Addition Of Fe2 Research Articles

Dual-targeting of tumor cells and tumor-associated macrophages by hyaluronic acid-modified MnO2 for enhanced sonodynamic therapy

In addition to tumor cells, M2-like tumor-associated macrophages (TAMs) also promote tumor progression. Accordingly, the strategy of targeted depletion or repolarization of M2-like TAMs becomes attractive. Here, we report a dual-targeting nanoagent SAMMH to tumor cells and M2-like TAMs for combinatorial tumor treatment. After co-loading the sonosensitizer spafloxacin (SPX) and oxidative phosphorylation inhibitor atavaquone (ATO) into hollow MnO2, the addition of Fe3+ and tannic acid-immobilized hyaluronic acid (HA) caused the formation of SAMMH through generating metal-polyphenol networks (MPNs) coatings outside. In vitro endocytosis assays demonstrated the efficient internalization of SAMMH by both tumor cells and M2-like TAMs through the specific CD44-HA interactions. The GSH-sensitive degradation of SAMMH results in the continuous release of SPX and ATO. Meanwhile, SAMMH could catalyze the endogenous H2O2 to extra O2, thus improving the therapeutic effect via the combination of Mn2+-induced CDT and O2-generation/O2-economy dual-enhanced sonodynamic therapy (SDT). Interestingly, SAMMH had a good targeted M2-like TAMs depleting capacity and could promote M2-to-M1 TAMs transformation by CDT-enhanced SDT, leading to a combinational anti-tumor effect. This dual-targeting nanoagent is a promising candidate to achieve CDT-enhanced SDT against both tumor cells and M2-like TAMs, thus providing new insights for the development of highly effective antitumor therapeutics.

Colorimetric and Fluorimetric Detection of Fe(III) Using a Rhodamine-Imidazole Hydrazone Based Chemosensor: Photophysical Properties, DFT, TGA, and DSC Studies.

Rhodamine-imidazole hydrazones (RIH-1 & RIH-2) based chemosensors have been synthesized. These are characterised and evaluated by FT-IR spectroscopy, 1H-NMR, 13C-NMR, LCMS, absorption and fluorescence spectroscopy. These chemosensors exhibit enhanced sensitivity and selectivity in detecting the biologically significant Fe3+ metal ion through both colorimetric and fluorescence changes. The optical properties have been investigated using binary acetonitrile-water (7:3 v/v) semi-aqueous solution. The probe RIH-1 can be deployed as a fluorescent and colorimetric probe for the detection of Fe3+ ion. It shows an absorption band at 559nm and an intensity band at 579nm increasing up to 50-fold with the increase in the concentration of Fe3+ with the detection limit as low as 11nM. In the visible light, RIH-1 helps in the detection of Fe3+ ion through the naked eye, while the addition of Fe3+ to the probe RIH-1 results in a colour change from colourless to pink. This is primarily due to the opening of the lactone ring in RIH-1. Notably, RIH-1 probe displays a high quantum yield of 0.51, after binding with Fe3+ ions. Indeed, it has been found that sensor RIH-1 is very effective in sensing Fe3+ ions through both fluorescence based and visual detection methods. Additionally, DFT studies of these chemosensors have been evaluated, TGA and DSC analysis showed good thermal stability.

Novel Schiff base decorated cyclotriphosphazene chemosensors for Fe and Cu ions detection

In this study, new 2-aminobenzothiazole derivative Schiff base decorated cyclotriphosphazene compounds (SBCTP 1 and 2), which are likely to have chemical sensor properties, were designed and synthesized successfully. The compounds were structurally characterized by mass analysis and NMR (1H, 13C and 31P) spectroscopies. Photophysical and chemosensory properties of SBCTP 1 and 2 against some analytes were examined by UV–vis and Fluorescence spectrophotometry. While a significant increase was observed in the UV–vis absorption signals observed at 350 nm with the addition of Fe3+ and Fe2+ ions and a new absorption band was observed at 290 nm with the addition of Cu2+. In addition, according to Job's plot obtained from UV–vis absorption titrations, the complex stoichiometries of SBCTP 1 and 2 with selective analytes were determined as 1:1 (L/M) and 1:2 (L/M), respectively. The selective interaction of donor atoms on SBCTP 1 and 2 with Cu2+, Fe2+ and Fe3+ ions give these compounds chemosensory properties. This study showed that the synthesized Schiff base decorated cyclotriphosphazene compounds (SBCTP 1 and 2) could be new chemosensors with high selective and immediate sensitivity for the detection of iron and copper ions.

