Shree Dev Bhoomi Institute of Education Science and Technology. Vill.Mazhaun, P.O. Poundha, Dehradun,Uttrakhand
Nanoparticles are tiny particles that range in size from 1 to 100 nm.The review provides an overview of nanoparticles, including their types, properties, synthesis methods, and various application. It highlights the importance and potential of nanoparticles in various fields, including medicine, electronic, energy and environmental science.The review discusses the advantages of nanoparticles, such as their enhanced properties due to their small and high surface-to-volume ratio. It also explores the challenges and considerations associated with nanoparticles, such as their potential toxicity and impact on the environment. Different synthesis method for nanoparticles, including chemical, physical, and biological approaches, are described. The review also discusses the characterization techniques used to analyse nanoparticles, such as electron microscopy, spectroscopy, and thermal analysis. In terms of application, the review provides example of how nanoparticles are used in drug delivery system, imaging and diagnostics, environmental remediation, energy storage, and catalysis. It hights the potential for nanoparticles to revolutionize these fields by offering targeted delivery, improved imaging capabilities, pollution removal, and enhanced energy efficiency. Overall, the review emphasizes the significant impact of nanoparticles on various industries and disciplines, as well as the importance of further research and development to fully explore their potential and address any potential risks or concerns.
Nanoparticles come in a The nanoparticles are the basic building blocks of nanotechnology. The size range of nanoparticles is between 1 and 100 nm, and they can be made of carbon, metal, metal oxide, or organic material.Aside from their composition, nanoparticles vary in dimension, shape, and size.Nanoparticles come in a variety of shapes and sizes, including zero-dimensional nanodots, which have their length, breadth, and height fixed at a single point, one-dimensional graphemes, which can only have one parameter, two-dimensional carbon nanotubes, which have both length and breadth, and three-dimensional gold nanoparticles, which have all three dimensions. The variety of sizes, shapes, and configurations, including those that are spherical, cylindrical, tubular, conical, hollow core, spiral, flat, etc1. In order to create new nanosized materials, nanotechnology entails the design, production, and application of materials at the atomic, molecular, and maceomolecular scales. Drug carriers that are solid, submicron-sized (less than 100 nm in diameter), and either biodegradable or not are referred to as pharmaceutical nanoparticles. Nanospheres and nanocapsules are collectively referred to as nanoparticles. In contrast to nanocapsules, which have a special polymeric membrane surrounding the drug, nanospheres are a matrix system in which the drug is uniformly dispersed. Nanotechnology is the study of very small objects. It involves the use and tinkering with of matter. The prefix derives from the Greek word vavoc through the Latin word nanus, which means literally "dwarf" and thus "very small"2. Due to their large surface area and nano scale size. NPs have distinct physical and chemical properties. These qualities make them suitable candidates for a variety of industrial and domestic applications, such as environmental, imaging, medical, energy-based research, and catalytic applications3.The structure of nanoparticles is intricate. They have two or three layers each. 1. A surface layer that has been functionalized by different small molecules, metal ions, surfactants, or polymers. 2. The shell layer is chemically distinct from the core and can be intentionally added. 3. the fundamental components; the heart of NPs4. Chemical or biological processes can be used to create nanoparticles. Due to the presence of some toxic chemicals, chemical synthesis has been linked to numerous negative effects, and physical synthesis is the biological way of producing nanoparticles.Utilizing a nicroorganism, an enzyme, a fungus, and a plant or plant extracts to synthesize. The creation of these environmentally friendly methods for synthesizing nanoparticles, particularly silver nanoparticles, which have numerous applications, is developing into a significant area of nanotechnology5. For the synthesis of NPs, there are primarily three different types of approaches. the methods of physical, chemical, and.While chemical and biological approaches are collectively referred to as the bottom-up approach, the physical approach is also known as the top down approach.The biological method is additionally known as the green system of NPs. All of these methods are further divided into different categories6. Examples include lithography, chemical vapour deposition, sol-gel process, co-precipitation, hydrothermal, electrospinning, laser ablation, sputtering, sonication, electron explosion, and arc discharged method7. The ability to modify the size and shape of nanoparticles for particular applications has greatly improved thanks to extensive research on nanoparticle synthesis methods. The preferred size, shape, surface properties, and the type of material being synthesized—for instance, metal, semiconductors, cremics, or polymer—all influence the choice of synthesis method8.
