Label-free determination of diffusion coefficients at the nanoscale through modelling of the Surface Plasmon Resonance signal.

Surface plasmon resonance (SPR) is normally used to measure the kinetic parameters of biomolecular interactions between a molecule immobilized on a gold surface and another one flowing in a microfluidic channel above the surface. During the SPR measurements, convection-diffusion phenomena occur inside the microfluidic channels, but they are generally minimized by appropriate experimental setup in order to obtain diffusion free kinetic parameters of the molecular interactions. In this work, for the first time, a commercial SPR apparatus has been used to obtain non canonical scientific parameters.

Correction: Fast detection of penicillium rot and the conservation status of packaged citrus fruit using an optical array sensor.

Correction for 'Fast detection of penicillium rot and the conservation status of packaged citrus fruit using an optical array sensor' by Alessia Cavallaro , , 2024, , 13702-13705, https://doi.org/10.1039/D4CC04700A.

Fast detection of penicillium rot and the conservation status of packaged citrus fruit using an optical array sensor.

A novel optical array sensor designed to detect the conservation status of citrus fruit as well as contamination of ripened fruits by green mold incited by the fungus is reported here. The device demonstrates high sensitivity, specificity, and cost-effectiveness, making it suitable for integration into the citrus fruit supply chain, including production and packaging systems.

Role of Density and Conformational Composition in the Surface-to-Bulk Molecular Dosing of Photosensitive Surfactant Monolayers.

Poorly water-soluble photosensitive monolayers might enable very precise control of the rate and number of desorbing molecules by controlling both the monolayer density and conformational composition. In this perspective, we systematically characterized the interfacial behavior of Langmuir monolayers consisting of a poorly water-soluble azobenzene-containing surfactant as a function of its trans/cis ratio. Precise control of the conformational ratio was achieved by controlling the UV irradiation time, allowing researchers to investigate compositions spanning from 100% trans to 90% cis.

Surface Plasmon Resonance Allows to Correlate Molecular Properties With Diffusion Coefficients of Linear Chain Alcohols.

Every biological and physicochemical process occurring in a fluid phase depends on the diffusion coefficient (D) of the species in solution. In the present work, a model to describe and fit the behaviour of as a function of structure and extensive thermodynamics parameters in binary solutions of linear chain organic molecules is developed. Supporting experimental and computational evidences for this model are obtained by measuring for a series of -alcohols through a novel surface plasmon resonance method and molecular dynamics simulations.

Dopamine sensing by fluorescent carbon nanoparticles synthesized using artichoke extract.

The practical and easy detection of dopamine levels in human fluids, such as urine and saliva, is of great interest due to the correlation of dopamine concentration with several diseases. In this work, the one-step synthesis of water-soluble carbon nanoparticles (CNPs), starting from artichoke extract, containing catechol groups, for the fluorescence sensing of dopamine is reported. Size, morphology, chemical composition and electronic structure of CNPs were elucidated by DLS, AFM, XPS, FT-IR, EDX and TEM analyses.

Carbon dots fluorescence can be used to distinguish isobaric peptide and to monitor protein oligomerization dynamics.

Carbon dots (CD) are widely investigated particles with interesting fluorescent properties which are reported to be used for various purposes, as they are biocompatible, resistant to photobleaching and with tuneable properties depending on the specific CD surface chemistry. In this work, we report on the possibility to use opportunely designed CD to distinguish among isobaric peptides almost undistinguishable by mass spectrometry, as well as to monitor protein aggregation phenomena. Particularly, cell-penetrating peptides containing the carnosine moiety at different positions in the peptide chain produce sequence specific fluorescent signals.

Smartphone-Based Sensing of Cortisol by Functionalized Rhodamine Probes.

During a stress condition, the human body synthesizes catecholamine neurotransmitters and specific hormones (called "stress hormones"), the most important of which is cortisol. The monitoring of cortisol levels should be extremely important to control the stress levels, and for this reason, it shows important medical applications. The common analytical methods (HPLC, GC-MS) cannot be used in real life, due to the bulky size of the instruments and the necessity of specialized personnel.

