The Formation of Carbon Dots from D-Glucose Studied by Infrared Spectroscopy.

Carbon dots (C-dots) obtained from D-glucose have attracted great interest because of their properties and as a model for understanding the synthesis process and the origin of photoluminescence in carbon-based nanostructures. Synthesising C-dots under hydrothermal conditions has become one of the most common methods for their preparation. Understanding the details of this process is quite difficult.

In Vitro Antiviral Activity of Hyperbranched Poly-L-Lysine Modified by L-Arginine against Different SARS-CoV-2 Variants.

The emergence of SARS-CoV-2 variants requires close monitoring to prevent the reoccurrence of a new pandemic in the near future. The Omicron variant, in particular, is one of the fastest-spreading viruses, showing a high ability to infect people and evade neutralization by antibodies elicited upon infection or vaccination. Therefore, the search for broad-spectrum antivirals that can inhibit the infectious capacity of SARS-CoV-2 is still the focus of intense research.

Bidimensional SnSe-Mesoporous Ordered Titania Heterostructures for Photocatalytically Activated Anti-Fingerprint Optically Transparent Layers.

The design of functional coatings for touchscreens and haptic interfaces is of paramount importance for smartphones, tablets, and computers. Among the functional properties, the ability to suppress or eliminate fingerprints from specific surfaces is one of the most critical. We produced photoactivated anti-fingerprint coatings by embedding 2D-SnSe nanoflakes in ordered mesoporous titania thin films.

Mesoporous ordered films self-assembly: trends and perspectives.

The synthesis of ordered mesoporous films self-assembly represents one of the main accomplishments in nanoscience. In fact, controlling the complex chemical-physical phenomena that govern the process triggered by the solvent's fast evaporation during film deposition has represented a challenging task. Several years after the first articles on the subject, the research in the field entered a new stage.

Modulating the poly-L-lysine structure through the control of the protonation-deprotonation state of L-lysine.

Designing the architecture of L-lysine-based polymeric structures is a highly challenging task that requires careful control of the amino acid reactive groups. Conventional processes to obtain branched polylysine need several steps and the addition of specific catalysts. In the present work, to gain a better understanding and control of the formation of L-lysine-based polymers, we have investigated the correlation between the protonation state of L-lysine and the corresponding hydrothermally grown structures.

At the root of l-lysine emission in aqueous solutions.

l-lysine is an essential amino acid whose peculiar optical properties in aqueous solutions are still in search of a comprehensive explanation. In crystalline form l-lysine does not emit, but when in an aqueous solution, as the concentration increases, emits in the blue. The origin of such fluorescence is not yet clear.

Harnessing Molecular Fluorophores in the Carbon Dots Matrix: The Case of Safranin O.

The origin of fluorescence in carbon dots (C-dots) is still a puzzling phenomenon. The emission is, in most of the cases, due to molecular fluorophores formed in situ during the synthesis. The carbonization during C-dots processing does not allow, however, a fine control of the properties and makes finding the source of the fluorescence a challenging task.

Highly Photostable Carbon Dots from Citric Acid for Bioimaging.

Bioimaging supported by nanoparticles requires low cost, highly emissive and photostable systems with low cytotoxicity. Carbon dots (C-dots) offer a possible solution, even if controlling their properties is not always straightforward, not to mention their potentially simple synthesis and the fact that they do not exhibit long-term photostability in general. In the present work, we synthesized two C-dots starting from citric acid and tris (hydroxymethyl)-aminomethane (tris) or arginine methyl ester dihydrochloride.

Improving the Photocatalytic Activity of Mesoporous Titania Films through the Formation of WS/TiO Nano-Heterostructures.

Heterostructures formed by anatase nanotitania and bidimensional semiconducting materials are expected to become the next-generation photocatalytic materials with an extended operating range and higher performances. The capability of fabricating optically transparent photocatalytic thin films is also a highly demanded technological issue, and increasing the performances of such devices would significantly impact several applications, from self-cleaning surfaces to photovoltaic systems. To improve the performances of such devices, WS/TiO heterostructures obtained by incorporating two-dimensional transition metal dichalcogenides layers into titania mesoporous ordered thin films have been fabricated.

Blocking viral infections with lysine-based polymeric nanostructures: a critical review.

The outbreak of the Covid-19 pandemic due to the SARS-CoV-2 coronavirus has accelerated the search for innovative antivirals with possibly broad-spectrum efficacy. One of the possible strategies is to inhibit the replication of the virus by preventing or limiting its entry into the cells. Nanomaterials derived from lysine, an essential amino acid capable of forming homopeptides of different shapes and sizes through thermal polymerization, are an exciting antiviral option.

Comparative Evaluation of Graphene Nanostructures in GERS Platforms for Pesticide Detection.

Graphene-enhanced Raman scattering (GERS) produces enhancement of the Raman signal, which is based on chemical rather than electromagnetic mechanism such as in the surface-enhanced Raman scattering. Graphene oxide, amino- and guanidine-functionalized graphene oxide, exfoliated graphene, and commercial graphene nanoplatelets have been used to investigate the GERS response with the change of graphene properties. Different graphene nanostructures have been embedded into organic-inorganic microporous films to build a platform for the fast and sensitive detection of pesticides in water.

Hydrophobic Thin Films from Sol-Gel Processing: A Critical Review.

Fabrication of hydrophobic thin films from a liquid phase is a hot topic with critical technological issues. Interest in the production of hydrophobic surfaces is growing steadily due to their wide applications in several industrial fields. Thin films from liquid phases can be deposited on different types of surfaces using a wide variety of techniques, while the design of the precursor solution offers the possibility of fine-tuning the properties of the hydrophobic coating layers.

