Polymeric Membrane Sensors for Detection of Titanium (III) Ions Based on Tripodal-or Calixarene-Ligand and Detection of Ohromium (VI) Using Metallo-Salen Ionophores

Currently, despite of many developments in the field of ion selective electrodes (ISEs), it continues to evolve. The introduction of low detection limit ISEs may open a new opportunity to determine trace target ions. Improvements of detection limits, selectivities, understanding the response mechanism and developing new membrane materials are constantly being reported in the literatures. Moreover, the development of ISEs used in hospital and industrial setting as well as in clinical, environmental and physiological research has been opened new horizons in front of us. This research is focused on the fabrication of new PVC-membrane sensors based on tris(2pyridyl) methylamine, tpm and c-methylcalix[4]resorcinarene, CMCR as an cationic ionophores for detection of titanium (III) cation, and also N,N′Bis(salicylidene) ethylenediamino cobalt(II),Co(SALEN) as an anionic ionophore for determining the chromate (II) anion. The complex reactions of Co(SALEN) with chromate (II) anion, tpm and CMCR with titanium (III) cation in water (H2O), acetonitrile (AN) and their binary mixture solutions at different temperatures by using the conductometric method, are investigated. The characterization and evalution of materials are described. In addition, a variety of analytical methods, including UV-Vis spectroscopy, FT-IR spectroscopy, Scanning Electron Microscopy (SEM), are used to study these processes. Later on, the application and validation of proposed ISEs with the potentiometric titration, atomic absorption spectrometry (AAs) and inductively coupled plasma atomic emission spectrometry (ICP-AES) are studied. Based on conductometric measurement results, the stoichiometry of complex formation for all the cases of ion-ionophore is 1:1. Furthermore, the average of stability constant (logKf) obtained for tpm-Ti(OH)(OH2)52+, CMCRTi(OH)(OH2)52+ and Co(SALEN)-CrO42- complexes at 25⁰C are 2.70, 3.13 and 3.02, respectively. Therefore, the mentioned ionophores can be used as sensing elements to fabricate ISE membranes for determination of titanium and chromate ions. These electroactive composite materials resulted in three new ionophore types which one based on selective ion–sensing membrane electrodes. They were fabricated for the determination of Ti (III) and CrO4 ions in solutions. The membrane sensors showed fast, stable and Nernstian response for the cation of titanium (III) and anion of chromate (II) over the concentration range from 1.0×10-6 to 1.0×10-2 M and 1.0×10-6 to 1.0×10-1 M at 25⁰C, over the pH range from 1 to 2.5 and 7 to 10 respectively. For titanium (III)cation, based on tpm and CMCR ionophores, the Nernstian slopes, detection limits and response times were 29.17±0.24 and 30.38±0.15 mV/decade of activity , 7.9×10-7 and 8.9×10-7 M, 20 and 15 s, respectively. For chromate (II)anion, using Co(SALEN) ionophore, the Nernstian slope, detection limit and response time was -28.33±0.10 mV/decade of activity, 7.9×10-7 M and <10 s. The direct determination of 4 to 39 μg/ml of titanium (III) standard solution and 2 to 48.5 μg/ml of chromate (II) standard solution showed an average recovery of 94.60, 94.70 and 96.03 % and a mean relative standard deviation of 1.8, 2.2 and 1.6% at 100.0 μg/ml for tpm, CMCR and Co(SALEN) sensors, respectively. Finally, the utilizing of electrodes as the end point indicators for potentiometric titration with EDTA and Pb(NO3)2 solutions for titanium (III) and chromate (II) sensors were successfully carried out respectively

Thermodynamic study of the complexation of p-Isopropylcalix[6]arene with Cs+ cation in dimethylsulfoxide-acetonitrile binary media.

