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Gold nanoparticles (Au NPs) have received great attention owing to their biocompatible nature, environmental, and widespread biomedical applications. Au NPs are known as capable to regulate inflammatory responses in several tissues and organs; interestingly, lower toxicity in conjunction with anti-inflammatory effects was reported to occur with Au NPs treatment. Several variables drive this benefit-risk balance, including Au NPs physicochemical properties such as their morphology, surface chemistry, and charge. In our research we prepared hybrid Au@LCC nanocolloids by the Pulsed Laser Ablation, which emerged as a suitable chemically clean technique to produce ligand-free or functionalized nanomaterials, with tight control on their properties (product purity, crystal structure selectivity, particle size distribution). Here, for the first time to our knowledge, we have investigated the bioproperties of Au@LCCs. When tested in vitro on intestinal epithelial cells exposed to TNF- α , Au@LCCs sample at the ratio of 2.6:1 showed a significantly reduced TNF gene expression and induced antioxidant heme oxygenase-1 gene expression better than the 1:1 dispersion. Although deeper investigations are needed, these findings indicate that the functionalization with LCCs allows a better interaction of Au NPs with targets involved in the cell redox status and inflammatory signaling. [ABSTRACT FROM AUTHOR]

N-TiO2-x nanocatalysts are developed by the pulsed laser ablation in liquid (PLAL) technique, a simple and surfactant-free preparation method. The PLAL approach allows synthesizing chemical-morphological fine-tuning water TiO2-based nanomaterials, starting from targets of different nature (powders and commercial high purity targets). The catalytic activity was investigated using methylene blue (cationic dye) and methyl orange (azo dye). A different photocatalytic response was found for the various kinds of N-TiO2-x. In the first 20 min, under UV and visible light, about 50% and 10% of the methyl orange were removed using the N-TiO2-x and TiO2 colloids, respectively. In addition, we observe that the response towards the methylene blue is comparable in all the synthesized samples under UV irradiation while differing by about 30% under a visible lamp. The enhanced photocatalytic response of the N-TiO2-x nanocatalysts with respect to the TiO2 one is dependent on the content of the nitrogen dopant, surface area, and nitrogen-oxygen bonding configurations. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Molybdenum oxide colloids prepared by pulsed laser ablation in water. • Mo oxide materials readily participate in redox reactions. • Cellular changes induced by Mo oxide particles were studied by Raman spectroscopy. • Smaller NPs are more toxic as they mostly interact with biomolecules, triggering ROS production. Abstract Tailored colloids of uniformly sized and engineered molybdenum oxide nanoparticles were produced, for the first time, by pulsed laser ablation in water. This green technique ensures the formation of contaminant-free nanostructures and the absence of by-products, very useful issues in biological applications. A selective tuning of Mo O chemical bonding configurations and a suitable control of nanoparticles size distributions were achieved during the ablation processes by varying the water temperature and by applying an external electric field. The metal redox properties are fundamental factors governing both cell uptake and interaction mode with Mo oxide nanoparticles. Micro-Raman spectroscopy was used to investigate the existence of cellular changes induced by Mo oxide colloids on the fibroblast cell line NIH/3T3 in relation to the molecular vibrations due to proteins, lipids and nucleic acids. The label-free micro-Raman spectroscopy provides an easy and noninvasive method to monitor the harmful effect of toxic agents on cells through ROS production or redox-dependent mechanisms. In view of potential biological applications, molybdenum oxide nanoparticles cytotoxicity towards NIH/3T3 cells was also investigated. A statistical analysis shows that, in the 10–100 μg/mL Mo concentration range, all the colloids are cytotoxic, progressively reducing the cell viability down to 75% upon increasing the concentration. The effect is less pronounced for the oxygen deficient MoO 3 samples where cell viability does not fall below 85%. These results open the way to identify potential bioactive products affecting cellular redox status, by using only the Raman spectral data, even before performing lengthy and expensive specific clinical analyses. [ABSTRACT FROM AUTHOR]

Laser synthesis emerges as a suitable technique to produce ligand-free nanoparticles, alloys and functionalized nanomaterials for catalysis, imaging, biomedicine, energy and environmental applications. In the last decade, laser ablation and nanoparticle generation in liquids has proven to be a unique and efficient technique to generate, excite, fragment and conjugate a large variety of nanostructures in a scalable and clean way. In this work, we give an overview on the fundamentals of pulsed laser synthesis of nanocolloids and new information about its scalability towards selected applications. Biomedicine, catalysis and sensing are the application areas mainly discussed in this review, highlighting advantages of laser-synthesized nanoparticles for these types of applications and, once partially resolved, the limitations to the technique for large-scale applications. [ABSTRACT FROM AUTHOR]

The development of graphene (G) substrates without damage on the sp2 network allows to tune the interactions with plasmonic noble metal surfaces to finally enhance surface enhanced Raman spectroscopy (SERS) effect. Here, we describe a new graphene/gold nanocomposite obtained by loading gold nanoparticles (Au NPs), produced by pulsed laser ablation in liquids (PLAL), on a new nitrogen-doped graphene platform (G-NH2). The graphene platform was synthesized by direct delamination and chemical functionalization of graphite flakes with 4-methyl-2-p-nitrophenyl oxazolone, followed by reduction of p-nitrophenyl groups. Finally, the G-NH2/Au SERS platform was prepared by using the conventional aerography spraying technique. SERS properties of G-NH2/Au were tested using Rhodamine 6G (Rh6G) and Dopamine (DA) as molecular probes. Raman features of Rh6G and DA are still detectable for concentration values down to 1 × 10−5 M and 1 × 10−6 M respectively. [ABSTRACT FROM AUTHOR]

The synthesis by pulsed laser ablation and the characterization of both the surface nanostructure and the optical properties of noble metal nanoparticle-based substrates used in Surface Enhanced Raman Spectroscopy are discussed with reference to application in the detection of anti-epileptic drugs. Results on two representative drugs, namely Carbamazepine and Perampanel, are critically addressed. [ABSTRACT FROM AUTHOR]

We have measured the photocatalytic water splitting activity of several titania colloids, modified by nanosecond pulsed laser irradiation. Photocatalysis has been tested using UV and visible light. We have found that laser irradiation increases the hydrogen production efficiency up to a factor of three for anatase, rutile and P25. A hydrogen production rate as high as 30 mmol g −1 h −1 has been obtained with good stability, tested by repeated runs. The chemical and morphological properties of the nanoparticles have been studied by electron microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy, showing that laser irradiation promotes the formation of disordered surface state and lattice distortion which could be responsible for the observed enhanced photocatalytic activity. [ABSTRACT FROM AUTHOR]