Coupling UVC254 nm-LED/H2O2 and Fenton processes for disinfection and contaminants of emerging concern removal in continuous mode for wastewater reclamation in accordance with EU 2020/741

A novel strategy based on the sequential combination of UVC254 nm-LED/H2O2 and the Fenton process at neutral pH in continuous flow mode for wastewater reclamation has been assessed. The concentration of Escherichia coli (E. coli) reached water class A according to the European Union (EU) Regulation 2020/741 (≤10 CFU/100 mL) and a 87 ± 2 % of the contaminants of emerging concern (CECs) load was removed, complying with the new proposal regarding Urban Wastewater Treatment (Directive COM (2022) 541). To reach these results, initially the municipal wastewater secondary effluent was kept under UVC254 nm-LED/H2O2 process with a hydraulic residence time (HRT) of 5 min, a liquid depth of 5-cm and 1.8 mmol L−1 of H2O2. In the sequence, addition of Fe2+ to the outside of the UVC254 nm-LED reactor was added to acquire the desired concentration of 1.8 mmol L−1 Fe2+ (Fenton process). To obtain the same disinfection and CECs degradation by only UVC254 nm-LED/H2O2 process, 45 min-HRT were necessary. These results show that the coupled processes are the best strategy, given the reduction in HRT (from 45 to 5 min) and total cost (from 1.79 to 0.54 € m−3). In addition, new research on the application at pilot scale will encourage to evaluate the long-term toxicity of the reclaimed wastewater and to identify the main transformation products of the most abundant CECs.

Porphyrin-based carbon dots as fluorescence probe for sensing of Fe3+ ion and S2- anion in aqueous solution

In this work, a facile bottom-up approach was employed to synthesize the porphyrin-citric acid-derived fluorescent carbon dots (Por-CA-CDs) using a single-step hydrothermal method. As-prepared Por-CA-CDs were well characterized using spectroscopic techniques such as FT-IR, high-resolution transmission electron microscopy, P-XRD, UV-Vis absorption, and photoluminescence spectroscopy. The synthesized Por-CA-CDs exhibited blue fluorescence with excellent photostability and diameter ranging from 2.4 to 6.4 nm. Por-CA-CDs show excitation-dependent emission behavior, with a quantum yield of 26% and were used for sensing of Fe3+ and S2− ions in an aqueous solution. Por-CA-CDs demonstrated a robust and selective reaction to Fe3+ compared to the other cations utilized in this investigation. The sensing capability of Por-CA-CDs with Fe3+ ions was evaluated with fluorescence spectroscopy, and results show a “Turn-Off” emission mode upon binding of Fe3+ with Por-CA-CDs. In metal ion sensing studies, the fluorescence intensity of Por-CA-CDs exhibited significant quenching upon the addition of Fe3+ at concentrations ranging from 0 to 230 μM, with a detection limit (LOD) of 3.2 × 10−8 M. The quenching efficiency and Stern-Volmer quenching constant were computed as 99.45% and 4.4 × 106 M−1, respectively. Interestingly, fluorescence of Por-CA-CDs can be regained with the addition of S2− (0-160 µM) with LOD of 4.3 × 10−6 M and Stern-Volmer quenching constant of 6 × 105 M−1. Most importantly, the toxicity assay revealed good reliability for samples in deionized, tap, and river water, suggesting applications for Fe3+ monitoring in complex environments.

