1,721,040 research outputs found
Controlled uptake-release of the citrate anion in a system capable of pH driven triple Cu2+ translocation
No full textTriple cation translocation is controlled by pH in a tripodal ligand. The movement of the cations induces the uptake/release of a citrate anion from the multicomponent recepto
Self-Assembled Monolayers of Silver Nanoparticles: From Intrinsic to Switchable Inorganic Antibacterial Surfaces
No full textThe layer-by-layer technique allows to graft molecular monolayers on bulk surfaces that, in turn, allow to graft monolayers of metal nanoparticles. This microreview focuses on the preparation of such materials featuring a monolayer of silver nanoparticles (AgNP) and their use as antimicrobial surfaces against both planktonic bacteria and biofilms. The role of Ag+ release and of direct cell/AgNP contact in the antibacterial action will be stressed as a function of the adhesive molecular layer, of the AgNP dimension and shape, of their surface density, and of the molecular overcoating. While these surfaces display an intrinsic antibacterial action, a further evolution will also be reviewed, in which additional photothermal antibacterial action can be switched on demand, using near-IR radiation and non-spherical AgNP or a combination of AgNP with non-spherical AuNP. The intrinsic and switchable photothermal action of these surfaces will be unraveled, and their synergistic effect stresse
Methods for glass surface coating with functional Self Assembled Monolayers
No full textA modified approach is presented to efficiently coat flat galss surfaces with function molecules. An optical method to check the efficiency of the coating is also presente
The pH controlled uptake/release of citrate by a tri-copper(II) complex
No full textThe pH controlled movement of three copper ions inside a
carefully designed receptor allows the recognition and uptake/
release of citrate in aqueous solution in a manner that can be
followed visuall
Dual mode antibacterial surfaces based on Prussian blue and silver nanoparticles
No full textPrussian Blue (PB) is an inexpensive, biocompatible, photothermally active material. In this paper, self-assembled monolayers of PB nanoparticles were grafted on a glass surface, protected with a thin layer of silica and decorated with spherical silver nanoparticles. This combination of a photothermally active nanomaterial, PB, and an intrinsically antibacterial one, silver, leads to a versatile coating that can be used for medical devices and implants. The intrinsic antibacterial action of nanosilver, always active over time, can be enhanced on demand by switching on the photothermal effect of PB using near infrared (NIR) radiation, which has a good penetration depth through tissues and low side effects. Glass surfaces functionalized by this layer-by-layer approach have been characterized for their morphology and composition, and their intrinsic and photothermal antibacterial effect was studied against Gram+ and Gram- planktonic bacteria
Enhanced kinetic inertness in the electrochemical interconvertion of Cu(I) double helical – Cu(II) monomeric complexes
No full textThree new ligands made of two iminoquinoline halves separated by an (R,R)-trans-1,2-cyclohexenediyl spacer have been synthesized. These ligands feature –OR functions appended in
the 8-positions of the quinoline rings (R = n-alkyl). The ligands display a behaviour similar to that of their analogues that contain unsubstituted quinolines, forming a bistable system with
copper. [Cu2L2]2+ helicates are obtained with Cu+ and [CuL]2+ monomers with Cu2+, as shown by UV/Vis titrations, determination of complex formation constants, mass and NMR
measurements, and X-ray crystallographic analysis. The OR groups are found to be noncoordinating, but the presence of such substituents on the quinoline rings slows the electrochemical interconversion of [Cu2L2]2+ into [CuL]2+. In particular, oxidation of [Cu2L2]2+ gives a reversible two-step profile in cyclic voltammetry experiments, due to the formation of the
Cu2+ helicate [Cu2L2]4+, that does not evolve into [CuL]2+in the CV experiment time scal
CATION TRANSLOCATION VS MOLECULAR FOLDING IN THE PH-CONTROLLED MOTION OF TWO CU2+ CATIONS
No full textDouble cation translocation can be pH switched in multi-compartment ligands. The nature of the ligand backbone determines if it is an authentic cation translocation or a translocation/rearrangement of the whole molecul
Spectroscopic evaluation of surface functionalization efficiency in the preparation of mercaptopropyltrimethoxysilane self-assembled monolayers on glass
No full textFour synthetic protocols have been examined for the preparation of a self-assembled monolayer of
propanethiol functions on glass surfaces, through the wet reaction of mercaptopropyltrimethoxysilane
(MPTS) on glass slides, in order to determine an optimal method to obtain dense –SH monolayers for
further reaction with maleimide-bearing molecules. We have also demonstrated that the surface density
of reactive –SH groups can be indagated by the coupling reaction with a maleimide-functionalized
rhodamine dye and by the examination of the absorption spectra of the glass slides. The reaction of
MPTS in dry toluene gives the most dense surface of reactive thiols, among the examined protocols. We
have also evidenced that thermal curing of the MPTS functionalized slides induces thiol coupling and
–S–S– formation, resulting in a dramatically lowered availability of –SH group
Prussian Blue and Its Analogs as Novel Nanostructured Antibacterial Materials
No full textPrussian blue is an ancient artificial pigment. Its biocompatibility and the possibility of synthesizing it in nanometric size stimulated the interest of the scientific community. Many uses of Prussian blue nanoparticles have been reported in the field of nanomedicine. More recently, interest into the potential application of Prussian blue nanoparticles as antibacterial agents has spread. Literature regarding Prussian blue and its analogs as antibacterial materials is still limited, but the number of papers has grown quickly over the last 2–3 years
Prussian Blue Nanoparticles as a Versatile Photothermal Tool
Full text linkPrussian blue (PB) is a coordination polymer studied since the early 18th century, historically known as a pigment. PB can be prepared in colloidal form with a straightforward synthesis. It has a strong charge-transfer absorption centered at ~700 nm, with a large tail in the Near-IR range. Irradiation of this band results in thermal relaxation and can be exploited to generate a local hyperthermia by irradiating in the so-called bio-transparent Near-IR window. PB nanoparticles are fully biocompatible (PB has already been approved by FDA) and biodegradable, this making them ideal candidates for in vivo use. While papers based on the imaging, drug-delivery and absorbing properties of PB nanoparticles have appeared and have been reviewed in the past decades, a very recent interest is flourishing with the use of PB nanoparticles as photothermal agents in biomedical applications. This review summarizes the syntheses and the optical features of PB nanoparticles in relation to their photothermal use and describes the state of the art of PB nanoparticles as photothermal agents, also in combination with diagnostic techniques
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