ABSTRACT:
In recent years, iron oxide nanoparticles (NPs) have pulled much attention in research field, due to their unique and special properties, such as superparamagnetism, surface-to-volume ratio, easy separation processes and greater surface area. This paper focuses on the synthesis, characterization and various applications of iron oxide nanoparticles. There are several physical, chemical, and biological techniques which have been adopted to synthesize iron oxide NPs with appropriate surface chemistry. The methods for the preparation of iron oxide NPs, size and shape control, and magnetic properties with recent biomedical, commercial, and industrial applications. Iron NPs have many applications in the fields of life sciences such as biomedicine, wastewater treatment, agriculture cancer therapy, drug delivery etc.
INTRODUCTION:
Nanoparticle(NPs) are very small moieties with diameters ranging from 1-100nm.NPs are made of inorganic or organic materials, which have numerous novel properties when compared with the bulk materials. NPs have many distinctive magnetic properties such as superparamagnetism, high coercivity, high magnetic susceptibility, etc. In recent years these NPs have become a great interest for researchers , as they have a broad range of applications, including: data storage, catalysis, wastewater treatment, cancer therapy and other bioapplications.
Iron oxide nanoparticles are the iron oxides particles having diameter 1-100nn. There are two main forms of these iron oxides: Magnetite(Fe3O4) , Maghemite(gamma-Fe2O3) (which is the oxidized form of magnetite) and hematite (α-Fe2O3). They possess superparamagnetic properties and therefore has vast number of applications. NPs which are formed of ferromagnetic materials having a size <10–20 nm possess an inimitable form of magnetism, which is called “superparamagnetism”.Because of their low toxicity, superparamagnetic properties, for example- surface area and volume ratio, and simple isolation methodology, iron oxide (Fe3O4 and g-Fe2O3) NPs have seeked much attention in research areas. It has interesting biomedical applications for protein immobilization, such MRI, and drug delivery.
Iron oxide nanoparticles have many advantages ,which makes it a better choice than others. They are widely used because they are inexpensive, have large surface-to-volume ratio, surface energies are high, have high chemical activity and provide great surface coating.
This paper focuses mainly on various strategies in the preparation, synthesis , characterization and recent commercial, industrial and biomedical applications of magnetic iron oxide NPs . The nanoparticles are synthesized with chemical methods such as co-precipitation, microemulsion, sol-gel method etc and biological methods using plant extract, bacteria , fungi etc. These methods are novel, cost effective, economical and have a good control over the shape of the NPs. Nontoxicity and biocompatible use of magnetic NPs can be advanced further by unique surface coating with organic / inorganic molecules, including surfactants, drugs, proteins, starches etc .
Methods for the preparation of iron nanoparticles:
Iron oxide magnetic NPs with appropriate properties can be prepared by various methods such as physical methods, chemical methods and biological techniques.
1. Physical methods: These methods usually have a vast number of disadvantages and likely to suffer from the inability to control the size of particles in the nanometer range.
2. Chemical methods: These methods are simple and efficient to produce stable, controlled and biocompatible iron oxide nanoparticles, in which the size, composition, and even the shape of these NPs can be managed. These nanoparticles can be synthesized through the co-precipitation method. In this method Fe2+ and Fe3+ are mixed with a base. The size, shape, and composition of iron NPs synthesized through chemical methods depend on the type of salt used ( eg: chloride salts, sulfates, nitrates etc.), Fe2+ and Fe3+ ratio, pH, and ionic strength of the media and the other reaction parameters like stirring rate.
3. Biological methods
CHEMICAL METHODS:
The chemical-based methods are mostly used because of their low production cost and high yield. In general, magnetites are synthesized by adding a base to an aqueous mixture of Fe2+ and Fe3+ chloride at 1:2 molar ratio, which gives a black colour solution. The chemical reaction of Fe3O4 precipitation is given as follows:
Fe 2+2Fe3+ 8OH → Fe3O4+4H2O————————–(1)
In addition,Fe3O4 NPs gets easily oxidised to Fe2O3 under ambient conditions .Thus it becomes very unstable . In order to avoid this ,the synthesis of Fe3O4 NPs should be done in anaerobic conditions. Under this anaerobic environment, a complete precipitation of Fe3O4 is likely between pH 9 and 14.
