes are produced. Aluminum metal is anodically oxidized in solutions of sulfuric, oxalic, or phosphoric acid to produce alumina membranes with a homogeneous and parallel porous structure [41-44]. The Steps involved in the formation of the AAO template are as follows.

Fig. 4: The steps involved in the formation of the AAO template [41]

Mesoporous carbon

One significant component of mesoporous materials is mesoporous carbon. Its pore diameter typically ranges from 2 to 50 nm, and its pore dispersion is uniform. Its specific Surface area is high and its pore structure is regular. In addition, it has chemical and thermal stability [45-46]. The most common approach for synthesizing mesoporous carbon is template-assisted synthesis [47]. The following is the standard template synthetic process for porous carbons:

Additional procedures like chemical vapor deposition or soft-templating techniques may also be employed, depending on the necessities [48-51].

Fig. 5: Preparation of mesoporous carbon template

Polymer microspheres

The polymer microsphere exhibits strong dispersity and is readily adjustable in terms of particle size. It is usually used to produce spherical particles with a hollow structure or nearly spherical core-shell particles following surface modification [52]. Several methods are employed to produce polymer microspheres, including emulsion polymerization, microemulsion polymerization, soap-free emulsion polymerization, suspension polymerization, and dispersion polymerization [53-56]. Solvent evaporation is used to produce microsphere templates [57, 58].

Fig. 6: Synthesis of microsphere template via solvent evaporation method [58, 59]

Emulsion polymerization

An emulsion including a monomer, water, and surfactant is usually the first step in this type of radical polymerization process. Emulsion polymerization mostly uses oil in water. Emulsion, in which the monomer droplets are emulsified in the oil in a constant water phase (with surfactants). Water: soluble polymers, such as hydroxyethyl or polyvinyl alcohol in some cases Furthermore, celluloses can be used as emulsifiers and stabilizers [60].

Microemulsion polymerization

Microemulsion in which monomers can be added to the system's water or oil phases to aid in the polymerization of the monomers. There are three methods for polymerizing microemulsions: chemical, photochemical, and high-energy radiation. Numerous morphologies of droplet-containing microemulsions have been used to study polymerization reactions. Some of the studies that were conducted in this category are as follows: The processes of polymerization in water-in-oil and oil-in-water microemulsions [61].

Soap-free emulsion polymerization

Also known as surfactant-free heterogeneous polymerization using water as a solvent, soap-free emulsion polymerization is a suggested environmentally acceptable method for producing monodisperse particles of polymers at low impurity levels. During water polymerization, the contacts amongst the polymer particles were stabilized by electrostatic forces. The main use of conventional soap-free emulsion polymerization has been the creation of submicron-sized polymer particles [62].

Suspension polymerization

In a typical suspension polymerization system, one or more water-insoluble monomers are distributed with an oil-soluble initiator in the continuous aqueous phase by using small amounts of suspending agents (stabilizers) with rapid stirring [63].

Dispersion polymerization

When a monomer is polymerized with a suitable polymeric stabilizer that is soluble in the reaction solution, a type of precipitation polymerization is known as dispersion polymerization. [64]. This process includes dissolving a monomer in a solvent or solvent mixture and polymerizing it with the help of a steric stabilizer. At first, the molecules of the stabilizer and monomer dissolve in a single phase. The process of homogenous nucleation of particles from the medium is similar to that of particle production in emulsion polymerization. As a result, the growing particles separate from the medium as the polymerization process occurs. A two-phase system is created at the end of the polymerization process [65].

Soft template

Flexible nanostructures composed of intermolecular interactions are frequently used as soft templates in the soft-template technique. Block copolymers, flexible organic molecules, and surfactants are examples of soft matter that compose the soft templates. Weak non-covalent bonds, such as hydrogen bonding, electrostatic, or van der Waals interactions, are often how these templates interact with the precursors [66]. Nowadays, the soft template technique has been employed to create polymer nanoparticles with a range of morphologies. Many soft templates include functionalized polymer, cyclodextrin, liquid crystalline polymer, and surfactant. Surfactants, which include cationic, anionic, and non-ionic amphiphiles, are the most commonly utilized in micelle creation as a nanoreactor [67,68]. The soft template has a wide range of potential applications in the synthesis of nanomaterials Because of its benefits, such as strong reproducibility, simplicity of the process, and the absence of the need for silicon removal [69, 70].