Detection of insulin oligomeric forms by a novel surface plasmon resonance-diffusion coefficient based approach.

Insulin is commonly used to treat diabetes and undergoes aggregation at the site of repeated injections in diabetic patients. Moreover, aggregation is also observed during its industrial production and transport and should be avoided to preserve its bioavailability to correctly adjust glucose levels in diabetic patients. However, monitoring the effect of various parameters (pH, protein concentration, metal ions, etc.

Modulating Polymer Ultrathin Film Crystalline Fraction and Orientation with Nanoscale Curvature.

We investigated the effect of nanoscale curvature on the structure of thermally equilibrated poly-3-hexylthiophene (P3HT) ultrathin films. The curvature-induced effects were investigated with synchrotron grazing incidence X-ray diffraction (GIXRD) and atomic force microscopy (AFM). Our results demonstrate that nanoscale curvature reduces the polymer crystalline fraction and the crystal length.

Time-of-flight SIMS investigation of peptides containing cell penetrating sequences.

Surface functionalization with biological molecules, such as peptides or proteins, is a very promising method for developing new biomaterials with many potential applications. However, due to their chemical complexity, the characterization of biological materials is often a very challenging task. In this context, time-of-flight secondary ion mass spectrometry is a very helpful characterization tool due to its ability to provide very detailed spatially resolved chemical information of the topmost layer.

Carbon dots as a versatile tool to monitor insulin aggregation.

The possibility to monitor peptide and protein aggregation is of paramount importance in the so-called conformational diseases, as the understanding of many physiological pathways, as well as pathological processes involved in the development of such diseases, depends very much on the actual possibility to monitor biomolecule oligomeric distribution and aggregation. In this work, we report a novel experimental method to monitor protein aggregation, based on the change of the fluorescent properties of carbon dots upon protein binding. The results obtained in the case of insulin with this newly proposed experimental approach are compared with those obtained with other common experimental techniques normally used for the same purpose (circular dichroism, DLS, PICUP and ThT fluorescence).

Smartphone-Based Dopamine Detection by Fluorescent Supramolecular Sensor.

Supramolecular recognition of dopamine by two quinoxaline cavitands was studied in solution by fluorescence titrations, ESI-MS and ROESY measurements. In addition, the tetraquinoxaline cavitand was dropped onto a siloxane-based polymeric solid support, obtaining a sensor able to detect dopamine in a linear range of concentrations 10 Mm-100 pM, with a detection limit of 1 pM, much lower than the normal concentration values in the common human fluids (plasma, urine and saliva), by using a simple smartphone as detector. This sensor shows also good selectivity for dopamine respect to the other common analytes contained in a saliva sample and can be reused after acid-base cycles, paving the way for the realization of real practical sensor for human dopamine detection.

Smartphone-Assisted Sensing of Trinitrotoluene by Optical Array.

Here we report the design and fabrication of an array-based sensor, containing functionalized Carbon Dots, Bodipy's and Naphthalimide probes, that shows high fluorescence emissions and sensitivity in the presence of low amounts of TNT explosive. In particular, we have fabricated the first sensor device based on an optical array for the detection of TNT in real samples by using a smartphone as detector. The possibility to use a common smartphone as detector leads to a prototype that can be also used in a real-life field application.

Direct Measurement of Surfactant-Mediated Picoforces among Nanoparticles in a Quasi-Two-Dimensional Environment.

The lack of methodologies which enable us to measure forces acting between nanomaterials is one of the factors limiting the full comprehension of their behavior and their more effective exploitation in new devices. Here we exploit the irreversible adsorption of surfactant-decorated nanoparticles at the air/water interface to investigate interparticle forces and the effect of the surfactant structure on them. We measured the interparticle repulsive forces as a function of the modulation of the interparticle distance by simultaneously performing compression isotherms and the grazing incidence small-angle X-ray scattering (GISAXS) structural characterization of the monolayers at water-vapor interfaces.

A super absorbent polymer containing copper to control the causative agent of mal secco disease of lemon.