The complexation reactions between the macrocyclic ionophore, p-isopropylcalix[6]arene and Cs+ cation were studied in dimethylsulfoxide-acetonitrile (DMSO-AN) binary non-aqueous solvents at different temperatures using a conductometry method. The conductance data show that the stoichiometry of the (p-isopropylcalix[6]-arene·Cs)+ complex in all binary mixed solvents is 1:1. The stability of the complexes is affected by the composition of the binary solvent media and a non-linear behavior was observed for changes of log K(f) of the complex versus the composition of the binary mixed solvents. The thermodynamic parameters (DH°(c) and DS°(c)) for formation of (p-isopropyl-calix[6]arene·Cs)+ complex were obtained from temperature dependence of the stability constant and the obtained results show that the (p-isopropylcalix[6]arene·Cs)+ complex is enthalpy destabilized, but entropy stabilized, and the values of the mentioned parameters are affected strongly by the nature and composition of the binary mixed solvents

Conductometric measurements of complexation study between 4-Isopropylcalix[4]arene and Cr3+ cation in THF–DMSO binary solvents

In the present work, the conductometric measurements for complexation process between Cr3+ cation and the macrocyclic ionophore, 4-Isopropylcalix[4]arene (IPC4) were studied in tetrahydrofuran–dimethylsulfoxide (THF–DMSO) binary non-aqueous medium at different temperatures. The results reveal that the stoichiometry of the IPC4–Cr3+ complex in all binary mixed solvents is 1:1. A non-linear behavior was observed for changes of logKf of this complex versus the composition of the binary mixed solvents, which was explained on the basis of changes occurring in the structure of the mixed solvents and also the preferential solvation of the cation, ionophore and the resulting complex in the solution. The thermodynamic parameters (DH�c and DS�c) for the formation of IPC4–Cr3+ complexes were obtained from the temperature dependence of the stability constant using the van’t Hoff plots. The results obtained in this study, show that the formed complex is enthalpy destabilized, but entropy stabilized and the values of the mentioned parameters are affected strongly by the nature and composition of the binary mixed solvents. The experimental data was tested by using artificial neural network (ANN) program and was in a good agreement with the estimated data

Two-dimensional-Ti3C2 magnetic nanocomposite for targeted cancer chemotherapy

Introduction: Cervical cancer is the leading cause of cancer-related death in women, so novel therapeutic approaches are needed to improve the effectiveness of current therapies or extend their activity. In recent decades, graphene analogs, such as Mxene, an emerging class of two-dimensional (2D) graphene analogs, have been drawing considerable attention based on their intrinsic physicochemical properties and performance as potential candidates for tumor therapy, particularly for therapeutic purposes. Here we explored the targeted drug delivery in cervical cancer in in vivo model. Mxene-based nanocarriers are not able to be precisely controlled in cancer treatment.Method: To solve this problem, the titanium carbide-magnetic core-shell nanocarrier (Ti3C2-Fe3O4@SiO2-FA) is also developed to provide synergetic anticancer with magnetic controlling ability along with pH-responsive drug release. A xenograft model of the cervix was used to investigate the effects of Cisplatin alone, or in combination with Ti3C2@FA and Ti3C2@ Fe3O4@SiO2-FA, on tumor growth following histological staining for evaluation of necrosis.Result and Discussion: A significant tumor-growth suppression effect is shown when the Ti3C2-Fe3O4@SiO2-FA nanocarrier is magnetically controlled Cisplatin drug release. It reveals a synergistic therapeutic efficacy used in conjunction with pharmaceuticals (p &lt; .001). According to the in vivo study, the Ti3C2@FA@Cisplatin nanocomposite exhibits less tumor growth than the drug alone or Ti3C2@FA@Cisplatin via increasing necrosis effect (p &lt; .001). Through this study, Mxene nanosheets are expanded for biomedical applications, not only through the fabrication of biocompatible magnetic Mxene nanocomposite but also through the development of functionalization strategies that enable the magnetic Ti3C2 nanocomposite to load high levels of Cisplatin for cervical cancer treatment (242.5%). Hence, Ti3C2-Fe3O4@SiO2-FA nanocarriers would be promising candidates to improve cancer treatment efficiency

A conductometric study of complexation reaction between meso-octamethylcalix[4]pyrrole with titanium cation in acetonitrile-ethanol binary mixtures.

The equilibrium constants and thermodynamic parameters for complexation process between titanium (III) cation and meso-octamethylcalix[4]pyrrole were determined by conductivity measurements in acetonitrile–ethanol (AN–EtOH) binary mixture at different temperatures. The conductance data show that the stoichiometry of the (meso-octamethylcalix[4]pyrrole.[Ti(OH)-(H2O)5])2+ complex in all binary mixed solvents is 1:1[I:M]. The stability of the formed complex is sensitive to the solvent composition and a non-linear behavior was observed for changes of log Kf of this complex versus the composition of the binary mixed solvents. The values of thermodynamic parameters (Hc and Sc) for formation of (meso-octamethylcalix[4]pyrrole.[Ti(OH)-(H2O)5])2+ complex were obtained from temperature dependence of the stability constant using van’t Hoff plots. The obtained results show that the formed complex is enthalpy destabilized, but entropy stabilized and a non-monotonic behavior was observed for variations of standard enthalpy and entropy changes versus the composition of the binary mixed solvents

A conductometric study of complexation reaction between meso-octamethylcalix[4]pyrrole with titanium cation in acetonitrile-ethanol binary mixtures.