Fig. 7: Soft template [68, 69]

Surfactant

Surfactant is a helpful chemical that may direct structure [71]. The surfactant employed has a large influence on particle sizes ranging from 1 to 50 nm. Surfactant-assisted nanoparticle production produces particles with a large surface area. A surfactant can also be used to prevent nanoparticle agglomeration in the solution [72, 73]. Surfactant Surfactant-assisted precipitation has recently gained attention in synthesis due to its ease of use, low cost, and capacity to develop different features [74]. Because polymer–surfactant complexes have an effective structure completely distinct from that of pure surfactant systems or pure water-soluble polymers, they are promising candidates for the production of diverse nanostructures [75, 76].

Fig. 8: Steps of the general role of surfactant in template synthesis [75]

High polymer

High surface area nanonetworks are being created by working with soft templates based on polymers. The resulting network can have a high surface area, big pore volume, and porous dispersion due to the polymer soft-template approach [77]. Mesoporous materials provide extremely large surface areas, finely regulated pore diameters, and clearly defined pore structures. Numerous mesoporous silica materials have found broad use as host materials for catalysts, polymers, metals, semiconductor nanoparticles, and carbon because of these advantageous features [78, 79]. This approach depends on the self-assembly of polymerizing organics (used as carbon precursors and templates, respectively) and triblock copolymers to generate organic–organic nanocomposites [80]. High polymers, known as block copolymers are made up of two or more chemically distinct polymer chains joined together at their ends. It can self-assemble into a large range of ordered forms via covalent bonding. Because block copolymers include multiple blocks with varying properties, it is easy to mold them into various morphologies, such as thin films or three-dimensional templates. The block copolymer’s overall synthesis approach. The three steps of assisted synthesis are (1) copolymer micelle generation; (2) precursor addition; and (3) self-assembly to a specific shape. Thus, the final product with the Intended morphology is formed upon the removal of the template [81].

Preparation of tri-block polymer

Poly (styrene-block-acrylic acid-block-ethylene glycol) block polymer CTA: cellulose trans acetate, AIBN: Azobisisobutyronitrile.

Fig. 9: Preparation of triblock polymer [81, 82]

Biopolymer

Especially in many synthetic processes and in several natural processes, biopolymers as well as their colloids can serve as templates and regulating agents [83]. The idea of employing biological substances as soft templates is quite intriguing, and a great deal of work has been done to use biological materials with regulated properties that are easily obtainable and economically priced. Biomolecules, unicellular creatures, and complex tissues are just a few examples of biological materials that can be used to create soft templates. The naturally occurring, distinctive structure of this biological template is superior to that of artificially made templates and permits extraordinary chemistry to occur on the template, promoting the production of regulated morphology, composition, and crystal structure [84, 85].

The most widely used type of biodegradable nanoparticles are called Biopolymeric Nanoparticles (BPNs), which are made of natural polymers found in biological species like proteins (like collagen, gelatin, β-casein, zein, and albumin), protein-mimicking polypeptides (like cationic polypeptides like polylysine and polyornithine), and polysaccharides (like hyaluronic acid, chitosan, alginate, starch, and heparin). These nanoparticles made of different biopolymers are presently being developed to deal with toxicity, biocompatibility, and biodegradability issues. Both metallic and biopolymeric nanoparticles (BPNs) are used in many different industries, while the latter are safer and eco-friendly. BPNs are currently being actively used in the food business, biomedical applications, diagnostic tool development, and household chemical sector [86]. Biomacromolecules (such as polysaccharides, proteins, and nucleic acids) can serve two primary purposes: (i) regulating the nucleation and development of the inorganic material and (ii) providing structural support by enclosing areas or serving as scaffolds or supports for the growth. The interplay between organic and inorganic matter allows nature to produce hybrid materials whose remarkable shapes and characteristics never cease to astound humans [87].

Table 1: Difference between soft template and hard template

S. No. Hard template Soft template Reference
1 The size and shape of the sample particle are directly determined by the hard template, which is a rigid material with a fixed structure The soft template lacks a definitive rigid structure.
2 Hard templates are prepared before the reaction. Soft templates are generated during the reaction. [88]
3 They are very reproducible and stable. They are not stable [89]
4 Hard templates are hard to remove. Soft templates are easier to make and remove than hard templates.
5 Hard templates are those created by the in situ physical or chemical conversion of a substance into its precursors. The soft-template method frequently employs flexible nanostructures as soft-templates, which are composed of intermolecular interactions. [90]
6 The hard template method consumes more time. The soft template method consumes less time than the hard template method.
7 Hard templating is a tedious strategy. Soft-templating synthesis of mesoporous carbons, this simple and cost-effective strategy
8 Hard template, the templating approach is more challenging and complicated. The soft templating approach is the simplicity of the one-step synthetic procedure for generating mesostructured materials. [90]
9 It applies to the physical or chemical growth or deposition of nanomaterials into the template’s nanopores, and the template is eventually removed; this allows for exact control over the target production’s dimensions and requirements. The aggregation by weak intermolecular or intramolecular interaction develops a specific structure of space. These aggregates feature a prominent structural interface that offers a special interface to produce a certain propensity. The dispersion of inorganic spices ultimately results in the production of nanomaterials with certain structures. [91]
10 The majority of the time, hard templates are made from previously prepared materials such as polymer microspheres, mesoporous carbon, and AAO templates [88-92] The soft template depends mostly on the micelle’s action to produce the organic-inorganic phase between target production, high polymer, biopolymer, and surfactant. [92]