Advantage of Nanoparticles
Following are a few benefits of nanoparticles:
Disadvantage of Nanoparticles
Despite these benefits, nanoparticles do have some drawbacks, such as the following:
Approaches for the synthesis of NPs
The methods used to create the nanoparticles can be categorized as bottom-up or top-down methods1. A simple representation of the precess is presented in figure.
Nanoparticles preparation method
Bottom-up method
The construction of materials from atoms to clusters to nanoparticles is known as the bottom-up or constructive method. The most popular bottom-up methods for producing nanoparticles are:
The sol is a colloidal suspension of solid particles in liquid. The gel is a mixture of solid macromolecules and a solvent. A chemical solution that serves as a precursor for an integrated system of discrete particles is used in this wet chemical process. In the sol-gel process, metal oxide and chlorides are frequently used as precursors. After the precursor is mixed with the host liquid using shaking, stirring, or sonication, a liquid and solid phase are produced1.
A solid is deposited on a heated surface using the well-known CVD process, which involves a chemical reaction between the gaseous and vapor phases. In thermal CVD, a high temperature greater than 900 c activates the reaction. By using CVD, nano-composite powder has been created. At 1400 degrees Celsius, SiC/Si3N composite powder was created using SiH4, CH4, WF6, and H2 as gas sources13.
By typically dissolving the metal salt of the product in the solvent, a starting solution is created in order to prepare fine particles by spray pyrolysis. The droplets are introduced to the furnace after being atomized from a starting solution. To create the finished product, processes such as solvent evaporation, solute diffusion drying, precipitation, reaction between the precursor and the surrounding gas, pyrolysis, or sintering may take place inside the furnace14.
D. Spinning
The forced conversion that the spinning procedure creates in the vapour above the substrate is constant. In spin coating, the evaporation rate is typically quite uniform. An essential step in the fabrication of semiconductors is the spin-coating of very thin, uniform photoresist films15. As a result, the synthesis of NPs processed by an SDR and a rotating disc inside of it aids in the control of physical parameters like temperature. In order to prevent chemical reactions inside the reactor, inert gases or nitrogen are typically filled with it. Precursor and water were pumped into the SDR, which rotated at various speeds. The result of the spinning is that the atoms fuse and precipitate, collect, and dry. Liquid flow rate, disc rotation speed, liquid precursor ratio, feed location, and disc surface are all factors in the synthesis of NPs16.
Destructive synthesis is employed in this process. The bigger molecules broke down into smaller ones, and these smaller ones then changed into nanoparticles.
It is an endothermic process in which heat drives chemical breakdown. This heat damages a compound's chemical bond. The temperature at which an element begins to chemically decompose is known as the decomposition temperature.17
Top-down lithographic methods alone or in combination with other fabrication techniques, such as reactive ion etching (RIE), can be used to create size- and shape-controlled nanoparticles. The conventional semiconductor industry and other fields requiring micro and nano patterns have made extensive use of photolithography, one of all top-down approaches, which has been well developed. Ion beam and e-beam lithography have the ability to directly write ultra-small structural units with extremely fine patterns as well as create masks or molds for use with other lithography techniques. However, the throughput and cost of these techniques are incredibly low. Nanoimprint lithography (NIL), which duplicates nano-patterns through a nanostructured master mold in an easy, parallel, and affordable manner, can resolve the aforementioned problem of top-down fabrication technique18.
Pulsed lasers are used to remove molecules from a substrate's surface in order to create microstructures, and they are widely used in the manufacturing of metals, ceramics, polymers, and glasses. By concentrating a laser beam, which absorbs energy to cause melting, evaporation, or vanishmablation, a substance is removed from a surface. The process that deals with both vaporization and melt ejection is known as laser ablation, and it is constant throughout the entire laser machining application19.