Gelation of gellan induced by trivalent cations and coexisting trivalent with monovalent cations studied by rheological and DSC measurements

The effect of trivalent cation Fe3+ on the gelation process of a sodium salt form of gellan (DG, deacylated gellan gum) was investigated by rheology and DSC studies. On addition of a fairly low concentration of Fe3+ (1 mM), both the complex modulus (G*) of a 1.0 % DG solution in gel state and the sol-gel transition temperature (Tgel) slightly decreased. At higher Fe3+ concentrations (2 and 3 mM), however, a slight increase in the G* and Tgel was observed. In the coexisting monovalent cation (K+) solutions, addition of Fe3+ always improved the G* in gel state and the Tgel in a concentration-dependent manner. Moreover, for all Fe3+ DG solutions, the ordered structure formation temperature (Torder) was always lower than Tgel and increased with increasing Fe3+ concentration. This finding indicates that the network formation in the DG solutions should occur in advance of the ordered structure formation of the DG chains and that the presence of Fe3+ unfavorably affected the conformational transition of DG. In coexisting cation solution, the presence of K+ ion made a favorable contribution to the binding of Fe3+ to the disordered DG chains and to the subsequent ordered structure formation of the DG chains.

A novel hybrid lanthanide metal-organic frameworks based on porphyrin for rapid detection of iron ions

BackgroundIron ion (Fe3+) is essential for the environment and human health. Detecting Fe3+ in water is crucial, making high-performance detection a key objective. Lanthanide metal-organic frameworks with abundant functional sites have been deemed a promising fluorescence sensor for Fe3+ detection. Currently, most metal-organic framework-based sensors for Fe3+ detection have cumbersome and time-consuming synthesis procedures and long detection times, which greatly limits their practical application. This study aims to construct a hybrid lanthanide metal-organic frameworks-based fluorescence sensor for Fe3+ detection that promises simple and rapid iron ion quantification in water. ResultsA novel hybrid lanthanide metal-organic frameworks (ECTMNs) was synthesized in one step using a solvothermal method with only 4 h. The frameworks comprise two metal ions, cerium and europium, serving as metal centers, and 4,4,4,4-(Porphine-5,10,15,20-tetrayl) tetrakis (TCPP) as an organic ligand. With the addition of Fe3+, the host-guest reaction occurred between Fe3+ and ECTMNs probe, leading to the gradual fluorescence burst of ECTMNs probe. A strong linear correlation between ECTMNs fluorescence intensity and Fe3+ concentration (1–90 μM) makes it a reliable sensor for Fe3+ monitoring with a detection limit of 0.3 μM. Moreover, the method was used to analyze real samples (tap water and river water), showing good recoveries (92–98 %) and low relative standard deviations (3.96–6.11 %), making it a promising option for rapidly detecting Fe3+. Significance and noveltyA rapid synthesis protocol for hybrid lanthanide metal-organic frameworks is proposed in this study. The obtained ECTMNs exhibits good water solubility, high stability, and specificity for Fe3+. Based on ECTMNs, an innovative fluorescence sensor is established for selectively detecting Fe3+ in water, which is a simple operation method with a low detection limit and short sensing time. It provides a novel method for accurately and rapidly detecting Fe3+ in environmental pollution and water safety monitoring.

Influence of Iron and Magnesium on Fouling Properties of Organic Matter Solution in Membrane Process.

Organic matter has been identified as a significant type of foulant in membrane processes for water treatment. Its fouling tendency is highly affected by the presence of ions and inorganics. While the effects of ions addition on organic fouling have been extensively researched in the past, studies on the effect of positively-charged inorganics, such as Fe2+ and Mg2+, on organic fouling are limited. This study investigates the influence of Fe2+ and Mg2+ addition on fouling properties of the Suwannee River Organic Matter (SROM) solution in the MF process, with and without Ca2+ ions. Results showed that increasing the concentration of Fe2+ and Mg2+ from 0-5 mM promoted SROM fouling, and resulted in an increased flux decline up to 33% and 58%, respectively. Cake layer resistance became more dominant with the addition of Fe2+ and Mg2+, and was counted for more than 60% of the fouling. Mg2+, however, caused higher internal pore blocking, and facilitated the formation of a less permeable cake layer, compared to Fe2+. This was evident in the analysis of the cake layer properties and the visualization of the fouling layer. In all cases, SROM fouling with Fe2+ and Mg2+ worsened with the addition of Ca2+ ions. The results of the study indicated the importance of understanding the interaction between organic matter and Fe2+ and Mg2+, which would provide useful insights on their fouling mechanism and control.