CONCLUSION

Because nanoscience and nanotechnology are by definition, multidisciplinary fields, biologists need to understand not only the basic principles of nanoscience but also the tools and techniques commonly used to manipulate nanomaterials. Since the hard template approach offers the potential to use multiple configurations for the tagging of mesoporous silica nanoparticles, it is a highly effective technology for making a variety of metal oxide and carbon-based mesoporous materials. In summary, construction frameworks and pore diameters can be used to differentiate between porous materials. The mesoporous microstructure of mesoporous silica is found in pores with diameters ranging from 2 to 50 nm. The mesoporous silica synthesis using template intervention approaches was reorganized into two groups: the endotemplate strategy (also known as the soft template) and the hard template (also known as the exotemplate method). Three separate steps that typically comprise a template-assisted approach are the formation of mesoporous substances using the template (e. g., sol-gel, precipitation, hydrothermal process, etc.) and template expulsion. While soft templates are found in fluid-like, non-rigid substances, such as surfactants, hard templates are typically solid-state materials with certain morphological properties and frameworks.

ABBREVIATIONS

Anodic Aluminum Oxide-(AAO)

FUNDING

Nil

AUTHORS CONTRIBUTIONS

Sakshi and Aishwarya collected the data and drafted the manuscript. Swapnil Guide to all authors the way of research study. Vishal serially analyzed, arranged, and evaluated the manuscript. Aditi, Darshana, and Deepti are translators. All the authors have contributed equally.

CONFLICTS OF INTERESTS

The authors declare no conflicts of interest.

REFERENCES

  1. Joudeh N, Linke D. Nanoparticle classification, physicochemical properties, characterization, and applications: a comprehensive review for biologists. J Nanobiotechnology. 2022 Jun 7;20(1):262. doi: 10.1186/s12951-022-01477-8, PMID 35672712, PMCID PMC9171489.

  2. Selmani A, Kovacevic D, Bohinc K. Nanoparticles: from synthesis to applications and beyond. Adv Colloid Interface Sci. 2022 May;303:102640. doi: 10.1016/j.cis.2022.102640, PMID 35358806.

  3. Kalia A, Kaur M, Shami A, Jawandha SK, Alghuthaymi MA, Thakur A. Nettle-leaf extract derived ZnO/CuO nanoparticle-biopolymer-based antioxidant and antimicrobial nanocomposite packaging films and their impact on extending the post-harvest shelf life of guava fruit. Biomolecules. 2021 Feb 5;11(2):224. doi: 10.3390/biom11020224, PMID 33562547, PMCID PMC7916056.

  4. Hamrayev H, Shameli K. Biopolymer-based green synthesis of zinc oxide (ZnO) nanoparticles. ”Biopolymer-based green synthesis of zinc oxide (ZnO) nanoparticles.” IOP Conference Series. IOP Conf Ser: Mater Sci Eng. 2021;1051:012088. doi: 10.1088/1757-899X/1051/1/012088.

  5. Sharma J, Sharma M, Basu S. Synthesis of mesoporous MgO nanostructures using mixed surfactants template for enhanced adsorption and antimicrobial activity. J Environ Chem Eng. 2017 Aug;5(4):3429-38. doi: 10.1016/j.jece.2017.07.015.

  6. Li DY, Sun YK, Gao PZ, Zhang XL, Ge HL. Structural and magnetic properties of nickel ferrite nanoparticles synthesized via a template-assisted sol–gel method. Ceram Int. 2014;40(10):16529-34. doi: 10.1016/j.ceramint.2014.08.006.

  7. Shanmuganathan R, Karuppusamy I, Saravanan M, Muthukumar H, Ponnuchamy K, Ramkumar VS. Synthesis of silver nanoparticles and their biomedical applications-a comprehensive review. Curr Pharm Des. 2019;25(24):2650-60. doi: 10.2174/1381612825666190708185506, PMID 31298154.

