Nanotheranostic fabrication of iron oxide for rapid photocatalytic degradation of organic dyes and antifungal potential

This research work includes the fabrication of iron oxide nanoparticles (Fe₂O₃ NPs) by green construction approach using Wisteria sinensis leaves extract. Due to its eco-friendly approach, the synthesis of iron oxide NPs (Fe₂O₃ NPs) using various plant sources, such as plant parts, and microbial cells have gained a lot of attention in recent years. Cost-effectiveness and ease of availability make Wisteria sinensis leaves extract a potential candidate for the construction of iron oxide NPs. The various key features like biocompatibility, non-toxicity capping, and stabilizing agents present in biological sources are advantageous for usage in a variety of applications. The phytoconstituents present in the leaf extract of Wisteria sinensis serve as reducing and stabilizing agents. The biologically fabricated (Fe₂O₃ NPs) were analyzed using FT-IR, XRD, UV–vis spectroscopy, and SEM. In the present work, the antioxidant and photocatalytic dye degradation efficiency of Fe₂O₃ NPs has been studied. The dye degradation efficiency of methylene blue dye was found to be 87% at 180 min upon exposure to sunlight. The capacity of Fe₂O₃ NPs to scavenge 2,2-diphenyl-1-picrylhydrazyl hydrate free radicals (DPPH) was examined using a UV–Vis spectrophotometer. The study compared the radical scavenging activity (RSA) of Fe₂O₃ nanoparticles (NPs) with that of the standard antioxidant ascorbic acid. The results demonstrated that Fe₂O₃ NPs have a greater ability to scavenge radicals than ascorbic acid. The half-maximal inhibitory concentration (IC50) of Fe₂O₃ NPs was observed to range from 0.12 to 0.17. Furthermore, Fe₂O₃ NPs displayed the highest antifungal activity, with an inhibition zone of 26.8 mm against F. oxysporum. These findings suggest that the biologically synthesized Fe₂O₃ NPs possess potent antimicrobial and dye degradation properties.     

Organometallic assembling of chitosan‐Iron oxide nanoparticles with their antifungal evaluation against Rhizopus oryzae

The ever‐increasing resistance of plant microbes towards fungicides and bactericides has been causing serious threat to plant production in recent years. For the development of an effective antifungal agent, we introduce a novel hydrothermal protocol for synthesis of chitosan iron oxide nanoparticles (CH‐Fe₂O₃ NPs) using acetate buffer of low pH 5.0 for intermolecular interaction of Fe₂O₃ NPs and CH. The composite structure and elemental elucidation were carried out by using X‐ray power diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X‐ray (EDX), Transmission Electron Microscopy (TEM), Fourier Transformed Infrared Spectroscopy (FTIR) and Ultraviolet Visible Absorption Spectroscopy (UV–vis spectroscopy). Additionally, antifungal activity was evaluated both In vitro and In vivo against Rhizopus oryzae which is causing fruit rot disease of strawberry. We compared different concentrations (0.25%, 0.50%, 075% and 1%) of CH‐Fe₂O₃ NPs and 50% synthetic fungicide (Matalyxal Mancozab) to figure out suitable concentration for application in the field. XRD analysis showed a high crystalline nature of the NPs with average size of 52 nanometer (nm). SEM images revealed spherical shape with size range of 50–70 nm, whereas, TEM also revealed spherical shape, size ranging from 0 nm to 80 nm. EDX and FTIR results revealed presence of CH on surface of Fe₂O₃ NPs. The band gap measurement showed peak 317–318 nm for bare Fe₂O₃ NPs and CH‐Fe₂O₃ NPs respectively. Antifungal activity in both In vitro and In vivo significantly increased with increase in concentration. The overall results revealed high synergetic antifungal potential of organometallic CH‐Fe₂O₃ NPs against Rhizopus oryzae and suggest the use of CH‐Fe₂O₃ NPs against other Phyto‐pathological diseases due to biodegradable nature.     

