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Given the complexity of separating nanoplastics from environmental samples, studies have usually been conducted using synthetic polystyrene nanobeads. By mechanical fragmentation in cryogenic conditions of daily-life plastic items, we produced “true-to-life” nanoplastics (T2LNPs), that promises to give a true insight into the interaction with biological systems. T2LNPs have been fully characterized by Fourier transform Infrared spectroscopy and by Atomic Force Microscopy. They result in populations of spheroidal nanoparticles with a broad multimodal size distribution. The mandatory need for a representative sample to evaluate the potential effects of nanoparticles on human health and the environment is demonstrated by the different protein corona identified on T2LNPs and synthetic polystyrene nanobeads upon incubation with human plasma.

We report on the interaction of small (

Freestanding lipid bilayers were challenged with 15 nm Au nanospheres either coated by a citrate layer or passivated by a protein corona. The effect of Au nanospheres on the bilayer morphology, permeability and fluidity presents strong differences or similarities, depending on the observation length scale, from the colloidal to the molecular domains. These findings suggest that the interaction between nanoparticles and lipid membranes should be conveniently treated as a multiscale phenomenon.

The preparation of chestnut husk-like ZnO starting from Zn powders is described, pointing out the role of ZnO(1-x) seeds in the self-catalytic liquid-solid growth process. The final architecture is made up of ZnO whiskers stemming from ZnO platelets which are self-assembled into spheroidal agglomerates. Whiskers can be converted into belts by using polyvinylpyrrolidone and configurations exhibiting whiskers and belts on the same husk are obtained through a sequential growth procedure. Polystyrene microspheres are employed in Raman microscopy proof of concept experiments to demonstrate the potential of ZnO whiskers in transduction of chemomechanical interactions, which opens promising perspectives for in-vivo bioapplications.

All aluminium products come from melting processes. At the melting temperature, aluminium and its alloys are highly reactive with the metals and the refractories which line the furnace inside. Investigation of interactions of aluminium and its alloys with the refractory materials upon heating is therefore an issue. In this paper this investigation is focused on the model system made of aluminium-silicon mixture at eutectic composition and corundum. In particular, the structural and microstructural features are investigated by high-temperature resolved X-ray diffraction (HTXRD) and bidimensional micro X-Ray diffraction (XRD2). During cooling we followed the crystallization of aluminium and silicon and few single crystallites of a new phase, possibly related to A(19)Fe(5)Si(2), were detected by microXRD(2).

In this article we evaluated by atomic force microscopy (AFM) the effects of the (novel) tetrabranched antimicrobial peptide SB006 on morphology and mechanical properties of the gram-negative bacterium Pseudomonas aeruginosa. AFM imaging showed that SB006 causes the appearance of significant fragmentariness in the bacterial membrane and a severe volume decrease. Quantitative evaluation of the degree of fragmentariness was allowed by a new ad hoc image analysis procedure. The rigidity of the treated and untreated bacteria was measured through AFM tip nanoindentation measurements, and no differences registered. These results support the membrane interaction hypothesis, according to which SB006 targets the bacterial membranes and disrupts their permeability (allowing the leakage of cytoplasmic material and the subsequent shrinkage), but it does not affect the bacterium wall, which determines its rigidity.

A microwave (MW) field can induce in a dielectric material an oscillatory polarization. By this mechanism part of the energy carried by the waves is converted into chaotic agitation, and the material heats up. MW heating is a nonequilibrium phenomenon, while conventional heating can generally be considered as quasi-static. Excess (or nonthermal) effects of MWs with respect to conventional heating lie in this difference. Macroscopically, MW heating can be described in the framework of linear nonequilibrium thermodynamics (NET). This approach indicates that in a dielectric material under MW heating the specific heat has a dynamic component linked to the variation of polarization with temperature, and that polarization and heat conduction are intertwined. In particular, linear NET provides a new phenomenological equation for heat conduction that is composed of the classic Fourier’s law and an additional term due to polarization relaxation. This term quantitatively describes the excess effect of MWs on thermal conduction.