  8. Laraib U, Sargazi S, Rahdar A, Khatami M, Pandey S. Nanotechnology-based approaches for effective detection of tumor markers: a comprehensive state-of-the-art review. Int J Biol Macromol. 2022 Jan 15;195:356-83. doi: 10.1016/j.ijbiomac.2021.12.052, PMID 34920057.

  9. Kumari S, Raturi S, Kulshrestha S, Chauhan K, Dhingra S, Andras K. A comprehensive review on various techniques used for synthesizing nanoparticles. J Mater Res Technol. 2023 Nov;27:1739-63. doi: 10.1016/j.jmrt.2023.09.291.

  10. Beyzaei H, Kooshki S, Aryan R, Zahedi MM, Samzadeh Kermani A, Ghasemi B. MgO nanoparticle-catalyzed synthesis and broad-spectrum antibacterial activity of imidazolidine-and tetrahydro pyrimidine-2-thione derivatives. Appl Biochem Biotechnol. 2018 Jan;184(1):291-302. doi: 10.1007/s12010-017-2544-y, PMID 28676962.

  11. Tang ZX, Lv BF. MgO nanoparticles as antibacterial agent: preparation and activity. Braz J Chem Eng. 2014 Sep;31(3):591-601. doi: 10.1590/0104-6632.20140313s00002813.

  12. Rane AV, Kanny K, Abitha VK, Thomas S. Methods for synthesis of nanoparticles and fabrication of nanocomposites. Synthesis of inorganic nanomaterials. Elsevier; 2018. p. 121-39. Available from: doi: 10.1016/b978-0-08-101975-7.00005-1.

  13. Hornak J. Synthesis, properties, and selected technical applications of magnesium oxide nanoparticles: a review. Int J Mol Sci. 2021;22(23):12752. doi: 10.3390/ijms222312752, PMID 34884556.

  14. Zhang Z, Yang S, Hu X, Xu H, Peng H, Liu M. Mechanochemical nonhydrolytic sol–gel-strategy for the production of mesoporous multimetallic oxides. Chem Mater. 2019 Jul 1;31(15):5529-36. doi: 10.1021/acs.chemmater.9b01244.

  15. Zhou M, Wei Z, Qiao H, Zhu L, Yang H, Xia T. Particle size and pore structure characterization of silver nanoparticles prepared by confined arc plasma. J Nanomater. 2009;2009:1-5. doi: 10.1155/2009/968058.

  16. Hamisu A, Gaya UI, Abdullah AH. Bi-template assisted sol-gel synthesis of photocatalytically-active mesoporous anatase TiO2 nanoparticles. Appl. 2021 Apr 23. doi: 10.14416/j.asep.2021.04.003.

  17. Xie Y, Kocaefe D, Chen C, Kocaefe Y. Review of research on template methods in preparation of nanomaterials. J Nanomater. 2016;2016:1-10. doi: 10.1155/2016/2302595.

  18. Gribov E, Koshevoy E, Chikunova I, Parmon V. Template-assisted SnO2: synthesis, composition, and photoelectrocatalytical properties. Catalysts. 2023;13(1):168. doi: 10.3390/catal13010168.

  19. Rangelov S, Petrov P. Template-assisted approaches for preparation of nanosized polymer structures. Nano-size polymers. Berlin: Springer International Publishing; 2016. p. 367-96. doi: 10.1007/978-3-319-39715-3_13.

  20. Veena Gopalan E, Malini KA, Santhoshkumar G, Narayanan TN, Joy PA, Al-Omari IA. Template-assisted synthesis and characterization of passivated nickel nanoparticles. Nanoscale Res Lett. 2010 Apr 2;5(5):889-97. doi: 10.1007/s11671-010-9580-7, PMID 20672108.

  21. Choma J, Jedynak K, Marszewski M, Jaroniec M. Polymer-templated mesoporous carbons synthesized in the presence of nickel nanoparticles, nickel oxide nanoparticles, and nickel nitrate. Appl Surf Sci. 2012 Feb;258(8):3763-70. doi: 10.1016/j.apsusc.2011.12.022.

  22. Poolakkandy RR, Menamparambath MM. Soft-template-assisted synthesis: a promising approach for the fabrication of transition metal oxides. Nanoscale Adv. 2020;2(11):5015-45. doi: 10.1039/d0na00599a, PMID 36132034.

  23. Savic S, Vojisavljevic K, Pocuca Nesic M, Zivojevic K, Mladenovic M, Knezevic N. Hard template synthesis of nanomaterials based on mesoporous silica. Metall Mater Eng. 2018;24(4, Dec). doi: 10.30544/400.