The equilibrium constants and thermodynamic parameters for complexation process between titanium (III) cation and meso-octamethylcalix[4]pyrrole were determined by conductivity measurements in acetonitrile–ethanol (AN–EtOH) binary mixture at different temperatures. The conductance data show that the stoichiometry of the (meso-octamethylcalix[4]pyrrole.[Ti(OH)-(H2O)5])2+ complex in all binary mixed solvents is 1:1[I:M]. The stability of the formed complex is sensitive to the solvent composition and a non-linear behavior was observed for changes of log Kf of this complex versus the composition of the binary mixed solvents. The values of thermodynamic parameters (Hc and Sc) for formation of (meso-octamethylcalix[4]pyrrole.[Ti(OH)-(H2O)5])2+ complex were obtained from temperature dependence of the stability constant using van’t Hoff plots. The obtained results show that the formed complex is enthalpy destabilized, but entropy stabilized and a non-monotonic behavior was observed for variations of standard enthalpy and entropy changes versus the composition of the binary mixed solvents

The clinical impact of exosomes in cardiovascular disorders: from basic science to clinical application

Cardiovascular disease (CVD) is the major cause of death globally; therefore, there is a need for the identification of valid biomarker that accurately predict the risk of developing cardiovascular disease, and novel therapeutic approaches for its treatment. Exosomes are very small extracellular vesicles containing protein, lipid, transcription factors, mRNAs, non-coding RNA and nucleic acid contents, that are important players in intercellular communication, and that act via long-range signals or cell-to-cell contact. The discovery of exosomes provides potential strategies for the diagnosis and treatment of cardiovascular disease. In the current review, we have explored the potential impact of exosomes on cardiovascular physiology, and their therapeutic potential in cardiovascular disorders with a emphasize on the existing preclinical studies

The impact of statin therapy on the survival of patients with gastrointestinal cancer

Statins are 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors that may play an important role in the evolution of cancers, due to their effects on cancer cell metabolism. Statins effect several potential pathways, including: cell proliferation, angiogenesis, apoptosis and metastasis. The number of trials assessing the putative clinical benefits of statins in cancer is increasing. Currently, there are several trials listed on the global trial identifier website clinicaltrials.gov. Given the compelling evidence from these trials in a variety of clinical settings, there have been calls for a clinical trial of statins in the adjuvant gastrointestinal cancer setting. However, randomized controlled trials on specific cancer types in relation to statin use, as well as studies on populations without a clinical indication for using statins, have elucidated some potential underlying biological mechanisms, and the investigation of different statins is probably warranted. It would be useful for these trials to incorporate the assessment of tumour biomarkers predictive of statin response in their design. This review summarizes the recent preclinical and clinical studies that assess the application of statins in the treatment of gastrointestinal cancers with particular emphasize on their association with cancer risk

Fabrication of a highly selective and sensitive CrO4 sensor based on a N,N'Bis(salicylidene)ethylenediaminocobolt(II)hydrate.

In this work a membrane was prepared by use of N,N′Bis(salicylidene) ethylenediamino cobalt(II) hydrate (Co(SALEN)2) as an ion carrier, polyvinylchloride (PVC) as matrix, and 2-nitrophenyl octyl ether (2NPOE) as a plasticizer for an ion-selective electrode used in the measurement of CrO42-anions in solution. The amounts of (Co(SALEN)2) and PVC were optimized in the preparation of the membrane. The response of the electrode was Nernstian within the concentration range 1.0 × 10-6 to 1.0 × 10-1 M. This sensor displays a drift in Nernstian response for this anion changes with the amount of ionophore and PVC. The effects of various parameters such as pH, different anion interferences, the amounts of ionophore and PVC and time on response of the coated ion-selective electrode were investigated. The response of the fabricated electrode at concentration range from 1.0× 10-6 to 1.0× 10-1 M is linear with a Nernstian slope of -28.33 mV