Biogenic synthesis of husked rice-shaped iron oxide nanoparticles using coconut pulp (Cocos nucifera L.) extract for photocatalytic degradation of Rhodamine B dye and their in vitro antibacterial and anticancer activity

In this present study, photocatalytic and in-vitro biological properties of biogenic preparation of husked rice-shaped iron oxide nanoparticles (Fe₂O₃ NPs) are investigated. Fe₂O₃ NPs have been prepared by the reduction of iron chloride (FeCl₃) using coconut pulp (Cocos nucifera L.) extract. The Fe₂O₃ NPs were characterized by various analytical techniques such as FE-SEM, TEM, XRD, FT-IR, TGA, VSM, PL, and UV-DRS. Based on the characterization results, the as-prepared Fe₂O₃ NPs are in husked rice shape and exhibit rhombohedral crystal phase and also show an excellent stability. The prepared Fe₂O₃ NPs was investigated as a catalyst for the photocatalytic degradation of Rhodamine B solution. The photocatalytic results indicated that the Fe₂O₃ NPs catalyst possesses good activity with efficiency of 92% after 50 min under visible-light irradiation. In addition, the Fe₂O₃ NPs showed good antibacterial and anticancer properties against Gram-negative Escherichia coli and Gram-positive, Staphylococcus aureus and HepG2 cell lines, resulting in effective antibacterial and anticancer activity. The prepared Fe₂O₃ NPs, thus, proved to be a potential material for environmental remediation and biological applications.     

Facile deposition of gold nanoparticles on core–shell Fe3O4@polydopamine as recyclable nanocatalyst

A simple and green method for the controllable synthesis of core–shell Fe₃O₄ polydopamine nanoparticles (Fe₃O₄@PDA NPs) with tunable shell thickness and their application as a recyclable nanocatalyst support is presented. Magnetite Fe₃O₄ NPs formed in a one-pot process by the hydrothermal approach with a diameter of ∼240 nm were coated with a polydopamine shell layer with a tunable thickness of 15–45 nm. The facile deposition of Au NPs atop Fe₃O₄@PDA NPs was achieved by utilizing PDA as both the reducing agent and the coupling agent. The satellite nanocatalysts exhibited high catalytic performance for the reduction of p-nitrophenol. Furthermore, the recovery and reuse of the catalyst was demonstrated 8 times without detectible loss in activity. The synergistic combination of unique features of PDA and magnetic nanoparticles establishes these core–shell NPs as a versatile platform for potential applications.     

Biosynthesis and Anti-Mycotoxigenic Activity of Zingiber officinale Roscoe-Derived Metal Nanoparticles

Mycotoxigenic fungi have attracted special attention due to their threat to food security and toxicity to human health. Aqueous extract of Zingiber officinale Roscoe was used as reducing and capping agent for the synthesis of silver (AgNPs), copper (CuNPs), and zinc oxide (ZnONPs) nanoparticles. UV-Visible spectra of the AgNPs, CuNPs, and ZnONPs showed absorption peaks at λ_max 416 nm, 472 nm, and 372 nm, respectively. Zeta potential of AgNPs, CuNPs, and ZnONPs were −30.9, −30.4 and −18.4 mV, respectively. ZnONPs showed the highest activity against Aspergillus awamori ZUJQ 965830.1 (ZOI 20.9 mm and MIC 24.7 µg/mL). TEM micrographs of ZnONPs-treated A. awamori showed cracks and pits in the cell wall, liquefaction of the cytoplasmic content, making it less electron-dense. The sporulation and ochratoxin A production of A. awamori was inhibited by ZnONPs in a concentration-dependent pattern. The inhibition percentage of OTA were 45.6, 84.78 and 95.65% for 10, 15, 20 of ZnONPs/mL, respectively.     