Effective SARS-CoV-2 antiviral activity of hyperbranched polylysine nanopolymers.

The coronavirus pandemic (COVID-19) had spread rapidly since December 2019, when it was first identified in Wuhan, China. As of April 2021, more than 130 million cases have been confirmed, with more than 3 million deaths, making it one of the deadliest pandemics in history. Different approaches must be put in place to confront a new pandemic: community-based behaviours (, isolation and social distancing), antiviral treatments, and vaccines.

Real-time quantitative detection of styrene in atmosphere in presence of other volatile-organic compounds using a portable device.

Exposure to styrene is a major safety concern in the fibreglass processing industry. This compound is classified by the International Agency for Research on Cancer as a possible human carcinogen. Several types of analytical equipment exist for detecting volatile organic compounds (VOCs) in the atmosphere; however, most of them operate ex-situ or do not provide easy discrimination between different molecules.

Boron Nitride-Titania Mesoporous Film Heterostructures.

The fabrication of optically active heterostructures in the shape of mesostructured thin films is a highly challenging task. It requires an integrated process to allow in one-step incorporating the two-dimensional materials within the mesoporous ordered host without disrupting the pore organization. Hexagonal boron nitride (BN) nanosheets have been successfully introduced into titania mesoporous films using a template-assisted sol-gel synthesis and evaporation-induced self-assembly.

Polymerization-Driven Photoluminescence in Alkanolamine-Based C-Dots.

Carbonized polymer dots (CPDs), a peculiar type of carbon dots, show extremely high quantum yields, making them very attractive nanostructures for application in optics and biophotonics. The origin of the strong photoluminescence of CPDs resides in a complicated interplay of several radiative mechanisms. To understand the correlation between CPD processing and properties, the early stage formation of carbonized polymer dots has been studied.

Carbon-based antiviral nanomaterials: graphene, C-dots, and fullerenes. A perspective.

The appearance of new and lethal viruses and their potential threat urgently requires innovative antiviral systems. In addition to the most common and proven pharmacological methods, nanomaterials can represent alternative resources to fight viruses at different stages of infection, by selective action or in a broad spectrum. A fundamental requirement is non-toxicity.

Reversible Aggregation of Molecular-Like Fluorophores Driven by Extreme pH in Carbon Dots.

The origin of carbon-dots (C-dots) fluorescence and its correlation with the dots structure still lack a comprehensive model. In particular, the core-shell model does not always fit with the experimental results, which, in some cases, suggest a molecular origin of the fluorescence. To gain a better insight, we have studied the response of molecular-like fluorophores contained in the C-dots at extreme pH conditions.

Anomalous Optical Properties of Citrazinic Acid under Extreme pH Conditions.

Citrazinic acid (CZA) is a weakly fluorescent molecular compound whose optical properties are dependent on aggregation states and chemical environment. This molecule and its derivatives have been recently identified as the source of the intense blue emission of carbon dots obtained from citric acid with a nitrogen source, such as ammonia or urea. Citrazinic acid has a strong tendency to aggregate and form tautomers whose optical properties are largely unexplored.

Fulleropyrrolidine-functionalized ceria nanoparticles as a tethered dual nanosystem with improved antioxidant properties.

Dual-tethered nanosystems which combine different properties at the nano scale represent a new fascinating frontier of research. In the present work, we present an example of a dual nanosystem designed to enhance the radical scavenging performances. Fulleropyrrolidine has been bonded to cerium oxide nanoparticles (nanoceria) to form a dual tethered system.

Integrating sol-gel and carbon dots chemistry for the fabrication of fluorescent hybrid organic-inorganic films.

Highly fluorescent blue and green-emitting carbon dots have been designed to be integrated into sol-gel processing of hybrid organic-inorganic materials through surface modification with an organosilane, 3-(aminopropyl)triethoxysilane (APTES). The carbon dots have been synthesised using citric acid and urea as precursors; the intense fluorescence exhibited by the nanoparticles, among the highest reported in the scientific literature, has been stabilised against quenching by APTES. When the modification is carried out in an aqueous solution, it leads to the formation of silica around the C-dots and an increase of luminescence, but also to the formation of large clusters which do not allow the deposition of optically transparent films.

Modulating the Optical Properties of Citrazinic Acid through the Monomer-to-Dimer Transformation.

Understanding the luminescence of carbon dots is a highly challenging task because of the complex reactions involved in the synthesis process. Several by-products form at different reaction stages and become possible sources of emission. Citrazinic acid and its derivatives, in particular, have been identified as intermediates that give rise to blue fluorescence.

From 2-D to 0-D Boron Nitride Materials, The Next Challenge.

The discovery of graphene has paved the way for intense research into 2D materials which is expected to have a tremendous impact on our knowledge of material properties in small dimensions. Among other materials, boron nitride (BN) nanomaterials have shown remarkable features with the possibility of being used in a large variety of devices. Photonics, aerospace, and medicine are just some of the possible fields where BN has been successfully employed.

Boron oxynitride two-colour fluorescent dots and their incorporation in a hybrid organic-inorganic film.

Bottom-up synthesis of fluorescent boron-nitride based dots is a challenging task because an accurate design of the structure-properties relationship is, in general, difficult to achieve. Incorporation of the dots into a solid-state matrix is also another important target to develop light-emitting devices. Two-colour fluorescent boron oxynitride nanodots have been obtained by a bottom-up synthesis route and incorporated into a hybrid organic-inorganic film.