Moreover ,in order to prevent iron NPs from oxidation and agglomeration, Fe3O4 NPs are usually coated with organic or inorganic molecules. These NPs can also be synthesize in the presence of nitrogen gas. Nitrogen gas is bubbled which, not only protects NP oxidation but also reduces the size.
TECHNIQUES FOR THE SYNTHESIS OF NANOPARTICLES :
CO-PRECIPITATION
Coprecipitation from aqueous solutions is one of the most commonly used methods. The reaction of Fe2 salt, in aqueous solution, with a base in the presence of mild oxidant lead to synthesis of spherical NP of about 30–100 nm in size.
There are many factors on which the size and stability of the nanoparticles depend such as: on the presence of counter ions, pH, ionic strength and the concentration of cations. The mean particle size should be from 15mm to 3mm . Change in pH and ionic strength may affect the size of the particles. These NPs usually form aggregates because of their large surface-area-to-volume ratio and therefore reduces the surface engery. To overcome this, anionic surfactants, which act as dispersing agents are usually added .This helps to stabilize the NPs. Surface of these nanoparticles can also be coated with proteins, starches, non-ionic detergents to stabilizes the electrolyte concentration of particles.
Apart from being simple and effective method , coprecipitation has some drawbacks.These aqueous solution have very high pH value which needs to be adjusted in both the synthesis and purification steps. On the other hand, this method produce wastewaters with very basic pH values ,which needs subsequent treatments for protecting the environment.
MICROEMULSIONS:
Microemulsion is a scattering of two immiscible phase, similar to water and oil which give rise to a thermodynamically stable system in presence of surfactants .It is isotropic in nature. These surfactant particles shape a monolayer at the interface between the two immiscible phase were the hydrophobic tails of the surfactant atoms remain in the oil phase and the hydrophilic head groups are present in aqueous phase. These frameworks (water/surfactant or oil/surfactant) can form different shapes independent from anyone else gathering, as altered , circular and round and hollow micelles which may exist together with prevalently oil or watery stages . Consequently, microemulsion and converse micelles course can be utilized to acquire controlled shape and size of iron oxide NPs.
Water-in-oil microemulsion contains nanosized water beads scattered in oil stage . These beads are settled by surfactant particles. Different sorts of NPs can be acquired because of the surfactant \’s nature and physiological conditions, which is the main benefit of this technology. In order to synthesize magnetite NPs, sodium hydroxide is combined with iron source, later lysed with acetone to evacuate the surfactant and washed with ethanol. Typically, the colloidal NPs show superparamagnetic conduct with high polarization values.The choice of surfactants relies on upon the physicochemical qualities of the framework. Distinctive surfactants, for example, cationic, anionic, or nonionic, can be utilized. The principle inconvenience related with this technique is unfavorable impacts of leftover surfactants on the properties and trouble in scale-up methods. Also the collection of the created NPs needs various washing forms and numerous stabilization treaments.
HYDROTHERMAL SYNTHESIS:
Hydrothermal synthesis deals with various wet chemical technologies . It crystallizes substance in a closed container from high temperature aqueous solution (usually in the range from 130 to 250deg C) at high vapor pressure ( in the range from 0.3 to 4 MPa). This system is inclined to acquire the profoundly crystalline iron oxide NPs. The reactions are performed in an autoclave or a reactor in an aqueous media, with a pressure of more than 2,000 psi and temperature above 200°C . . The lack of hydration of metal salts and low dissolvability of oxides in fluid stage cause supersaturation of the medium. Consequently studies have demonstrated impacts of temperature, precursor, and the time on morphology and molecule measure. The precursor concentration tends to increases the particle size. Monodispersed particles usually produce a short residence times .However the effect of residence time on the particle size is more , then concentration.