D. Sputtering
By bombarding the target surface with highly energetic ions of an inert gas (argon), which results in the ejection of atoms and clusters, materials from the target's surface (a solid) can be vaporized. A controlled inert gas is first introduced into the vacuum chamber as part of the aputtering method, and then the cathode is electrically energized to produce self-sustaining plasma. The materials that sputtered together make up a vapour steam. In order to hit and stick to the substrate in order to form a thin film or surface coating, this vapour steam travels through the chamber20.
In mechanical milling, a sustable powder charge and an appropriate milling medium are placed in a high energy mill. Reducing particle size and blending particles into new phases are the goals of milling. The balls may drop freely and strike the powder and balls below them or they may roll down the surface of the chamber in a series of parallel layers. The energy transferred from the balls to the powder during mechanical milling or alloying depends on the kinetics of the process. The industries of powder metallurgy, processing minerals, and ceramics all heavily rely on milling of materials. The high energy ball mills, such as tumbler ball mills, vibratory mills, and planetary ball mills, have typically been used for these purposes21.
Classification of nanoparticles
The three types of nanoparticles—organic, inorganic, and carbon-based—are used to categorize them:
The organic molecules used to create this class of organic nanoparticles have a minimum size of 100 nm22. Organic-based NPs, also known as nanocapsules and are non-toxic, environmentally friendly. When exposed to heat or light, ferritin, liposomes, micelles, and dendrimers become highly sensitive organic nanoparticles or polymers23.
A new class of controlled-structure polymers with nanometric dimensions is the dendrimer. Typically, dendrimers used in drug delivery and imaging have multiple functional groups on their surface and range in size from 10 to 100 nm. Dendrimers have been used in the pharmaceutical industry as non-steroidal anti-inflammatory drugs, antimicrobials, anticancer agents, pro-drugs, and screening agents for high-throughput drug development2.
The use of liposomes as a DDS for chemotherapy is deemed desirable due to their simple functionalization, effective drug encapsulation, biocompatible properties, and ability to control their size. liposomes are spherical vesicles with one or several phospho-lipid bilayers. Although surface modification can help, a short circulation half-life is a significant drawback to their clinical application24.
They are made of non-carbon substances like metals, metal oxides, and metal salts. In accordance with the atom packing, they can take on a variety of shapes (including spheres, cylinders, oblate, ellipsoids, cubes, and stars) while still maintaining the crystallinity of metal-based compounds25.
A. Metal based nanoparticles
The process for synthesizing metal-based nanoparticles to nanometric size can be destructive or constructive22.
B. Gold nanoparticles
The size of gold nanoparticles is on the nanometer scale. They can absorb and scatter visible and near-infrared light thanks to their special physical and chemical properties6. Given that they are among the most stable, non-toxic, and simple to synthesize NPs and display a variety of fascinating properties, including assembly of different types and the quantum size effect, gold NPs make excellent study materials26.
A variety of new products and scientific applications have resulted from the unique physiochemical properties of Ag-NPs, such as their electrical and thermal scattering, catalystic activity, and non-linear optical properties27.
Due to their smaller size, metal oxide NPs have a higher surface area, making them useful in a variety of applications, including biosensors, bionanotechnology, and nanomedicines. Examples include copper oxide, titanium dioxide, and zinc oxide28.
ZnO is a suitable additive for textiles and surfaces that come into contact with the human body due to its safety and compatibility with human skin.Gram-positive and Gram-negative bacteria, as well as spores that can withstand high temperatures and pressure, are resistant to ZnO NPs29.
TiO2's crystal structure, shape, and size are all related to its antimicrobial properties. It is suggested that TiO2 NPs may be particularly sensitive to oxidative stress caused by the production of ROS. In order to combat MRSA, beta lactums, cephalosporins, aminoglycosides, lincosamides, and tetracycline were enhanced by TiO2 nanoparticles28.
They are composed of carbon atoms that have Sp2 bonds. They comprise nano-diamonds, nano-horns, nano-onions, grapheme, fullerenes, single- and multi-walled carbon nanotubes, carbon nanofibres, and nano-graphite. Chemical vapor deposition, laser ablation, and arch discharge are the three synthesis techniques for materials made of carbon25.
