Galectins (Gal) are a family of glycan-binding proteins characterized by their affinity for β-galactosides. Galectin-1 (Gal-1), a dimeric lectin with two galactoside-binding sites, regulates cancer progression and immune responses. Coordination chemistry has been engaged to develop versatile multivalent neoglycoconjugates for binding Gal-1. In this study we report a fast and original method to synthesize hybrid gold nanoparticles in which a hydrochloride lactose-modified chitosan, named CTL, is mixed with dicarboxylic acid-terminated polyethylene glycol (PEG), leading to shell-like hybrid polymer-sugar-metal nanoparticles (CTL-PEG-AuNPs). The aim of this paper is to preliminarily study the interaction of the CTL-PEG-AuNPs with a target protein, namely, Gal-1, under specific conditions. The molecular interaction has been measured by Transmission Electron Microscopy (TEM), UV-vis, and Raman Spectroscopy on a large range of Gal-1 concentrations (from 0 to 10 M). We observed that the interaction was strongly dependent on the Gal-1 concentration at the surface of the gold nanoparticles.

Gold nanoparticles (GNP) are very suitable agents for thermal destruction of cancer cells because of their photothermal heating ability. In this work, photothermal properties of different sizes and shapes of GNPs were studied regarding different parameters such as GNP concentration, laser excitation intensity, and exposure time. By using the heat transfer theory, the temperature elevation in the GNP solutions was converted in temperature elevation at the GNP surface. This allows us to determine the absorption cross section (σ abs ) of two different sizes of spherical gold nanoparticles (GNS), which were compared with the theoretical calculations based on the Mie theory, and both results were in a good agreement. σ abs was determined also for gold nanourchins with different sizes (50, 80, and 90 nm) with high precision. Finally, the temperature elevation speeds were experimentally measured for all GNPs, and we have demonstrated that they are proportional to the GNP surface area as demonstrated in the classical diffusive heat transport theory. The proposed approaches can be used to monitor the local heat generation around the GNP and pave the way to the optimization of the photothermal properties of GNPs.

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Gold nanoparticle interaction with proteins is characterized by using scattering correlation spectroscopy. Protein orientation and binding affinity regarding the nanoparticle surface are discussed.

Galectins (Gal) are a family of dimeric lectins, composed by two galactoside-binding sites implicated in the regulation of cancer progression and immune responses. In this study, we report for the first time the synthesis and the physical-chemical characterization of galectin-1-complex-gold COOHterminated polyethlenglicole (PEG)-coated NPs (Gal-1 IN PEG-AuNPs) and their ability to recognize glucose in an aqueous solution with a concentration varying from 10 mM to 100 pM. The chemical protocol consistsof three steps: (i) complexation between galectin-1Gal-1 and tetrachloroauric acid (HAuCl 4) to form gold-protein grains; (ii) staking process of COOH-terminated polyethlenglicole molecules (PEG) onto Gal-1-Au complex and (iii) reduction of hybrid metal ions to obtain a colloidal stable solution. During the complexation, the spectral signatures related to the Gal-1 orientation on the gold surface have been found to change due to its protonation state. The effective glucose monitoring was detected by UV-Vis, Raman spectroscopy and Transmission Electron Microscopy (TEM). Overall, we observed that the interaction is strongly dependent on the Gal-1 conformation at the surface of gold nanoparticles.

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We study the interaction between one aptamer and its analyte (the MnSOD protein) by the combination of Surface Enhanced Raman Scattering and multivariate statistical analysis. We observe the aptamer structure...