Determination of the residual weight fraction of a crystalline drug in a largely amorphous pharmaceutical composite is still a challenging question. None of the quantitative X-ray diffraction (QXRD) methods found in the literature is suitable for these inclusion systems. The composite's diffraction patterns present a structured amorphous halo (arising from the amorphous matrix and drug molecular clusters) in which the crystalline drug peaks rise up. Moreover, the matrix traps a non-negligible quantity of water (which cannot be directly detected by X-ray diffraction) and the crystal structure of the drug may be unknown. In this work, a development of the QXRD analysis based on the diffraction–absorption technique is presented. The method is standardless, avoids the interpretation of the amorphous halo and the knowledge of the crystal structures of the phases, and takes into account the absorbed water. Results are in excellent agreement with those obtained by differential scanning calorimetry (DSC). The general features of the technique open its application to other classes of largely amorphous composite materials, like glass systems generated in the stabilization/solidification of toxic waste.

This chapter is a tutorial to the description of nanosystems by classical interfacial thermodynamics. After synthetically recalling the necessary basics, it shows by working examples of increasing complexity that several properties of inorganic, biological, and hybrid nano-objects are not stand-alone weird subjects but rather aspects of colloid and interface energetics. Touched topics include melting temperature and solubility of nanocrystals, superhydrophobic surfaces, and biomolecular machines.

A study is presented of the nanomechanical phenomena experienced by nanoparticle-conjugated biomolecules. A thermodynamic framework is developed to describe the binding of thrombin-binding aptamer (TBA) to thrombin when the TBA is conjugated to nanorods. Binding results in nanorod aggregation (viz. directed self-assembly), which is detectable by absorption spectroscopy. The analysis introduces the energy of aggregation, separating it into TBA–thrombin recognition and surface-work contributions. Consequently, it is demonstrated that self-assembly is driven by the interplay of surface work and thrombin-TBA recognition. It is shown that the work at the surface is about −10 kJ mol−1 [mol superscript -1] and results from the accumulation of in-plane molecular forces of pN magnitude and with a lifetime of, MIT-IQS Exchange Program

A flow type quartz crystal microbalance (QCM) (bio)chemical sensor was developed for the real time determination of heavy metal ions that is suitable for environmental monitoring. A new process has been developed which enables to obtain surface-modified gold electrodes with high heavy metal ions complexing ability. The sensing performances of the piezoelectric sensor used in a flow-through setup were investigated by monitoring the frequency variation induced by the presence of heavy metal ions, such as copper and lead, as model ions, in aqueous media. X-Ray Reflectivity (XRR) and Atomic Force Microscopy (AFM) were carried out to characterize the unmodified and modified gold surfaces.

The paper deals with an appealing route to activate silicon microcantilevers (90, 110 and 130 μm long, 35 μm wide and 2 μm thick) for specific binding of biochemical species. The method consists in coating the underivatized microcantilevers with a biofunctional copolymer (based on N , N -dimethylacrylamide bearing silanating moieties) that was developed for low-density microarray assays on microscope glass slides. Coating deposition was obtained by dip-coating and its microstructure investigated by analyzing the resonance frequency values of bare and coated microcantilevers, by SEM and SFM imaging, SFM tip-scratch tests and XRR experiments. Results indicate that the coating is 2.5 nm thick and has a density of 1.22 g/cm 3 . The coating surface is nanostructured, displaying nanoblobs, which are from few up to 20 nm wide and, on average, 1.6 nm high. The diameter of the biggest nanoblobs is of the same order of magnitude of the gyration radius of the copolymer chains, suggesting that nanoblobs may identify individual macromolecules.

In potassium niobiosilicate (KNS) glasses, nanostructuring can be driven and controlled by thermal treatments at the glass transition temperature and/or by modulation of the chemical composition. The tight relationship between nanostructure and nonlinear optical properties suggests these bulk nanomaterials as an appealing route to nanophotonics. The focus of this paper is placed on assessing the phase transformations which occur in these materials upon annealing at the glass transition temperature and subsequent heating. High-temperature resolved X-ray diffraction (HTXRD) and high-resolution transmission electron microscopy (HRTEM) experiments are integrated with previously published results for in-depth insight. It will be shown that nanostructuring evolves from nucleation of niobium-rich nanocrystals, which are up to 20 nm large, uniformly distributed in the matrix bulk, and metastable. Formation kinetics as well as phase transformation of the nanocrystals are determined by the glass composition. Depending on it, nanocrystal nucleation can be preceded or not by phase separation, and the nanocrystals' phase transition can be of first or second order.

