Polypeptide Chain Growth Mechanisms and Secondary Structure Formation in Glycine Gas-Phase Deposition on Silica Surfaces.

Peptide formation by amino acids condensation represents a crucial reaction in the quest of the origins of life as well as in synthetic chemistry. However, it is still poorly understood in terms of efficiency and reaction mechanism. In the present work, peptide formation has been investigated through thermal condensation of gas-phase glycine in fluctuating silica environments as a model of prebiotic environments.

TiO₂-Chitosan Hybrid Materials for Drug Delivery Applications: Conjugation Reaction with a Model Drug and Evaluation of the Functional Properties.

The combination of TiO₂ and chitosan is known to allow the achievement of implantable devices which combines the mechanical properties of TiO₂, with the presence of chitosan, which ensures antibacterial properties combined with an in-situ drug-delivery of biomolecules physisorbed and/or covalently linked to chitosan. In this study, 5-aminofluorescein (5-AF), a derivative of fluorescein containing a primary amino group, has been used as model molecule to simulate a drug. This dye is characterized by low cost and low toxicity, and due to its high molar absorptivity it can easily be detected by means of absorption and emission spectroscopies.

Machine learning approach for elucidating and predicting the role of synthesis parameters on the shape and size of TiO nanoparticles.

In the present work a series of design rules are developed in order to tune the morphology of TiO nanoparticles through hydrothermal process. Through a careful experimental design, the influence of relevant process parameters on the synthesis outcome are studied, reaching to the develop predictive models by using Machine Learning methods. The models, after the validation and training, are able to predict with high accuracy the synthesis outcome in terms of nanoparticle size, polydispersity and aspect ratio.

Nearly free surface silanols are the critical molecular moieties that initiate the toxicity of silica particles.

Inhalation of silica particles can induce inflammatory lung reactions that lead to silicosis and/or lung cancer when the particles are biopersistent. This toxic activity of silica dusts is extremely variable depending on their source and preparation methods. The exact molecular moiety that explains and predicts this variable toxicity of silica remains elusive.

Morphology, Surface Structure and Water Adsorption Properties of TiO Nanoparticles: A Comparison of Different Commercial Samples.

Water is a molecule always present in the reaction environment in photocatalytic and biomedical applications of TiO and a better understanding of its interaction with the surface of TiO nanoparticles is crucial to develop materials with improved performance. In this contribution, we first studied the nature and the surface structure of the exposed facets of three commercial TiO samples (i.e.

Migration study of organotin compounds from food packaging by surface-enhanced Raman scattering.

The potential of surface-enhanced Raman scattering (SERS) has been investigated for the rapid analysis of two representative organotin compounds (OTCs): dibutyltin maleate (DTM) and tributyltin chloride (TBT), after migration tests from polyvinyl chloride (PVC), as a model food packaging material in aqueous food simulant (acetic acid 3% w/v). OTCs, often used as heat stabilizers additives for PVC, are classified as endocrine disrupting chemicals (EDCs) and their migration potential has to be controlled in compliance with the normative prescriptions for food contact materials. In this study, colloidal silver nanoparticles (AgNPs) were applied as liquid SERS substrate for direct-in-liquid analysis of food simulant after standardized migration tests of PVC samples spiked with OTCs.

Monitoring the Reactivity of Formamide on Amorphous SiO by In-Situ UV-Raman Spectroscopy and DFT Modeling.

Formamide has been recognized in the literature as a key species in the formation of the complex molecules of life, such as nucleobases. Furthermore, several studies reported the impact of mineral phases as catalysts for its decomposition/polymerization processes, increasing the conversion and also favoring the formation of specific products. Despite the progresses in the field, in situ studies on these mineral-catalyzed processes are missing.

Toward a novel framework for bloodstains dating by Raman spectroscopy: How to avoid sample photodamage and subsampling errors.