A. Carbon-nanotubes
The development of an oil-removing membrane with high permeation flux benefits significantly from the high specific surface area and oleophilic properties of CNTs[30]. Single-walled carbon nanotubes have a diameter between 0.4 and 2 nm, while multi-walled nanotubes range in size from 2 to 100 nm. Carbon nanotubes are made up of enrolled graphite sheets31.
B. Graphene
A single sheet of carbon atoms, arranged hexagonally in a crystalline lattic resembling a honeycomb and reaching even micro and millimeter in both lateral sizes, is represented by a two-dimensional (2D) grapheme. High intrinsic strength, thermal conductivity, biocompatibility, and low toxicity are all characteristics of this material. most significant advantages for its use in biosensing32.
C. Fullerenes
Fullerenes are spherical carbon-based NPs that are made of carbon atoms bound together via Sp2 hybridization. Round, mono-layered fullerenes with a diameter of up to 8.3 nm and poly-layered fullerenes with a diameter of 4-36 nm are created by collectively combining between 28 and 1500 carbon atoms33.
Method of evaluation for release of drug
The following techniques can be used to examine the drug's release from NPs in vitro:
Commonly, controlled agitation and centrifugation are used to conduct release studies. The dialysis technique is typically preferred due to the lengthy process and technical challenges involved in separating nanoparticles from release media.There are five potential ways that drugs can be released:(a)The drug may deposit on the surface,(b)diffuse through the nanoparticle matrix,(c)diffuse through the polymer wall of nanocapsules,(d) erode the matrix of the nanoparticles,or(e)diffuse through both erosion and diffusion. Using a bioexponential function, the kinetic analysis of drug release from nanoparticles can be explained.
C= Ae
Where C is the concentration of drug remaining in the nanoparticles at time t, A and B are system characteristic constant (A is used for diffusion control system and B for erosion control system) and
Characterization parameters of NPs
With the aid of cutting-edge microscopic methods like scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM), nanoparticles are typically identified by their size, morphology, and surface charge. The physical stability and in vivo distribution of the nanoparticles are influenced by the average particle diameter, their size distribution, and charge. Several methods, including nuclear magnetic resonance, optical microscopy, electron microscopy, dynamic light scattering, and atomic force microscopy, are used to measure the size of particles34.
The size and qualitative characteristics of NPs can both be determined using nuclear magnetic resonance (NMR). The sensitivity to molecular mobility is complemented by the selectiveness offered by chemical shift to provide knowledge of the physicochemical status of the components inside the nanoparticles34.
The DSC analysis was used to determine the physical state of the native drug contained within the nanoparticles. The native drug, polymer, and NPs each weighed about 2 mg. Separately into various sealed standard aluminum pans, they were heated at a rate of 10°C/min under nitrogen atmosphere and scanned between 25°C and 300°C. As a guide, use an empty aluminum pan35.
By using a scanning electron microscope, the NPs' particle sizes were measured and found to range from 350 nm to 600 nm, depending on the amount of polymer present35. The two parameters that affect NPs the most are particle size and morphology. The primary goals of nanoformulation are drug release and targeted drug delivery, and it has been determined from the data gathered that the drugs released are impacted by particles. Therefore, the loaded drug will be exposed to the particle's surface, hastening the release of the drug. Smaller particles often foam aggregates while being stored. Make a connection between stability and smaller particle size as a result. It was discovered that the rate of degradation for PLGA increased with increasing particle size36.
The surface charge property of NPs is frequently described using the zeta potential of NPs. It is affected by the makeup of the particles and the medium in which it is dispersed and reflects the electrical potential of the particles. It has been demonstrated that NPs with a zeta potential above + 30 mV are able to be suspended because the surface charge prevents the particles from aggregating37.
To ascertain a solution's optical characteristics, absorbance spectroscopy is employed. The sample solution is illuminated, and the amount of light absorbed is measured. when the wavelength is changed and absorbance at each wavelength is measured. Beer-Lambert's law can be applied to the absorbance to determine a solution's concentration. The uv-visible spectrophotometer's optical measurement has a variety of absorbance peaks, such as 410 nm38.