In the present work the arrangement of nanostructured nimesulide embedded inside crospovidone microparticles is experimentally studied. The analysis was carried out by observing cross-sections of the microparticles with electron and Raman microscopes. Scanning electron microscopy (SEM) gave a morphological picture of the cross-sections, energy dispersive X-ray spectroscopy (EDS) allowed to investigate the nimesulide distribution at molecular level in- and outside the crospovidone matrix, and microRaman spectroscopy (μRaman) shed some light on the nimesulide phase composition. The drug resulted to be constrained by crospovidone into three main arrangements: an amorphous phase dispersed into the molecular cross-linked network of the polymer, nanocrystals wrapped up by the polymer, and drug layers, made of micro- and nanocrystals, segregated onto the popcorn-like surface of the polymer. According to X-ray diffraction data, the micro- and nanocrystals are highly disordered and made of crystallites with an average diameter of 17 nm.

Dispersion into crospovidone is a widely employed method for enhancing the solubility of poorly water-soluble drugs, since the 3D polymeric network stabilizes the active substance in molecular clusters and nano-crystalline phases. Nimesulide loaded into crospovidone shows two polymorphic modifications: the native material (form I) and the phase reported on ICDD and CSD databases (form II). Microstructure and polymorphism of the composites have been investigated as they affect the drug dissolution rate and in vivo absorption kinetics (i.e. the bio-availability of the drug from its dosage form). Differential scanning calorimetry (DSC) showed that the lower melting form (form II) is metastable. X-ray diffraction (XRD) evidenced that the embedded crystalline phases are made up of nano-crystallites and that no significant difference on their size exists. Quantitative analysis of the composites turned out to be a challenge with both XRD (preferred orientation effects and form I crystalline structure unknown) and DSC (high nimesulide-crospovidone reactivity). Nevertheless, the results suggest a direct correlation between crospovidone and form II weight fractions.

A method for the highly sensitive determination of the Young's modulus of TiO2 thin films exploiting the resonant frequency shift of a SU-8 polymer microcantilever (MC) is presented. Amorphous TiO2 films with different thickness ranging from 10 to 125 nm were grown at low temperature (90 °C) with subnanometer thickness resolution on SU-8 MC arrays by means of atomic layer deposition. The resonant frequencies of the MCs were measured before and after coating and the elastic moduli of the films were determined by a theoretical model developed for this purpose. The Young's modulus of thicker TiO2 films (>75 nm) was estimated to be about 110 GPa, this value being consistent with the value of amorphous TiO2. On the other hand we observed a marked decrease of the Young's modulus for TiO2 films with a thickness below 50 nm. This behavior was found not to be related to a decrease of the film mass density, but to surface effects according to theoretical predictions on size-dependent mechanical properties of nano- and microstructures.

In this paper, self-assembled polystyrene nanospheres are proposed as a shape characterizer sample for SPM tips. Ordered arrays or 2D islands of polystyrene spheres may be prepared either by sedimentation or by crystallization of the colloidal spheres' suspension. The self-assembling mechanism guarantees high reproducibility; thus the characterizer sample can be 'freshly' prepared at each use, avoiding the problem of time and use deterioration and reducing the problem of sample structure fidelity that occurs when lithographic structures are employed. The spheres could also be deposited on the sample itself in order to speed up the characterization process in applications requiring frequent tip characterizations. We present numerical calculations of geometrical convoluted profiles on the proposed structures showing that, for a variety of different tip shapes, at the border between a couple of touching spheres the tip flanks do not come into contact with the spheres. Due to this behaviour, touching spheres are an optimum characterizer sample for SPM tip curvature radius characterization, enabling a straightforward procedure for calculating the curvature radius from the amplitude of tip oscillation along profiles connecting spheres' centres. The new procedure for the characterization of SPM probes was assessed exploiting different kinds of self-assembled structures and comparing results to those obtained by spiked structures and SEM observations.