Answers to questions about the time of bloodstains formation are often essential to unravel the sequence of events behind criminal acts. Unfortunately, the relevance of preserved evidence to the committed offence usually cannot be verified, because forensic experts are still incapable of providing an accurate estimate of the bloodstains' age. An antidote to this impediment might be substituting the classical dating approach - founded on the application of calibration models - by the comparison problem addressed using likelihood ratio tests.

Flexible and Transparent Substrates Based on Gold Nanoparticles and TiO for in Situ Bioanalysis by Surface-Enhanced Raman Spectroscopy.

Flexible and transparent substrates are emerging as low cost and easy-to-operate support for surface-enhanced Raman spectroscopy (SERS). In particular, in situ SERS detection approach for surface characterization in transmission modality can be efficiently employed for non-invasive analysis of non-planar surfaces. Here we propose a new methodology to fabricate a homogenous, transparent, and flexible SERS membrane by the assistance of a thin TiO porous layer deposited on the PDMS surface, which supports the uniform loading of gold nanoparticles over large area.

The puzzling issue of silica toxicity: are silanols bridging the gaps between surface states and pathogenicity?

Background: Silica continues to represent an intriguing topic of fundamental and applied research across various scientific fields, from geology to physics, chemistry, cell biology, and particle toxicology. The pathogenic activity of silica is variable, depending on the physico-chemical features of the particles. In the last 50 years, crystallinity and capacity to generate free radicals have been recognized as relevant features for silica toxicity.

The Case of Formic Acid on Anatase TiO (101): Where is the Acid Proton?

Carboxylic-acid adsorption on anatase TiO is a relevant process in many technological applications. Yet, despite several decades of investigations, the acid-proton localization-either on the molecule or on the surface-is still an open issue. By modeling the adsorption of formic acid on top of anatase(101) surfaces, we highlight the formation of a short strong hydrogen bond.

The interaction of SiO nanoparticles with the neuronal cell membrane: activation of ionic channels and calcium influx.

Aim: To clarify the mechanisms of interaction between SiO nanoparticles (NPs) and the plasma membrane of GT1-7 neuroendocrine cells, with focus on the activation of calcium-permeable channels, responsible for the long lasting calcium influx and modulation of the electrical activity in these cells.

Materials & Methods: Nontoxic doses of SiO NPs were administered to the cells. Calcium imaging and patch clamp techniques were combined with a pharmacological approach.

Enzyme activation by alternating magnetic field: Importance of the bioconjugation methodology.

Iron oxide nanoparticles (NPs) are attractive materials for enzyme immobilization and, thanks to their superparamagnetism, can be accessed by remote stimuli. This can be exploited to activate molecules that are not remotely actuable. Here, we demonstrate that thermophilic enzymes chemically linked to NPs can be activated in a "wireless" fashion by an external alternate magnetic field (AMF).

Formamide Adsorption at the Amorphous Silica Surface: A Combined Experimental and Computational Approach.

Mineral surfaces have been demonstrated to play a central role in prebiotic reactions, which are understood to be at the basis of the origin of life. Among the various molecules proposed as precursors for these reactions, one of the most interesting is formamide. Formamide has been shown to be a pluripotent molecule, generating a wide distribution of relevant prebiotic products.

Detection of insect's meal in compound feed by Near Infrared spectral imaging.

Insects have recently emerged as a new protein source for both food and feed. Some studies have already demonstrated that insects' meal can be successfully added to animal feed without threaten animals' growth indices. However, effective and validated tests to individuate insects' meal in feed are strongly needed to meet traceability and safety concerns and to support the European legislation under development.

Silica nanoparticles actively engage with mesenchymal stem cells in improving acute functional cardiac integration.

Aim: To assess functional effects of silica nanoparticles (SiO-NPs) on human mesenchymal stem cell (hMSC) cardiac integration potential.