Simple Surfactant Concentration‐Dependent Shape Control of Polyhedral Fe3O4 Nanoparticles and Their Magnetic Properties

The shape and size of monodisperse Fe₃O₄ nanoparticles (NPs) are controlled using a chemical solution synthesis in the presence of the surfactant cetylpyridinium chloride (CPC). Cubic Fe₃O₄ NPs surrounded by six {100} planes are obtained in the absence of CPC. Increasing the CPC content during synthesis causes the shape of the resulting Fe₃O₄ NPs to change from cubic to truncated cubic, cuboctahedral, truncated octahedral, and finally octahedral. During this evolution, the predominantly exposed planes of the Fe₃O₄ NPs vary from {100} to {111}. The shape control results from the synergistic effect of the pyridinium cations, chloride anions, and long‐chain alkyl groups of CPC, which is confirmed by comparison with NPs synthesized in the presence of various related cationic surfactants. The size of the cubic Fe₃O₄ NPs can be tuned from 50 to 200 nm, by changing the concentration of oleic acid in the reaction solution. The Fe₃O₄ NPs exhibit shape‐dependent saturation magnetization, remanent magnetization, and coercivity.     

Biosynthesis,Characterization and Antibacterial Application of Novel Silver Nanoparticles against Drug Resistant Pathogenic Klebsiella pneumoniae and Salmonella Enteritidis

The present study highlights the biosynthesis of silver nanoparticles (AgNPs) using culture supernatant of Massilia sp. MAHUQ-52 as well as the antimicrobial application of synthesized AgNPs against multi-drug resistant pathogenic Klebsiella pneumoniae and Salmonella Enteritidis. Well-defined AgNPs formation occurred from the reaction mixture of cell-free supernatant and silver nitrate (AgNO₃) solution within 48 h of incubation. UV-visible spectroscopy analysis showed a strong peak at 435 nm, which corresponds to the surface plasmon resonance of AgNPs. The synthesized AgNPs were characterized by FE-TEM, EDX, XRD, DLS and FT-IR. From FE-TEM analysis, it was found that most of the particles were spherical shape, and the size of synthesized nanoparticles (NPs) was 15–55 nm. EDX spectrum revealed a strong silver signal at 3 keV. XRD analysis determined the crystalline, pure, face-centered cubic AgNPs. FT-IR analysis identified various functional molecules that may be involved with the synthesis and stabilization of AgNPs. The antimicrobial activity of Massilia sp. MAHUQ-52 mediated synthesized AgNPs was determined using the disk diffusion method against K. pneumoniae and S. Enteritidis. Biosynthesized AgNPs showed strong antimicrobial activity against both K. pneumoniae and S. Enteritidis. The MICs of synthesized AgNPs against K. pneumoniae and S. Enteritidis were 12.5 and 25.0 μg/mL, respectively. The MBC of biosynthesized AgNPs against both pathogens was 50.0 μg/mL. From FE-SEM analysis, it was found that the AgNPs-treated cells showed morphological changes with irregular and damaged cell walls that culminated in cell death.     

Investigation of anti-human ovarian cancer effects of decorated Au nanoparticles on Thymbra spicata extract modified Fe3O4 nanoparticles

This work describes an eco-friendly approach for in situ immobilization of Au nanoparticles on the surface of Fe₃O₄ nanoparticles, with the help of Thymbra spicata extract and ultrasound irradiations, without using any toxic reducing and capping agents. The combination of Fe₃O₄ NPs and Au NPs in one hybrid nanostructure (Fe₃O₄@Thymbra spicata/Au NPs) represents a promising strategy for targeted biomedical applications. The structure, morphology, and physicochemical properties were characterized by various analytical techniques such as fourier transformed infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), inductively coupled plasma (ICP) and vibrating sample magnetometer (VSM). MTT assay was used on common ovarian cancer cell lines i.e., SW-626, PA-1, and SK-OV-3 to survey the cytotoxicity and anti-ovarian cancer effects of Fe₃O₄@Thymbra spicata/Au NPs. The best results of cytotoxicity and anti-ovarian cancer properties were seen in the concentration of 1000 µg/mL. Fe₃O₄@ Thymbra spicata/Au NPs had very low cell viability and high anti-ovarian cancer activities dose-dependently against PA-1, SW-626, and SK-OV-3 cell lines without any cytotoxicity on the normal cell line (HUVEC). For investigating the antioxidant properties of Fe₃O₄@ Thymbra spicata/Au NPs, the DPPH test was used in the presence of butylated hydroxytoluene as the positive control. Fe₃O₄@Thymbra spicata/Au NPs inhibited half of the DPPH molecules in the concentration of 107 µg/mL. Maybe significant anti-human ovarian cancer potentials of Fe₃O₄@Thymbra spicata/Au NPs against common human ovarian cancer cell lines are linked to their antioxidant activities. After confirming the above results in the clinical trial researches, this formulation can be administrated for the treatment of several types of human ovarian cancers in humans.     

