In recent years, titanium(iv) dioxide nanoparticles (TiO2NPs) have shown promising potential in various biological applications such as antimicrobials, drug delivery, photodynamic therapy, biosensors, and tissue engineering.

Photoacoustic detection signal has been used to build a new strategy to determine the mesoscale self-assembly of metal nanoparticles in terms of size distribution and aggregate packing density (metal nanoparticles...

Nanomaterials such as gold nanoparticles employed as solid-state sensors have attracted attention in recent years due to their ability to detect poisonous elements in the indoor/outdoor environment. Herein, chemoresistive sensors based on gold nanoparticles (AuNPs) functionalized with mixed thiol ligands were tested as sensing materials. Specifically, the electrical response of gold nanoparticles-based sensors was tested against Hg0 vap, H2S, SO2, NH3, and relative humidity (RH) at room temperature. Gold nanoparticles samples were synthesized by the wet reduction method and then deposited as thin films on suitable interdigitated transducers. Electrical conductivity measurements allowed evaluating a semiconducting behavior of the colloids. A selective and reproducible sensing behavior toward Hg0 vap was observed in the range 0.1–1.0 ng/mL, allowing simple and reliable resistive devices to be obtained. An irreversible interaction mechanism, based on formation of an Au–Hg direct bond, was observed in the case of isolated AuNPs samples. Interconnected AuNPs exhibited a reversible behavior as assessed by Micro Raman, XRD, XPS, AFM, SEM, and UV–vis and FTIR spectroscopies together with DLS measurements. Broadening of the plasmonic band and an increase in the mean particle size upon contact with Hg0 vap was observed. Morphological characterization revealed the formation of aggregates after interaction between Hg0 vap and AuNPs. XRD and Micro Raman measurements collected on the nonexposed and Hg-exposed nanoparticles suggest their structural rearrangement at the surface and formation of an Au–Hg alloy with Hg mechanically trapped within the bulk material. The simple and cost-effective fabrication of these sensors has prospect in the future as nanodevices for real-time outdoor air quality monitoring.

Amino and sulfonate ending groups thiols are used as functionalizing agents to stabilize of gold nanoparticles (AuNPs), obtaining hydrophilic AuNPs with a 10–20 nm diameter range and tunable surface charge. The nanomaterial is extensively characterized from a physicochemical point of view by UV–Vis and Fourier‐transform infrared spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, synchrotron radiation X‐ray photoelectron spectroscopy (XPS), and dynamic light scattering to investigate the bonding between the two thiols and the metal surface. Systems are also biologically characterized on human multiforme glioblastoma T98G cells to understand their behavior in cell culture for biomedical applications. NMR and XPS studies evidence the presence of amino ending thiols with different chain lengths, 6‐amino‐1‐hexanethiol hydrochloride (6EA) or cysteamine (CY) and sodium 3‐mercapto‐1‐propanesulfonate (3MPS) on the metal surface: the relative molar ratio between the thiols bound to the AuNPs (3MPS/6EA or 3MPS/CY) is measured. On selected samples, the anti‐PD‐L1 antibody is loaded using AuNPs/antibody combination in a 2:1 weight ratio. Comparing different AuNPs concentrations (10 and 50 µg mL−1), the effect on colony‐forming capacity after 24 h exposure is evaluated. The synthesized AuNPs are nontoxic, and they do not affect cell proliferation. These small particles can be used for targeting, opening tangible and interesting perspectives for further biomedical studies.

No abstract