Studies have shown that there are two approaches for this method, one is with surfactant and another one is without surfactant. The one-stage aqueous process manages the arrangement of exceedingly crystalline Fe3O4 nano powder without utilizing any surfactants. These are obtained at 140 deg C which possess saturation magnetization. On other hand the hydrothermal process for preparaing Fe3O4 in the presence of a surfactant produces NPs with a superparamagnetic behaviour at room temperature.
Moreover, this treatment is one of the most successful ways of growing crystals for iron oxide NPs. Hydrothermal synthesis is conductive to prepare the unusual iron oxide nanostructures such as iron oxide nanocubes , iron oxide hollow spheres ,and so on.
SOL-GEL METHOD:
This method follows two basic principles: hydroxylation and condensation of molecular precursor in the solution. \”Sol\” is obtained from nanometric particles. These sols are then dried or gelled either by dissolvable expulsion or by chemical reaction to get three-dimensional metal oxide arrangement. The solvent utilized is water. The reaction is performed at room temperature; but high treatment is required to acquire the last crystalline state.
The parameters impacting the synthesis are pH, nature, and concentration of salt precursor, energy, temperature, and properties of gel. The advantages include amorphous phase, monodispersity, great control of molecule size, control of microstructure, the product formed is homogenous, and opportunities to create insert atoms, which keep up their soundness and properties inside the matrix. It is a simple technique for the generation of metal oxides from salts at particular conditions.
BIOLOGICAL METHODS:
Physical and chemical techniques are being utilized broadly for generation of metal and metal oxide nanoparticles. Thus, this generation requires the utilization of exceptionally receptive and lethal diminishing agents such as sodium borohydride and hydrazine hydrate, which cause undesired impacts on the environment, plant and animal life it supports. Various organisms act as clean, eco-friendly and sustainable precursors to deliver most stable and well functionalised nanoparticles. These may include bacteria, actinomycetes, fungi, yeast, viruses. Thus it is critical to investigate a more dependable and practical process for the synthesis of nanomaterials. In order to keep the prices of the final finished nanotechnology-based products affordable to consumers, industries must keep up a sensitive harmony between ecologically stable green procedures and their manageability. The green nanotechnology-based generation forms work under green conditions without the mediation of dangerous chemicals.
Some of the advantages of using green synthesis over the conventional physical and chemical properties are as follows:
(a) It is a clean and eco-accommodating strategy, as harmful chemicals are not utilized
(b) In this process , the biologically active components like enzymes plays important roles as reducing agent
(c) The nanoparticles produced can be scale-up and its cost effective
Green Routes for the synthesis of iron nanoparticles
Synthesis by Microorganisms:
BACTERIA
Mostly iron- reducing bacteria are used in synthesis of iron nanoparticles.Geobacter meta -lireducens and Shewanella putrifaciens are the most ordinarily considered microorganism that produce crystals of magnetite as a by-product of their metabolism in the growth medium. Iron-reducing bacteria generally breathe with oxidized Fe3 compound in the form of Fe3 oxyhydroxide under anaerobic condition and emit inadequately crystalline Fe2 into surrounding environment. The Fe(II) so formed then adsorbs onto excess ferric hydroxide grain where it is changed into magnetite.
Different studies have shown the formation of spherical iron oxide nanoparticles using Actinobacter sp.under aerobic conditions.
In another review, maghemite (γ-Fe2O3) and greigite (Fe3S4) were integrated utilizing similar types of bacterium by changing the iron precrusor. The synthesized nanoparticle showed superparamagnetic behaviour . Actinobacter sp.were capable for extracellular synthesis of attractive nanoparticles when presented in an aqueous arrangement of ferric salts under oxygen consuming conditions for 48–72 h. The arrangement of iron oxide nanoparticles was characterized by TEM, XRD, FTIR, from the change in colour of reaction medium from medium to dark brown. Bacteriogenisis of NPs is a complex phenomenon and it requires the use of enzyme iron reductase which is produced by Actinobacter sp for the synthesis. Iron reductase , reduces Fe3+ and Fe2+ for the formation of magnetic nanoparticles. Other microorganisms like Thermoanaerobacter sp can also be used to produce NPs under anaerobic conditions. Bacillus subtilis strains are capable of synthesizing nanoparticles of spherical shape with a diameter of 60-80mm.