  24. Wade TL, Wegrowe JE. Template synthesis of nanomaterials. Eur Phys J Appl Phys. 2005 Jan;29(1):3-22. doi: 10.1051/epjap:2005001.

  25. Bechelany M, Amin A, Brioude A, Cornu D, Miele P. ZnO nanotubes by template-assisted sol–gel route. J Nanopart Res. 2012 Jul 6;14(8), doi: 10.1007/s11051-012-0980-8.

  26. Ahmad S, Riaz U, Kaushik A, Alam J. Soft template synthesis of superparamagnetic Fe3O4 nanoparticles a novel technique. J Inorg Organomet Polym Mater. 2009 May 2;19(3):355-60. doi: 10.1007/s10904-009-9276-6.

  27. Yamauchi Y, Kuroda K. Rational design of mesoporous metals and related nanomaterials by a soft‐template approach. Chem Asian J. 2008 Apr;3(4):664-76. doi: 10.1002/asia.200700350, PMID 18327878.

  28. Zhang H, Wang L, Tan Z, Li Z, Ding G, Jiao Z. Preparation of SnO2 nanoparticles by hard template method for high selectivity gas sensors. J Nanosci Nanotechnol. 2011 Dec;11(12):11023-7. doi: 10.1166/jnn.2011.4008, PMID 22409048.

  29. Perez Page M, Yu E, Li J, Rahman M, Dryden DM, Vidu R. Template-based syntheses for shape controlled nanostructures. Adv Colloid Interface Sci. 2016 Aug;234:51-79. doi: 10.1016/j.cis.2016.04.001, PMID 27154387.

  30. Templated growth formation of mesoporous silica materials: a soft-hard template approach. Nusantara science and technology proceedings. Galaxy Science; 2022 Nov 22. doi: 10.11594/nstp.2022.2747.

  31. Li WC, Lu AH, Weidenthaler C, Schüth F. Hard-templating pathway to create mesoporous magnesium oxide. Chem Mater. 2004 Nov 11;16(26):5676-81. doi: 10.1021/cm048759n.

  32. Lu Q, Li Q, Zhang J, Li J, Lu J. Facile mesoporous template-assisted hydrothermal synthesis of ordered mesoporous magnesium silicate as an efficient adsorbent. Appl Surf Sci. 2016 Jan;360:889-95. doi: 10.1016/j.apsusc.2015.11.081.

  33. Wang C, Cui B, Wang Y, Wang M, Zeng Z, Gao F. Preparation and size control of efficient and safe nanopesticides by anodic aluminum oxide templates-assisted method. Int J Mol Sci. 2021;22(15):8348. doi: 10.3390/ijms22158348, PMID 34361113.

  34. Jang J. Conducting polymer nanomaterials and their applications. Emissive Mater Nanomater Berlin Heidelberg. 2006. p. 189-260. Available from: doi: 10.1007/12_075.

  35. Zou Y, Zhou X, Zhu Y, Cheng X, Zhao D, Deng Y. sp 2-hybridized carbon-containing block copolymer templated synthesis of mesoporous semiconducting metal oxides with excellent gas sensing property. Acc Chem Res. 2019 Mar 4;52(3):714-25. doi: 10.1021/acs.accounts.8b00598.

  36. Lee J, Kim J, Hyeon T. Recent progress in the synthesis of porous carbon materials. Adv Mater. 2006 Aug;18(16):2073-94. doi: 10.1002/adma.200501576.

  37. Junais PM, Athika M, Govindaraj G, Elumalai P. Supercapattery performances of nanostructured cerium oxide synthesized using polymer soft-template. J Energy Storage. 2020 Apr;28:101241. doi: 10.1016/j.est.2020.101241.

  38. Kim M, Sohn K, Na HB, Hyeon T. Synthesis of nanorattles composed of gold nanoparticles encapsulated in mesoporous carbon and polymer shells. Nano Lett. 2002 Oct 26;2(12):1383-7. doi: 10.1021/nl025820j.

  39. Li X, Zou M, Wang Y. Soft-template synthesis of mesoporous anatase TiO₂ nanospheres and its enhanced photoactivity. Molecules. 2017;22(11):1943. doi: 10.3390/molecules22111943, PMID 29125570.

  40. Pal N, Bhaumik A. Soft templating strategies for the synthesis of mesoporous materials: inorganic, organic-inorganic hybrid and purely organic solids. Adv Colloid Interface Sci. 2013 Mar;189-190:21-41. doi: 10.1016/j.cis.2012.12.002, PMID 23337774.

  41. Houng MP, Lu WL, Yang TH, Lee KW. Characterization of the nanoporous template using anodic alumina method. J Nanomater. 2014;2014:1-7. doi: 10.1155/2014/130716.