Assessment of antioxidant and cytotoxic potential of silver nanoparticles synthesized from root extract of Reynoutria japonica Houtt

Free radicals, mostly consist of reactive oxygen species, are generated in human body by several exogenous and endogenous systems. Overproduction of free radicals is known to cause several degenerative disorders including cancer. The aim of this study is to synthesize silver nanoparticles (AgNPs) using root extract of Reynoutria japonica and to investigate its antioxidant and cytotoxic potential. AgNPs were synthesized by green approach and subsequently characterized using UV–vis spectroscopy, SEM, TEM, FTIR, XRD, EDS and DLS. The antioxidant activity was investigated using DPPH, FRAP, H₂O₂, and ABT?⁺ radical scavenging assays while the cytotoxic effect was assessed using different human cancer cell lines including lung (A549), liver (Hep-G2) and breast (MDA-MB-231) by MTS assay. Moreover, the specificity of NPs was assessed against two normal human cell lines e.g. alveolar and renal primary epithelial cells (HPAEpiC and HRPTEpiC). The UV–vis spectra confirmed the synthesis of AgNPs by producing a characteristic peak at 410 nm. Further analysis confirmed that AgNPs were crystalline in nature, predominantly spherical in shape, with an average width and area of 17.34 nm and 164.46 nm², respectively. DLS analysis revealed that NPs possess a high negative zeta potential value (?28.5 mV), thus facilitating its electrostatic stabilization. AgNPs showed dose dependent antioxidant activity against DPPH, FRAP, H₂O₂ and ABTS with IC₅₀ values 19.25, 22.45, 24.20 and 18.88 µg/ml, respectively. The AgNPs depicted significant cytotoxic effects against A549, Hep-G2 and MDA-MB-231 cell lines with IC₅₀ values of 4.5, 5.1 and 3.46 µg/ml, respectively. Moreover, the NPs exhibited highest selectivity index (>2.0) for A549, Hep-G2 and MDA-MB-231, confirming its specificity towards cancer cell lines. In conclusion, AgNPs prepared from root extract of R. japonica possess strong antioxidant and cytotoxic potential which suggests that they should be investigated further in order to develop safe and effective antioxidant and/or cytotoxic formulations.     

Cu nanoparticles immobilized on modified magnetic zeolite for the synthesis of 1,2,3‐triazoles under ultrasonic conditions

Magnetically recoverable copper nanoparticle‐loaded natural zeolite (CuNPs/MZN) as an efficient catalyst was synthesized. The Fe₃O₄ magnetic nanoparticles were immobilized into the pores of natural clinoptilolite zeolite, which were modified with epichlorohydrine and ethylenediamine species and then CuNPs were decorated on the surface of functionalized zeolite (CuNPs/MZN). The catalysts were successfully characterized by Fourier transform‐infrared, CHN, thermogravimetric analysis, inductively coupled plasma, X‐ray diffraction, scanning electron microscopy and transmission electron microscopy techniques. The 1,2,3‐triazoles were readily synthesized through using the catalyst in high yields and short reaction times under ultrasonic conditions via CuAAC reactions of aryl azides and terminal alkynes. The CuNPs/MZN was easily separated from the reaction mixture by an external magnet and reused several times successfully. The catalyst could be used for the synthesis of various organic compounds.     

