Colorimetric nanodiagnostics for Point-Of-Care applications: detection of salivary biomarkers and environmental contaminants

Nanomaterials offer many unique opportunities for the development of effective and rapid point-of-care (POC) devices to be exploited in many fields, including early diagnosis, health monitoring, and pollutant detection. In particular, gold nanoparticles (AuNPs) exhibit tunable catalytic and plasmonic properties, which are key enabling tools to design and develop innovative detection schemes in several sensing applications. The aim of this PhD project was the development of AuNPs-based colorimetric POCs to detect heavy metal ion contaminations and specific biomarkers in non-invasive biological fluids. First, we developed a novel strategy that exploits the combination of the plasmonic and catalytic properties of AuNPs to achieve an ultrafast (1 min) and sensitive colorimetric sensor for highly toxic methyl mercury. Taking advantage of the AuNP nanocatalyst to promote the rapid reduction of methyl mercury with nucleation on the particle surface and consequent aggregation-induced plasmonic shift, we were able to detect by naked-eye mercury contaminations as low as 20 ppb, which is relevant for food contaminations or biological fluid assessment. Moreover, an innovative and versatile platform, based on multibranched AuNPs, was developed for the detection of salivary biomarkers. Coupling etching and growing reactions in a reshaping process onto the nanostars surface, we created a customizable platform with boosted color change readout for fast detection of salivary glucose at low concentrations. The nanosensor performance was validated on samples from patients with diabetes, proving its potential as a novel non-invasive tool for frequent monitoring of glycaemia. As side project we also investigated the platinum nanoparticles enzymatic activity in a colorimetric sensor for inorganic mercury contamination monitoring in water sources

Experimental Realization of the Deutsch-Jozsa Algorithm with a Six-Qubit Cluster State

We describe the first experimental realization of the Deutsch-Jozsa quantum algorithm to evaluate the properties of a 2-bit boolean function in the framework of one-way quantum computation. For this purpose a novel two-photon six-qubit cluster state was engineered. Its peculiar topological structure is the basis of the original measurement pattern allowing the algorithm realization. The good agreement of the experimental results with the theoretical predictions, obtained at $\sim$1kHz success rate, demonstrate the correct implementation of the algorithm.Comment: 5 pages, 2 figures, RevTe

Chemical characterization of the globular cluster NGC 5634 associated to the Sagittarius dwarf spheroidal galaxy

As part of our on-going project on the homogeneous chemical characterization of multiple stellar populations in globular clusters (GCs), we studied NGC 5634, associated to the Sagittarius dwarf spheroidal galaxy, using high-resolution spectroscopy of red giant stars collected with FLAMES@VLT. We present here the radial velocity distribution of the 45 observed stars, 43 of which are member, the detailed chemical abundance of 22 species for the seven stars observed with UVES-FLAMES, and the abundance of six elements for stars observed with GIRAFFE. On our homogeneous UVES metallicity scale we derived a low metallicity [Fe/H]=-1.867 +/-0.019 +/-0.065 dex (+/-statistical +/-systematic error) with sigma=0.050 dex (7 stars). We found the normal anti-correlations between light elements (Na and O, Mg and Al), signature of multiple populations typical of massive and old GCs. We confirm the associations of NGC 5634 to the Sgr dSph, from which the cluster was lost a few Gyr ago, on the basis of its velocity and position and the abundance ratios of alpha and neutron capture elements.Comment: 16 pages, 10 figures, 11 tables; accepted for publication on Astronomy and Astrophysic