  42. Sterk L, Gorka J, Jaroniec M. Polymer-templated mesoporous carbons with nickel nanoparticles. Colloids Surf A Physicochem Eng Aspects. 2010 Jun;362(1-3):20-7. doi: 10.1016/j.colsurfa.2010.03.028.

  43. Preiss LC, Landfester K, Munoz Espi R. Biopolymer colloids for controlling and templating inorganic synthesis. Beilstein J Nanotechnol. 2014 Nov 17;5:2129-38. doi: 10.3762/bjnano.5.222, PMID 25551041.

  44. Nidhin M, Indumathy R, Sreeram KJ, Nair BU. Synthesis of iron oxide nanoparticles of narrow size distribution on polysaccharide templates. Bull Mater Sci. 2008;31(1):93-6. doi: 10.1007/s12034-008-0016-2.

  45. Vodyashkin AA, Kezimana P, Vetcher AA, Stanishevskiy YM. Biopolymeric nanoparticles–multifunctional materials of the future. Polymers. 2022 Jun 4;14(11):14(11):2287. doi: 10.3390/polym14112287, PMID 35683959.

  46. Padalkar S, Capadona JR, Rowan SJ, Weder C, Won YH, Stanciu LA. Natural Biopolymers: novel templates for the synthesis of nanostructures. Langmuir. 2010 Feb 9;26(11):8497-502. doi: 10.1021/la904439p, PMID 20143858.

  47. Dutta S, Patra AK, De S, Bhaumik A, Saha B. Self-assembled TiO2 nanospheres by using a biopolymer as a template and its optoelectronic application. ACS Appl Mater Interfaces. 2012 Feb 29;4(3):1560-4. doi: 10.1021/am201759w, PMID 22335551.

  48. Schnepp Z, Wimbush SC, Antonietti M, Giordano C. Synthesis of highly magnetic iron carbide nanoparticles via a biopolymer route. Chem Mater. 2010 Aug 24;22(18):5340-4. doi: 10.1021/cm101746z.

  49. Bapitha R, Alagar M. Synthesis and characterization of bio-template assisted lead oxide nanoparticles. J Adv Chem Sci. 2017;3(3):499-501.

  50. Kim YY, Neudeck C, Walsh D. Biopolymer templating as synthetic route to functional metal oxide nanoparticles and porous sponges. Polym Chem. 2010;1(3):272. doi: 10.1039/b9py00366e.

  51. Fu X, Lin L, Wang D, Hu Z, Song C. Preparation of CdS hollow spheres using poly-(styrene-acrylic acid) latex particles as template. Colloids Surf A Physicochem Eng Aspects. 2005 Jul;262(1-3):216-9. doi: 10.1016/j.colsurfa.2005.04.037.

  52. Ibadat NF, Ongkudon CM, Saallah S, Misson M. Synthesis and characterization of polymeric microspheres template for a homogeneous and porous monolith. Polymers. 2021;13(21):3639. doi: 10.3390/polym13213639, PMID 34771196.

  53. Roy M, Haloi DJ, Barman J. Emulsion prepared vinyl acetate-based terpolymer: a review on their preparations, properties, and applications. Asian J Green Chem. 2024;8(2):108-23. doi: 10.48309/ajgc.2024.413885.1441.

  54. Pavel FM. Microemulsion polymerization. J Dispers Sci Technol. 2004 Dec 29;25(1):1-16. doi: 10.1081/DIS-120027662.

  55. Shibuya K, Nagao D, Ishii H, Konno M. Advanced soap-free emulsion polymerization for highly pure, micron-sized, monodisperse polymer particles. Polymer. 2014 Jan;55(2):535-9. doi: 10.1016/j.polymer.2013.12.039.

  56. Abu Thabit NY, Makhlouf ASH. Recent advances in nanocomposite coatings for corrosion protection applications. Handbook of nanoceramic and nanocomposite coatings and materials. Elsevier; 2015. p. 515-49. doi: 10.1016/b978-0-12-799947-0.00024-9.

  57. Okubo M. editor. Polymer particles. Adv Polym Sci Berlin Heidelberg; 2005. doi: 10.1007/b14102.

  58. Tuncel A, Kahraman R, Piskin E. Monosize polystyrene microbeads by dispersion polymerization. J Appl Polym Sci. 1993 Oct 10;50(2):303-19. doi: 10.1002/app.1993.070500212.

  59. Saralidze K, Koole LH, Knetsch MLW. Polymeric microspheres for medical applications. Materials. 2010 Jun 7;3(6):3537-64. doi: 10.3390/ma3063537.

