Libero Liggieri's research while affiliated with Italian National Research Council and other places

Publications (46)

Article
Full-text available
The input of chemical and physical sciences to life sciences is increasingly important. Surface science as a complex multidisciplinary research area provides many relevant practical tools to support research in medicine. The tensiometry and surface rheology of human biological liquids as diagnostic tools have been very successfully applied. Additio...
Article
Full-text available
The surface properties of saponin and saponin-chitosan mixtures were analysed as a function of their bulk mixing ratio using vibrational sum-frequency generation (SFG), surface tensiometry and dilational rheology measurements. Our experiments show that saponin-chitosan mixtures present some remarkable properties, such as a strong amphiphilicity of...
Article
Full-text available
We studied silica suspensions with chitosan and biodegradable synthetic surfactant lau-royl ethyl arginate (LAE). Hydrophilic and negatively charged silica nanoparticles were neutralised due to the coating with chitosan. That presence of LAE led to the partial hydrophobisation of their surface, which favoured their attachment to the surface of a th...
Article
The kinetics of spontaneous emulsification is investigated on aqueous pendant drops in paraffin oil. Optical microscopy in transmission mode is used for high-spatial-resolution image recording. The influence of a lipophilic surfactant (Span 80) and two water-soluble surfactants (CTAB and SDS) is investigated. As time runs, the drop interface turns...
Article
Full-text available
Carbonaceous particles are accounted among the most common environmental pollutants. This makes necessary a careful examination of their potential impact on the physico-chemical properties of different biological films, e.g. tear film, skin, or lung surfactant. This work analyzes the interaction of three different types of carbonaceous particles wi...
Article
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The interaction of hydrophobic silicon dioxide particles (fumed silicon dioxide), as model air pollutants, and Langmuir monolayers of a porcine lung surfactant extract has been studied in order to try to shed light on the physicochemical bases underlying the potential adverse effects associated with pollutant inhalation. The surface pressure−area i...
Article
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The dynamic and equilibrium properties of adsorption layers of poly (oxyethylene) alkyl ether (CnEOm) can be well described by the reorientation model. In its classical version, it assumes two adsorption states; however, there are obviously surfactants that can adsorb in more than two possible conformations. The experimental data for C14EO4 and C14...
Article
Full-text available
Langmuir monolayers containing different amounts of cholesterol and cholesteryl stearate were studied at two different temperatures (24 °C and 35 °C). The main goal was to contribute towards the understanding of how the variations in the chemical composition may affect the physico‐chemical properties of these specific lipid monolayers. The model mi...
Article
The pulmonary surfactant (PS) is a complex mixture of lipids and proteins dispersed in the aqueous lining layer of the alveolar surface. Such a layer plays a key role in maintaining the proper lung functionality. It acts as a barrier against inhaled particles and pathogens, including viruses, and may represent an important entry point for drugs del...
Article
Intraocular liquids tamponade agents, such as perfluorocarbon liquids (PFCLs), semifluorinated alkanes (SFAs), silicone oils (SOs) and heavy silicone oils (HSOs), are a crucial intraoperative and/or postoperative tool in vitreoretinal surgery, in particular for the management of complex vitreoretinal diseases. However, their use is not without comp...
Article
Full-text available
The adsorption behaviour of linear poly(oxyethylene) alkyl ether (CnEOm) is best described by a reorientation model. Based on a complete set of experimental data, including the adsorption kinetics, the equilibrium surface tension isotherm and the surface dilational visco-elasticity, the thermodynamic and kinetic adsorption parameters for some CnEOm...
Article
In this review, we highlight and discuss the effects of interfacial properties on the major mechanisms governing the aging of emulsions: flocculation, coalescence and Ostwald ripening. The process of emulsification is also addressed, as it is well recognized that the adsorption properties of emulsifiers play an important role on it. The consolidate...
Article
We report here an overview of current trends and a selection of recent results regarding the characterization of emulsions by Diffusing Wave Spectroscopy (DWS). We provide a synopsis of the state of the art of the DWS technique, and a critical discussion of experiments performed on samples in which Brownian and ballistic dynamics coexist. A novel a...
Article
Full-text available
The present work is aimed at investigating the chemicophysical properties of the interface between silicone oils (SOs) used in vitreoretinal surgery and aqueous solutions, in the presence of surfactant biomolecules. Such molecules are thought to play an important role in the formation of SO emulsions in vitrectomised eyes, in which the natural vitr...
Article
Full-text available
Surface tension experiments were performed using the drop profile analysis tensiometry method. The hexane was injected into the measuring cell at certain times before the formation of the solution drop. The influence of the capillary diameter and solution drop size on the measured apparent dynamic surface tension was studied. The amount of hexane t...