FUNGI:
Magnetic NPs of various sizes can be produced extracellularly by using fungi ,such as Verticillium sp.,Fusarium oxysporum. These are mixed with Fe2+ and Fe3+ salts at room temperature which leads to the formation of NPs. The fungi emits cationic proteins ,thus causing extracellular hydrolysis of the anionic iron particles.This leads to arrangement of crystalline magnetite particles. These particles show a ferrimagnetic transition with limited amount of spontaneous magnetism at low temperature.A study shows the use of Alternaria alternate fungus for synthesis of iron NPs. These NPs were about 9-3 nm .
ALAGE:
A review done by Subramaniyam et al shows that soil micro algae, Chlorococcum sp., with an iron chloride precursor can synthesize spherical nanoiron ranging in size from 20–50 nm. Macroalgae such as brown seaweed extract combined with ferric chloride solution lead to reduction reaction and formation of iron oxide NPs. The reduction of ferric chloride was caused due to presence of sulphate polysaccharides in the water extract of brown seaweed.The reaction changed the yellow coloured reaction mixture into dark brown . The nanoparticles diameter was observed by TEM. Also some biomolecules such as carbonyl and amine from polysaccharides and glycoproteins are present in algal cell which are involved in synthesis of nanoiron and this is confirmed by FTIR analysis.
However the synthesis of iron nanoparticles from microorganisms is a very slow process and is less monodispersed.
SYNTHESIS OF IRON NANOPARTICLES BY PLANT EXTRACT
Many researches are going on production of iron nanoparticles by using various plant extracts. Plant removes, diminish the metal particles in a shorter time as compared to microbes .Depending upon plant sort and grouping of phytochemicals, nanoparticles ,these are incorporated inside very quickly without taking much time whereas microorganism-based techniques require a more extended time All these reasons, alongside the simple accessibility of plants in nature,make them more favored organic assets than organisms.
Synthesis at room temperature:
Commonly used plants:
Tea extract is the most commonly used plant extract for the production of iron nanoparticles. A study showed that green tea(Camellia sinensis) was used in synthesis of iron nanoparticles. Green tea extract was concentrated to respond with 0.1M FeCl3solution.These reaction took place at room temperature, in few minute. Tea extract produced polyphenol which acted as both capping agent and reducing agent too. Stable nanoparticles were formed without the use of any surfactant or polymers.This process brought green nanoscale zero valent iron NPs which were stable and had unique properties.
A similar methodology for union of iron nanoparticles was used but with little modifications in another study. GT-Fe, NPs were produced from the extract of green tea.They acted as Fenten-like catalysts and was also able to degrade cationic dyes like Methylene blue(MB) and anionic dyes like Methylene Orange(MO). Practically total evacuation of both colors was accomplished in 200 and 350 minutes for MB and MO, respectively. On account of GT-Fe NPs, right around 100% expulsion of MB and MO was observed at an initial dye concentration of 10mg/L and 100mg/L. The proficiency was marginally lower for MB (96.3%for10mg/Land86.6%for100mg/L)and significantly bring down on account of MO (61.6% for 10mg/L and 47.1% for 100mg/L) when iron nanoparticles were incorporated utilizing the conventional borohydride reduction method.
Comparable findings were found in investigation of Nadagouda et al. They assessed the impact of concentrate fixation on size of iron nanoparticles. Nanoscale zero valent iron (nZVI) blend was done at room temperature utilizing diverse volumes of tea concentrate and Fe(NO3)3 arrangement. It was found that size and morphology of particles could be changed by changing the grouping of concentrate and addition of iron salt. Machado et al. [42] assessed the possibility of a few tree leaves for generation of nZVI.