  60. Lv R, Cao C, Zhu H. Synthesis and characterization of ZnS nanowires by AOT micelle-template inducing reaction. Mater Res Bull. 2004 Aug;39(10):1517-24. doi: 10.1016/j.materresbull.2004.04.019.

  61. Rezaei M, Khajenoori M, Nematollahi B. Preparation of nanocrystalline MgO by surfactant-assisted precipitation method. Mater Res Bull. 2011 Oct;46(10):1632-7. doi: 10.1016/j.materresbull.2011.06.007.

  62. Chauhan S. Synthesis of ordered mesoporous carbon by soft template method. Mater Today Proc. 2023;81:842-7. doi: 10.1016/j.matpr.2021.04.257.

  63. Kumar A, Kumar J. On the synthesis and optical absorption studies of nano-size magnesium oxide powder. J Phys Chem Solids. 2008 Nov;69(11):2764-72. doi: 10.1016/j.jpcs.2008.06.143.

  64. Cao X, Yu F, Li L, Yao Z, Xie Y. Copper nanorod junctions templated by a novel polymer-surfactant aggregate. J Cryst Growth. 2003 Jun;254(1-2):164-8. doi: 10.1016/S0022-0248(03)01115-1.

  65. Liang C, Li Z, Dai S. Mesoporous carbon materials: synthesis and modification. Angew Chem Int Ed Engl. 2008 Apr 28;47(20):3696-717. doi: 10.1002/anie.200702046, PMID 18350530.

  66. Badini Confalonieri GA, Vega V, Ebbing A, Mishra D, Szary P, Prida VM. Template-assisted self-assembly of individual and clusters of magnetic nanoparticles. Nanotechnology. 2011 Jun 8;22(28):285608. doi: 10.1088/0957-4484/22/28/285608, PMID 21654034.

  67. Zhai Y, Dou Y, Liu X, Park SS, Ha CS, Zhao D. Soft-template synthesis of ordered mesoporous carbon/nanoparticle nickel composites with a high surface area. Carbon. 2011 Feb;49(2):545-55. doi: 10.1016/j.carbon.2010.09.055.

  68. Alexandridis P, Tsianou M. Block copolymer-directed metal nanoparticle morphogenesis and organization. Eur Polym J. 2011 Apr;47(4):569-83. doi: 10.1016/j.eurpolymj.2010.10.021.

  69. Hsia C, Yen M, Chiu H, Lee C. Polydimethylsiloxane soft template-assisted synthesis of silver nanoparticles via vapor‐solid reaction growth. J Chin Chem Soc. 2004 Apr;51(2):271-7. doi: 10.1002/jccs.200400043.

  70. Lee W, Park SJ. Porous anodic aluminum oxide: anodization and templated synthesis of functional nanostructures. Chem Rev. 2014 Jun 13;114(15):7487-556. doi: 10.1021/cr500002z, PMID 24926524.

  71. Phalak SD, Bodke V, Yadav RR, Pandav S, Ranaware M. A systematic review on nano drug delivery system: solid lipid nanoparticles (Sln). Int J Curr Pharm Res. 2024 Jan 15:10-20. doi: 10.22159/ijcpr.2024v16i1.4020.

  72. Arun Pardhe H, C Nagalakshmi N, Mg H, Kumar Chourasia P, S N A review: medicinal plants with antidepressant properties. IP Indian J Neurosci. 2020;6(1):1-5. doi: 10.18231/j.ijn.2020.001.

  73. Liu Y, Goebl J, Yin Y. Templated synthesis of nanostructured materials. Chem Soc Rev. 2013;42(7):2610-53. doi: 10.1039/c2cs35369e, PMID 23093173.

  74. Huczko A. Template-based synthesis of nanomaterials. Appl Phys A. 2000;70(4):365-76. doi: 10.1007/s003390051050.

  75. Hulteen JC, Martin CR. A general template-based method for the preparation of nanomaterials. J Mater Chem. 1997;7(7):1075-87. doi: 10.1039/a700027h.

  76. Li H, Wang L, Wei Y, Yan W, Feng J. Preparation of templated materials and their application to typical pollutants in wastewater: a review. Front Chem. 2022 Apr 5;10:882876. doi: 10.3389/fchem.2022.882876, PMID 35480393, PMCID PMC9037039.

  77. Zhu S, Zhao N, Li J, Deng X, Sha J, He C. Hard-template synthesis of three-dimensional interconnected carbon networks: rational design, hybridization and energy-related applications. Nano Today. 2019;29:100796. doi: 10.1016/j.nantod.2019.100796.