With the help of this technique for characterizing NPs, we can learn about the morphology, shape, size, chemical composition, and orientation of the materials. The surface of the sample will be determined by the secondary electrons and backscattered electrons released when the solution of NPs is transformed into dry powder and mounted on a sample holder during SEM characterization. The morphology of NPs can be determined by analyzing the depression and elevation of the surface because the release of electron from nanomaterials varies depending on their surface39.
Using a particle size analyzer, dynamic light scattering at a fixed angle of 173 at 25 c, photon correlation spectroscopy was used to analyze the particle size and size distribution in terms of the average volume diameters and polydispersity index of the prepared particles. Samples were examined three times40.
Application of nanoparticles:
Specific physical and chemical characteristics, including mechanical, magnetic, optical, and thermal characteristics, are displayed by nanoparticles. Because of its uniqueness, NPs have found application in a variety of fields. A few of these fields include the following.
Clinical medicine has benefited greatly from nanopaticles' contributions to drug and gene delivery as well as medical imaging. In biomedical applications, ion oxide particles like magnetite (Fe3O4) or its oxidized form, hametite (Fe2O3), are most frequently used. Because of their antimicrobial activity, Ag NPs are being used more and more in household products, wound dressings, and catheters. As drug carriers, photothermal agents, and contrast agents, gold nanoparticles are showing great promise in the treatment of cancer. The development of biodegradable nanoparticles as efficient drug delivery vehicles has attracted a lot of attention over the past few decades. Drug delivery research has made use of a variety of polymers because they can efficiently transport medications to their intended location, increasing therapeutic benefits while lowering side effects41.
NPs can assist in the visualization of particular body parts when used as imaging agents. For instance, iron oxide nanoparticles, or Fe3O4NPs, have been used as MRI contrast agents to improve the visibility of organs and tissues. Because Au NPs can accumulate in some cancerous tumors, they have unique optical, electrical, and catalytic properties and are being investigated for use in diagnostics.
NPs have the ability to promote tissue and organ growth and repair. For instance, because titanium dioxide nanoparticles (TiO2) can promote bone cell growth, they have been investigated for use in tissue engineering.
Certain nanoparticles (NPs), like copper nanoparticles (CuNPs) and silver NPs (Ag NPs), possess potent antibacterial qualities and are being investigated for application in a range of medical products, including bandages and medical devices. Overall, NPs are being actively researched for a variety of applications and have significant potential for use in the medical sector. However, in order to ensure the safe and responsible use of NPs in medicine, it is imperative to carefully weigh the benefits and potential risks of doing so6.
The traditional UV sunscreen doesn't use drugs that are stable over time. Sunscreen containing nanoparticles, like titanium dioxide, has many benefits. Due to their ability to both absorb and reflect UV rays while remaining transparent to visible light, titanium oxide and zinc oxide nanoparticles have found application in sunscreens. Iron oxide nanoparticles are used as a pigment in some lipsticks1.
The drug must stay encapsulated until the particle binds to the target in order to prevent nonspecific toxicity. It cannot diffuse out the particles while they are still in the circulatory system. Nanoparticles have a great potential for targeted drug delivery at the site of disease, which has several important implications, including:
conjugation of antibodies to carbon nanotubes with fluorescent or radiolabelling to increase cell specificity42.
Understanding the functions of proteins, which are an essential component of the language, machinery, and structure of cells, is crucial for the continued development of human cells. In immunohistochemistry, gold nanoparticles are frequently utilized to detect protein-protein interactions. surface improved The technique of Raman scattering spectroscopy is widely recognized for its ability to identify and detect individual dye molecules. The multiplexing power of protein probes can be significantly increased by integrating both techniques into a single NPs probe. Hydrophilic oligonucleotides with a Raman dye at one end and a small molecules recognition element terminally capped are used to coat the NPs.
The foundation of photodynamic cancer therapy is the cytotoxic atomic oxygen produced by lasers, which destroys cancer cells. Compared to healthy tissue, cancer cells absorb a higher quality of a specific dye that is used to produce atomic oxygen. Thus, only the radiation from cancer cells Sadly, the patient becomes extremely sensitive to daylight exposure as a result of the leftover dye molecules migrating to their skin and eyes. Up to six weeks may pass before this effect fades. The hydrophobic dye molecules were encased in porous nanoparticles to prevent this side effect. The dye did not spread to the other areas of the body; instead, it remained contained inside the cromosil NPs43.