Eco‐friendly magnetic clinoptilolite containing Cu(0) nanoparticles (CuNPs/MZN): as a new efficient catalyst for the synthesis of propargylamines via A3 and KA2 coupling reactions

In this reaserch a new and eco‐friendly magnetic catalyst for the synthesis of propargylamines is reported. Initial incorporation of Fe₃O₄ magnetic nanoparticles (MNPs) into the pores of the natural clinoptilolite zeolite followed by modification with epichlorohydrine and ethylenediamine and then immobilization of CuNPs on the surface of functionalized zeolite gave the desired catalyst (CuNPs/MZN). The CuNPs/MZN was fully characterized by various techniques such as FT‐IR, CHN, TGA, ICP, XRD, SEM, TEM and BET. A host of propargylamines were readily synthesized through using the catalyst in high yields and short reaction times via A³ and KA² coupling reactions of aldehydes/ketones, amines, and phenylacetylene. The CuNPs/MZN was easily separated from the reaction mixture by an external magnet and reused several times successfully. The catalyst has the potential for catalysis of various organic transformations.     

Signal amplification for DNA detection based on the HRP-functionalized Fe3O4 nanoparticles

An electrochemical approach for the sensitive detection of sequence-specific DNA has been developed. Horseradish peroxidase (HRP) assembled on the Fe₃O₄ nanoparticles (NPs) were utilized as signal amplification sources. High-content HRP was adsorbed on the Fe₃O₄ NPs via layer-by-layer (LbL) technique to prepare HRP-functionalized Fe₃O₄ NPs. Signal probe and diluting probe were then immobilized on the HRP-functionalized Fe₃O₄ NPs through the bridge of Au NPs. Thereafter, the resulting DNA-Au-HRP-Fe₃O₄ (DAHF) bioconjugates were successfully anchored to the gold nanofilm (GNF) modified electrode surface for the construction of sandwich-type electrochemical DNA biosensor. The electrochemical behaviors of the prepared biosensor had been investigated by the cyclic voltammetry (CV), chronoamperometry (i-t), and electrochemical impedance spectroscopy (EIS). Under optimal conditions, the proposed strategy could detect the target DNA down to the level of 0.7 fmol with a dynamic range spanning 4 orders of magnitude and exhibited excellent discrimination to two-base mismatched DNA and non-complementary DNA sequences.     

One-pot synthesis of magnetic nanoparticles assembled on polysiloxane rod and their response to magnetic field

Rod-like assembled magnetite (Fe₃O₄) nanoparticles (NPs) were successfully synthesized in a one-pot process using a polysiloxane template derived from a dialkoxysilane. The assembly was constructed using the thiol-ene click reaction between thiol groups on the polysiloxane chain and allyl groups on Fe₃O₄ NPs. The thiol-containing polysiloxane chain and the allyl-containing Fe₃O₄ NPs were synthesized by the hydrolysis–condensation of 3-mercaptopropyl(dimethoxy)methylsilane and iron (III) allylacetylacetonate, respectively. Fe₃O₄ NPs of around 5 nm were uniformly dispersed on the siloxane rods and exhibited neither remanent magnetization nor coercivity. A fluid containing a dispersion of rod-like assembled Fe₃O₄ NPs showed yield stress even without the application of an external magnetic field, whereas spherical Fe₃O₄ NPs exhibited no yield stress. The rod-like assembled Fe₃O₄ NPs on anisotropic siloxane clearly exhibited typical magnetorheological behavior.     

Matrices based on meso antibacterial framework

In this paper, the synthesis of three types of porous materials (PMs) (porous Fe₃O₄, MIL-101 metal-organic framework (MOF), and MCM-41 mesoporous silica) by hydrothermal method was performed. The incorporation of Ag nanoparticles (Ag NPs) was carried out after the synthesis reaction of supports in MCM-41 and MIL-101 MOF. Ag core@ porous Fe₃O₄ core–shell system was prepared via a one-pot hydrothermal method. Ag-MIL-101 was obtained using Urtica dioica leaf extract as the green solvent and reducing agent. The antibacterial activity of Ag-PM nanocomposites (NCs) was investigated on both Gram-negative and Gram-positive bacteria. The size of the silver NPs was determined to be 12 and 30 nm in MCM-41 and MIL-101 MOF, respectively. The diameter of Ag core in Ag@Fe₃O₄ shell was ~135 nm. The antibacterial activity of Ag-PMs was in the order Ag-MCM-41 > Ag-MIL-101 > Ag core@Fe₃O₄ shell. The loading percent of Ag NPs in MCM-41 (84%) was more than that in MIL-101 (53%) and Fe₃O₄ (31%). The release of Ag⁺ ions from Ag-MCM-41, Ag-MIL-101, and Ag@Fe₃O₄ NCs was 46, 2, and 1 ppm, respectively. The release of the Ag⁺ ions and, consequently, the antibacterial activity of NCs depend on the uniform distribution, particles size, and the absence of aggregation of Ag NPs in PMs.     