Methods: SiO-NPs were synthesized and their internalization effects on hMSCs analyzed with particular emphasis on interaction of hMSCs with the cardiac environment Results: SiO-NP internalization affected the area and maturation level of hMSC focal adhesions, accounting for increased in vitro adhesion capacity and augmented engraftment in the myocardial tissue upon cell injection in infarcted isolated rat hearts. SiO-NP treatment also enhanced hMSC expression of Connexin-43, favoring hMSC interaction with cocultured cardiac myoblasts in an ischemia-like environment.

Does the Abiotic Formation of Oligopeptides on TiO₂ Nanoparticles Require Special Catalytic Sites? Apparently Not.

The oligomerization of non-activated amino acids catalyzed by nanostrucrured mineral oxide surfaces holds promises as a sustainable route for the industrial production of polypeptides. To analyze the influence of the surface type on the catalytic process, we performed, via a mild Chemical Vapor Deposition approach, the oligomerization of Glycine on two samples of TiO2 nanoparticles characterized by different relative amounts of defective surface terminations. Based on infrared spectroscopy and mass spectrometry data, we show herein that the formation of peptide bonds on titania nanoparticles does not require highly energetic surface terminations, but can occur also on the most abundant and thermodynamically most stable {101} facets of nanosized anatase.

SiO nanoparticles modulate the electrical activity of neuroendocrine cells without exerting genomic effects.

Engineered silica nanoparticles (NPs) have attracted increasing interest in several applications, and particularly in the field of nanomedicine, thanks to the high biocompatibility of this material. For their optimal and controlled use, the understanding of the mechanisms elicited by their interaction with the biological target is a prerequisite, especially when dealing with cells particularly vulnerable to environmental stimuli like neurons. Here we have combined different electrophysiological approaches (both at the single cell and at the population level) with a genomic screening in order to analyze, in GT1-7 neuroendocrine cells, the impact of SiO NPs (50 ± 3 nm in diameter) on electrical activity and gene expression, providing a detailed analysis of the impact of a nanoparticle on neuronal excitability.

Preparation and Characterization of Magnetic and Porous Metal-Ceramic Nanocomposites from a Zeolite Precursor and Their Application for DNA Separation.

In this work, metal-ceramic nanocomposites were obtained through short (up to 2 h) thermal treatments at relatively moderate temperatures (750–800 °C) under a reducing atmosphere, using Fe-exchanged zeolite A as the precursor. The as-obtained materials were characterized by X-ray powder diffraction analysis, N2 adsorption at –196 °C, and highresolution transmission electron microscopy. The results of these analyses showed that the nanocomposites consisted of a dispersion of metallic Fe nanoparticles within a porous ceramic matrix, mainly based on amorphous silica and alumina.

Rapid and sensitive detection of pyrimethanil residues on pome fruits by Surface Enhanced Raman Scattering.

Surface Enhanced Raman Scattering (SERS) supported by gold nanoparticles (AuNPs) was applied to detect and quantify residues of pyrimethanil on pome fruits, a widely used fungicide in horticultural species. Spheroidal AuNPs with different size were fabricated and compared in this study. The analytical procedure was set up on a silicon dioxide flat substrate to standardize SERS methodology.

Magnetic states of nanostructures containing Ni ions at the surface of SiO nanospheres.

Ultra-small magnetic particles containing Ni ions were grown at the surface of SiO spheroidal nanoparticles (typical diameter: 50 nm) starting from NiCl solutions. Depending on preparation details, two samples characterized by magnetic sub-nanostructures or lamellar sub-nanoparticles at the SiO nanosphere surface were obtained. The decorated SiO nanospheres were submitted to physico-chemical and magnetic characterization.

On the surface effects of citrates on nano-apatites: evidence of a decreased hydrophilicity.

The surface structure and hydrophilicity of synthetic nanocrystalline apatite with strongly bound citrates on their surface are here investigated at the molecular level, by combining advanced IR spectroscopy, microgravimetry and adsorption microcalorimetry. Citrate are found to form unidentate-like and ionic-like complexes with surface Ca ions, with a surface coverage closely resembling that present in bone apatite platelets (i.e.