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The orientation of phosphate bridges as well as the VO6 octahedron arrangement determine the effectiveness of exchange pathways leading to specific magnetic properties. This was concluded in an analysis of the magnetic behavior of several oxovanadium(IV) phosphates which show magnetic diversity, due partly to the possible involvement of phosphate groups in the spin transfer between V(super IV) centers. These and previous results are part of a topological scheme leading to a magnetostructural correlation allowing predictions on the magnitude of magnetic interaction in related oxovanadium phosphates.

Chemical research has established a way of creating layered oxovanadium phosphate hydrates M(VOPO4)2.nH2O using Ba2+ cations and arsenate anions. A partial charge model and valence matching principle were used. X-ray single crystal data analysis is used to identify the barium lamellar derivative Ba(VOPO4)2.4H20. Structure determination analysis is discussed.

A synthetic approach to a V-P-O framework is reported based on the concept that the framework in the final solid is influenced by the properties of ionic aggregates in solution. A revised version of the partial charge model by Livage is applied to the synthesis of a reported oxovanadium phosphate and a novel V(IV)-Fe(III) bimetallic oxovanadium phosphate (H3N(CH2)2NH3)2(H3N(CH2)2NH2)(FeIII(H2O)2(VIVO)8(OH)4(HPO4)4(PO4)4).-4H2O. Both compounds have structural directing agents in the form of ethylenediamine.

A layer transition metal hypophosphite serves as host lattice for intercalation reactions. Several two-dimensional systems arise due to the low connectivity of pseudotetrahedral species and related anions. Water and pyridine intercalation processes are studied using thermal analysis, variable-temperature X-ray powder diffraction and spectroscopic techniques.

The synthesis and characterization of (eta5-C5H5)Fe(eta5-C5H4) CH=N(CH2)2N= CH(eta5-C5H4)Fe(eta5-C5H5), its related amine and the pentanuclear complex (Cu(Fc2L)2(NO3)2).2CH3OH were reported. The pentanuclear complex consisted of (Cu(Fc2L)2(NO3)2) neutral units and methanol molecules as analyzed by single-crystal X-ray crystallography. Potentiometric titrations were performed to investigate the reactions of (eta5-C5H5)Fe(eta5- C5H4)CH2NH(CH2)2NHCH2(eta5-C5H4)Fe(eta5-C5H5),FcL with copper(II).

A detailed study on the behavior of a pH-driven and anion-controlled nano-supramolecular gate-like ensemble obtained by anchoring suitable polyamines on the pore outlets of mesoporous materials of the type MCM-41 is reported. The results provide insight into the pH-controlled open/close mechanism attributed to hydrogen-bonding interactions between amines (open-gate) and Coulombic repulsion between ammonium groups (closed-gate).

Here, a new bio‐inspired nanoarchitectonics approach for the design of optical probes is presented. It is based on nanodevices that combine 1) an enzymatic receptor subunit, 2) a signaling subunit (consisting of a labeled reporter attached to a silica surface), and 3) a mechanism of communication between the two sites based on the production of chemical messengers by the enzymatic subunit, which induces the detachment of the reporter molecules from the silica surface. As a proof of concept, a urea nanosensor based on the release of Alexa‐Fluor‐647‐labeled oligonucleotide from enzyme‐functionalized Janus gold–mesoporous‐silica nanoparticles (Au–MSNPs) was developed. The Janus particles were functionalized on the silica face with amino groups to which the labeled oligonucleotides were attached by electrostatic interactions, whereas the gold face was used for grafting urease enzymes. The nanodevice was able to release the fluorescent oligonucleotide through the enzyme‐mediated hydrolysis of urea to ammonia and the subsequent deprotonation of amino groups on the silica face. This simple nanodevice was applied for the fluorometric detection of urea in real human blood samples and for the identification of adulterated milk. Given the large variety of enzymes and reporter species that could be combined, this is a general new paradigm that could be applied to the design of a number of optical probes for the detection of target analytes. Designing biosensors: A new paradigm for the design of optical sensors based on nanodevices incorporating an enzymatic receptor subunit and a hybrid signaling subunit that communicate through chemical messengers is presented. As a proof of concept, a urea nanosensor based on the release of an oligonucleotide labeled with Alexa Fluor 647 from urease‐functionalized Janus gold–mesoporous‐silica nanoparticles (Au–MSNPs) was developed. [ABSTRACT FROM AUTHOR]

