Nanothermodynamics mediates drug delivery

© Springer International Publishing Switzerland 2015. The efficiency of penetration of nanodrugs through cell membranes imposes further complexity due to nanothermodynamic and entropic potentials at interfaces. Action of nanodrugs is effective after cell membrane penetration. Contrary to diffusion of water diluted common molecular drugs, nanosize imposes an increasing transport complexity at boundaries and interfaces (e.g., cell membrane). Indeed, tiny dimensional systems brought the concept of “nanothermodynamic potential,” which is proportional to the number of nanoentities in a macroscopic system, from either the presence of surface and edge effects at the boundaries of nanoentities or the restriction of the translational and rotational degrees of freedom of molecules within them. The core element of nanothermodynamic theory is based on the assumption that the contribution of a nanosize ensemble to the free energy of a macroscopic system has its origin at the excess interaction energy between the nanostructured entities. As the size of a system is increasing, the contribution of the nanothermodynamic potential to the free energy of the system becomes negligible. Furthermore, concentration gradients at boundaries, morphological distribution of nanoentities, and restriction of the translational motion from trapping sites are the source of strong entropic potentials at the interfaces. It is evident therefore that nanothermodynamic and entropic potentials either prevent or allow enhanced concentration very close to interfaces and thus strongly modulate nanoparticle penetration within the intracellular region. In this work, it is shown that nano-sized polynuclear iron (III)-hydroxide in sucrose nanoparticles have a nonuniform concentration around the cell membrane of macrophages in vivo, compared to uniform concentration at hydrophobic prototype surfaces. The difference is attributed to the presence of entropic and nanothermodynamic potentials at interfaces

New π-electron donor (1,4-thioxane-2,3-diyldithio)ethylenedithiotetrathiafulvalene (ETOEDT-EDT-TTF) and its derivatives. Synthesis and characterization

We report more efficient way for the synthesis of 4,5-(1,4-oxathiane-2,3-diyldithio)-1,3-dithiole-2-thione and three new TTF-derived nonsymmetrical electron donors: the (1,4-thioxane-2,3-diyldithio)ethylenedithiotetrathiafulvalene (ETOEDT-EDT-TTF), (1,4-thioxane-2,3-diyldithio)propylenedithiotetrathiafulvalene (ETOEDT-PDT-TTF), and (1,4-thioxane-2,3-diyldithio)dimethylenedithiotetrathiafulvalene (ETOEDT-DMDT-TTF). For the first time we also present extended studies of the molecular structure, vibrational and electronic excitations of the donors. Based on theoretical and experimental Raman and infrared spectra as well as analysis of electron excitations of three new TTF-derived donors their spectral properties were described and discussed. © 2007 Elsevier Ltd. All rights reserved

Synthesis, experimental and theoretical investigation of a new type nickel dithiolene complex

A new nickel complex with an extended multisulfur dithiolene ligand, [Ni(dmeodddt)2] (dmeodddt = 5,6-dimethoxy-5,6-dihydro-1,4-dithiine-2, 3-dithiolate), has been synthesized and characterized by IR, Raman, UV-Vis and NMR spectroscopy. Its crystal structure has been determined by X-ray crystallography, showing that the Ni atom is tetra-coordinated and has a square planar geometry with the methoxy groups placed above and below the metal dithiolene core, due to stereochemical hindrance. Electrochemical measurements showed that the complex exhibits four 1e reversible redox waves. The results of theoretical calculations showed a good agreement with the experimental findings and gave answers about its electronic structure. © 2013 Elsevier Ltd. All rights reserved

New type dithiolene complex based on 4,5-(1,4-dioxane-2,3-diyldithio)-1,3-dithiol ligand: Synthesis, experimental and theoretical investigation

A new Nickel complex with an extended multisulfur dithiolene ligand Ni(edodddt)2 (edodddt = 2,3,4α,8α-tetrahydro-dithiine [2,3-b] [1,4] dioxo-6,7-dithiolene) has been synthesized and characterized by electrochemical measurements, IR, UV-Vis and NMR spectroscopy. Its crystal structure was resolved by X-ray diffraction on a single crystal. DFT calculations were made in order to compare the results with the experimental findings and gain an insight of the properties of this new dithiolene complex. © 2009 Elsevier Ltd. All rights reserved

Synthesis and non-linear optical properties of some novel nickel derivatives

The synthesis of a new nickel complex with an extended multi-sulfur dithiolene ligand Ni(etodddt)2 (etodddt = 4,5-(1,4-oxathiane-2,3- diyldithio)-1,3-dithiole) is described. It is characterized analytically and spectroscopically. The structure of the compound is determined by single crystal X-ray crystallography. Its redox potentials are determined using cyclic voltammetry and are compared with similar dithiolene complexes. Several other nickel derivatives are synthesized: bis(5,6-dihydro-1,4-dithiine-2,3-dithiole) nickel (Ni(dddt)2) and bis(6,7-dihydro-5H-[1,4] dithiepine-2,3- ddithiole) nickel (Ni(pddt)2). The non-linear optical response of the synthesized dithiolenes is measured in the visible (532 nm) and in the infrared (1064 nm) using the Z-scan technique with picosecond laser pulses. Both the refractive and absorptive parts of the third-order susceptibility χ(3) are determined and the second-order hyperpolarizabilities γ of the dithiolenes are determined and compared between them and with other reported in the literature data. The second hyperpolarizabilities of the synthesized metal derivatives are calculated by employing a series of computational approaches, involving density functional theory and a semi-empirical method. The first strong transition of the derivatives is attributed mainly to HOMO-LUMO pair connected with the intramolecular charge transfer π → π. Similar trends are observed between the experimental and the theoretical second hyperpolarizabilities, although the former are much larger due to resonance enhancement. The reported analysis demonstrates the complementarity of both experimental and theoretical results. It is shown that modest substitution of Ni(SCH)4, for example substitution of four H atoms by two S2C2H4 groups, leads to a very large increase of the second hyperpolarizability. © 2010 Elsevier B.V. All rights reserved