Another study showed that at room temperature , distinctive volumes of tea concentrate and Fe(NO3)3 was used to check the impact on the size of the nanoparticles when there was change in the concentration of the tea extract. As a result , it showed that there was decrease in the size of the particles as the concentration increased. The size of the nanoparticles produced by borohydride reduction method was about 50 – 500 nm. The biocompatibility of nZVI incorporated utilizing green tea and borohydride as the diminishing agent was surveyed utilizing methyltetrazolium(MTS) and lactatedehydrogenase(LDH) assay. LDH spillage expanded with an expansion in molecule size, focusing on the cellular rmembrane . Thus , this synthesis of nZVI was found to be nontoxic to human keratinocytes
.Plant Extract Derived from Agrowaste.
Destruction of plants and its parts is one of the major drawbacks of using plant resources for nanoparticle. Njagi et al. utilized aqueous Sorghum sp. (crossover sorghum) bran extract for nZVI synthesis.In double-refined water the extract was prepared using sorghum bran powder at various temperatures for 60 minutes. In light of the XRD design, the nanoparticles were observed to be amorphous in nature. The synergist action for the corruption of bromothymol blue was observed to be higher for higher centralization of nanoparticles.
Another study used eucalyptus globulus leaf extract as a bioreducing specialist to integrate nZVI. Oenothein B wich is a polyphenol compound was responisible for the stabilization and production of nZVT . The nanoparticles were observed to be steady even following two months. 0.8g/L of nZVI was adequate to expel 98.1% of 400mg/L hexavalent Cr inside 30 minutes. Langmuir and Freundlich adsorption isotherm clarified the adsorption procedure. Evacuation of Cr took after pseudo-second-arrange dynamic model. The sorption limit of the adsorbent was found to be mainly influenced by reaction time and initial Cr (VI) concentration.For higher concentration of Cr , more time was required so for71.9% removalofchromium 90 mins were required when initial concentration in soil was 400mg/L.
Pomegranate leaf extract was used to effectively integrate Fe0/Fe3O4 nanoparticles by Rao et al. Yarrowia lipolytica (Yeast cells) was coated with these nanoparticles .Two strains of this yeast cells were use (NCIM 3589 and NCIM 3590) . Yarrowia lipolytica, is viewed as a decent biosorbent itself. The bionanocomposite was assessed for its ability to evacuate hexa valent chromium. These magnetically altered yeast cells had the sorption capacity three times more than that of unmodified yeast cells.
Other plants used:
Narayanan et al. [31] synthesized superparamagnetic magnetite/gold (Fe3O4/Au) hybrid nanoparticles at room temperature using grape seed proanthocyanidin (GSP) for the first time. These nanohybrids were used as better CT contrast agents than conventionally used iodine-contrast agents.Thelong-termbiocompatibilityevenathigherdoses warranteditsuseinmedicalapplications
Superparamagnetic magnetite/gold(Fe3O4/Au) hybrid nanoparticles were synthesized at room temperature using grape seed proanthocyanidin(GSP) . They had a long term biocompatibility . Another study shows that about 26 different leaf extracts were screened for the production of nanoparticles. Significance of blend factors like extraction, time, temperature and leaf mass to dissolvable volume proportion was checked. The optimum temperature was found to be 80 deg C. 80∘C was distinguished as the optimumtemperature,whereasinextractiontimeandleafmass, dissolvable volume proportion differed according to leaf sort. The quality of the concentrates arranged was evaluated by deciding their cell reinforcement movement utilizing the ferric antioxidant cancer power (FRAP) strategy. Plant polyphenols assume an imperative part in presenting cell reinforcement property and, thus, the aggregate polyphenol content(TPC)of the extract was estimated using the Folin-Ciocalteu method.On the basis of results obtained from FRAP assay and TPC content ,pomegranate ,mulberry, and cherry concentrates were utilized for nZVI union. Iron nanoparticles framed by blending plant concentrate and Fe (III) solution were characterized by TEM.