Article
Full-text available
An increase in temperature typically leads to a decrease in the interfacial tension of a water/oil interface. The addition of surfactants to the system can complicate the situation significantly, i.e., the interfacial tension can increase or decrease with an increasing temperature. For most concentrations of the two studied surfactants, the cationi...
Article
Full-text available
The surface tension of C13DMPO aqueous solution drops in hexane vapor is studied using the drop profile method. The hexane was injected into the measuring cell at three different conditions: before the formation of the solution drop, at a certain moment during the adsorption process, and after reaching the equilibrium of surfactant adsorption. The...
Article
Full-text available
A comparative study is reported on the interfacial properties of a set of surfactants and is discussed in terms of the e�ects on the features of the corresponding oil-water emulsions. The surfactants are saponin, Tween 80 and citronellol glucoside (CG), while the oil is Miglyol 812N—A Medium Chain Triglyceride (MCT) oil. Due to their high biocompat...
Article
Full-text available
In this communication, the single element version of the fractional Maxwell model (single-FMM or Scott–Blair model) is adopted to quantify the observed behavior of the linear interfacial dilational viscoelasticity. This mathematical tool is applied to the results obtained by capillary pressure experiments under low-gravity conditions aboard the Int...
Article
This work focuses on the surface properties of binary dispersions of nanoparticles, namely Titania (TiO 2 )and amorphous silica (SiO 2 ), associated to a short chain ionic surfactant (CTAB)which has the role of modifying their amphiphilicity, inducing the segregation of particle-surfactant complexes at the liquid interface. The foams produced by th...
Article
In this work we investigate the surface properties and foamability of saponin and mixed saponin-chitosan solutions. These natural compounds are widely used in various cosmetic, pharmaceutical and food technologies because of their efficiency as bio-active components and their biodegradability. These compounds and their mixture were investigated ver...
Article
Full-text available
Capillary pressure experiments are performed in microgravity conditions on board the International Space Station to quantify the dynamic interfacial behavior of mixed adsorption layers of TTAB and C13DMPO at the water/hexane interface. While the non-ionic surfactant C13DMPO is soluble in both bulk phases, water and hexane, the cationic surfactant T...
Conference Paper
Full-text available
The formation and stability of emulsions in vitrectomized eyes is linked to the properties of the silicone oil-aqueous humor interface, in particular the surface tension. In the presence of natural surfactants, such as serum and plasma, the value of the surface tension is likely to change, but little quantitative information is presently available....
Article
The control of the behavior of oil in water emulsions requires deepen investigations on the adsorption properties of the emulsion stabilizers at interfaces, being these fundamental to explain the (de)stabilization mechanisms. In this work, we present an extensive study on oil-in-water emulsions stabilized by Sodium Dodecyl Sulfate (SDS) below its c...
Article
The effect of the degree of dissociation on the adsorption kinetics of partially dissociated ionic surfactants was examined theoretically. The equilibrium and dynamic surface tension (ST) curves with different degrees of dissociation were theoretically generated for surfactants following the Langmuir adsorption isotherm. Two cases were examined. In...
Article
The adsorption kinetics of ionic surfactant decanoic acid was examined. Dynamic and equilibrium surface tensions (ST) were measured using a video-enhanced pendant bubble tensiometer. The equilibrium ST data and the complete ST relaxation profiles were compared with theoretical profiles predicted by both non-ionic and ionic models. The quasi-equilib...
Article
The adsorption kinetics of ionic surfactant decanoic acid was examined. Dynamic and equilibrium surface tensions (ST) were measured using a video-enhanced pendant bubble tensiometer. The equilibrium ST data and the complete ST relaxation profiles were compared with theoretical profiles predicted by both non-ionic and ionic models. The quasi-equilib...
Article
Silica nanoparticles (SiNP) can be incorporated in phospholipid layers to form hybrid organic-inorganic bidimensional mesostructures. Controlling the dynamics in these mesostructures paves the way to high-performance drug-delivery systems. Depending on the different hydrophobicity/hydrophilicity of SiNP, recent X-ray reflectivity experiments have d...
Article
Highly hydro and oleophobic materials applied to needs of the marine environment represent a relatively young field achieving growing interest as innovative solution, where technological and ecological aspects allow to be merged, taking into account the limitations imposed by international laws in terms of environmental protection.In this work a su...
Book
This book describes the most important experimental methods for characterizing liquid interfaces, such as drop profile analysis, bubble pressure and drop volume tensiometry, capillary pressure technique, and oscillating drops and bubbles. It presents practical experimental details as well as the underlying theoretical bases. In addition, the book c...