Simple surface functionalization of magnetic nanoparticles with methotrexate-conjugated bovine serum albumin as a biocompatible drug delivery vehicle

Magnetic nanoparticles (MNPs) functionalized with methotrexate (MTX)-conjugated bovine serum albumin (BSA) as a biocompatible drug delivery vehicle were synthesized using a facile method. Characterization of the functionalized MNPs (Fe₃O₄@BSA-MTX NPs) was performed using various techniques including UV–visible spectroscopy, dynamic light scattering, vibrating sample magnetometry and X-ray diffraction. The particle size and zeta potential of Fe₃O₄@BSA-MTX NPs were 105.7 ± 3.81 nm (mean ± SD) and −18.2 mV, respectively. MTX release from Fe₃O₄@BSA-MTX NPs showed an enzyme-dependent release pattern. Hemo-biocompatibility of Fe₃O₄@BSA-MTX NPs was confirmed using hemolysis test. In addition, the cytotoxicity of functionalized MNPs and free MTX against MCF-7 cell line was investigated using MTT assay. The results of experiments revealed that the Fe₃O₄@BSA-MTX NPs as a biocompatible carrier could improve the therapeutic effect of MTX.     

Ultrafast Preparation of Monodisperse Fe3O4 Nanoparticles by Microwave‐Assisted Thermal Decomposition

Thermal decomposition, as the main synthetic procedure for the synthesis of magnetic nanoparticles (NPs), is facing several problems, such as high reaction temperatures and time consumption. An improved a microwave‐assisted thermal decomposition procedure has been developed by which monodisperse Fe₃O₄ NPs could be rapidly produced at a low aging temperature with high yield (90.1 %). The as‐synthesized NPs show excellent inductive heating and MRI properties in vitro. In contrast, Fe₃O₄ NPs synthesized by classical thermal decomposition were obtained in very low yield (20.3 %) with an overall poor quality. It was found for the first time that, besides precursors and solvents, magnetic NPs themselves could be heated by microwave irradiation during the synthetic process. These findings were demonstrated by a series of microwave‐heating experiments, Raman spectroscopy and vector‐network analysis, indicating that the initially formed magnetic Fe₃O₄ particles were able to transform microwave energy into heat directly and, thus, contribute to the nanoparticle growth.     

Synthesis of novel magnetic sulfur-doped Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> nanoparticles for efficient removal of Pb(II)

In this work, we report the synthesis of magnetic sulfur-doped Fe₃O₄ nanoparticles (Fe₃O₄:S NPs) with a novel simple strategy, which includes low temperature multicomponent mixing and high temperature sintering. The prepared Fe₃O₄:S NPs exhibit a much better adsorption performance towards Pb(II) than bare Fe₃O₄ nanoparticles. FTIR, XPS, and XRD analyses suggested that the removal mechanisms of Pb(II) by Fe₃O₄:S NPs were associated with the process of precipitation (formation of PbS), hydrolysis, and surface adsorption. The kinetic studies showed that the adsorption data were described well by a pseudo second-order kinetic model, and the adsorption isotherms could be presented by Freundlich isotherm model. Moreover, the adsorption was not significantly affected by the coexisting ions, and the adsorbent could be easily separated from water by an external magnetic field after Pb(II) adsorption. Thus, Fe₃O₄:S NPs are supposed to be a good adsorbents for Pb(II) ions in environmental remediation.     