A difficult coexistence: Resolving the iron-induced nitrification delay in groundwater filters

Rapid sand filters (RSF) are an established and widely applied technology for the removal of dissolved iron (Fe2+) and ammonium (NH4+) among other contaminants in groundwater treatment. Most often, biological NH4+oxidation is spatially delayed and starts only upon complete Fe2+ depletion. However, the mechanism(s) responsible for the inhibition of NH4+oxidation by Fe2+ or its oxidation (by)products remains elusive, hindering further process control and optimization. We used batch assays, lab-scale columns, and full-scale filter characterizations to resolve the individual impact of the main Fe2+ oxidizing mechanisms and the resulting products on biological NH4+ oxidation. modeling of the obtained datasets allowed to quantitatively assess the hydraulic implications of Fe2+ oxidation. Dissolved Fe2+ and the reactive oxygen species formed as byproducts during Fe2+ oxidation had no direct effect on ammonia oxidation. The Fe3+ oxides on the sand grain coating, commonly assumed to be the main cause for inhibited ammonia oxidation, seemed instead to enhance it. modeling allowed to exclude mass transfer limitations induced by accumulation of iron flocs and consequent filter clogging as the cause for delayed ammonia oxidation. We unequivocally identify the inhibition of NH4+oxidizing organisms by the Fe3+ flocs generated during Fe2+ oxidation as the main cause for the commonly observed spatial delay in ammonia oxidation. The addition of Fe3+ flocs inhibited NH4+oxidation both in batch and column tests, and the removal of Fe3+ flocs by backwashing completely re-established the NH4+removal capacity, suggesting that the inhibition is reversible. In conclusion, our findings not only identify the iron form that causes the inhibition, albeit the biological mechanism remains to be identified, but also highlight the ecological importance of iron cycling in nitrifying environments.

Engineered‐Doping Strategy for Self‐Sufficient Reactive Oxygen Species Blossom to Amplify Ferroptosis/Cuproptosis Sensibilization in Hepatocellular Carcinoma Treatment

AbstractFerroptosis and cuproptosis are emerging modes of programmed cell death and have been increasingly used to eliminate tumor cells. However, converting ferroptosis/cuproptosis into effective treatments is challenging because of the inherent antioxidant and plasma membrane repair systems and inefficient copper ion delivery. Herein, an engineered doping method is developed to encapsulate ZnO2 with Cu2+‐doped ZIF‐8 and modify the surface by transferrin (Tf). In the resulting ZnO2@Cu/ZIF‐8‐Tf nanosystem, Tf specifically binds to transferrin receptors for targeting and aggregation. In the tumor microenvironment, Cu2+/Fe3+ is released from the nanosystem and reacted with glutathione (GSH) to produce Cu+/Fe2+. Excessive accumulation of Cu+ interfered with the tricarboxylic acid cycle and induced coproptosis. Furthermore, the additional Fe2+ caused iron overload and enhanced ferroptosis. ZnO2 supplied hydrogen peroxide to mediate the overproduction of reactive oxygen species (ROS). Moreover, the depletion of GSH deactivated glutathione peroxidase 4 (GPX4) and inhibited the system Xc−‐GSH‐GPX4 pathway, and the amplified ROS triggered lipid peroxidation and reprogrammed lipid metabolism, causing malfunctioning of both antioxidant and membrane repair systems. In summary, the ferroptosis/cuproptosis pathways are activated at multiple levels in the ZnO2@Cu/ZIF‐8‐Tf nanosystem, which ensures its outstanding antitumor effect.