  78. Zhao J, Shao Q, Ge S, Zhang J, Lin J, Cao D. Advances in template prepared nano-oxides and their applications: polluted water treatment, energy, sensing and biomedical drug delivery. Chem Rec. 2020 Jul;20(7):710-29. doi: 10.1002/tcr.201900093, PMID 31944590.

  79. Liu D, Hu Y, Zeng C, Qu D. Soft-templated ordered mesoporous carbon materials: synthesis, structural modification and functionalization. Acta Phys Chim Sin. 2016a;32(12):2826-40. doi: 10.3866/PKU.WHXB201609141. 10.3866/pku.Whxb201609141.

  80. Xie Y, Kocaefe D, Chen C, Kocaefe Y. Review of research on template methods in preparation of nanomaterials. J Nanomater. 2016;2016:1-10. doi: 10.1155/2016/2302595.

  81. Patil N, Bhaskar R, Vyavhare V, Dhadge R, Khaire V, Patil Y. Overview on methods of synthesis of nanoparticles. Int J Curr Pharm Sci. 2021;13(2):11-6. doi: 10.22159/ijcpr.2021v13i2.41556.

  82. Kumar L, Singh S, Horechyy A, Fery A, Nandan B. Block copolymer template-directed catalytic systems: recent progress and perspectives. Membranes. 2021;11(5):318. doi: 10.3390/membranes11050318, PMID 33925335.

  83. Wang C, Cui B, Wang Y, Wang M, Zeng Z, Gao F. Preparation and size control of efficient and safe nanopesticides by anodic aluminum oxide templates-assisted method. Int J Mol Sci. 2021;22(15):8348. doi: 10.3390/ijms22158348, PMID 34361113.

  84. Kang H, Jeong S, Yang JK, Jo A, Lee H, Heo EH. Template-assisted plasmonic nanogap shells for highly enhanced detection of cancer biomarkers. Int J Mol Sci. 2021;22(4):1752. doi: 10.3390/ijms22041752, PMID 33578653.

  85. Nguyen VTA, Gauthier M, Sandre O. Templated synthesis of magnetic nanoparticles through the self-assembly of polymers and surfactants. Nanomaterials (Basel). 2014;4(3):628-85. doi: 10.3390/nano4030628, PMID 28344240.

  86. Bai S, Wang Y, Han Y. Template synthesis of metal nanoparticles within organic cages. Chin J Chem. 2019;37(12):1289-90. doi: 10.1002/cjoc.201900366.

  87. Salata O. Applications of nanoparticles in biology and medicine. J Nanobiotechnology. 2004;2(1):3. doi: 10.1186/1477-3155-2-3, PMID 15119954.

  88. Nimisha O, Mary APR, Ramanarayanan R. Template assisted green synthesis of nickel oxide nanoparticles for photocatalytic applications. IOP conf ser. IOP Conf Ser: Mater Sci Eng. 2022 Oct 1;1258(1):012010. doi: 10.1088/1757-899X/1258/1/012010.

  89. Ullah R, Hameed A, Azam A, Aziz T, Farhan, Qiao S. Facile synthesis of silver and gold nanoparticles using chicken feather extract as template and their biological applications. Biomass Conv Bioref. 2022. doi: 10.1007/s13399-022-03447-4.

  90. McCaffrey R, Long H, Jin Y, Sanders A, Park W, Zhang W. Template synthesis of gold nanoparticles with an organic molecular cage. J Am Chem Soc. 2014;136(5):1782-5. doi: 10.1021/ja412606t, PMID 24432779.

  91. Perez Page M, Yu E, Li J, Rahman M, Dryden DM, Vidu R. Template-based syntheses for shape controlled nanostructures. Adv Colloid Interface Sci. 2016;234:51-79. doi: 10.1016/j.cis.2016.04.001, PMID 27154387.

  92. Liu J, Yang T, Wang DW, Lu GQ, Zhao D, Qiao SZ. A facile soft-template synthesis of mesoporous polymeric and carbonaceous nanospheres. Nat Commun. 2013 Dec 17;(1):4. doi: 10.1038/ncomms3798.

  93. Bhange MA, Pethe AM, Hadke AV. Design and development of phytosomal soft nanoparticles for liver targeting. Int J Appl Pharm. 2023 Jan 7:280-9. doi: 10.22159/ijap.2023v15i1.46303.

  94. Raikar PR, Dandagi PM. Functionalized polymeric nanoparticles: a novel targeted approach for oncology care. Int J Appl Pharm. 2021 Nov 7:1-18. doi: 10.22159/ijap.2021v13i6.42714.