Hydrothermal synthesis using plant extract:
Hydrothermal synthesis includes the arrangement of the plant extract and disintegration of the desired molarity of the metal salt in it. The mixture is then permitted to respond in a Teflon-lined autoclave under atmospheric pressure at various temperatures for a specific period of time. The temperature should be low in this process then only the calcination process will change the precursor into crystalline nanoparticles.
In some studies aloe vera gel was utilised for this process. This led to the formation of nanoparticles with high purity which was detected by XRD. Particle size increased when the time and temperature was increased . These nanoparticles showed paramagnetic behaviour. The magnetite nanoparticles formed exhibit super crystallinity and saturated magnetism when the reaction time and temperature were increased. One of the reason for such poor magnetism was due to gylcoprotiens coat which had aloin, aloe-emodin etc originating from aloe vera.
For a superior comprehension of surface properties, exhaustive surface characterization, methods are utilized, for example, surface morphology, spatial distribution of the functional groups and chemical composition. Fundamental strategies utilized to examine attractive NPs include: X-beam diffraction examination, Fourier change infrared spectroscopy, TEM, SEM, AFM, X-beam photoelectron spectroscopy, vibrating test magnetometry etc.
In order to characterize the center size, size distribution and morphology , there is a combination of different methods such as transmission electron microscopy (TEM), small angle X-rays scattering (SAXS), XRD etc. The hydrodynamic distance across of scattered NPs can be evaluated with diffusing procedures, e.g, dynamic and static light dissipating (DLS and SLS).
A comparison using FTIR spectra of samples can be done to evaluate the homogeneity, and sample structure. For these types of analysis , the samples can be compacted with KBr and then analysed under a spectrophotometer. Zeta potential and the size of the particle could be determined by Nano Size ZS apparatus.In a study the ground material was suspended in water and then homogenized to measure the zeta potential with ultrasound for 15-20 mins. As a result it XRD showed the presence of two phases containing magnetite and elementary iron in sample.
The scattering methods helps to reveal the intensity weighted averages. Thus this techniques are sensitive to huge NPs and clusters. TEM provide direct visualization of number weighted structures. The samples prepared for TEM is usually done by drying or by cryo-preparation methods.NP agglomeration and non- homogeneousity can occur in the NPs assembly during the drying process . This may lead to collapse of the dispersant layer, which helps to determine the wet shell thickness. The benefit of characterizing NPs with various, correlative methods can be exemplified on the pressing thickness and density profile of dispersants adsorbed on NP surfaces. These parameters can be measured and evaluated with SANS.
Since these techniques have their advantages and disadvantages , it would be beneficial for the NPs to characterize with multiple other methods. However attention should ge given on the best result obtained.
APPLICATIONS OF IRON NANOPARTICLES:
Degradation of dyes:
Green tea incorporated nZVI (Fe0) nanoparticles were utilized for its catalytic degradation of dyes : methylene blue (MB) and methyl orange (MO) . The outcomes show that the entire removal of methylene blue (MB) and methyl orange (MO) colors from water was accomplished at a concentration of 10–200 mg/L. As a result MB was removed more quickly, when compared to MO. Almost complete expulsion of the colors was accomplished after 200 min for MB and 350 min for MO, under the considered conditions. Green tea incorporated Fe nanoparticles turned out to be more viable as a Fenton-like catalyst both as far as energy and percentage removal, when contrasted with iron nanoparticles created by borohydride lessening reduction method.
A study showed that the degradation of dyes can also be done by the polyphenolic compounds of iron nanoparticles. These polyphenols were achieved from the eucalyptus plant and was used for adsorption- flocculation against a test with Acid black 194 dye. 1.6g per gram of Fe NPs were absorbed by the Acid black 194 dye at 25 deg C temperature. As a result about 100% decolourisation of dye and 87% expulsion of total organic carbon was observed. Iron polyphenol nanoparticles (Fe-P NPs) were produced by three unique plants i.e., E. tereticornis, M. nesophila and R. officinalis , for decolourisation of dyes. E. tereticornis Fe-P NPs indicated great movement against color degredation when contrasted with different nanoparticles and ascribed to little size and great dispersibility of particles when broken down under SEM.