Degradation of tetracycline wastewater by Fe-TiO2/Bi2MoO6/PTFE photocatalytic composite membrane

A Fe-TiO2/Bi2MoO6/PTFE photocatalytic composite membrane was innovatively fabricated for TCH wastewater treatment. It was characterized by XRD, SEM-EDS, FT-IR, BET, XPS, UV–vis, water contact angle, membrane flux, and BSA adsorption. The Fe-TiO2/Bi2MoO6 particles were securely adhered to the PTFE membrane, confirmed by repeated tests, exhibiting remarkable stability. The addition of Fe3+ and the incorporation of TiO2 increased the surface area, while the formation of the Fe-TiO2/Bi2MoO6 heterojunction facilitated the efficient separation of photogenerated electron-hole pairs. Furthermore, the doping of Fe3+ simultaneously disperses TiO2 and Bi2MoO6, enhancing their interactions. This leads to a close bonding between TiO2, Bi2MoO6, and Fe3+, further enhancing the hydrophilicity of the composite membrane. Treating TCH wastewater for 2 h with Fe-TiO2/Bi2MoO6/PTFE composite membrane under UV light achieved 87.4 % TCH removal and up to 76.1 % TOC reduction. The presence of inorganic anions (Cl−, CO32−, and NO3−) and humic acid (HA) have an inhibitory effect on the removal of TCH. The free radical trapping experiment identifies ·O2− as the primary reactive species. The E. coli colony assay shows no notable antibacterial activity in the treated effluent. LC-MS analysis reveals possible TCH degradation pathways in wastewater at different times.

A fast, convenient and stable fluorescent probe for detecting Fe3+/2+ and its applications

A turn-on benzimidazole-based fluorescent probe (E)-2-((4-(5-bromo-1H-benzo[d]imidazole-2-yl)benzylidene)amino)phenol (BRAP) for the detection of Fe3+/2+ was developed. The probe BRAP was designed and synthesized using 2-hydroxyaniline as the recognition site and benzimidazole as the fluorophore. It was highly selective and sensitive with a detection limit as low as 2.1 × 10−8 mol/L and didn't interfere with other analytes. Using EtOH: H2O (v:v = 9:1) as the detection system, BRAP had non-fluorescence at 466 nm, which was mainly due to isomerization and rotation of the CN bond. The dihedral angle rotation hindered the charge transfer between benzimidazole and 2-hydroxyaniline. However, upon the addition of Fe3+/2+, the CN bond in probe BRAP was cleaved to form compound 3, whose electrons were transferred from the benzimidazole ring to the benzaldehyde portion upon excitation and showed blue fluorescence. In addition, the optimized structure and orbital energies of probe BRAP and its products were calculated by comparing three functional combinations with time-dependent density functional theory (TD-DFT) and the optimal functional and basis set [B3LYP/6-311 + G(d,p)]. In addition, the probe BRAP combined with a smartphone was explored for the rapid detection of Fe3+/2+ in wine.

A new multifunctional phenanthroline-derived probe for colorimetric sensing of Fe2+ and fluorometric sensing of Zn2.

A new phenanthroline derivativebearing imidazole group, (2-(3,5-di(pyridin-4-yl)phenyl)-1-p-tolyl-1H-imidazo[4,5-f][1,10]phenanthroline) (1), has been devised. 1can be used as a multifunctionalprobe exhibiting a highly sensitive colorimetric response to Fe2+ and a selectively ratiometric fluorescent response to Zn2+in a buffer-ethanol solution. The absorption enhancement accompanied by a visual color change from colorless to red upon addition of Fe2+, makes 1a suitable naked-eye sensor for Fe2+. Moreover, 1displayed a Zn2+-induced red-shift of emission (44 nm) showing a color change from blue to light cyan under a 365-nm UV lamp. Its practical imaging applicability for intracellular Zn2+was confirmed in HeLa cells using a confocal microscope. The improved emission properties and cell imaging capability would provideanew approach forfluorescencesensationfor Zn2+.

Design, synthesis and biological evaluation of 5H-[1,2,4]triazino[5,6-b]indole derivatives bearing a pyridinocycloalkyl moiety as iron chelators.