Nanothermodynamics mediates drug delivery

© Springer International Publishing Switzerland 2015. The efficiency of penetration of nanodrugs through cell membranes imposes further complexity due to nanothermodynamic and entropic potentials at interfaces. Action of nanodrugs is effective after cell membrane penetration. Contrary to diffusion of water diluted common molecular drugs, nanosize imposes an increasing transport complexity at boundaries and interfaces (e.g., cell membrane). Indeed, tiny dimensional systems brought the concept of “nanothermodynamic potential,” which is proportional to the number of nanoentities in a macroscopic system, from either the presence of surface and edge effects at the boundaries of nanoentities or the restriction of the translational and rotational degrees of freedom of molecules within them. The core element of nanothermodynamic theory is based on the assumption that the contribution of a nanosize ensemble to the free energy of a macroscopic system has its origin at the excess interaction energy between the nanostructured entities. As the size of a system is increasing, the contribution of the nanothermodynamic potential to the free energy of the system becomes negligible. Furthermore, concentration gradients at boundaries, morphological distribution of nanoentities, and restriction of the translational motion from trapping sites are the source of strong entropic potentials at the interfaces. It is evident therefore that nanothermodynamic and entropic potentials either prevent or allow enhanced concentration very close to interfaces and thus strongly modulate nanoparticle penetration within the intracellular region. In this work, it is shown that nano-sized polynuclear iron (III)-hydroxide in sucrose nanoparticles have a nonuniform concentration around the cell membrane of macrophages in vivo, compared to uniform concentration at hydrophobic prototype surfaces. The difference is attributed to the presence of entropic and nanothermodynamic potentials at interfaces

Nanothermodynamics mediates drug delivery

© Springer International Publishing Switzerland 2015. The efficiency of penetration of nanodrugs through cell membranes imposes further complexity due to nanothermodynamic and entropic potentials at interfaces. Action of nanodrugs is effective after cell membrane penetration. Contrary to diffusion of water diluted common molecular drugs, nanosize imposes an increasing transport complexity at boundaries and interfaces (e.g., cell membrane). Indeed, tiny dimensional systems brought the concept of “nanothermodynamic potential,” which is proportional to the number of nanoentities in a macroscopic system, from either the presence of surface and edge effects at the boundaries of nanoentities or the restriction of the translational and rotational degrees of freedom of molecules within them. The core element of nanothermodynamic theory is based on the assumption that the contribution of a nanosize ensemble to the free energy of a macroscopic system has its origin at the excess interaction energy between the nanostructured entities. As the size of a system is increasing, the contribution of the nanothermodynamic potential to the free energy of the system becomes negligible. Furthermore, concentration gradients at boundaries, morphological distribution of nanoentities, and restriction of the translational motion from trapping sites are the source of strong entropic potentials at the interfaces. It is evident therefore that nanothermodynamic and entropic potentials either prevent or allow enhanced concentration very close to interfaces and thus strongly modulate nanoparticle penetration within the intracellular region. In this work, it is shown that nano-sized polynuclear iron (III)-hydroxide in sucrose nanoparticles have a nonuniform concentration around the cell membrane of macrophages in vivo, compared to uniform concentration at hydrophobic prototype surfaces. The difference is attributed to the presence of entropic and nanothermodynamic potentials at interfaces

Nanothermodynamics mediates drug delivery

© Springer International Publishing Switzerland 2015. The efficiency of penetration of nanodrugs through cell membranes imposes further complexity due to nanothermodynamic and entropic potentials at interfaces. Action of nanodrugs is effective after cell membrane penetration. Contrary to diffusion of water diluted common molecular drugs, nanosize imposes an increasing transport complexity at boundaries and interfaces (e.g., cell membrane). Indeed, tiny dimensional systems brought the concept of “nanothermodynamic potential,” which is proportional to the number of nanoentities in a macroscopic system, from either the presence of surface and edge effects at the boundaries of nanoentities or the restriction of the translational and rotational degrees of freedom of molecules within them. The core element of nanothermodynamic theory is based on the assumption that the contribution of a nanosize ensemble to the free energy of a macroscopic system has its origin at the excess interaction energy between the nanostructured entities. As the size of a system is increasing, the contribution of the nanothermodynamic potential to the free energy of the system becomes negligible. Furthermore, concentration gradients at boundaries, morphological distribution of nanoentities, and restriction of the translational motion from trapping sites are the source of strong entropic potentials at the interfaces. It is evident therefore that nanothermodynamic and entropic potentials either prevent or allow enhanced concentration very close to interfaces and thus strongly modulate nanoparticle penetration within the intracellular region. In this work, it is shown that nano-sized polynuclear iron (III)-hydroxide in sucrose nanoparticles have a nonuniform concentration around the cell membrane of macrophages in vivo, compared to uniform concentration at hydrophobic prototype surfaces. The difference is attributed to the presence of entropic and nanothermodynamic potentials at interfaces