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761.
Polysaccharides based hydrogels show several peculiar properties which can be so reassumed: • Capability to absorb a great amount of water once immersed in biological fluids, assuming, consequently, a structure similar to extracellular matrix or biological tissue • Tissotropic property, i.e. possibility to be injected through a needle without lose of their rheological properties. These fundamental properties make them ideal materials for several biomedical applications, such as cellular scaffold, coatings for biomedical disposals, treatments for different diseases, controlled release of drugs, etc. Hyaluronane, Carboxymethyl cellulose and Alginic acid based 50% hydrogels (i.e. 50% of the carboxylate groups present in the macromolecule chain were involved in the cross-linking reaction) are synthesised. Their effectiveness in promoting cells adhesion and proliferation was verified. Furthermore the possibility of injecting and sterilising hydrogels permitted to test the effect of Hyal 50% in the osteoarthritis therapy. It was found that the in vivo effect of Hyal 50% in the treatment of surgically created chondral defect in the rabbit knee was positive. These materials can be both chemically and morphologically modified. In fact, the insertion of sulphate groups increase their hemocompatibility as demonstred by the increase of TT (time necessary to turn the fibrinogen to thrombin). Furthermore microporous hydrogels were obtained and tested as drug controlled release systems. 相似文献
762.
Michael Wilms Lesly V. Melendez Dr. Rohan J. Hudson Dr. Christopher R. Hall Samantha Prabath Ratnayake Prof. Dr. Trevor Smith Prof. Dr. Enrico Della Gaspera Prof. Dr. Gary Bryant Dr. Timothy U. Connell Prof. Dr. Daniel E. Gómez 《Angewandte Chemie (International ed. in English)》2023,62(24):e202303501
We report a new composite material consisting of silver nanoparticles decorated with three-dimensional molecular organic cages based on light-absorbing porphyrins. The porphyrin cages serve to both stabilize the particles and allow diffusion and trapping of small molecules close to the metallic surface. Combining these two photoactive components results in a Fano-resonant interaction between the porphyrin Soret band and the nanoparticle-localised surface-plasmon resonance. Time-resolved spectroscopy revealed the silver nanoparticles transfer up to 37 % of their excited-state energy to the stabilising layer of porphyrin cages. These unusual photophysics cause a 2-fold current increase in photoelectrochemical water-splitting measurements. The composite structure provides a compelling proof of concept for advanced photosensitiser systems with intrinsic porosity for photocatalytic and sensing applications. 相似文献
763.
Samantha A. Ranaweera Bruno Donnadieu William P. Henry Mark G. White 《Acta Crystallographica. Section C, Structural Chemistry》2023,79(4):142-148
The stepwise addition of Cu2+ ions to the nonplanar cyclic Schiff base 5,9,14,18-tetramethyl-1,4,10,13-tetraazacyclooctadeca-5,8,14,17-tetraene-7,16-dione (H4daaden, C18H28N4O2), yields a one-end-open dinuclear copper chelate. The pyridine adduct of the dinuclear copper chelate, namely, [μ-6,11-dimethyl-7,10-diazahexadeca-5,11-diene-2,4,13,15-tetraolato(4−)](pyridine)dicopper(II), [Cu2(C16H20N2O4)(C5H5N)], was characterized by single-crystal X-ray crystallography. The two CuII atoms of the copper chelate display different coordination modes, i.e. inner-N2O2 and outer-O2O2. The Cu atom which is bonded in the outer-O2O2 mode is axially bonded to a pyridine molecule, which suggests that the electron-donating ability of the O2O2 site to the Cu atom is poor. As a result, the O2O2-bonded Cu atom has a coordination number of five, showing square-bipyramidal geometry around the Cu atom. The N2O2-coordinated site provides sufficient electron density to the other Cu atom to be stabilized with a coordination number of four, showing square-planar geometry around the Cu atom. The electron-donating ability of the ligand coordination sites plays a key role in determining the coordination number of the Cu atoms of the dicopper chelate. 相似文献