Separation of chiral compounds using magnetic molecularly imprinted polymer nanoparticles as stationary phase by microchip capillary electrochromatography

In this work, a simple and rapid approach was developed for separation and detection of chiral compounds based on a magnetic molecularly imprinted polymer modified poly(dimethylsiloxane) (PDMS) microchip coupled with electrochemical detection. Molecularly imprinted polymers were prepared employing Fe₃O₄ nanoparticles (NPs) as the supporting substrate and norepinephrine as the functional monomer in the presence of template molecule in a weak alkaline solution. After extracting the embedded template molecules, Fe₃O₄@polynorepinephrine NPs (MIP–Fe₃O₄@PNE NPs) showed specific molecular recognition selectivity and high affinity towards the template molecule, which were then used as stationary phase of microchip capillary electrochromatography for chiral compounds separation. Mandelic acid and histidine enantiomers were used as model compounds to test the chiral stationary phase. By using R‐mandelic acid as the template molecule, mandelic acid enantiomer was effectively separated and detected on the MIP‐Fe₃O₄@PNE NPs modified PDMS microchip. Moreover, the successful separation of histidine enantiomers on the MIP–Fe₃O₄@PNE NPs modified microchip using L‐histidine as template molecule was also achieved.     

Oxidase-functionalized Fe(3)O(4) nanoparticles for fluorescence sensing of specific substrate

This study reports the development of a reusable, single-step system for the detection of specific substrates using oxidase-functionalized Fe₃O₄ nanoparticles (NPs) as a bienzyme system and using amplex ultrared (AU) as a fluorogenic substrate. In the presence of H₂O₂, the reaction pH between Fe₃O₄ NPs and AU was similar to the reaction of oxidase and the substrate. The catalytic activity of Fe₃O₄ NPs with AU was nearly unchanged following modification with poly(diallyldimethylammonium chloride) (PDDA). Based on these features, we prepared a composite of PDDA-modified Fe₃O₄ NPs and oxidase for the quantification of specific substrates through the H₂O₂-mediated oxidation of AU. By monitoring fluorescence intensity at 587 nm of oxidized AU, the minimum detectable concentrations of glucose, galactose, and choline were found to be 3, 2, and 20 μM using glucose oxidase–Fe₃O₄, galactose oxidase–Fe₃O₄, and choline oxidase–Fe₃O₄ composites, respectively. The identification of glucose in blood was selected as the model to validate the applicability of this proposed method.     

Pectin mediated green synthesis of Fe3O4/Pectin nanoparticles under ultrasound condition as an anti-human colorectal carcinoma bionanocomposite

This work described the one-pot synthesis of apple pectin encapsulated Fe₃O₄ nanoparticles (Fe₃O₄/Pectin NPs) which is prepared by co-precipitation of Fe(II/(III) ions in alkaline solution mediated by pectin under ultrasound condition. This process led to formation of magnetic nanoparticles within the network of pectin. Physicochemical characterization of the as-synthesized Fe₃O₄/Pectin NPs was carried out through electron microscopy (SEM and TEM), energy dispersive X-ray spectroscopy (EDX), vibrating sample magnetometer (VSM) and X-ray diffraction (XRD). The in vitro cytotoxic and anti-colorectal cancer effects of biologically synthesized Fe₃O₄/Pectin NPs against Ramos.2G6.4C10, HCT-8 [HRT-18], HCT 116, and HT-29 cancer cell lines were assessed. The anti-colorectal cancer properties of the Fe₃O₄/Pectin NPs could significantly remove Ramos.2G6.4C10, HCT-8 [HRT-18], HCT 116, and HT-29 cancer cell lines in a time and concentration-dependent manner by MTT assay. The IC₅₀ of the Fe₃O₄/Pectin NPs were 317, 337, 187, and 300 µg/mL against Ramos.2G6.4C10, HCT-8 [HRT-18], HCT 116, and HT-29 cancer cell lines. The antioxidant activity of Fe₃O₄/Pectin NPs was determined by DPPH method. The Fe₃O₄/Pectin NPs showed the high antioxidant activity according to the IC₅₀ value. It seems that the anti-human colorectal cancer effect of recent nanoparticles is due to their antioxidant effects.