The avidity of cancer cells for iron highlights the potential for iron chelators to be used in cancer therapy. Herein, we designed and synthesized a novel series of 5H-[1,2,4]triazino[5,6-b]indole derivatives bearing a pyridinocycloalkyl moiety using a ring-fusion strategy based on the structure of an iron chelator, VLX600. The antiproliferative activity evaluation against cancer cells and normal cells led to the identification of compound 3k, which displayed the strongest antiproliferative activity in vitro against A549, MCF-7, Hela and HepG-2 with IC50 values of 0.59, 0.86, 1.31 and 0.92μM, respectively, and had lower cytotoxicity against HEK293 than VLX600. Further investigations revealed that unlike VLX600, compound 3k selectively bound to ferrous ions, but not to ferric ions, and addition of Fe2+ abolished the cytotoxicity of 3k. Flow cytometry assays demonstrated that 3k arrested the cell cycle at the G1 phase and induced significant apoptosis in A549 cells in dose and time-dependent manners, corresponding to JC-1 staining assay results. Western blot analysis of Bcl-2, Bax and cleaved caspase-3 proteins further provided evidences that induction of apoptosis by 3k in A549 cells might be at least via the mitochondria pathway. These above results highlight that 3k is a valuable lead compound that deserves further investigation as an iron chelator for the treatment of cancer.

Microwave Synthesis of Carbon Quantum Dots from Arabica Coffee Ground for Fluorescence Detection of Fe3+, Pb2+, and Cr3.

In this study, carbon quantum dots (CQDs), which were synthesized from arabica coffee ground-derived activated carbon, have been successfully employed as a fluorescence sensor to detect Fe3+ ions. CQDs were fabricated using microwave heating for 5-10 min, which emitted vibrant blue light at 455 nm when exposed to excitation at 365 nm. Dynamic light scattering (DLS) analysis revealed that the average size of CQDs was 10.12 nm with a quantum yield of 6.01%. Fluorescence detection was developed for sensing Fe3+, Pb2+, and Cr3+ ions. The addition of the three metal ions resulted in a decrease in the fluorescence (FL) intensity of the CQDs, with the addition of Fe3+ ions demonstrating a more significant decrease in FL compared to the addition of both Cr3+ and Pb2+ ions. The results indicated that the CQDs synthesized from activated carbon of arabica coffee waste performed as a selective fluorescent detector for Fe3+ ions, with a detection limit of 0.27 μM.

An easy-to-prepare AIE fluorescent sensor based on bis-(naphthyl acetyl)-hydrazone for selectively relay detection of Fe3+, F− and H2PO4−

It is important to identify and detect ions as they are essential in the life system. The development of fluorescent sensors with easy-to-prepare and high sensitivity has always been a topic of widespread concern. Herein, an easily prepared fluorescent sensor based on bis-(naphthyl acetyl)-hydrazone (BNH) was successfully synthesized. Remarkably, the BNH exhibits blue aggregation-induced emission (AIE) fluorescence. The blue fluorescence of BNH was quenched by the addition of Fe3+, and then enhanced by the addition of F− and H2PO4−, while the fluorescence opened by F− was quenched again by Al3+. The LODs (limits of lowest detection) of BNH for Fe3+ is 4.46 × 10−7 M. This study provides a simple and feasible AIE fluorescence sensor synthesis method for efficient and sensitive detecting Fe3+, F− and H2PO4−.

Synthesis of a novel N-fused ring based organic molecule probe and its detection of iron

In this work, a simple one-step reaction was used to obtain a novel N-fused ring based compound 3. According to the UV–vis absorbance, fluorescence spectra tests, compound 3 has a good selectivity to the detection of Fe2+ and Fe3+, thus it can be further developed into the probe of Fe2+ and Fe3+. After the addition of Fe2+ and Fe3+, the 3 solution (1,4-Dioxane/H2O, v/v = 9:1) is turned yellow and its fluorescence is decreased. Based on the results of Job's plot and HRMS spectra, the possible sensing mechanism is proposed as the formation of complexes. As calculated, the limit of detection of 3 on Fe2+ is 0.203 µM while on Fe3+ is 0.331 µM. Noteworthily, probe 3 can response quickly (within 10 s) to Fe2+ and Fe3+. In addition, probe 3 can be further processed into portable test strips for visual identification of Fe2+ and Fe3+.