Chapter
Drops and bubbles are objects of everyday life and we meet them in various situations. Walking with open eyes through the nature allows us to see the beauty of liquid menisci, as demonstrated in Fig. 1.

Citations

... However, the tensiometry and surface rheological measurements of human bio-fluids have been very successfully applied to be used as diagnostic tools [219] though there is a necessity for further characterization of how different ions (salts) in the bio-colloids affect interfacial viscoelasticity [220]. The investigations at different stages will help us comprehend the com- The cross-scale investigation during the drying process involves different physical mechanisms, such as phase separation, phase transition, self-assembling mechanism, etc. ...
... Moreover, modifying silica particles' surface hydrophobicity leads to improved overall compound stability [52]. This gives the ability to finely tune the interparticle interactions, which can modify the way the particles assemble under applied stress [53]. Silica and its derivates are also expected to self-aggregate and form a network of particles within the matrix, increasing the formation of links and resulting in an overall integrated structure [54]. ...
... A second group of applications of surface science principles is discussed with respect to the formulation of artificial tears and of synthetic lung surfactants. Understanding the mechanisms of these biological liquids and their design and application is vital for the successful treatment of malfunctions of the eye [3] or of the lungs, respectively. In particular, due to the still-existing COVID-19 pandemic, it was a hot topic to show in a Special Issue of a journal, summarizing various aspects of surface science applications in pulmonology, how essential the understanding of the mechanisms of pulmonary surfactants in the human lungs is [4,5]. ...
... Fumed (pyrogenic) silica is another variety of silica used in various applications due to its low density, high surface area, and high viscosity. Fumed silica nanoparticles were found to incorporate into LS monolayers in an LBT and disrupt structure at the interface, inhibiting the function of LS (Guzman et al., 2022). ...
... The Langmuir trough is a common experimental setup used for studies dealing with the dilational properties of fluid/fluid interfaces [62,63]. It consists of two barriers, arranged parallel at opposite extremes of the trough, that can be used to compress or expand the area available for the interface under controlled conditions. ...
... Understanding the mechanisms of these biological liquids and their design and application is vital for the successful treatment of malfunctions of the eye [3] or of the lungs, respectively. In particular, due to the still-existing COVID-19 pandemic, it was a hot topic to show in a Special Issue of a journal, summarizing various aspects of surface science applications in pulmonology, how essential the understanding of the mechanisms of pulmonary surfactants in the human lungs is [4,5]. ...
... After Joos, some researchers further developed the reorientation model. Fainerman et al. [18] indicated that the reorientation model can be generalized for more than two adsorption states required to better describe the adsorption layer properties of ...
... A simpler lipid mixture, lacking cholesterol and sphingomyelin, was also prepared in order to characterize a monolayer uniquely composed of three natural phospholipids, PC-PE-PS (Fig. 1A shows the molar lipid compositions). Previously, synthetic lipid monolayers, for example using DPPC (1,2dipalmitoyl-sn-glycerol-3-phosphocholine) and POPC (1palmitoyl-2-oleoyl-glycero-3-phosphocholine), or complex mixtures such as the so-called canonical mixture (containing POPC, sphingomyelin and cholesterol), were employed to mimic cellular membranes as well as lung surfactants [17][18][19][20][21][22][23][24][25][26]. Even though Langmuir monolayers are not well suited to address transmembrane processes, their versatility allows the investigation of lipid structure and organization of single membrane leaflets at the air/water interface, by exploiting a plethora of interfacial in situ techniques [27][28][29], thus offering the possibility of untangling different questions of biophysical interest. ...
... Silicone oils (SO) are liquid intraocular tamponades, classified as class IIb medical devices within the European Union, i.e., implantable, surgical invasive devices for long-term use (>30 days) [1]. Silicone oils have been traditionally used and have still an irreplaceable role in the surgical management of complex vitreoretinal diseases [2]. However, their use can be associated with potentially severe complications, whose pathogenetic mechanisms remain not fully understood [3]. ...
... Different hypotheses have been postulated regarding the interaction between phospholipids and cholesterol. For example the existence of phospholipid/cholesterol complexes [67,71], whose stoichiometry would depend on the phospholipid nature, while it has also been suggested that phospholipid headgroups act as ''umbrellas", protecting cholesterol from water [72,73], which should lead to a decrease of the water fraction content within the headgroups-layer, emerging incompatible with our experimental findings. Here, BAM and NR experiments on PM monolayers ( Fig. 3C and Fig. 6) have showed the existence of densely packed L o phases rich in cholesterol and SM. ...