A tracking-based nanoimaging method for fast detection of surfaces' inhomogeneities using gold nanoparticles.

The localization of surfaces inhomogeneities is central to many areas of technology, chemistry and biology, ranging from surface defects in industry to the identification and screening of early bio-defects inside cells. The development of methods that enable direct, sensitive, and rapid detection of those inhomogeneities is both relevant and timely. To address this challenge, we developed a far-field nanoimaging method to detect the presence of surface's nanodefects that modify the signal emitted by gold nanoparticles (AuNPs) under laser irradiation.

Feasibility study on mouse live imaging after spinal cord injury and poly(lactide-co-glycolide) bridge implantation.

Spinal cord injury (SCI) causes permanent paralysis below the damaged area. SCI is linked to neuronal death, demyelination, and limited ability of neuronal fibers to regenerate. Regeneration capacity is limited by the presence of many inhibitory factors in the spinal cord environment.

Spectral properties of single gold nanoparticles in close proximity to biological fluorophores excited by 2-photon excitation.

Metallic nanoparticles (NPs) are able to modify the excitation and emission rates (plasmonic enhancement) of fluorescent molecules in their close proximity. In this work, we measured the emission spectra of 20 nm Gold Nanoparticles (AuNPs) fixed on a glass surface submerged in a solution of different fluorophores using a spectral camera and 2-photon excitation. While on the glass surface, we observed the presence in the emission at least 3 components: i) second harmonic signal (SHG), ii) a broad emission from AuNPS and iii) fluorescence arising from fluorophores nearby.

3D orbital tracking in a modified two-photon microscope: an application to the tracking of intracellular vesicles.

The objective of this video protocol is to discuss how to perform and analyze a three-dimensional fluorescent orbital particle tracking experiment using a modified two-photon microscope(1). As opposed to conventional approaches (raster scan or wide field based on a stack of frames), the 3D orbital tracking allows to localize and follow with a high spatial (10 nm accuracy) and temporal resolution (50 Hz frequency response) the 3D displacement of a moving fluorescent particle on length-scales of hundreds of microns(2). The method is based on a feedback algorithm that controls the hardware of a two-photon laser scanning microscope in order to perform a circular orbit around the object to be tracked: the feedback mechanism will maintain the fluorescent object in the center by controlling the displacement of the scanning beam(3-5).

Dual control of dopamine synthesis and release by presynaptic and postsynaptic dopamine D2 receptors.

Dysfunctions of dopaminergic homeostasis leading to either low or high dopamine (DA) levels are causally linked to Parkinson's disease, schizophrenia, and addiction. Major sites of DA synthesis are the mesencephalic neurons originating in the substantia nigra and ventral tegmental area; these structures send major projections to the dorsal striatum (DSt) and nucleus accumbens (NAcc), respectively. DA finely tunes its own synthesis and release by activating DA D2 receptors (D2R).

A modular supervised algorithm for vessel segmentation in red-free retinal images.

In this paper, a supervised algorithm for vessel segmentation in red-free images of the human retina is proposed. The algorithm is modular and made up of two fundamental blocks. The optimal values of two algorithm parameters are found out by maximizing proper measures of performances (MOPs) able to evaluate from a quantitative point of view the results provided by the proposed algorithm.