Hexagonal 2D magnesium sulfide nanosheets biosensor for fluorescence detection of ferritin in serum sample: 2D alkaline earth metal sulfide (2D-AEMS) as an effective fluorescent biosensor

We have developed a highly sensitive and selective ferritin biosensor using the two dimensional (2D) fluorescent Magnesium Sulfide (MgS) nanosheets (NS) using ultra-sonication probe method. Ferritin (Fe3+) is spherical iron containing blood protein which acts as a storage house for iron. This Fe3+ protein is an important biomarker for the detection of iron deficiency (anemia) such as, oxidative stress and cancer. Ultrasonication probe with one pot stirring method to synthesizethe 2D MgS NS was physicochemical, morphological, and analytical studied. The greenish-blue fluorescence of synthesized 2D MgS NS was optimized with maximum intensity at the excitation wavelength of 370 nm and emission wavelength of 435 nm. The quantum yield was 52.6 % found for fluorescent 2D MgS NS. The key role of 1-methylimidazole revealed 2D hexagonal nanosheets with high stability of fluorescence. Besides, the greenish-blue fluorescence of the proposed material was well quenched with the addition of Fe3+, resulting in a linear upward trend in the Stern-Volmer plot owing to static quenching. Further, the selectivity analysis of novel MgS NS shows an excellent selectivity for Fe3+ in the presence of other analytes showing 77 % quenching efficiency and LOD 9 nM with a wide linear range of 10 to 200 nM for Fe3+ detection. The proposed biosensor was successfully employed to detect Fe3+ in blood serum samples with excellent linearity and applicability in clinical diagnosis.

Influence of iron substitution on structural, morphological, optical, dielectric and ferroelectric properties of lead-free strontium calcium titanate ceramics

The influence of lead-free iron substituted strontium calcium titanate on structural, morphological, optical, dielectric and ferroelectric properties were studied. Powder X - ray diffraction pattern confirms the presence of well crystalline phase and Fe addition led to the increase in crystallite size. Morphological studies confirm growth of grain size by addition of Fe3+ ions up to 20% and beyond 20%, it limits the grain size. UV–Vis spectroscopy shows substitution of Ti4+ ions by Fe3+ ions led to the visible red shift due to which it finds applications as new UV–Vis materials having tunable optical properties. Fourier transform infrared spectroscopic shows the presence of relevant modes which confirms the formation of desired composition in perovskite phase. FT-Raman spectroscopic confirm the presence of vibrational modes corresponding to orthorhombic phase thus confirming substitution of Ti4+ ions by Fe3+ ions due to the presence of A1g mode. Dielectric constant value increases with the doping of Fe3+ ions up to 20% and beyond this a decrease in the values are observed.

Novel fluorescence sensing of D-A type imidazole derivatives to Fe3+ and its application on rewritable paper

D-A type fluorescent probe usually shows a fluorescence quenching response to Fe3+, and relatively few probes can exhibit the fluorescence color change response. Herein, two high-luminescence D-A type imidazole derivatives TPABM and TPAFM were synthesized and used as Fe3+ fluorescent probes with an obvious fluorescence color change and remarkable sensing performance. Upon the addition of Fe3+, the original emission of TPABM and TPAFM was quenched, while a new emission peak emerged in the red-shifted direction, resulting in the fluorescence color changing from deep blue to green. This phenomenon may be caused by the coordination between the molecular imidazole ring and Fe3+ with a 1:1 ratio, which efficiently decreased the LUMO energy level of the probe molecules and formed a new CT emission with a lower energy gap. Furthermore, the probe molecules exhibited the potential for detecting Fe3+ in actual water samples and could be appropriated for the preparation of rewritable paper using a simple method. By using filter paper soaked with probe molecules as writing paper, Fe3+ aqueous solution as ink, and NaF aqueous solution as an eraser, the cycle of fluorescence writing and erasing was realized under UV irradiation.