Copper has shown promise in the fight against cancer, and nanoparticles have been shown to trigger both intrinsic and extrinsic apoptotic pathways for the death of cancerous cells. Hela cells, Md A-MB-231 human breast cancer cell lines, Caco-2 human colon cancer cells, HepG2 human liver cancer cells, and McF-7 human breast cancer cells are all susceptible to the anticancer effects of copper and copper oxide nanoparticles. In rats given CFA (Complete Freund's adjuvant, which simulates the course of human arthritis), copper nanoparticles enhanced antioxidant enzymes and decreased pro-inflammatory markers, demonstrating their anti-inflammatory and anti-arthritic properties. CuNPs' ability to heal wounds was demonstrated in an in vivo study on mice, where there was a notable increase in the concentration of fibrocytes that eventually formed collagen for wound contraction and repair44.
Nanomaterials are crucial to green processes and environmental remediation. They have the ability to treat pollutants and clean up hazardous waste sites. The self-cleaning nanoscale surface coatings can replace a number of chemicals used in maintenance procedures for cleaning. Fe NPs are becoming more and more popular due to their quickly evolving uses in heavy metal remediation and water disinfection. NPs function as effective, environmentally friendly fertilizers that can boost crop yields and replace pesticides in the management and control of plant diseases.
Since the existence of drinkable water is essential to the survival of the species, one of the most pressing problems facing the world today is water contamination. Water contamination has a number of negative effects on socioeconomic development, the environment, and human health. The number of commercial and non-commercial techniques available to address this issue is growing as a result of technological advancements45.
Essential oils, organic acids, and bacteriocins are examples of organic compounds that have been utilized as antimicrobial packaging materials.In the food industry, nanobiosensors are used to detect pathogens during processing. Numerous nanoparticles (NPs) possess antimicrobial properties, including Ag, chitosan, copper, and metal oxide NPs like zinc oxide or titanium oxide (TiO2). The diagnosis of infectious diseases using conventional methods is a laborious, time-consuming, and slow process, particularly in an emergency. Microbial biosensors have set a new standard for fast, affordable, and precise diagnosis of infectious agents, hormone abnormalities, and DNA. Microbial biosensors have been used in forensic identification to analyze body fluidic traces containing DNA and miRNA as evidence. These portable biosensors may represent a viable array system that can reduce expenses and boost.
Nanotechnology has been expanding quickly and has many uses in many different fields. NPs affect both humans and animals and result in a variety of health issues with the kidneys, lungs, and other organs.Nonetheless, more needs to be done to address the dearth of knowledge regarding the dangers of extended use. Green synthesis provides a secure method for creating non-toxic NPs with extra advantageous properties. One of the most interesting research fields at the moment is nanomedicine, which covers drug delivery, cancer diagnosis, and other therapeutic options. It is necessary to produce NPs with consistent sizes, consistent properties, biocompatibility with drug loading, and limited release to the intended cells. NPs are recognized to have made significant advancements in the fields of therapy and diagnosis. Their expectations must be expanded to include other domains, such as the management of parasitic infections and the response to cancer therapy, which has been curtailed and is still insufficient46.
CONCLUSION
An extremely appealing platform for a wide range of biological applications is provided by nanoparticles. Due to their superior and adaptable physical, chemical, and biological properties when compared to bulk materials, nanomaterials are fascinating substances. We briefly discussed nanoparticles in this review, including their benefits and drawbacks. Different techniques, such as top-down and bottom-up synthesis, are used to prepare NPs. Various types of nanomaterials, such as carbon-based, gold, titanium, dendrimers, and liposomes, are being researched for the purpose of targeted drug delivery. Nanostructured scaffolds have a higher surface-area-to-volume ratio, which makes them suitable as selective substrates for absorbing particular proteins and encouraging cell adhesion. The development of biosensors using NPs based on metal and carbon has numerous applications in the biomedical and agricultural sectors. Individual discussions are held for the various characteristic parameters, antimicrobial activities, protein detector, drug release time, and waste water treatment activities of different nanomaterials.
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