1,721,248 research outputs found
Clinical translation of nanoparticles for neural stimulation
No full textNanoparticles enable wireless neural stimulation without the need for genetic manipulation. However, challenges remain for their potential application in the cure of human neurodegenerative diseases. A careful analysis of the different nanomaterials and energy sources that proved effective in animal models will direct their clinical translatability
The effects of reiterated cell photo-stimulation with an azobenzene
Full text linkOptical stimulation of living cells is an innovative and successful tool, having a significant impact on neuroscience. A recently synthesized amphiphilic azobenzene, named Ziapin2, has been developed exploiting a non-covalent approach for targeting the membrane and achieving cell photostimulation. Here, we investigate, using both experimental data and mathematical modelling, the effect of repetitive light stimulation on the cell response. We discuss some possible explanations for the drop in the stimulation efficiency in reiterated stimulation processes
Fluorescent probes for optical investigation of the plasma membrane
Full text linkThe biological functions of the cell membrane are regulated by its physicochemical properties, such as the transmembrane potential, phase state and hydration. Therefore, the in situ investigation of these properties is attracting a rising interest in the field of membrane biophysics. In these regards, a wide variety of fluorescent membrane probes has been developed, providing powerful tools for fluorescence microscopy and/or fluorescence spectroscopy to study the microscopic analogs of viscosity, polarity, and hydration, as well as the molecular order and electrostatic potential at the sites of their location. Despite the success of this approach, further developments rely on the design of fluorescence probes with optimized photophysical properties. This review discusses the most successful fluorescent molecular probes and their application to the study of the plasma membrane viscosity, lipid order and potential
Bringing Microbiology to Light: Toward All-Optical Electrophysiology in Bacteria
No full textThe observation of neuron-like behavior in bacteria, such as the occurrence of electric spiking and extended bioelectric signaling, points to the role of membrane dynamics in prokaryotes. Electrophysiology of bacteria, however, has been overlooked for long time, due to the difficulties in monitoring bacterial bioelectric phenomena with those probing techniques that are commonly used for eukaryotes. Optical technologies can allow a paradigm shift in the field of electrophysiology of bacteria, as they would permit to elicit and monitor signaling rapidly, remotely, and with high spatiotemporal precision. In this perspective, we discuss about the potentiality of light interrogation methods in microbiology, encouraging the development of all-optical electrophysiology of bacteria
Exact diagonalization of Hubbard models for the optical properties of single-wall carbon nanotubes
Full text linkExcitonic states of single-walled carbon nanotubes (SWNTs) have usually been calculated using many-body perturbation theories or mean field approaches because a large number of sites cannot be considered within an exact diagonalization (ED) calculation based on the Hubbard model. We use a small crystal approach and show that, for the π structure of nanotubes, an ED calculation is possible. We apply this approach to small-diameter SWNTs and the results show that a crossing of the first bright state with the second excited states occurs when U, the correlation parameter of the Hubbard model, equals 4t, where t is the hopping integral. Two or three strong two-photon absorption (TPA) states are found at energies above the first bright state for U/t≤3. Beyond this value, these states become relevant for TPA below the first bright state. A number of dark states are always calculated below the first bright state at energies that, in the intermediate coupling regime, are of the order of tens to hundreds of meV. This result seems to be consistent with recent experiments
New technologies for developing second generation retinal prostheses
No full textInherited or age-dependent retinal dystrophies such as Retinitis pigmentosa (RP) and macular degeneration (MD) are among the most prevalent causes of blindness. Despite enormous efforts, no established pharmacological treatment to prevent or cure photoreceptor degeneration has been identified. Given the relative survival of the inner retina, attempts have been made to restore vision with optogenetics or with retinal neuroprostheses to allow light-dependent stimulation of the inner retinal network. While microelectrode and photovoltaic devices based on inorganic technologies have been proposed and in many cases implanted in RP patients, a new generation of prosthetics based on organic molecules, such as organic photoswitches and conjugated polymers, is demonstrating an unexpected potential for visual rescue and intimate interactions with functioning tissue. Organic devices are starting a new era of tissue electronics, in which light-sensitive molecules and live tissues integrate and tightly interact, producing a new ecosystem of organic prosthetics and intelligent biotic/abiotic interfaces. In addition to the retina, the applications of these interfaces might be extended in the future to other biomedical fields
Urban mobility and air quality: impact of the opening of the new Lecco cross-ways on air pollution.
No full textShaping thiophene oligomers into fluorescent nanobeads forming two-dimensionally patterned assemblies by the capillary effect
No full textWe demonstrate that highly stable fluorescent nanobeads can be obtained by emulsion copolymerization of oligothiophene methyl methacrylates and styrene and that deposition on a planar surface by microfluidic lithography induces the spontaneous nanobead self-assembling. The average nanobead diameter was controlled in the submicron scale by varying the amount of surfactant used in the polymerization reaction. Photoluminescence and pump-probe experiments proved that the nanobeads had retained the optical signature of the oligothiophenes, yet preventing their aggregation. Scanning electron microscopy images of the self-assembled nanobeads are reported
- …