Abstract: Apoptotic signaling pathways are altered in numerous pathologies such as cancer. In this scenario, caspase‐9/PP2Acα interaction constitutes a key target with pharmacological interest to re‐establish apoptosis in tumor cells. Very recently, a short peptide (C9h) known to disrupt caspase‐9/PP2Acα interaction with subsequent apoptosis induction was described. Here, we prepared two sets of mesoporous silica nanoparticles loaded with safranin O (S2) or with C9h peptide (S4) and functionalized with ϵ‐polylysine as capping unit. Aqueous suspensions of both nanoparticles showed negligible cargo release whereas in the presence of pronase, a marked delivery of safranin O or C9h was observed. Confocal microscopy studies carried out with HeLa cells indicated that both materials were internalized and were able to release their entrapped cargos. Besides, a marked decrease in HeLa cell viability (ca. 50 %) was observed when treated with C9h‐loaded S4 nanoparticles. Moreover, S4 provides peptide protection from degradation additionally allowing for a dose reduction to observe an apoptotic effect when compared with C9h alone or in combination with a cell‐penetrating peptide (i.e., Mut3DPT‐C9h). Flow cytometry studies, by means of Annexin V‐FITC staining, showed the activation of apoptotic pathways in HeLa as a consequence of S4 internalization, release of C9h peptide and disruption of caspase‐9/PP2Acα interaction. [ABSTRACT FROM AUTHOR]

Magnetic micro-sized mesoporous silica particles were used for the preparation of a gated material able to release an entrapped cargo in the presence of an azo-reducing agent and, to some extent, at acidic pH. The magnetic mesoporous microparticles were loaded with safranin O and the external surface was functionalized with an azo derivative 1 (bearing a carbamate linkage) yielding solid S1. Aqueous suspensions of S1 at pH 7.4 showed negligible safranin O release due to the presence of the bulky azo derivative attached onto the external surface of the inorganic scaffold. However, in the presence of sodium dithionite (azoreductive agent), a remarkable safranin O delivery was observed. At acidic pH, a certain safranin O release from S1 was also found. The pH-triggered safranin O delivery was ascribed to the acid-induced hydrolysis of the carbamate moiety that linked the bulky azo derivatives onto the mesoporous inorganic magnetic support. The controlled release behavior of S1 was also tested using a model that simulated the gastro intestinal tract. [ABSTRACT FROM AUTHOR]

Within nanotechnology, gold and silver nanostructures have unique physical, chemical, and electronic properties [1,2], which make them suitable for a number of applications. Moreover, biosynthetic methods are considered to be a safer alternative to conventional physicochemical procedures for both the environmental and biomedical applications, due to their eco-friendly nature and the avoidance of toxic chemicals in the synthesis. For this reason, employing bio routes in the synthesis of functionalized silver nanoparticles (FAgNP) have gained importance recently in this field. In the present study, we report the rapid synthesis of FAgNP through the extract of pepino (Solanum muricatum) leaves and employing microwave oven irradiation. The core-shell globular morphology and characterization of the different shaped and sized FAgNP, with a core of 20-50 nm of diameter is established using the UV-Visible spectroscopy (UV-vis), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and Zeta potential and dynamic light scanning (DLS) studies. Moreover, cytotoxic studies employing HeLa (human cervix carcinoma) cells were undertaken to understand FAgNP interactions with cells. HeLa cells showed significant dose dependent antiproliferative activity in the presence of FAgNP at relatively low concentrations. The calculated IC50 value was 37.5 µg/mL, similar to others obtained for FAgNPs against HeLa cells. [ABSTRACT FROM AUTHOR]