The aim of this study was to determine the effectiveness of a Super absorbent polymer (SAP) containing copper (SAP-Cu) in controlling mal secco disease (MSD) of lemon caused by the fungus . Super absorbent polymer containing copper was characterized by atomic absorption spectrometry (AAS) and UV-VIS spectroscopy. tests were performed to determine the inhibitory effects of SAP-Cu against the pathogen on both potato-dextrose-agar medium and naturally infected lemon cuttings.

Fluorescence sensing by carbon nanoparticles.

Sensing is one of the most important fields in which chemists, engineers and other scientists are involved to realize sensoristic devices that can detect different analytes, both chemicals and biologicals. In this context, fluorescence sensing paves the way for the realization of smart sensoristic devices due to the possibility to detect the target analyte a change in colour or emission. Recently (since 2006), carbon nanoparticles, which are a "new class" of nanostructures based on carbon atoms, have been widely used in sensing applications due to their intriguing optical properties.

Carbon dots surface chemistry drives fluorescent properties: New tools to distinguish isobaric peptides.

The possibility to design rational carbon dots surface functionalization for specific analytical and bioanalytical applications is hindered by the lack of a full knowledge of the surface chemical features driving fluorescent properties. In this model study, we have synthesized four different peptides, three of which are isobaric and not distinguishable by common MSMS experiments. After having characterized the peptides conformations by CD analyses, we have covalently bonded all four peptides to carbon dots by using different experimental procedures, which produce different functional groups on the carbon dots surface.

Comprehensive step-by-step procedure to setup a molecular communication through liquid experiment.

Molecular communication allows information to be exchanged in environments where electromagnetic waves are prohibited. It employs the exchange of information particles travelling through fluids. The transmitter releases several chemical messengers inside the communication channel, encoding the message it intends to send in an appropriate way.

Inhibitory Activity of Shrimp Waste Extracts on Fungal and Oomycete Plant Pathogens.

(1) Background: This study was aimed at determining the inhibitory effect of new natural substances obtained by minimal processing from shrimp wastes on fungi and oomycetes in the genera , , , , and ; the effectiveness of the substance with the highest activity in preventing citrus and apple fruit rot incited by and , respectively, was also evaluated. (2) Methods: The four tested substances, water-extract, EtOAc-extract, MetOH-extract and nitric-extract, were analyzed by HPLC-ESI-MS-TOF; preliminary tests were carried out to determine the minimal inhibitory/fungicidal concentrations (MIC and MFC, respectively) of the raw dry powder, EtOAc-extract, MetOH-extract and nitric-extract for each pathogen. (3) Results: in the agar-diffusion-assay, nitric-extract showed an inhibitory effect on all pathogens, at all concentrations tested (100, 75, 50 and 25%); the maximum activity was on , and ; the diameters of inhibition halos were directly proportional to the extract concentration; values of MIC and MFC of this extract for all pathogens ranged from 2 to 3.

Revealing Contamination and Sequence of Overlapping Fingerprints by Unsupervised Treatment of a Hyperspectral Secondary Ion Mass Spectrometry Dataset.

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) has been successfully applied for chemical imaging of overlapping fingermarks. The resulting big dataset has been treated by means of an unsupervised machine learning approach based on uniform manifold approximation and projection. The hyperspectral matrix was composed of 49 million pixels associated with 518 peaks.

Agile Detection of Chemical Warfare Agents by Machine Vision: a Supramolecular Approach.

The supramolecular detection by image analysis of a simulant chemical warfare agent on a solid device containing a selective molecular sensor based on a BODIPY scaffold is reported. The recognition properties were investigated in solution, demonstrating high affinity (log K 6.60) and sensitivity (LOD 10 ppt).

Testing Surgical Face Masks in an Emergency Context: The Experience of Italian Laboratories during the COVID-19 Pandemic Crisis.

The first wave of the COVID-19 pandemic brought about a broader use of masks by both professionals and the general population. This resulted in a severe worldwide shortage of devices and the need to increase import and activate production of safe and effective surgical masks at the national level. In order to support the demand for testing surgical masks in the Italian context, Universities provided their contribution by setting up laboratories for testing mask performance before releasing products into the national market.