Waste water treatment:
Industries produce a large amount of wastewater everyday which can be treated by the principle of precipitation. Precipitation methods are very easy to operate , cheap and remove the metals from the waste water. Tragically, not every one of the contaminants can be expelled completely . Hence other mechanical steps are required to remove the low concentrations metals. This can be done by iron nanoparticles. These nanoparticles does not produce any harmful compounds . Metals are diminished and adsorbed onto iron surface, and makes the separation easier from the treated waste water in the sludge of minimal volume compared to the traditional methods.
In a study nZVI was used to remove copper(Cu) and nickel(Ni) from the wastewater. The concentrations of Cu, Ni and COD were analyzed and appropriate characterization of reaction conditions were done by pH, temperature and conductivity. nZVI particles removed about 99% of copper from the wastewater within 73 hours. Around 80% of nickel was removed in 6 hours.nZVI .This method was cheap, relatively faster and effective.
Antibacterial Activity
Iron nanoparticles are known to possess good anti microbial properties. The antibacterial impact of Tridax Procumbens integrated Fe3O4 nanoparticles was explored in a study against gram negative microbes Pseudomonas aeruginos. The leaf extract of Dodonaea viscosa was utilized for the synthesis of ZVI, copper and Ag nanoparticles. NPs that were synthesized contained antimicrobial activity which were assessed against human pathogens viz gram negative bacteria such as, E.coli, Klebsiella pneumonia, Pseudomonas fluorescens and gram-positive bacteria Bacillus subtilis and Staphylococcus aureus .These biosynthesised NPs were demonstrated as powerful antimicrobial specialists against specific human pathogens.
Other Applications of drug
Magnetic nanoparticles serves as potential materials for information storage, can act as carriers, gene delivery, DNA, biomolecules separation, treatment of tumours, catalysis and other biomedical uses. They can be used in both the ways –vivo and in vitro.
- For treatment of inflammatory joint disease, fluorescently functionalized analogue emitted by the superparamagnetic iron NPs when coated with polyvinyl alcohol, was used.
- These NPs can appropriately select the targeted tissue . Thus they can be used in cancer therapy. These magnetic iron nanoparticles can be directly injected into the body and guided by magnets to reach the exact site .Upon application of a strong magnetic field, heat was produced. This heat formed , can destroy the tumor cells and does not even damages the healthy cells.
CONCLUSION:
Significant advance has been made in the synthesis and characterization of iron oxide NPs for application in nanobiotechnology . Iron oxide being soluble in aqueous solution and colloidal shape is one of the major property that should be kept in mind when selecting the synthesis techniques. Iron’s reactivity is vital . Finely separated iron is considered pyrophoric. This is one of its drawback . The extraordinary reactivity of iron makes it hard to examine and applicable. A lot of efforts has been made in past few years to alter the iron oxide NPs surface chemistry to hydrophilic and biocompatible. Design of these NPs with powerful surface coatings is the major challenge so that they can provide optimum performance in biological applications.Hence these iron NPs can routinely be used in the fields of MRI, gene therapy, target-specific drug delivery, cancer treatments, in other diagnostics, and many more. Although magnetic NPs contain numerous distinctive properties, more toxicological research is required and the criteria to evaluate toxicity should be clearly defined. The utilization of better and quicker strategies to build up our comprehension of NP toxicity will advance the field
Various green agents are used for the production of iron NPs such as polymers, bacteria, fungi, plant extracts, etc., and their reaction pathways to some extent follows green nanotechnology methods, which will provide a strong foundation for the production of many biochemical or functional nanoparticles that can serve as building blocks in the advancement of new products that can be applicable in environment.
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